science for a changing world Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1997 St Thomas I Isla de V* Culebra Isla de Vieques PUERTO RICO St John I U. S. V I R G I N ISLANDS Saint Croix I U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-97-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands and other agencies V CALENDAR FOR WATER YEAR 1997 1996 OCTOBER S M T W T F S 12345 NOVEMBER S M T W T F S 1 2 DECEMBER S M T W T F S 1234567 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1997 JANUARY SMTWTFS 1234 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 APRIL SMTWTFS 12345 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 S M JULY T W T 12345 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 FEBRUARY SMTWTFS 1 2345678 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 MAY SMTWTFS 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 AUGUST SMTWTFS 1 2 3456789 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 2345678 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 M JUNE T W T F S 1234567 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SEPTEMBER SMTWTFS 123456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1997 by RL. Dfaz, Z. Aquino, C. Figueroa-Alamo, R.J. Vachier, and A.V. Sanchez St Thomas I Isla de Ap Culebra Isla de Vieques PUERTO RICO St John I U. S. V I R G I N ISLANDS Saint Croix I U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-97-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands and other agencies U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For additional information on the water resources investigation programs in Puerto Rico and the U.S. Virgin Islands write to: Chief, Caribbean District, Water Resources Division U.S. Geological Survey GSA Center, 651 Federal Drive Suite 400-15 Guaynabo, Puerto Rico 00965 Telephone: (787)749-4346 1998 PREFACE This annual hydrologic data report of Puerto Rico and the U.S. Virgin Islands is one of a series of annual reports that document hydrologic data gathered from the U.S. Geological Survey's surface- and ground-water data-collection networks in each state, Puerto Rico, the U.S. Virgin Islands, and the other Trust Territories. These records of streamflow, ground-water levels, and quality of water provide the hydrologic information needed by state, local and Federal agencies, and the private sector for developing and managing our Nation's land and water resources. The report is the culmination of a concerted effort by dedicated personnel of the U.S. Geological Survey, Water Resources Division who collected, compiled, analyzed, verified, and organized the data, and who typed, edited, and assembled the report. In addition to the authors, who had primary responsibility for assuring that the information contained herein is accurate, complete and adheres to Geological Survey policy and established guidelines, the following personnel contributed significantly to the collection, processing and tabulations of the data: Jos6 M. Agis Rafael Pena-Cortez George Arroyo Ronald T. Richard Gregory Cherry Carlos C. Rodriguez Iris M. Concepcidn Julio A. Rodriguez Israel Cruz Miguel Rodriguez Angel G. Ferrer Rafael M. Rodriguez Robert Fitzhugh Jose" Ren6 S4nchez Pedro Galindo Luis Santiago-Rivera Wilfredo Garcfa Carlos Santos Hector Guardiola Luis Soler Evelyn S. Guevara Angel Torres Sen6n Guzman-Rfos Heriberto Torres-Sierra Felipe Hernandez James Torres Sandra Lagares Jose" A. Torres Jos6 Merced Ahmed Valencia Carlos Narvaez Luis Vega Ruth I. Guzman typed the text of the report. Francisco Maldonado prepared the illustrations. This report was prepared in cooperation with agencies of the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and with other federal agencies under the general supervision of Rafael W. Rodriguez, District Chief, Caribbean District, San Juan, Puerto Rico. REPORT DOCUMENTATION PAGE Form Approved OMBNo. 0704-0188 Davis Highway, Suite 1204 Deluding sugge 14, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE April 17, 1998 3. REPORT TYPE AND DATES COVERED Annual - October 1, 1996 to September 30,1997 4. TITLE AND SUBTITLE Water Resources Data for Puerto Rico and the U.S. Virgin Islands Water Year 1997 6. AUTHOR(S) Pedro L. Diaz, Zaida Aquino, Carlos Figueroa-Alamo, Ricardo J. Vachier, Ana V. Sanchez 5. FUNDING NUMBERS 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 8. PERFORMING ORGANIZATION REPORT NUMBER USGS-WDR-PR-97-1 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(eS) U.S. Geological Survey, Water Resources Division GSA Center, 651 Federal Drive, Suite 400-15 Guaynabo, Puerto Rico 00965 10. SPONSORING / MONITORING AGENCY REPORT NUMBER USGS-WDR-PR-97-1 11. SUPPLEMENTARY NOTES Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands, and other agencies. 12a. DISTRIBUTION/AVAILABILITY STATEMENT NO RESTRICTION ON DISTRIBUTIONS 12b. DISTRIBUTION CODE 13. ABSTRACT (Maximum 200 words) Water resources data for surface-water, quality-of-water, and ground-water records for the 1997 water year for Puerto Rico and the U.S. Virgin Islands consists of records of discharge, water quality of streams, and water levels of wells. This report contains discharge records for 74 streamflow-gaging stations; daily sediment records for 26 streamflow stations; 95 partial-record or miscellaneous streamflow stations; stage records for 16 reservoirs; water-quality records for 16 streamflow-gaging stations, 42 ungaged streamsites, 11 lake sites, 2 lagoons, and 1 bay; and water-level records for 68 observation wells. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating local and federal agencies in Puerto Rico and the U.S. Virgin Islands. 14. SUBJECT TERMS * Surface water, * Water quality, *Ground water, Aquifers, Chemical analysis, Gaging stations, Hydrologic data sediments, Streamflow, Water analysis, Water levels, Lakes 15. NUMBER OF PAGES 564 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT 20. LIMITATION OF ABSTRACT NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std 239-18 298-102 CONTENTS Preface...................................................................._^ List of surface-water and water-quality stations, in downstream order, for which records are published in this volume....................................................................................................... vii List of ground-water wells, by basin, for which records are published in this volume..................................................................................................................................................... xi List of discontinued surface-water discharge or stage-only stations....................................................................................... xiii Introduction................................................................................................................................................^ Cooperation..................................................................................................................................................................................2 Summary of hydrologic conditions..............................................................................................................................................3 Rainfall.....................................................^ Surface water........................................................................................................................................................................3 Ground water............................................................................................................................._^ Water quality.........................................................................................................................................................................8 Special networks and programs...................................................................................................................................................9 Explanation of records .................................................................................................................................................................9 Station identification numbers ............................................................................................................................................10 Downstream order system............................................................................................................................................10 Latitude-longitude system............................................................................................................................................10 Records of stage and water discharge.................................................................................................................................19 Data collection and computation.............................................................................................................................19 Data Presentation.....................................................................................................................................................20 Station manuscript ................................................................................................................................................20 Data table of daily mean values............................................................................................................................21 Statistics of monthly mean data............................................................................................................................22 Summary statistics................................................................................................................................................22 Identifying estimated daily discharge..........................................................................................................................23 Accuracy of the records...............................................................................................................................................23 Records of surface-water quality ........................................................................................................................................24 Classification of records..........................................................................................................................................................^ Arrangement of records...............................................................................................................................................24 On-site measurements and sample collection..............................................................................................................24 Water temperature......................................................................................................................................................................25 Sediment ......................................................................................................................_^ Laboratory measurements............................................................................................................................................25 Data presOTtation.......................................^^^ Remark codes...............................................................................................................................................................27 Records of ground-water levels..........................................................................................................................................27 Data collection and computation.................................................................................................................................27 Data presentation .........................................................................................................................................................28 Records of ground-water quality........................................................................................................................................28 Data collection and computation .................................................................................................................................29 Data presentation .........................................................................................................................................................29 Access to U.S. Geological Survey Water Data..........................................................................................................................29 Definition of terms.....................................................................................................................................................................30 Publications on Techniques of Water-Resources Investigations...............................................................................................40 Surface- and quality-of-water records for Puerto Rico..............................................................................................................43 Discharge at partial-record stations in Puerto Rico .................................................................................................................435 Water-quality at partial-record stations in Puerto Rico ...........................................................................................................447 Ground-water records for Puerto Rico.....................................................................................................................................463 Surface-water records for the U.S. Virgin Islands...................................................................................................................527 Ground-water records for the U.S. Virgin Islands ..................................................................................................................533 Index........................................................................................................................................................................................541 VI ILLUSTRATIONS Page Figure 1. Graph showing monthly-mean discharge of selected streams in Puerto Rico.........................................................4 2. Graph showing ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands........................................................................................................................................................7 3. Map showing location of fecal coliform bacteria concentration at sampled sites................................................. 11 4. Map showing location of fecal streptococci bacteria concentration at sampled sites............................................ 12 5. Map showing location of surface-water stations in Puerto Rico........................................................................... 13 6. Map showing location of water-quality stations in Puerto Rico............................................................................ 14 7. Map showing location of low-flow partial-record stations in North-central Puerto Rico..................................... 15 8. Map showing location of ground-water stations in Puerto Rico............................................................................ 16 9. Map showing location of surface-water stations in U.S. Virgin Islands ............................................................... 17 10. Map showing location of ground-water stations in the U.S. Virgin Islands......................................................... 18 11. Grid showing system for numbering wells and miscellaneous site (latitude and longitude)................................ 19 12. Map showing the Rio Guajataca basin.................................................................................................................. 45 13. Map showing the Rio Camuy basin...................................................................................................................... 55 14. Map showing the Rio Grande de Arecibo basin................................................................................................... 57 15. Map showing the Rio Grande de Manatf basin................................................................................................... 111 16. Map showing the Rio Cibuco basin.................................................................................................................... 131 17. Map showing the Rio de la Plata basin............................................................................................................... 139 18. Map showing the Rio Hondo to the Rfo Puerto Nuevo basins........................................................................... 165 19. Map showing the Rio Grande de Loiza basin..................................................................................................... 193 20. Map showing northeastern river basins the Rio Herrera to the Rio Ant<5n Rufz basins..................................... 307 21. Map showing southeastern river basins the Rio Humacao to the Rfo Seco basins............................................. 347 22. Map showing south coast river basins the Rfo Salinas to the Rfo Jacaguas basins............................................ 365 23. Map showing south coast river basins the Rfo Inabdn to the Rfo Loco basins ..................................................381 24. Map showing the Rfo Guanajibo basin...............................................................................................................401 25. Map showing the Rfo Yagiiez and the Rfo Grande de Anasco basins................................................................417 26. Map showing the Rfo Culebrinas basin.....................................................................:........................................429 TABLES Page Table 1. Island-wide monthly rainfall for the water year 1997 and annual averages for the 30-year reference period, 1961-90........................................................................................................................3 2. Highest water level recorded during water year 1997 and previous highest ground- - water levels at selected ground-water wells in Puerto Rico and the U.S. Virgin Islands...................................................................................................................................................................7 3. Lowest ground-water levels recorded during water year 1997 and previous lowest ground-water levels at selected wells in Puerto Rico ........................................................................................ 7 4. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1997....................................................................................................... 9 5. Factors for conversion of chemical constituents in milligrams per liter to milli- equivalents per liter............................................................................................................................................. 34 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, y\\ FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME (Letter after station name designates type of data: (d) discharge, (c) chemical, (b) biological, (s) sediment, (p) pesticide, (e) elevation, gage heights) Station number Page RIO GUAJATACA BASIN Rio Guajataca at Lares (d,c,b)....................................................................................................... 50010500 46 Lago Guajataca at Damsite near Quebradillas (e)........................................................................ 50010800 49 Canal Principal de Diversiones at Lago Guajataca (c,b).............................................................. 50011000 50 Rio Guajataca above mouth near Quebradillas (c,b).................................................................... 50011400 52 RIO CAMUY BASIN Rio Camuy near Bayaney (d)........................................................................................................ 50014800 56 RIO GRANDE DE ARECIBO BASIN Lago Garzas near Adjuntas (e)............................................................................................. 50020100 58 Rio Grande de Arecibo near Adjuntas (c,b).................................................................................. 50020500 59 Rio Grande de Arecibo below Utuado (d,s).................................................................................. 50024950 61 Rio Grande de Arecibo near Utuado (c,b).................................................................................... 50025000 71 Rio Saliente at Coabey near Jayuya(d)................................................................................50025155 73 Rio Caonillas at Paso Palma (d,s)................................................................................................. 50026025 74 Rio Caonillas above Lago Caonillas near Jayuya (c,b)................................................................ 50026050 86 Lago Caonillas at Damsite near Utuado (e).......................................................................... 50026140 88 Rio Grande de Arecibo below Lago Dos Bocas near Florida (c,b).............................................. 50027250 89 Rfo Grande de Arecibo above Arecibo (d,s)................................................................................. 50027750 91 Rio Tanamd near Utuado (d,c,b,s)........................................................................................ 50028000 98 Rio Tanamd at Charco Hondo (d)........................................................................................ 50028400 107 Rfo Grande de Arecibo at Central Cambalache (d,c,b)................................................................ 50029000 108 RIO GRANDE DE MANATI BASIN Rfo Orocovis at Orocovis (d)................................................................................................ 50030460 112 Rfo Orocovis near Orocovis (c,b)......................................................................................... 50030700 113 Rfo Grande de Manatf near Morovis (d,c,b)................................................................................. 50031200 115 Lago El Guineo at Damsite near Villalba (e)........................................................................ 50032290 118 Lago de Matrullas at Damsite near Orocovis (e).................................................................. 50032590 119 Rfo Bauta near Orocovis (d)................................................................................................. 50034000 120 Rfo Grande de Manatf at Ciales (d).............................................................................................. 50035000 121 Rfo Grande de Manatf at Highway 149 at Ciales (c,b)................................................................. 50035500 122 Rfo Cialitos at Highway 649 at Ciales (c,b)......................................................................... 50035950 124 Rfo Grande de Manatf at Highway 2 near Manatf (d.c.b.p).......................................................... 50038100 126 LACUNA TORTUGUERO BASIN Laguna Tortuguero Outlet near Vega Baja (c,b).......................................................................... 50038200 129 RIO CIBUCO BASIN Rfo Cibuco below Corozal (d,c,b)................................................................................................ 50038320 132 Rfo Cibuco at Vega Baja (d,c,b)................................................................................................... 50039500 135 RIO DE LA PLATA BASIN Lago Carite at Gate Tower near Cayey (e)................................................................................... 50039990 140 Rfo de La Plata at Proyecto La Plata (c,b).................................................................................... 50043000 141 Rfo de La Plata at Comerio (d,s)................................................................................................... 50043800 143 Rfo de La Plata near Comerio (c.b).............................................................................................. 50044000 150 Rfo Guadiana near Naranjito (c,b)........................................................................................ 50044850 152 Lago La Plata at Damsite near Toa Alta (e)................................................................................. 50045000 154 Rfo de La Plata below La Plata Dam (d,s).................................................................................... 50045010 155 Rfo de La Plata at Highway 2 near Toa Alta (d,c,b,s,p)............................................................... 50046000 161 RIO HONDO BASIN Rfo Hondo at Flood Channel near Catano (c,b)............................................................................ 50047530 166 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO DE BAYAMON BASIN Rio de Bayamon at Arenas (d)...................................................................................................... 50047535 168 Rio Sabana at Vista Monte (d).............................................................................................. 50047540 169 Lago de Cidra at Damsite near Cidra (e)...................................................................................... 50047550 170 Rio de Bayam6n below Cidra Dam (d,s)...................................................................................... 50047560 171 Rio de Bayamon near Aguas Buenas (c,b)................................................................................... 50047600 178 Rio de Bayamon near Bayamon (d).............................................................................................. 50047850 180 Rio Guaynabo near Bayamon (c,b)....................................................................................... 50047990 181 Rio de Bayamon at Flood Channel at Bayam6n (c,b,p)............................................................... 50048510 183 RIO PUERTO NUEVO BASIN Rio Piedras: Lago Las Curias at Damsite near Rio Piedras(e)......................................................................... 50048680 185 Rio Piedras near Rio Piedras (c,b,p).............................................................................................50048800 186 Rio Piedras at Hato Rey (d,c,b).................................................................................................... 50049100 188 Laguna San Jose: Laguna San Jose No 2 at San Juan (c,b)....................................................................................... 50049820 191 Bahia de San Juan: Bahia de San Juan No 5 at San Juan (c,b)........,............................................................................ 50049920 192 QUEBRADA BLASINA BASIN Quebrada Blasina near Carolina (c,b)........................................................................................... 50050300 194 RIO GRANDE DE LOIZA BASIN Rio Grande de Loiza at Quebrada Arenas (d)............................................................................... 50050900 196 Quebrada Blanca at El Jagual (d,s)....................................................................................... 50051150 197 Quebrada Salvatierra near San Lorenzo (d,s)....................................................................... 50051180 204 Rio Cayaguas at Cerro Gordo (d)......................................................................................... 50051310 211 Rio Grande de Loiza at Highway 183 near San Lorenzo (d,s)..................................................... 50051800 212 Rio Turabo above Borinquen (d,s)........................................................................................ 50053025 219 Rio Grande de Loiza at Caguas (d,c,b,s)...................................................................................... 50055000 226 Rio Caguitas near Aguas Buenas (d,s).................................................................................. 50055100 235 Rio Caguitas near Caguas (d,s)............................................................................................. 50055170 242 Rio Caguitas at Villa Blanca at Caguas (d,s)........................................................................ 50055225 248 Rio Caguitas at Highway 30 at Caguas (c,b)........................................................................ 50055250 255 Rio Bairoa at Bairoa (d,s)..................................................................................................... 50055390 257 Rio Bairoa near Caguas (c,b)................................................................................................ 50055400 263 Rio Gurabo: Rio Gurabo below El Mango (d,s)........................................................................................ 50055750 265 Rio Valenciano near Juncos (d,s)..................................................................................... 50056400 272 Rio Gurabo at Gurabo (d,s)................................................................................................... 50057000 279 Rio Gurabo near Gurabo (c,b).............................................................................................. 50057025 286 Rio Canas at Rio Canas (d,s)................................................................................................ 50058350 288 Lago Loiza at Damsite near Trujillo Alto (c,b,e).......................................................................... 50059000 295 Rio Grande de Loiza below Damsite (d,s).................................................................................... 50059050 297 Rio Grande de Loiza below Trujillo Alto (c,b)............................................................................. 50059100 304 Rio Canovanas near Campo Rico (d).................................................................................... 50061800 306 RIO ESPIRITU SANTO BASIN Quebrada Sonadora near El Verde........................................................................................ 50063440 308 Rio Espfritu Santo near Rio Grande (d,c,b).................................................................................. 50063800 310 Rio Grande near El Verde (d)............................................................................................... 50064200 313 RIO MAMEYES BASIN Rio Mameyes near Sabana (d,s).................................................................................................... 50065500 314 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, IX FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO SABANA BASIN Rio Sabana at Sabana (d).............................................................................................................. 50067000 321 RIO FAJARDO BASIN Rio Fajardo above Fajardo (d,s).................................................................................................... 50070500 322 Rio Fajardo near Fajardo (d,c,b,p,s)............................................................................................. 50071000 333 Rio Fajardo below Fajardo (c,b)................................................................................................... 50072500 342 RIO BLANCO BASIN Quebrada Guaba near Naguabo (d)............................................................................................... 50074950 344 Rio Icacos near Naguabo (d)......................................................................................................... 50075000 345 RIO HUMACAO BASIN Rio Humacao at Las Piedras (d)................................................................................................... 50081000 348 Rio Humacao at Highway 3 at Humacao (c,b)............................................................................. 50082000 349 RIO GUAYANES BASIN Rio Guayanes at Yabucoa (c,b,p)................................................................................................. 50083500 351 Rio Guayanes above mouth at Playa de Guayanes (c,b).............................................................. 50086500 353 RIO MAUNABO BASIN Rio Maunabo at Lizas (d)............................................................................................................. 50090500 355 Rio Maunabo at Maunabo (c,b).................................................................................................... 50091000 356 RIO CHICO BASIN Rio Chico at Providencia (c,b)...................................................................................................... 50091800 358 RIO GRANDE DE PATILLAS BASIN Rio Grande de Patillas near Patillas (d,c,b).................................................................................. 50092000 360 Lago Patillas at Damsite near Patillas (e)..................................................................................... 50093045 363 RIO SALINAS BASIN Rio Lapas near Rabo del Buey (d)................................................................................................ 50100200 366 Rio Majada at La Plena (d)........................................................................................................... 50100450 367 RIO COAMO BASIN Rio Coamo at Coamo (d).............................................................................................................. 50106100 368 Rio Coamo near Coamo (c,b)....................................................................................................... 50106500 369 RIO DESCALABRADO BASIN Rio Descalabrado near Los Llanos (d).......................................................................................... 50108000 371 RIO JACAGUAS BASIN Rio Toa Vaca above Lago Toa Vaca (d,s)............................................................................ 50110900 372 Lago Guayabal at Damsite near Juana Diaz (e)............................................................................ 50111300 379 Rio Jacaguas at Juana Dfaz (d)..................................................................................................... 50111500 380 RIO INABON BASIN Rio Inabon at Real Abajo(d)........................................................................................................ 50112500 382 RIO BUCANA BASIN Rio Bucan£: Rio Cerrillos above Lago Cerrillos near Ponce (d)....................................................................... 50113800 383 Lago Cerrillos at Damsite near Ponce (e)..................................................................................... 50113950 384 Rio Cerrillos near Ponce (d,c,b).................................................................................................... 50114000 385 Rio Bucana at Hwy 14 Bridge near Ponce (d).............................................................................. 50114390 388 X SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO PORTUGUES BASIN Rio Portugu6s near Ponce (d,c,b).................................................................................................. 50115000 389 Rio Portugu6s at Ponce (c,b,p)...................................................................................................... 50116200 392 RIO GUAYANILLA BASIN Rfo Guayanilla near Guayanilla (d).............................................................................................. 50124200 394 Rio Guayanilla at Central Rufma (c.b.p)...................................................................................... 50124700 395 RIO YAUCO BASIN Lago Lucchetti at Damsite near Yauco (e)................................................................................... 50125780 397 RIO LOCO BASIN Lago Loco at Damsite near Yauco (e).......................................................................................... 50128900 398 Rfo Loco at Gudnica (c,b,p).......................................................................................................... 50129700 399 RIO GUANAJIBO BASIN Rfo Guanajibo at Highway 119 at San German (d)...................................................................... 50131990 402 Rfo Guanajibo near San German (c,b).......................................................................................... 50133600 403 Rfo Rosario near Hormigueros (d,c,b,s)............................................................................... 50136400 405 Rfo Guanajibo near Hormigueros (d,c,b,p)................................................................................... 50138000 413 RIO YAGUEZ BASIN Rfo Yaguez near Mayaguez (c,b).................................................................................................. 50138800 418 RIO GRANDE DE ANASCO BASIN Lago Guayo at Damsite near Castaner (e)............................................................................ 50141500 420 Rfo Grande de Anasco near Lares (c,b)........................................................................................ 50143000 421 Rfo Grande de Anasco near San Sebastian (d,c,b,s)..................................................................... 50144000 423 Rfo Grande de Anasco near Anasco (c.b.p).................................................................................. 50146000 426 RIO CULEBRINAS BASIN Rfo Culebrinas near San Sebastian (c,b)....................................................................................... 50147600 430 Rfo Culebrinas at Highway 404 near Moca (d)............................................................................ 50147800 432 Rfo Culebrinas near Aguada (c,b,p).............................................................................................. 50149100 433 Discharge at partial-record stations and miscellaneous sites Low-flow partial-record stations................................................................................................................... 436 Analyses of samples collected of water-quality partial-record stations and miscellaneous sites............................................................................................................ 448 ST THOMAS, US VIRGIN ISLANDS Bonne Resolution Gut at Bonne Resolution (d)........................................................................... 50252000 528 Turpentine Run at Mount Zion (d)................................................................................................ 50274000 529 ST JOHN, US VIRGIN ISLANDS Guinea Gut at Bethany (d)............................................................................................................ 50295000 530 STCROIX, US VIRGIN ISLANDS Jolly Hill Gut at Jolly Hill (d)....................................................................................................... 50345000 531 GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED XI Page RIO GUAJATACA BASIN Well 182422067015100 Local number 165 ....................................................................................................................464 Well 182647066552400 Local number 202 ....................................................................................................................465 RIO GRANDE DE ARECIBO BASIN Well 182737066370900 Local number 204 ....................................................................................................................466 Well 182616066364100 Local number EN-1 ..................................................................................................................468 Well 182737066370900 Local number FL-1 ..................................................................................................................469 Well 182209066340600 Local number TI-1 ...................................................................................................................470 RIO GRANDE DE MANATI BASIN Well 182549066304300 Local number 166 ...................................................................................................................471 Well 182757066325600 Local number 206 ....................................................................................................................472 Well 182710066303700 Local number 207 ....................................................................................................................473 Well 182308066260400 Local number 210 ....................................................................................................................474 Well 182548066265700 Local number CS-7 ................................................................................................................475 Well 182506066280200 Local number HI-2,,,.,.,,,,.....,,,,...,.,...,,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,.476 RIO CIBUCO BASIN Well 182647066201700 Local number 70 .....,....,...,,,,,,,...,,.,,,,.,,,,,,..,,,,.,,,,.,,,,...,.,,,,,,,,,,,.,477 Well 182615066235300 Local number 211 .,,........,,,....,,,,..,,,,...,,,.,.,,,,,,.,,,,,,,,,,,,.,,,,,,,,,,,,478 Well 182515066194000 Local number 212 ,.,.,..,,,.,,,..,....,,,,...,,,,..,,...,,,,.,.,,,,,,,.,.,,,.,.,,,,,,.,,479 Well 182330066185700 Local number 213 ...,.,,.......,,,,,,,.,,.,,,...,..,.,.,,,......,,,...,,,,,,,,,,,,.,,,,,,,480 Well 182614066261500 Local number PA-2.,,,,,,,,,,,..,.,,,,,,,,,,,,,,.,,,,,,,,,..,,,,,,,,,.,,,,,,,,,481 Well 182712066251700 Local number TO-3,,,....,,,....,,,...,,,,...,,,,.,,,,,..,,,.,.,.,,,,.,,,,,,,,,,.,,,,,482 RIO DE LA PLATA BASIN Well 182530066135400 Local number 216 .,.,,,,..,.,,,,.....,,,,,,,,,,,.,,,,.,,,,,.,,,,,,..,,,,,,,,,.,,,,,483 Well 182655066142400 Local number 217 ,,,.v.,,,.......,,,,,,,,....,,,,,,.,,..,.,.,,,,,.,,,,,,,,,,,,,,,,,.,484 Well 182804066173500 Local number DA-1 ,...,.,,..,..,...,.......,,.,,.,.,,,,,.,,.,,.,,,,...,,,,,,,,,,,,,,,,,,485 Well 182620066163203 Local number HG-4 ..,,,..,,.,,,,....,,,,,,.,.,,,..,..,,.,,,,,.,,,,,..,..,,,,,,,,,,,,,486 Well 182657066162700 Local number SA-1 .,.....,,,,,..,.,,,,.,...,,,,,,,,,,,,,,,,,.,...,,,...,,,,,.,,,...,,,,487 Well 182657066162701 Local number SA-3 .,,,...,,,.,,,.,,,,..,,,.....,,.,.,,,,,,,,,,,,,,.,,,,,,,,,,..,,,,,488 Well 182548066164101 Local number MA-2,...,,,.,.,...,.,.,..,,,,...,,,,,,,,..,,,,,,,,,,,,,,,, Well 182526066165001 Local number SR-2 ,....,,,,...,,,,....,,,....,,,,,.,.,,,,.,,.,,,.,,,,..,,,,,,,,,,,,,,,490 Well 182654066150600 Local number TB-1 ,,.......,,,,,,,,,.,,,,,,,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,491 RIO HONDO TO RIO PUERTO NUEVO BASINS Well 182441066082600 Local number 219 ...,,,,,,,,,,,,,,,...,,,..,,,,,,,,,,,,,,..,,,,,,,,,,,,,,,,,,,,,492 Well 182511066045401 Local number PN-2.,,.,,,,.,,,,,.,.,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,493 Well 182435066052700 Local number PN-5 ,.,,,,,,,.,,.,,,...,.,,,,..,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,494 Well 182445066043401 Local number PN-6,,...,.,,,.,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,495 Well 182443066041502 Local number PN-8c ....,,,,..,,.,,,.,,,,.,,,..,.,,,..,.,,,,,,.,,..,,,,.,,,,,,,,.,,,,,496 Well 182417066042700 Local number PN-10,,,,,,,,,,,,,.,,,,,,,,,,,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,497 Well 182349066032600 Local number PN-13 ,,,,,,,,,,,,,..,,,,..,,,,.,..,,.,..,,,,,,,,,,,,,,,,,,,,,,,,,,498 Well 182406066034700 Local number PN-19....,,,,,,,,,,,,,,,.,,,,,..,,,.,,,,,..,,,,,,,,..,,,,,,,,,,,,,,499 XII GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED-Continued Page RIO GRANDE DE LOIZA BASIN Well 181550065593200 Local number 50 ......................................................................................................................500 Well 182515065594100 Local number 222 ....................................................................................................................501 Well 181513065554601 Local number CJ-TW3B ..........................................................................................................502 Well 181352066025300 Local number CJ-TW19A........................................................................................................503 RIO HERRERA TO RIO ANTON RUIZ BASINS Well 181823065401900 Local number RF-04 ................................................................................................................504 Well 181917065382701 Local number RF-12 ................................................................................................................505 Well 182131065421100 Local number RP-04 ................................................................................................................506 Well 182138065431800 Local number RS-02................................................................................................................507 RIO HUMACAO TO RIO SECO BASINS Well 175858066100200 Local number 6 ........................................................................................................................508 Well 180415065513900 Local number 96 ......................................................................................................................509 Well 175719066085500 Local number P-13...................................................................................................................510 RIO SALINAS TO RIO JACAGUAS BASINS Well 175829066232200 Local number 87 ......................................................................................................................511 Well 180002066132200 Local number HW-TW-01 .......................................................................................................512 Well 180001066122002 Local number HW-TW-03C ....................................................................................................513 Well 175947066130601 Local number HW-TW-05B ....................................................................................................514 Well 175957066123400 Local number HW-TW-13.......................................................................................................515 Well 175903066165000 Local number PG-07................................................................................................................516 Well 175943066224800 Local number PS-07.................................................................................................................517 Well 180206066135500Local number RM-05...............................................................................................................518 Well 180104066152300 Local number RM-10...............................................................................................................519 RIO INABON TO RIO LOCO BASINS Well 180133066503300 Local number 132 ....................................................................................................................520 Well 175950066354200 Local number 141 ....................................................................................................................521 Well 180045066381600 Local Number AN-1 ................................................................................................................522 RIO GUANAJIBO BASIN Well 180132067033800 Local number 143 ....................................................................................................................523 Well 180628067084300 Local number CA-1..................................................................................................................524 RIO CULEBRINAS BASIN Well 182442067091700 Local number 200 ....................................................................................................................525 ST. CROIX, U.S. VIRGIN ISLANDS Well 174225064472000 Local number 2 ........................................................................................................................534 Well 174243064475100 Local number 3 ........................................................................................................................535 Well 174316064480800 Local number 13 ......................................................................................................................536 ST. THOMAS, U.S. VIRGIN ISLANDS Well 182038064550300 Local number 6........................................................................................................................537 Well 182038064580000 Local number 8 ........................................................................................................................538 ST. JOHN, U.S. VIRGIN ISLANDS Well 181956064464500 Local number 11 ......................................................................................................................539 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS Xflf The following continuous-record streamflow stations in Puerto Rico and the U.S. Virgin Islands have been discontinued or converted to partial-record stations. Daily streamflow or stage records were collected for the period of record shown for each station. Station Station name number 50007000 Quebrada de los Cedros near Isabela 50010600 Rio Guajataca above Lago de Guajataca 50011000 Canal Diversion Lago Guajataca 50011200 Rio Guajataca below Lago Guajataca 50011400 Rio Guajataca above mouth near Quebradillas 50013000 Rio Camuy near Lares 50014000 Rio Criminales near Lares 50014600 Rio Camuy at Tres Pueblos Sinkhole 50015700 Rio Camuy near Hatillo 50016000 Rio Camuy near Camuy 50021000 Rio Pellejas at Central Pellejas 50021050 Rio Pellejas below Central Pellejas 50021500 Rio Pellejas near Utuado 50023000 Rio Vivi near Central Pellejas 50027200 Rio Grande de Arecibo blw. Lago dos Bocas 50029000 Rfo Grande de Arecibo at Central Cambalache 50031500 Rio Sana Muerto near Orocovis 50035200 Rio Grande de Manati at Hwy 145 at Ciales 50035950 Rio Cialitos at Hwy 649 at Ciales 50038360 Rio Mavilla near Corozal 50038600 Rio Unibon near Morovis 50038700 Rio Morovis at Morovis 50038900 Rio Indio at Vega Baja 50039600 Rio Cibuco at Central San Vicente 50043200 Rio Usabon near Barranquitas 50043400 Rio Aibonito Tributary near Aibonito 50044600 Rio Guadiana near Naranjito 50044650 Quebrada del Toro near Naranjito 50044800 Quebrada Anones near Naranjito 50045700 Rio Lajas at Toa Alta 50047820 Rio de Bayam6n at Hwy 174 near Bayamon 50048000 Rio de Bayamon at Bayamon 50049000 Rio Piedras at Rio Piedras 50049310 Quebrada Josefina at Pinero Avenue 50053050 Rio Turabo at Borinquen 50054000 Quebrada de las Quebradillas near Caguas 50055650 Quebrada Caimito near Juncos 50056000 Rio Valenciano near Las Piedras 50056900 Quebrada Mamey near Gurabo 50058300 Quebrada Arena near Caguas Drainage area (mi2) 6.91 - — — - 7.62 4.68 — — - 5.46 7.89 9.55 5.66 169 200 3.68 132 17 9.51 5.29 1.26 — — 9.15 1.13 1.73 0.54 2.32 8.65 31.90 71.90 12.5 3.84 7.89 6.25 0.82 6.85 2.30 — Period of record 1970 1984-89 1970 1969-70,1984-87 1969-70,1984-89 1969-71 1969-70 1990-96 1984-96 1969-73 1968-70 1972-75 1969-71 1969-75 1970-71 1969-83 1965-70 1972 1970-82 1969-70 1969-70 1968 1963,66,71 1969-72 1968-69,71 1968-71 1971 1971 1971 1966-75 1966 1963-67 1971-82, 1987-93 1988-91 1984-90 1969-71,73 1984-87 1971 1984-92 1971 XIV WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS-Continued Station Station name number 50059000 Rio Piedras at Rio Piedras 50061300 Rio Canovanillas near Lofza 50062500 Rio Herrera near Colonia Dolores 50063300 Rio Espiritu Santo near El Verde 50063500 Quebrada Toronja at El Verde 50065700 Rio Mameyes at Hwy 191 at Mameyes 50072000 Rio Fajardo at Fajardo 50073200 Rio Daguao at Daguao 50073400 Quebrada Palma at Daguao 50074000 Rio Santiago at Naguabo 50075500 Rfo Blanco at Florida 50076000 Rfo Blanco near Florida 50077000 Rfo Blanco at Rfo Blanco 50077400 Rfo Blanco at Colonia La Fe 50078500 Rfo Anton Rufz at Central Pasto Viejo 50081500 Rfo Humacao near Humacao 50082000 Rfo Humacao at Hwy 3 at Humacao 50082200 Rfo Humacao near La Suiza 50082800 Rfo Guayan6s near Colonia Laura 50083500 Rfo Guayan6s near Yabucoa 50084000 Rfo Limones near Yabucoa 50085100 Rfo Guayan6s at Central Roig 50086100 Rfo del Ingenio at Comunas 50086500 Rfo Guayan6s at Playa Guayan<5s 50087200 Cano Santiago near Central Roig 50091000 Rfo Maunabo at Maunabo 50091200 Rfo Maunabo near Maunabo 50091400 Rfo Jacaboa near Lamboglia 50091700 Rfo Chico at Patillas 50091800 Rfo Chico at Providencia 50094200 Rfo Grande de Patillas at Patillas 50094300 Rfo Grande de Patillas at Providencia 50094400 Rfo Nigua at Pitahaya 50095200 Rfo Guamanf at Guayama 50095500 Rfo Guamanf near Guayama 50099000 Quebrada Aguas Verdes near Salinas 50106500 Rfo Coamo near Coamo 50106900 Rfo Coamo below Lago Coamo near Coamo 50107200 Rfo Coamo at mouth near Santa Isabel 50108200 Rfo Descalabrado at Las Ollas 50108500 Rfo Descalabrado near Santa Isabel 50111200 Rfo ToaVaca near Villalba 50111700 Rfo Jacaguas near Juana Dfaz 50111750 Rfo Jacaguas below Quebrada Guan£bana 50112100 Rfo Jacaguas near Arris 'rainage rea (mi ) 12.5 14.40 2.75 2.23 0.064 11.80 21.60 2.26 4.84 4.99 11.00 12.30 17.60 18.80 4.33 9.23 17.30 19.90 4.69 17.20 7.89 26.60 5.50 34.00 6.04 12.40 12.70 4.13 6.82 4.90 27.90 29.00 5.86 8.22 12.30 0.39 46.00 65.40 69.30 13.90 18.10 21.40 53.20 56.30 59.60 Period of record 1971-82,1987-93 1968-73 1968-72 1968-73 1983-96 1967-85 1960-63 1966-82 1972-77 1966-82 1966-82 1983-85 1973-77 1967-70 1968 1973 1983-85 1965-66,1969-71 1969-82 1969-71 1969-71 1965-66,1968,70 1965-66,1968-69 1965-66,1968-71 1965-71 1965,67,1969-82 1971-72 1965-73 1965,1969-72 1965,1967-69,1971 1967,1969,1971 1971 1965,1969,1970-71,1973 1969-71 1969-70 1989 1967-68,1984-85,1986 1967-68 1967-68 1965,1967-71 1966-67 1966-70 1966-68 1989 1966-67 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DISCONTINUED STREAMFLOW STATIONS-Continued XV Station Station name number 50112600 Rio Inabdn at Goto Laurel 50113100 Rio Guayo near Coto Laurel 50113500 Rio Inab6n near Arus 50114400 Rio Bucan* near Ponce 50114700 Rio BucanS near Playa de Ponce 50115900 Rio Portugu& at Hwy 14 at Ponce 50116500 Rio Portugues at Highway 2 Bypass at Ponce 50119000 Rio Matilde at Ponce 50121000 Rio Tallaboa at Penuelas 50122000 Rio Tallaboa at Tallaboa 50124000 Rfo Guayanilla nr Guayanilla 50124500 Rio Guayanilla at Guayanilla 50125900 Rfo Duey above Diversion near Yauco 50126150 Rio Yauco above Diversion Monserrate near Yauco 50128000 Rfo Yauco near Yauco 50129000 Rfo Loco near Yauco 50129500 Rfo Loco near GuSnica 50129900 Laguna Cartagena near Boquerdn 50130320 Quebrada Mamey at Joyuda 50136000 Rfo Rosario at Rosario 50141000 Rfo Yahuecas near Adjuntas 50145000 Rfo Grande de Anasco at El Espino 50147000 Rfo Culebrinas at San Sebastian 50214500 Quebrada Resaca near Monte Resaca, Culebra 50215000 Drainage Canal at Culebra Airport, Culebra 50231000 Quebrada Confresf Tributary near Isabel II, Vieques 50232000 Quebrada La Mina near Esperanza, Vieques 50233000 Quebrada Pil6n at Colonia Puerto Real, Vieques 50276000 Turpentine Run at Mariendal 50292600 Lameshur Bay Gut at Lameshur, St. John 50294000 Fish Bay Gut at Fish Bay, St. John 50295500 Cruz Bay Gut at Cruz Bay, St. John, V 50332000 River Gut at River 50333500 River Gut near Golden Grove 50333700 River Gut at Hwy 66 at Fairplanes 50334500 Bethehem Gut at Hwy 66 at Fairplanes 50337500 Gut 4.5 at Cane Valley 50348000 Salt River at Canaan 50349000 Gut 10 near Altona Drainage area (mi2) .. 11.80 30.20 25.60 28.40 __ 20.50 19.40 24.20 31.50 18.50 20.80 8.93 27.20 45.50 8.50 21.00 .. 0.38 16.40 15.40 108.00 16.70 0.23 0.08 0.28 0.68 0.67 2.97 0.38 1.48 0.09 1.42 5.40 5.89 4.11 0.2 0.36 0.13 Period of record 1967-71 1965, 1968-71 1964-65 1965-81 1964-67 1965-82 1964-65 1965-66 1959-82 1959-63 1961-69 1971-82 1977-80 1978-85 1962-64,1977-85 1963-67 1963-69 1984-86 1986-88 1975-86 1980-85 1959-66,1961-63 1960-82 1991-93 1991-93 1991-93 1991-96 1991-96 1963-69,1978-86 1992-94 1992-94 1992-93 1991-93 1990-93 1990-96 1990-96 1991-93 1991-93 1991-93 XVI THIS PAGE WAS LEFT BLANK INTENTIONALLY WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 ' INTRODUCTION The Water Resources Division of the U.S. Geological Survey, in cooperation with local and federal agencies obtains a large amount of data pertaining to the water resources of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the area. To make these data readily available to interested parties outside the Geological Survey, the data are published annually in this report series entitled "Water Resources Data for Puerto Rico and the U.S. Virgin Islands, 1997." This report includes records on both surface and ground water. Specifically, it contains: (1) Discharge records for 74 streamflow-gaging stations, daily sediment records for 26 streamflow stations, 95 partial-record or miscellaneous streamflow stations, stage records for 16 reservoirs, and (2) water-quality records for 16 streamflow-gaging stations, and for 42 ungaged streamsites, 11 lake sites, 2 lagoons, and 1 bay; and (3) water-level records for 67 observation wells. Water-resources data for Puerto Rico for calendar years 1958-67 were released in a series of reports entitled "Water Records of Puerto Rico". Water-resources data for the U.S. Virgin Islands for the calendar years 1962-69 were released in a report entitled "Water Records of U.S. Virgin Islands." Included were records of streamflow, ground-water levels, and water- quality data for both surface and ground water. Beginning with the 1968 calendar year, surface-water records for Puerto Rico were released separately on an annual basis. Ground-water level records and water-quality data for surface and ground water were released in companion reports covering periods of several years. Data for the 1973-74 reports were published under separate covers. Water-resources data reports for 1975-76, 1977, 1978, 1979-80, 1981-82, 1983, 1984, 1985, 1986,1987, 1988, 1989, 1990, 1991, 1992, 1993,1994, 1995, and 1996 water years consist of one volume each and contain data for streamflow, water quality and ground water. Publications similar to this report are published annually by the Geological Survey for all States. These official Survey reports have an identification number consisting of the two-letter State abbreviation, the last two digits of the water year, and the volume number. For example, this volume is identified as "U.S. Geological Survey Water-Data Report PR-97-1." These water- data reports are for sale in paper copy or in microfiche by the National Technical Information Service, U.S. Department of Commerce, Springfield, Virginia, 22161. Additional information, including current prices, for ordering specific reports may be obtained from the District Chief at the address given on back of the title page or by telephone (787) 749-4346. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 COOPERATION The U.S. Geological Survey has had cooperative agreements with organizations of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands for the systematic collections of water resources data since 1958. Organizations that supplied data are acknowledged in the station descriptions. Organizations that assisted in collecting data through cooperative agreements with the Survey are: Puerto Rico Environmental Quality Board Puerto Rico Aqueduct and Sewer Authority Puerto Rico Department of Agriculture Puerto Rico Industrial Development Company Puerto Rico Department of Housing Puerto Rico Highway Authority Puerto Rico Department of Natural and Environmental Resources Puerto Rico Department of Health Puerto Rico Electric Power Authority Puerto Rico Solid Waste Management Authority Puerto Rico Legislature Puerto Rico Civil Defense U.S. Virgin Islands Department of Planning and Natural Resources Funds were also provided by the Corps of Engineers, U.S. Army, for the collection of records at six gaging stations published in this report. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 3 SUMMARY OF HYDROLOGIC CONDITIONS Rainfall Rainfall throughout Puerto Rico during the water year 1997 (October 1996 to September 1997) averaged about 77 percent of normal. During the months of October, December, and from March to September, rainfall was deficient with averages below normal that ranged from 8 to 81 percent. Significant deficient rainfall conditions were recorded during April, when recorded rainfall averaged 81 percent below normal. For the months of November, January, and February rainfall was above normal. Significant above normal rainfall conditions were recorded during January when rainfall averaged 214 percent of normal. Annual rainfall averaged about 85 percent of normal in northern Puerto Rico, 60 percent of normal in southern Puerto Rico, 76 percent of normal in western Puerto Rico, and 82 percent of normal in eastern Puerto Rico. Monthly average rainfall islandwide for the 1997 water year and for the 30-year period 1961-1990 used to define normal rainfall, as reported by the National Oceanic and Atmospheric Administration, are listed in table 1. Table 1. Islandwide monthly rainfall for the water year 1997 and annual averages for the 30-year reference period, 1961-1990 Month October November December January February March April May June July August September 1997 Water Year (inches) 4.71 7.11 3.18 6.13 3.30 2.09 0.87 3.53 2.19 4.64 5.97 4.64 30-year normal (inches) 8.29 6.55 4.38 2.86 2.52 3.02 4.46 6.96 4.99 5.08 6.89 7.14 TOTAL 48.36 63.14 Surface Water Streamflow in Puerto Rico was, in general, below normal during water year 1997, based on the index stations with monthly-mean discharges lower than the long-term monthly median flow during several months. A monthly comparison of the monthly-mean flows for the period of record at the index stations on the Rio Grande de Manatf, the Rio Fajardo, the Rio Inabdn, and the Rio Grande de Anasco are shown in figure 1. Islandwide, streamflow was below the long-term monthly median as recorded by the four index stations for the months of October and from April to July. In the north coast, the Rio Grande de Manatf index station recorded flows below the long-term monthly median during October, April to July, and September. Monthly mean flows during these months ranged from 26 to 63 percent of the long-term median of the monthly mean flows. Mean monthly flows were above normal from November to March and August. A historical maximum monthly mean flow was recorded during January with 401 percent of the long-term median. In the east coast, the index station on the Rio Fajardo, recorded monthly mean flows below the long-term median during October, December, and from April to August. Monthly mean flows during these months ranged from 45 to 94 percent of the long-term median of the monthly mean flows. The mean monthly flows were equal to the long-term monthly median during March and above normal during November, January, and September when mean monthly flows were 215,155, and 109 percent, respectively, of the long-term monthly median of the monthly mean flows. NORTH RIO GRANDE DE MANATl AT HWY 2 (50038100) 10,000 1,000 § CO ffi g m o LU O CO ONDJFMAMJJAS SOUTH RlO INABON AT REAL ABAJO (50112500) 1,000 o ONDJFMAMJJAS EAST RlO FAJARDO NEAR FAJARDO (50071000) 1,000 100 § CO cc UJ Q. UJ UJ g m o UJ O ONDJFMAMJJAS WEST RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN (50144000) 1997 MONTHLY MEAN - —— 1964-96 MEDIAN OF MONTHLY-MEAN ONDJFMAMJJAS Unshaded area indicates range between highest and lowest monthly-mean discharges for the period of record to water year 1997. Figure 1 .-Monthly-mean discharge of selected streams in Puerto Rico. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 In the south coast, the Rio Inabon index station, recorded monthly mean flows below the long-term median from October to December, and from March to September. Monthly mean flows during these months ranged from 20 to 93 percent of the long-term median of the monthly mean flows. Historical minimum monthly mean flows of 2.8 and 6.2 cubic feet per second were recorded during April and September, respectively. In the west coast, the Rfo Grande de Anasco index station, recorded mean monthly flows below normal during October, April to July, and September. Monthly mean flows during these months ranged from 41 to 91 percent of the long-term median of the monthly mean flows. Mean monthly flows were above normal from November to March, and during August ranging from 109 to 217 percent of the long-term median of the monthly mean flows. A historical maximum monthly mean flow was recorded during January with 217 percent of the long-term median. Ground-Water Levels Ground-water levels in most aquifers in Puerto Rico and the U.S. Virgin Islands generally declined during water year 1997. The ground-water levels were relatively unchanged from October to January after the effects of hurricane Hortense on September 9-10,1996, and in response to high soil moisture and rainfall. From February to September, the ground-water levels declined in response to below-normal rainfall and sustained ground-water withdrawals. Record-low and record-high water levels were recorded at several observation wells in Puerto Rico and the U.S. Virgin Islands during water year 1997 (tables 2 and 3). Ground-water levels in the North Coast Limestone aquifers of Puerto Rico fluctuated from October to January in response to seasonal rainfall patterns. From February to September, the water levels declined in response to below-normal rainfall in the area. At the Sabana Hoyos index well, the ground-water level declined 2.90 ft. (fig. 2). In the South Coast aquifer of Puerto Rico, the ground-water levels generally declined in response to rainfall and streamflow patterns, irrigation, and ground-water withdrawals. The ground-water levels declined from November to September as streamflow in the area diminished and ground-water withdrawals increased for irrigation purposes. At the Alomar index well, the water level declined 3.65 ft. (fig. 2). In the U.S. Virgin Islands (St. Thomas, StCroix, and St. John) ground-water levels generally declined during water year 1997 in response to below-normal rainfall and sustained ground-water withdrawals. At the Guinea Gut observation well in St. John, U.S. Virgin Islands, the ground-water levels declined by 19.60 ft. from February to September (fig. 2). WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Table 2. Highest ground-water levels recorded during water year 1997 and previous highest ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands [PR, Puerto Rico; St.T, St. Thomas; St.C, St. Croix; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year] Well name or number Manati 3 Hill 2 RF-12 Fairplains 2 VIEO-6 Kirwan Terrace Local number 166 HI-2 RF-12 2 8 Location PR PR PR St.C St.T 1997 Highest water level (ft-blsd) 22.11 267.% 2.90 19.02 14.34 Date (mm-dd-yy) 01-25-97 01-24-97 11-22-96 02-08-97 12-06-96 12-07-96 Previous highest water level (ft-blsd) 22.43 282.62 4.64 19.45 22.79 Date (mm-dd-yy) 09-20-96 09-10-96 01-15-96 11-04-89 01-21-93 Period of record (mm-yy) 01-82 to 09-97 05-96 to 09-97 08-95 to 09-97 06-83 to 09-97 10-91 to 09-97 Table 3. Lowest ground-water levels recorded during water year 1997 and previous lowest ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands [PR, Puerto Rico; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year] Well name or number Encantada 1 Tiburones 1 RF-04 RF-12 RP-04 RS-02 Vivoni Col. Amistad CR-TW-9A Local number EN-1 TI-1 RF-04 RF-12 RP-04 RS-02 143 CR-TW-9A Location PR PR PR PR PR PR PR PR 1997 lowest water level (ft-blsd) 313.74 292.79 18.82 10.64 14.05 7.13 40.70 7.22 Date (mm-dd-yy) 07-05-97 07-06-97 01-17-97 07-21-97 to 07-25-97 08-21-97 08-22-97 08-21-97 07-09-97 to 07-13-97 09-26-97 08-14-97 Previous lowest water level (ft-blsd) 313.34 292.44 18.22 10.45 9.66 6.95 40.09 5.99 Date (mm-dd-yy) 08-23-96 06-05-96 05-07-96 to 05-13-96 07-07-96 07-08-96 04-26-96 04-02-96 04-03-96 04-04-96 07-21-96 07-22-96 07-28-96 05-19-93 05-20-93 Period of record (mm-yy) 08-96 to 09-97 05-96 to 09-97 08-95 to 09-97 08-95 to 09-97 08-95 to 09-97 08-95 to 09-97 10-85 to 09-97 07-92 to 09-97 27 28 29 30 ^ 31 |— October November December January February March April < 1997 HI O WELL 70, SABANA HOYOS, PUERTO RICO May June July August September CO 40 6 I HI CD HI LL. LJJ HI _l DC HII 42 44 46 WELL 87, ALOMAR WELL, PUERTO RICO October November December January February March April May June July August September 1997 WELL 11, GUINEA GUT ST. JOHN U.S. VIRGIN ISLANDS 10 20 30 l_______I I_______I October November December January February March April May June July August September 1997 Figure 2. -Ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands. 8 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Water Quality In water year 1997, the U.S. Geological Survey in cooperation with several local government agencies, collected water- quality data at 73 surface-water stations in Puerto Rico. The water-quality data collected at these stations included the major chemical constituents and several additional constituents that are listed in table 4. The highest concentration of each of these additional constituents detected during water year 1997 and the station where it was detected are summarized in table 4. Table 4. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1997 [All constituent concentrations are in milligrams per liter; MBAS, Methylene blue active substance] Station number Station name Constituent Concentration 50044850 50129700 50146000 50146000 50091800 * 50091800 50106500 50144000 50091800 Rio Guadiana near Naranjito Rio Loco at Guanica Rio Grande de Anasco near Afiasco Rio Grande de Anasco near Anasco Rio Chico at Providencia * Rio Chico at Providencia Rio Coamo near Coamo Rio Grande de Anasco near San Sebastian Rio Chico at Providencia Sulfide Boron Manganese Iron Zinc Cyanide Phenols Phenols Phenols MBAS 2.6 2.2 0.61 11 0.25 <0.010 0.09 0.09 0.09 4.8 Cyanide concentrations at all water-quality stations were below the detection limit (<0.010). The presence of high concentrations of fecal coliform (fig. 3) and fecal streptococcal (fig. 4) bacteria continued to be the principal surface-water quality problem in Puerto Rico during water year 1997. A bacteria concentration exceeding one million colonies per hundred milliliters of raw water was determined for a water sample collected at the station on San Juan Bay (50049920). This station is located in the San Juan metropolitan area, which has the highest population concentration in Puerto Rico. In addition to the effluent from the San Juan metropolitan area the streams are also receiving effluents from sewage treatment plants in the upper basin. The main sources of contamination in surface-water systems in Puerto Rico are discharges of liquid wastes from industrial and municipal sources. The highest concentration of fecal coliform and fecal streptococcal bacteria in surface waters in Puerto Rico generally occurred in streams draining from densely populated and industrialized areas. Suspended sediment concentrations were monitored at 26 stations in Puerto Rico during the 1997 water as part of the cooperative program between the U.S. Geological Survey and various Commonwealth and Federal agencies. High suspended sediment concentrations are a common problem in many streams in Puerto Rico. Most of the streams with high suspended sediment concentration were related to land use, especially urban development, agriculture, and other activities where soil movement was involved. The high suspended sediment concentrations affect the water quality for drinking water and decrease the storage capacities of reservoirs used for water supply. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 SPECIAL NETWORKS AND PROGRAMS Hydrologic Bench-Mark Network is a network of 57 sites in small drainage basins around the country whose purpose is to provide consistent data on the hydrology, including water quality, and related factors in representative undeveloped watersheds nationwide, and to provide analyses on a continuing basis to compare and contrast conditions observed in basins more obviously affected by the activities of man. National Stream Quality Accounting Network (NASQAN) is a nationwide data-collection network designed by the U.S. Geological Survey to meet many of the information needs of government agencies and other groups involved in natural or regional water-quality planning and management. The 500 or so sites on NASQAN are generally located at the downstream ends of hydrologic accounting units designated by the U.S. Geological Survey Office of Water Data Coordination in consultation with the Water Resources Council. The objectives of NASQAN are (1) to obtain information on the quality and quantity of water moving within and from the United States through a systematic and uniform process of data collection, summarization, analysis, and reporting such that the data may be used for, (2) description of the areal variability of water quality in the Nation's rivers through analysis of data from this and other programs, (3) detection of changes or trends with time in the pattern of occurrence of water-quality characteristics, and (4) providing a nationally consistent data base useful for water-quality assessment and hydrologic research. The National Trends Network (NTN) is a 150-station network for sampling atmospheric deposition in the United States. The purpose of the network is to determine the variability, both in location and in time, of the composition of atmospheric deposition, which includes snow, rain, dust particles, aerosols, and gases. The core from which the NTN was built was the already-existing deposition-monitoring network of the National Atmospheric Deposition Program (NADP). The National Water-Quality Assessment (NAWOA) Program of the U.S. Geological Survey is a long-term program with goals to describe the status and trends of water-quality conditions for a large, diverse, and geographically distributed part of the Nation's ground- and surface-water resources, and to identify, describe, and explain the major natural and human factors that affect these observed conditions and trends. Assessment activities have begun in more than one-third of the study units and ultimately will be conducted in 60 study units (major watersheds and aquifer systems) that represent a wide range of environmental settings nationwide and that account for a large percentage of the Nation's water use. A wide array of chemical constituents will be measured in ground water, surface water, streambed sediments, and fish tissues. The coordinated application of comparative hydrologic studies at a wide range of spatial and temporal scales will provide information for decision making by water-resources managers and a foundation for aggregation and comparison of findings to address water-quality issues of regional and national interest. Radiochemical Programs is a network of regularly sampled water-quality stations where samples are collected to be analyzed for radioisotopes. The streams that are sampled represent major drainage basins in the conterminous United States. Tritium Network is a network of stations which has been established to provide baseline information on the occurrence of tritium in the Nation's surface waters. In addition to the surface-water stations in the network, tritium data are also obtained at a number of precipitation stations. The purpose of the precipitation stations is to provide an estimate sufficient for hydrologic studies of the tritium input to the United States. EXPLANATION OF RECORDS The surface- and ground-water records published in this report are for the 1997 water year that began October 1, 1996 and ended September 30, 1997. A calendar of the water year is provided on the inside of the front cover. The records contain streamflow data, water-quality data for surface and ground water, and ground-water-level data. The locations of the stations and wells where the data were collected are shown in figures 3 to 10. The following sections of the introductory text are presented to provide users with a more detailed explanation of how the hydrologic data published in this report were collected, analyzed, computed, and arranged for presentation. 10 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Station Identification Numbers Each data station, whether streamsite or well, in this report is assigned a unique identification number. This number is unique in that it applies specifically to a given station and to no other. The number usually is assigned when a station is first established and is retained for that station indefinitely. The systems used by the U.S. Geological Survey to assign identification numbers for surface-water stations and for ground-water well sites differ, but both are based on geographic location. The "downstream order" system is used for regular surface-water stations and the "latitude-longitude" system is used for wells. Downstream Order System Since October 1, 1950, the order of listing hydrologic-station records in Survey reports is in a downstream direction along the main stream. All stations on a tributary entering upstream from a main-stream station are listed before that station. A station on a tributary that enters between two main-stream stations is listed between them. A similar order is followed in listing stations in first rank, second rank, and other ranks of tributaries. As an added means of identification, each hydrologic station and partial-record station has been assigned a station number. These are in the same downstream order used in this report. In assigning station numbers, no distinction is made between partial-record stations and other stations; therefore, the station number for a partial-record station indicates downstream order position in a list made up of both types of stations that may be established; hence, the numbers are not consecutive. The complete 8-digit number for each station such as 50028000, which appears just to the left of the station name, includes the 2-digit part number "50" plus the 6-digit downstream order number "028000." Latitude-Longitude System The 8-digit downstream order station numbers are not assigned to wells and miscellaneous sites where only random water-quality samples or discharge measurements are taken. The well and miscellaneous site numbering system of the U.S. Geological Survey is based on the grid system of latitude and longitude. The system provides the geographic location of the well or miscellaneous site and a unique number for each site. The number consists of 15 digits. The first 6 digits denote the degrees, minutes, and seconds of latitude, the next 7 digits denote degrees, minutes, and seconds of longitude, and the last 2 digits (assigned sequentially) identify the wells or other sites within a 1-second grid. The numbers shown in the grid correspond to the local numbers assigned to each well as visited in the field. An example is well 16 (fig. 11). 6? '15' GT'OO1 45' 30' 15' 66'dO' 45' !30' ATLANTIC OCEAN 18°30' 18°00' CARIBBEAN SEA EXPLANATION FECAL COUFORM • < 1000 • 1000-10,000 • 10,000-100,000 • 100,000-1,000,000 Figure 3.--Maximum concentration of fecal coliform bacteria at the water-quality sampling sites in Puerto Rico. 67'15' 67'00! 45' 30' 15' S6'00! 45' 65'30' 18*30' 15' 18'00* ATLANTIC OCEAN y^lr^ «* * ^ 10 20 30 KILOMETERS ! CARIBBEAN SEA 10 i 20 MILES EXPLANATION FECAL STREPTOCOCCI • < 1000 ^ 1000-10,000 V 10,000-100,000 ^ 100,000-1,000,000 Figure 4.--Maximum concentration of fecal streptococci bacteria at the water-quality sampling sites in Puerto Rico. 67'15' 67*00' 45' 30' 15' 86W 65'30V ATLANTIC OCEAN *f X 18*30' £ .^ 15' 18'OQ1 30 KILOMETERS f I 20 MILES CARIBBEAN SEA EXPLANATION A 0920 CONT1NOUS STREAMFLOW m STATION AND NUMBER 093045 LAKE-ELEVATION STATION • AND NUMBER 0564 DAILY SEDIMENT STATION ' AND NUMBER Figure 5.--Location of surface-water stations in Puerto Rico. 18*30' - 18"00! ATLANTIC OCEAN „«« ,*& , &<" -.•!*• ..a^ .i-,0 EXPLANATION QUALITY OF WATER STATIONS CARIBBEAN SEA BIOLOGICAL CHEMICAL oaso SEDIMENT (Daily) o9io SEDIMENT (Quaterty) Figure 6.--Location of water-quality stations in Puerto Rico. 67°15' 67*00' 45' 30' 15' 66*00' 45s 65*30' ATLANTIC OCEAN 18*30' Rio Cuiebring.s 1485 15' - 18 8760 7953 48750 895 047750 047810 0476 7598 043998 043950 10 20 KILOMETERS CARIBBEAN SEA 10 20 MILES EXPLANATION A LOW-FLOW PARTIAL-RECORD STATION 043850 STATION IDENTIFICATION NUMBER Figure 7.—Location of low-flow partial-record stations in northcentral Puerto Rico. (ft 67'15' 67*00' 45' 15' 66'00! 65'30' ATLANTIC OCEAN 18°30! 15' 18 V00' 10 20 10 ity»«fc> ^° 30 KILOMETERS CARIBBEAN SEA EXPLANATION 6 WELL AND WELL NUMBER 20 MILES Figure 8.--Location of ground-water stations in Puerto Rico. 17 65*G55 65W 64C50' 18*24' 18°20' 01234 KILOMETERS 01234 MILES 64"5G' 45' 64°4G! ST. JOHN 18"22' 18°18* 01234 KILOMETERS XV !!!!! ^ (___T__ |__T___| 0 1 2 3,4 MILES 45' 40' 64S35' ST. CROIX 17°45' 17S40S 012^4 KILOMETERS I 01234 MILES 3450 EXPLANATION SURFACE-WATER STATION AND NUMBER Figure 9.--Location of surface-water stations in the U.S. Virgin Islands. 18 65*G5! 18'24' 18a20' : — 65W 01234 KILOMETERS 64*50' 45! 64*40' ST. JOHN °22' 1818' 01234 KILOMETERS \ \ I \______ 0 1 2 3 , 4 MILES 64*50' 45! 64*35' ST. CROIX 17'45! 17"40! 01234 KILOMETERS EXPLANATION WELL AND WELL NUMBER 01234 MILES Figure 10.—Location of ground-water stations in the U.S. Virgin Islands. WATER RESOURCES DATA FOR PUERTO RICO AND THE ILS. VIRGIN ISLANDS, 1997 19 sr 10*0 *' — or— 10*00' I7»$J' — 134 a(| 131* \ v .'« /r •27 •74 C/ C COORDINATES FOR WELLS 27 (160160066474000) AND 74 (160136066471000) COORDINATES FOR WELLS 132 (160133066603300) AND 1S4 (160120066603200) COORDINATES FOR WELL 131 (160066066602700) COORDINATES FOR WELL 16 (176022066496600) Figure 11. --Grid shoving system for numbering veils and miscellaneous sites (latitude and longitude). Records of Stage and Water Discharge Records of stage and water discharge may be complete or partial. Complete records of discharge are those obtained using a continuous stage-recording device through which either instantaneous or mean daily discharges may be computed for any time, or any period of time, during the period of record. Complete records of lake or reservoir content, similarly, are those for which stage or content may be computed or estimated with reasonable accuracy for any time, or period of time. They may be obtained using a continuous stage-recording device, but need not be. Because daily mean discharges and end-of-day contents commonly are published for such stations, they are referred to as "daily stations." By contrast, partial records are obtained through discrete measurements without using a continuous stage-recording device and pertain only to a few flow characteristics, or perhaps only one. The nature of the partial record is indicated by table titles such as "Low-flow partial records." Records of miscellaneous discharge measurements or of measurements from special studies, such as low-flow seepage studies, may be considered as partial records, but they are presented separately in this type of report. Location of all complete-record stations for which data are given in this report are shown in figures 5 and 8. Data Collection and Computation The data obtained at a complete-record gaging station on a stream or canal consists of a continuous record of stage, individual measurements of discharge throughout a range of stages, and notations regarding factors that may affect the relationships between stage and discharge. These data, together with supplemental information, such as weather records, are used to compute daily discharges. The data obtained at a complete-record gaging station on a lake or reservoir consist of a record of stage and of notations regarding factors that may affect the relationship between stage and lake content. These data are used with stage-area and stage-capacity curves or tables to compute water-surface areas and lake storage. Continuous records of stage are obtained with analog recorders that trace continuous graphs of stage or with digital recorders that punch stage values on paper tapes at selected time intervals or electronic satellite data collector platforms that receive stage values at selected time intervals. Measurements of discharge are made with current meters using methods adapted by the Geological Survey as a result of experience accumulated since 1880. These methods are described in standard textbooks, in Water-Supply Paper 2175, and in U.S. Geological Survey Techniques of Water-Resources Investigations, Book 3, Chapter A6. 20 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 In computing discharge records, results of individual measurements are plotted against the corresponding stages, and stage-discharge relation curves are then constructed. From these curves, rating tables indicating the approximate discharge for any stage within the range of the measurements are prepared. If it is necessary to define extremes of discharge outside the range of the current-meter measurements, the curves are extended using: (1) logarithmic plotting; (2) velocity-area studies; (3) results of indirect measurements of peak discharge, such as slope-area or contracted-opening measurements, and computations of flow- over-dams or weirs; or (4) step-backwater techniques. Daily mean discharges are computed by applying the daily mean stages (gage heights) to the stage-discharge curves or tables. If the stage-discharge relation is subject to change because of frequent or continual change in the physical features that form the control, the daily mean discharge is determined by the shifting-control method, in which correction factors based on the individual discharge measurements and notes of the personnel making the measurements are applied to the gage heights before the discharges are determined from the curves or tables. This shifting-control method also is used if the stage-discharge relation is changed temporarily because of aquatic growth or debris on the control. At some stations the stage-discharge relation is affected by changing stage; at these stations the rate of change in stage is used as a factor in computing discharge. In computing records of lake or reservoir contents, it is necessary to have available from surveys, curves or tables defining the relationship of stage and contents. The application of stage to the stage-content curves or tables gives the contents from which daily, monthly or yearly changes then are determined. If the stage-content relationship changes because of deposition of sediment in a lake or reservoir, periodic surveys may be necessary to redefine it. Even when this is done, as time between the last survey increases, the contents computed may increase in error. Discharges over lake or reservoir spillways are computed from stage-discharge relationships much as other stream discharges are computed. For some gaging stations there are periods when no gage-height record is obtained, or the recorded gage height is so faulty that it cannot be used to compute daily discharge or contents. This happens when the recorder stops or otherwise fails to operate properly, intakes are plugged, the float is loose in the well, or for various other reasons. For such periods, the daily discharges are estimated from the recorded range in stage, previous or following record, discharge measurements, weather records, and comparison with other station records from the same or nearby basins. Likewise, daily contents may be estimated from operator's logs, previous or following record, inflow-outflow studies, and other information. Information explaining how estimated daily-discharge values are identified in station records is included in the next two sections, "Data Presentation" (REMARKS paragraph) and "Identifying Estimated Daily Discharge." Data Presentation Steamflow data in this report are presented in a new format that is considerably different from the format in data reports prior to the 1992 water year. The major changes are that statistical characteristics of discharge now appear in tabular summaries following the water-year data table and less information is provided in the text or station manuscript above the table. These changes represent the results of a pilot program to reformat the annual water-data report to meet current user needs and data preferences. The records published for each continuous-record surface-water discharge station (gaging station) now consist of four parts, the manuscript or station description; the data table of daily mean values of discharge for the current water year with summary data; a tabular statistical summary of monthly mean flow data for a designated period, by water year; and a summary statistics table that includes statistical data of annual, daily, and instantaneous flows as well as data pertaining to annual runoff, 7-day low-flow minimum, and flow duration. Station manuscript The manuscript provides, under various headings, descriptive information, such as station location; period of record; historical extremes outside the period of record; record accuracy; and other remarks pertinent to station operation and regulation. The following information, as appropriate, is provided with each continuous record of discharge or lake content. Comments to follow clarify information presented under the various headings of the stations descriptions. LOCATION.—Information on locations is obtained from the most accurate maps available. The location of the gage with respect to the cultural and physical features in the vicinity and with respect to the reference place mentioned in the station name is given. 21 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DRAINAGE AREA.-Drainage areas are measured using the most accurate maps available. Drainage areas are updated as better maps become available. PERIOD OF RECORD.--This indicates the period for which there are published records for the station or for an equivalent station. An equivalent station is one that was in operation at a time that the present station was not, and whose location was such that records from it can reasonable be considered equivalent with records from the present station. REVISED RECORDS.-Because of new information, published records occasionally are found to be incorrect, and revisions are printed in later reports. Listed under this heading are all the reports in which revisions have been published for the station and the water years to which the revisions apply. If a revision did not include daily, monthly, or annual figures of discharge, that fact is noted after the year dates as follows: "(M)" means that only the instantaneous maximum discharge was revised; "(m)" that only the instantaneous minimum was revised; and "(P)" that only peak discharges were revised. If the drainage area has been revised, the report in which the most recently revised figure was first published is given. GAGE.—The type of gage in current use, the datum of the current gage, and a condensed history of the types, locations, and datums of previous gages are given under this heading. REMARKS.—All periods of estimated daily-discharge record will either be identified by date in this paragraph of the station description for water-discharge stations or flagged in the daily-discharge table. (See next section, "Identifying Estimated Daily Discharge.") If a remarks statement is used to identify estimated record, the paragraph will begin with this information presented as the first entry. The paragraph is also used to present information relative to the accuracy of the records, to special methods of computations, to conditions that affect natural flow at the station and, possibly, to other pertinent items. For reservoir stations, information is given on the dam forming the reservoir, the capacity, outlet works and spillway, and purpose and use of the reservoir. COOPERATION.-Records provided by a cooperating organization or obtained for the Geological Survey by a cooperating organization are identified here. EXTREMES OUTSIDE PERIOD OF RECORD.-Included here is information concerning major floods or unusually low flows that occurred outside the stated period of record. The information may or may not have been obtained by the U.S. Geological Survey. REVISIONS.--If a critical error in published records is discovered, a revision is included in the first report published following discovery of the error. Although rare, occasionally the records of a discontinued gaging station may need revision. Because, for these stations, there would be no current or, possibly, future station manuscript published to document the revision in a "Revised Records" entry, users of data for these stations who obtained the record from previously published data reports may wish to contact the District office to determine if the published records were ever revised after the station was discontinued. Of course, if the data were obtained by computer retrieval, the data would be current and there would be no need to check because any published revision of data is always accompanied by revision of the corresponding data in computer storage. Manuscript information for lake or reservoir stations differs from that for stream stations in the nature of the "Remarks" and in the inclusion of a skeleton stage-capacity table when daily contents are given. Data table of daily mean value The daily table of discharge records for stream-gaging stations gives mean discharge for each day of the water year. In the monthly summary for the table, the line headed "TOTAL" gives the sum of the daily figures for each month; the line headed "MEAN" gives the average flow in cubic feet per second for the month; and the lines headed "MAX" and "MIN" give the maximum and minimum daily mean discharges, respectively, for each month. Discharge for the month also is usually expressed in cubic feet per second per square mile (line headed "CFSM"); or in inches (line headed "IN"); or in acre-feet (line headed" AC- FT"). Figures for cubic feet per second per square mile and runoff in inches or in acre-feet may be omitted if there is extensive regulations or diversion or if the drainage area includes large noncontributing areas. 22 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Statistics of monthly mean data A tabular summary of the mean (line headed "MEAN"), maximum (line headed "MAX"), and minimum (line headed "MIN") of monthly mean flows for each month for a designated period is provided below the mean values table. The water years of the first occurrence of the maximum and minimum monthly flow are provided immediately below those figures. The designated period will be expressed as "FOR WATER YEARS - BY WATER YEAR (WY)," and will list the first and last water years of the range of years selected from the PERIOD OF RECORD paragraph in the station manuscript. It will consist of all of the station records within the specified water years, including complete months of record for partial water years, if any, and may coincide with the period of record for the station. The water years for which the statistics are computed will be consecutive, unless a break in the station record is indicated in the manuscript. Summary statistics A table titled "SUMMARY STATISTICS" follows the statistics of monthly mean data tabulation. This table consists of four columns, with the first column containing the line headings of the statistics being reported. The table provides a statistical summary of yearly, daily, and instantaneous flows, not only for the current water year but also for the previous calendar year and for a designated period, as appropriate. The designated period selected, "WATER YEARS __-____," will consist of all of the station records within the specified water years, inclusive, including complete months of record for partial water years, if any, and may coincide with the period of record for the station. The water years for which the statistics are computed will be consecutive, unless a break in the station record is indicated in the manuscript. All of the calculations for the statistical characteristics designated ANNUAL (see line headings below), except for the "ANNUAL 7-DAY MINIMUM" statistic, are calculated for the designated period using complete water years. The other statistical characteristics may be calculated using partial water years. The date or water year, as appropriate, of the first occurrence of each statistic reporting extreme values of discharge is provided adjacent to the statistic. Repeated occurrences may be noted in the REMARKS paragraph of the manuscript or in footnotes. Because the designated period may not be the same as the station period of record published in the manuscript, occasionally the dates of occurrence listed for die daily and instantaneous extremes in the designated-period column may not be within the selected water years listed in the heading. When this occurs, it will be noted in the REMARKS paragraph or in footnotes. Selected streamflow duration curve statistics and runoff data are also given. Runoff data may be omitted if there is extensive regulation or diversion of flow in the drainage basin. The following summary statistics data, as appropriate, are provided with each continuous record of discharge. Comments to follow clarify information presented under the various line headings of the summary statistics table. ANNUAL TOTAL.--The sum of the daily mean values of discharge for the year. At some stations the annual total discharge is adjusted for reservoir storage or diversion. The adjusted figures are identified by a symbol and corresponding footnotes. ANNUAL MEAN.~The arithmetic mean of the individual daily mean discharges for the year noted or for the designated period. At some stations the yearly mean discharge is adjusted for reservoir storage or diversion. The adjusted figures are identified by a symbol and corresponding footnotes. HIGHEST ANNUAL MEAN.-The maximum annual mean discharge occurring for the designated period. LOWEST ANNUAL MEAN.-The minimum annual mean discharge occurring for the designated period. HIGHEST DAILY MEAN.-The maximum daily mean discharge for the year or for the designated period. LOWEST DAILY MEAN.-The minimum daily mean discharge for the year or for the designated period. ANNUAL 7-DAY MINIMUM.-The lowest mean discharge for 7 consecutive days for a calendar year or a water year. Note that most low-flow frequency analyses of annual 7-day minimum flows use a climatic year (April 1 - March 31). The date shown in the summary statistics table is the initial date of the 7-day period. (This value should not be confused with the 7-day 10-year low-flow statistics). 23 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 INSTANTANEOUS PEAK FLOW.-The maximum instantaneous discharge occurring for the water year or for the designated period. Note that secondary instantaneous peak discharges above a selected base discharge are stored in District computer files for stations meeting certain criteria. Those discharge values may be obtained by writing to the District Office. (See address on back of the title page of this report.) INSTANTANEOUS PEAK STAGE.~The maximum instantaneous stage occurring for the water year or for the designated period. If the dates of occurrence for the instantaneous peak flow and instantaneous peak stage differ, the REMARKS paragraph in the manuscript or a footnote may be used to provide further information. INSTANTANEOUS LOW FLOW.--The minimum instantaneous discharge occurring for the water year or for the designated period. ANNUAL RUNOFF.-Indicates the total quantity of water in runoff for a drainage area for the year. Data reports may use any of the following units of measurements in presenting annual runoff data: Acre-foot (AC-FT) is the quantity of water required to cover 1 acre to a depth of 1 foot and is equivalent to 43,560 cubic feet or about 326,000 gallons or 1,233 cubic meters. Cubic feet per second per square mile (CFSM) is the average number of cubic feet of water flowing per second from each square mile of area drained, assuming the runoff is distributed uniformly in time and area. Inches (INCHES) indicates the depth to which the drainage area would be covered if all of the runoff for given time period were uniformly distributed on it. 10 PERCENT EXCEEDS.-The discharge that is exceeded 10 percent of the time for the designated period. 50 PERCENT EXCEEDS.--The discharge that is exceeded 50 percent of the time for the designated period. 90 PERCENT EXCEEDS.~The discharge that is exceeded 90 percent of the time for the designated period. Data collected at partial-record stations follow the information for continuous-record sites. Data for partial-record discharge stations are presented in a table of discharge measurements at low-flow partial-record stations. These measurements are generally made in times of drought to give better areal coverage to those events. Those measurements and others collected for some special reason are called measurements at miscellaneous sites. Identifying Estimated Daily Discharge Estimated daily-discharge values published in the water-discharge tables are identified by flagging individual daily values with the letter symbol "e" and printing a table footnote, "e Estimated." Accuracy of the Records The accuracy of streamflow records depends primarily on: (1) The stability of the stage-discharge relation or, if the control is unstable, the frequency of discharge measurements; and (2) the accuracy of measurements of stage, measurements of discharge, and interpretation of records. The accuracy attributed to the records is indicated under "REMARKS." "Excellent" means that about 95 percent of the daily discharges are within 5 percent of the true; "good," within 10 percent; and "fair," within 15 percent. Records that do not meet the criteria mentioned, are rated "poor." Different accuracies may be attributed to different parts of a given record. Daily mean discharges in this report are given to the nearest hundredth of a cubic foot per second for values less than 1 ft3/s; to the nearest tenth between 1.0 and 10 ft3/s; to whole numbers between 10 and 1,000 ft3/s; and to 3 significant figures for more than 1,000 ftVs. The number of significant figures used is based solely on the magnitude of the discharge value. The same rounding rules apply to discharges listed for partial-record stations and miscellaneous sites. 24 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Information used in the preparation of the records in this publication, such as discharge-measurement notes, gage- height records, temperature measurements, and rating tables are on file in the Caribbean District office. Also, most of the daily mean discharges are in computer-readable form and have been analyzed statistically. Information on the availability of the unpublished information or on the results of statistical analyses of the published records may be obtained from the District office. Records of Surface-Water Quality Records of surface-water quality ordinarily are obtained at or near stream-gaging stations because interpretation of records of surface-water quality nearly always requires corresponding discharge data. Records of surface-water quality in this report may involve a variety of types of data and measurement frequencies. Classification of Records Water-quality data for surface-water sites are grouped into one of three classifications. A continuing-record station is a site where data are collected on a regularly scheduled basis. Frequency may be once or more times daily, weekly, monthly, or quarterly. A partial-record station is a site where limited water-quality data are collected systematically over a period of years. Frequency of sampling is usually less than quarterly. A miscellaneous sampling site is a location other than a continuing or partial-record station, where random samples are collected to give better areal coverage to define water-quality conditions in the river basin. A careful distinction needs to be made between "continuing records" as used in this report and "continuous recordings," which refers to a continuous graph or a series of discrete values punched at short intervals on a paper tape. Some records of water quality, such as temperature and specific conductance, may be obtained through continuous recordings; however, because of costs, most data are obtained only monthly or less frequently. Locations of stations for which records on the quality of surface water appear in this report are shown in figure 6. Arrangement of Records Water-quality records collected at a surface-water daily record station are published immediately following that record, regardless of the frequency of sample collection. Station number and name are the same for both records. Where a surface-water daily record station is not available or where the water quality differs significantly from that at the nearby surface-water station, the continuing water-quality record is published with its own station number and name in the regular downstream-order sequence. Water-quality data for partial-record stations and for miscellaneous sampling sites appear in separate tables following the table of discharge measurement at miscellaneous sites. On-site Measurements and Sample Collection In obtaining water-quality data, a major concern needs to be assuring that the data obtained represent the in situ quality of the water. To assure this, certain measurements, such as water temperature, pH, and dissolved oxygen, need to be made onsite when the samples are taken. To assure that measurements made in the laboratory also represent the in situ water, carefully prescribed procedures need to be followed in collecting the samples, in treating the samples to prevent changes in quality pending analysis, and in shipping the samples to the laboratory. Procedures for onsite measurements and for collecting, treating, and shipping samples are given in publications on "Techniques of Water-Resources Investigations," Book 1, Chap. D2; Book 3, Chap. C2; Book 5, Chap. Al, A3, and A4. Detailed information on collecting, treating, and shipping samples may be obtained from the Geological Survey District office. One sample can define adequately the water quality at a given time if the mixture of solutes throughout the stream cross section is homogeneous. However, the concentration of solutes at different locations in the cross section may vary widely with different rates of water discharge, depending on the source of material and the turbulence and mixing of the stream. Some streams must be sampled through several vertical sections to obtain a representative sample needed for an accurate mean concentration and for use in calculating load. All samples obtained for the National Stream Quality Accounting Network (see definitions) are obtained from at least several verticals. Whether samples are obtained from the centroid of flow or from several verticals, depends on flow conditions and other factors which must be evaluated by the collector. 25 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Chemical-quality data published in this report are considered to be the most representative values available for the stations listed. The values reported represent water-quality conditions at the time of sampling as much as possible, consistent with available sampling techniques and methods of analysis. In the rare case where an apparent inconsistency exists between a reported pH value and the relative abundance of carbon dioxide species (carbonate and bicarbonate), the inconsistency is the result of a slight uptake of carbon dioxide from the air by the sample between measurement of pH in the field and determination of carbonate and bicarbonate in the laboratory. For chemical-quality stations equipped with digital monitors, the records consist of daily maximum, minimum, and mean values for each constituent measured and are based upon hourly punches beginning at 0100 hours and ending at 2400 hours for the day of record. More detailed records, when available, (hourly values) may be obtained from the U.S.G.S. District office whose address is given on the back of the title page of this report. Water Temperature Water temperatures are measured at most of the water-quality stations. In addition, water temperatures are taken at time of discharge measurements for water-discharge stations. For stations where water temperatures are taken manually once or twice daily, the water temperatures are taken at about the same time each day. Large streams have a small diurnal temperature change; shallow streams may have a daily range of several degrees and may follow closely the changes in air temperature. Some streams may be affected by waste-heat discharges. At stations where recording instruments are used, either mean temperatures or maximum and minimum temperatures for each day are published. Water temperatures measured at the time of water-discharge measurements are on file in the District office. Sediment Suspended-sediment concentrations are determined from samples collected by using depth-integrating and pumping sediment samplers. Samples usually are obtained at several verticals in the cross section, or a single sample may be obtained at a fixed point and a coefficient applied to determine the mean concentration in the cross sections. During periods of rapidly changing flow or rapidly changing concentration, samples may have been collected more frequently (twice daily or hourly). The published sediment discharges for days of rapidly changing flow or concentration were computed by the subdivided-day method (time-discharge weighted average). Therefore, for those days when the published sediment discharge value differs from the value computed as the product of discharge times mean concentration times 0.0027, the reader can assume that the sediment discharge for that day was computed by the subdivided-day method. For periods when no samples were collected, daily discharges of suspended sediment were estimated on the basis of water discharge, sediment concentrations observed immediately before and after the periods, suspended-sediment loads for other periods of similar discharge, and computed by the subdivided-day method using the transport curves. At other stations, suspended-sediment samples were collected periodically at many verticals in the stream cross section. Although data collected periodically may represent conditions only at the time of observations, such data are useful in establishing seasonal relations between quality and streamflow and in predicting long-term sediment-discharge characteristics of the stream. In addition to the records of suspended-sediment discharge, records of the periodic measurements of the particle-size distribution of the suspended sediment are included for some stations. Laboratory Measurements Sediment samples, samples for biochemical-oxygen demand (BOD), samples for indicator bacteria, and daily samples for specific conductance are analyzed locally. All other samples are analyzed in the Geological Survey laboratories in Denver, Co. or Ocala, Fla. Methods used in analyzing sediment samples and computing sediment records are given in TWRI, Book 5, Chap. Cl. Methods used by the Geological Survey laboratories are given in TWRI, Book 1, Chap. D2; Book 3, Chap. C2; Book 5, Chap. Al, A3, and A4. 26 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Presentation For continuing-record stations, information pertinent to the history of station operation is provided in descriptive headings preceding the tabular data. These descriptive headings give details regarding location, drainage area, period of record, type of data available, instrumentation, general remarks, cooperation, and extremes for parameters currently measured daily. Tables of chemical, physical, biological, radiochemical data, and so forth, obtained at a frequency less than daily are presented first, and tables of "daily values" of specific conductance, pH, water temperature, dissolved oxygen, and suspended sediment then follow in sequence, when these parameters are studied. In the descriptive headings, if the location is identical to that of the discharge gaging station, neither the LOCATION nor the DRAINAGE AREA statements are repeated. The following information, as appropriate, is provided with each continuous-record station. Comments that follow clarify information presented under the various headings of the station description. LOCATION.~See Data Presentation under "Records of Stage and Water Discharge;" same comments apply. DRAINAGE AREA.-See Data Presentation under "Records of Stage and Water Discharge;" same comments apply. PERIOD OF RECORD.-This indicates the periods for which there are published water-quality records for the station. The periods are shown separately for records of parameters measured daily or continuously and those measured less than daily. For those measured daily or continuously, periods of record are given for the parameters individually. INSTRUMENTATION.-Information on instrumentation is given only if a water-quality monitor temperature record, sediment pumping sampler, or other sampling device is in operation at a station. REMARKS.-Remarks provide added information pertinent to the collection, analysis, or computation of the records. COOPERATION.-Records provided by a cooperating organization or obtained for the Geological Survey by a cooperating organization are identified here. EXTREMES.—Maximums and minimums are given only for parameters measured daily or more frequently. None are given for parameters measured weekly or less frequently, because the true maximums or minimums may not have been sampled. Extremes, when given, are provided for both the period of record and for the current water year. REVISIONS.~If errors in published water-quality records are discovered after publication, appropriate updates are made to the Water-Quality File in the U.S. Geological Survey's computerized data system, WATSTORE, and subsequently by monthly transfer of update transactions to the U.S. Environmental Protection Agency's STORET system. Because the usual volume of updates makes it impractical to document individual changes in the State data-report series or elsewhere, potential users of U.S. Geological Survey water-quality data are encouraged to obtain all required data from the appropriate computer file to insure the most recent updates. The surface-water-quality records for partial-record stations and miscellaneous sampling sites are published in separate tables following the table of discharge measurements at miscellaneous sites. No descriptive statements are given for these records. Each station is published with its own station number and name in the regular downstream-order sequence. 27 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Remark Codes The following remark codes may appear with the water-quality data in this report: PRINTED OUTPUT REMARK E Estimated value > Actual value is known to be greater than the value shown < Actual value is known to be less than the value shown K Results based on colony count outside the acceptance range (non-ideal colony count) L Biological organism count less than 0.5 percent (organism may be observed rather than counted) D Biological organism count equal to or greater than 15 percent (dominant) & Biological organism estimated as dominant Records of Ground-Water Levels Only ground-water level data from a basic network of observation wells are published herein. This basic network contains observation wells so located that the most significant data are obtained from the fewest wells in the most important aquifers. Data Collection and Computation Measurements of water levels are made in many types of wells under varying conditions, but the methods of measurement are standardized to the extent possible. The equipment and measuring techniques used at each observation well ensure that measurements at each well are of consistent accuracy and reliability. Each well is identified by means of (1) a 15-digit number that is based on latitude and longitude and (2) a local number that is provided for local needs. See figure 10. Water-level records are obtained from direct measurements with a steel tape or from the graph or punched tape of a water-stage recorder. The water-level measurements in this report are given in feet with reference to land-surface datum (Isd). Land-surface datum is a datum plane that is approximately at land surface at each well. If known, the elevation of the land- surface datum is given in the well description. The height of the measuring point (MP) above or below land-surface datum is given in each well description. Water levels in wells equipped with recording gages are reported for every day and as an instantaneous observation at noon. Water levels are reported to as many significant figures as can be justified by the local conditions. For example, in a measurement of a depth to water of several hundred feet, the error of determining the absolute value of the total depth to water may be a few tenths of a foot, whereas the error in determining the net change of water level between successive measurements may be only a hundredth of a few hundredths of a foot. For lesser depths to water, the accuracy is greater. Accordingly, most measurements reported to a hundredth of a foot, but some are given to a tenth of a foot or a larger unit. 28 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Presentation Each well record consists of three parts, the station description, the data table of water levels observed during the water year and a graph of the water levels for the current water year and other selected period. The description of the well is presented first through use of descriptive headings preceding the tabular data. The comments to follow clarify information presented under the various headings of the well description. LOCATION.-This paragraph follows the well-identification number and reports the latitude and longitude (given in degrees, minutes, and seconds); a landline location designation; the hydrologic-unit number; the distance and direction from a geographic point of reference; and the owner's name. AQUIFER.—This entry designates by name (if a name exists) and geologic age the aquifer(s) open to the well. WELL CHARACTERISTICS.--This entry describes the well in terms of depth, diameter, casing depth and/or screened interval, method of construction, use, and additional information such as casing breaks, collapsed screen, and other changes since construction. INSTRUMENTATION.-This paragraph provides information on both the frequency of measurment and the collection method used, allowing the user to better evaluate the reported water-level extremes by knowing whether they are based on weekly, monthly, or some other frequency of measurement. DATUM.—This entry describes both the measuring point and the land-surface elevation at the well. The measuring point is described physically (such as top of collar, notch in top of casing, plug in pump base and so on), and in relation to land surface (such as 1.3 ft above land-surface datum). The elevation of the land-surface datum is described in feet above (or below) sea level; it is reported with a precision depending on the method of determination. REMARKS.—This entry describes factors that may influence the water level in a well or the measurement of the water level. It should identify wells that also are water-quality observation wells, and may be used to acknowledge the assistance of local (non-Survey) observers. PERIOD OF RECORD.-This entry indicates the period for which there are published records for the well. It reports the month and year of the start of publication of water-level records by the U.S. Geological Survey and the words "to current year" if the records are to be continued into the following year. Periods for which water-level records are available, but are not published by the Geological Survey, may be noted. EXTREMES FOR PERIOD OF RECORD.-This entry contains the highest and lowest water levels of the period of published record, with respect to land-surface datum, and the dates of their occurrence. A table of water levels follows the station description for each well. Water levels are reported in feet below land- surface datum and all taped measurements of water level are listed. For wells equipped with recorders, daily values tables are published for the instantaneous water-level observation at noon. The highest and lowest water levels of the water year and their dates of occurrence are shown on a line below the table. Because all values are not published for wells with recorders, the extremes may be values that are not listed in the table. Missing records are indicated by dashes in place of the water level. A hydrograph for a selected period of record follows each water-level table. Records of Ground-Water Quality Records of ground-water quality in this type of report differ from other types of records in that for most sampling sites they consist of only one set of measurements for the water year. The quality of ground water ordinarily changes only slowly; therefore, for most general purposes one annual sampling, or only a few samples taken at infrequent intervals during the year, is sufficient. Frequent measurement of the same constituents is not necessary unless one is concerned with a particular problem, such as monitoring for trends in nitrate concentration. In the special cases where the quality of ground water may change more rapidly, more frequent measurements are made to identify the nature of the changes. 29 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Data Collection and Computation The records of ground-water quality in this report were obtained mostly as a part of special studies in specific areas. Consequently, a number of chemical analyses are presented for some counties but none are presented for others. As a result, the records for this year, by themselves, do not provide a balanced view of ground-water quality Statewide. Such a view can be attained only by considering records for this year in context with similar records obtained for these and other counties in earlier years. Most methods for collecting and analyzing water samples are described in the "U.S. Geological Survey Techniques of Water-Resources Investigations" manuals listed on a following page. The values reported in this type of report represent water- quality conditions at the time of sampling as much as possible, consistent with available sampling techniques and methods of analysis. All samples are obtained by trained personnel. The wells sampled are pumped long enough to assure that the water collected comes directly from the aquifer and has not stood for a long time in the well casing where it would have been exposed to the atmosphere and to the material, possibly metal, comprising the casings. Data Presentation The records of ground-water quality, when available, are published in a section titled QUALITY OF GROUND WATER immediately following the ground-water level records. Data for quality of ground water are listed alphabetically by County, and are identified by well number. The prime identification number for wells sampled is the 15-digit number derived from the latitude-longitude locations. No descriptive statements are given for ground-water-quality records; however, the well number, depth of well, date of sampling, and other pertinent data are given in the table containing the chemical analyses of the ground water. The REMARK codes listed for surface-water-quality records are also applicable to ground-water-quality records. ACCESS TO U.S. GEOLOGICAL SURVEY WATER DATA The U.S. Geological Survey provides near real-time stage and discharge data for many of the gaging stations equipped with the necessary telemetry and historic daily-mean and peak-flow discharge data for most current or discontinued gaging stations through the world wide web (WWW). These data may be accessed at http://water.usgs.gov Some water-quality and ground-water data also are available through the WWW. In addition, data can be provided in various machine-readable formats on magnetic tape or 3-1/2 inch floppy disk. Information about the availability of specific types of data or products, and user charges, can be obtained locally from each of the Water Resources Division District Offices (see address on the back of the title page). 30 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 DEFINITION OF TERMS Terms related to streamflow, water-quality, and other hydrologic data as used in this report, are defined below. See also the table for converting inch- pound units to the International System of units (SI) on the inside of the back cover. Acre-foot (AC-FT, acre-ft) is the quantity of water required to cover 1 acre to a depth of 1 foot and is equal to about 326,000 gallons or 1,233 cubic meters. Adenosine triphosphate (ATP) is an organic, phosphate-rich, compound important in the transfer of energy in organisms. Its central role in living cells makes it an excellent indicator of the presence of living material in water. A measure of ATP therefore provides a sensitive and rapid estimate of biomass. ATP is reported in micrograms per liter of the original water sample. Algae growth potential (AGP) is the maximum algal dry weight biomass that can be produced in a natural water sample under standardized laboratory conditions. The growth potential is the algal biomass present a stationary phase and is expressed as milligrams dry weight of algae produced per liter of sample. Aquifer is a geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs. Artesian means confined and is used to describe a well in which the water level stands above the top of the aquifer, tapped by the well. A flowing artesian well is one in which the water level is above the land surface. Bacteria are microscopic unicellular organisms, typically spherical, rodlike, or spiral and threadlike in shape, often clumped into colonies. Some bacteria cause disease, while others perform an essential role in nature in the recycling of materials; for example, by decomposing organic matter into a form available for reuse by plants. Total coliform bacteria are a particular group of bacteria that are used as indicators of possible sewage pollution. They are characterized as aerobic or facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria which ferment lactose with gas formation within 48 hours at 35 °C. In the laboratory these bacteria are defined as all the organisms which produce colonies with a golden-green metallic sheen within 24 hours when incubated at 35°C ± 1.0°C on M-Endo medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. 31 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Fecal coliform bacteria are bacteria that are present in the intestines or feces of warm-blooded animals. They are often used as indicators of the sanitary quality of the water. In the laboratory they are defined as all organisms which produce blue colonies within 24 hours when incubated at 44.5°C ± 0.2'C on M-FC medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. Fecal streptococcal bacteria are bacteria found also in intestines of warm-blooded animals. Their presence in water is considered to verify fecal pollution. They are characterized as Gram-positive, cocci bacteria which are capable of growth in brain-heart infusion broth. In the laboratory they are defined as all the organisms which produce red or pink colonies within 48 hours at 35'C ± 1.0'C on KF-streptococcus medium (nutrient medium for bacterial growth). Their concentrations are expressed as number of colonies per 100 mL of sample. Bed material is the unconsolidated material of which a streambed, lake, pond, reservoir, or estuary bottom is composed. Biochemical oxygen demand (BOD) is a measure of the quantity of dissolved oxygen, in milligrams per liter, necessary for the decomposition of organic matter by microorganisms, such as bacteria. Biomass is the amount of living matter present at any given time, expressed as the mass per unit area or volume of habitat. Ash mass is the mass or amount of residue present after the residue from the dry mass determination has been ashed in a muffle furnace at a temperature of 500'C for 1 hour. The ash mass values of zooplankton and phytoplankton are expressed in grams per cubic meter (g/m3), and periphyton and benthic organisms in grams per square meter (g/m2). Dry mass refers to the mass of residue present after drying in an oven at 105°C for zooplankton and periphyton, until the mass remains unchanged. This mass represents the total organic matter, ash and sediment, in the sample. Dry-mass values are expressed in the same units as ash mass. Organic mass or volatile mass of the living substance is the difference between the dry mass and the ash mass and represents the actual matter. The organic mass is expressed in the same units as for ash and dry mass. Wet mass is the mass of living matter plus contained water. Bottom material: See Bed material. Cells/volume refers to the number of cells of any organism which is counted by using a microscope and grid or counting cell. Many planktonic organisms are multicelled and are counted according to the number of contained cells per sample, usually milliliters (mL) or liters (L). Chemical oxygen demand (COD) is a measure of the chemically oxidizable material in the water, and furnishes an approximation of the amount of organic and reducing material present. The determined value may correlate with natural water color or with carbonaceous organic pollution from sewage or industrial wastes. Chlorophyll refers to the green pigments of plants. Chlorophyll a and fe are the two most common green pigments in plants. Color unit is produced by one milligram per liter of platinum in the form of the chloroplatinate ion. Color is expressed in units of the platinum-cobalt scale. Contents is the volume of water in a reservoir or lake. Unless otherwise indicated, volume is computed on the basis of a level pool and does not include bank storage. 32 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Control designates a feature downstream from the gage that determines the stage-discharge relation at the gage. This feature may be a natural constriction of the channel, an artificial structure, or a uniform cross section over a long reach of the channel. Control structure as used in this report is a structure on a stream or canal that is used to regulate the flow or stage of the stream or to prevent the intrusion of salt water. Cubic foot per second (ft3/s) is the rate of discharge representing a volume of 1 cubic foot passing a given point during 1 second and is equivalent to 7.48 gallons per second or 448.8 gallons per minute or 0.02832 cubic meters per second. Cubic foot per second-day (ft3/s/day) is the volume of water represented by a flow of 1 cubic foot per second for 24 hours. It is equivalent to 86,400 cubic feet, approximately 1.9835 acre-feet, about 646,000 gallons, or 2,445 cubic meters. Cubic feet per second per square mile (CFSM) is the average number of cubic feet of water flowing per second from each square mile of area drained, assuming that the runoff is distributed uniformly in time and area. Discharge is the volume of water (or more broadly, volume of fluid plus suspended sediment), that passes a given point within a given period of time. Instantaneous discharge is the discharge at a particular instant of time. Mean discharge (MEAN) is the arithmetic mean of individual daily mean discharges during a specific period. Annual 7-day minimum is the lowest mean discharge for 7 consecutive days for a calendar year or a water year. Note that most low-flow frequency analyses of annual 7-day minimum flows use a climatic year (April 1 - March 31). The date shown in the summary statistics table is the initial date of the 7-day period. (This value should not be confused with the 7-day 10-year low-flow statistic.) Dissolved refers to that material in a representative water sample which passes through a 0.45 um membrane filter. This is a convenient operational definition used by Federal agencies that collect water data. Determinations of "dissolved" constituents are made on subsamples of the filtrate. Dissolved-solids concentration of water is determined either analytically by the "residue-on-evaporation" method, or mathematically by totaling the concentrations of individual constituents reported in a comprehensive chemical analysis. During the analytical determination of dissolved solids, the bicarbonate (generally a major dissolved component of water) is converted to carbonate. Therefore, in the mathematical calculations of dissolved-solids concentration, the bicarbonate value, in milligrams per liter, is multiplied by 0.492 to reflect the change. Diversity index is a numerical expression of evenness of distribution of aquatic organisms. The formula for diversity index is: __ s d = -111og2 1 n n Where ni is the number of individuals per taxon, n is the total number of individuals, and s is the total number of taxa in the sample of the community. Diversity index values range from zero, when all the organisms in the sample are the same, to some positive number, when some or all of the organisms in the sample are different. Drainage area of a stream at a specified location is that area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream above the specified point. Figures of drainage area given herein include all closed basins, or noncontribution areas, within the area unless otherwise noted. 33 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Drainage basin is a part of the surface of the earth that is occupied by a drainage system, which consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water. Gage height (gh) is the water-surface elevation referred to some arbitrary gage datum. Gage height is often used interchangeably with the more general term "stage," although gage height is more appropriate when used with a reading on a gage. Gaging station is a particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained. Ground-water station is a well at which observations of ground-water level are made, either continuously by recorder, or periodically by hand. In addition, various chemical or physical parameters may be obtained, usually on a periodic basis. Hardness of water is a physical-chemical characteristic that is commonly recognized by the increased quantity of soap required to produce lather. It is attributable to the presence of alkaline earths (principally calcium and magnesium) and is expressed as equivalent calcium carbonate (CaCO3). Hydrologic Bench-Mark Network is a network in small drainage basins around the country whose purpose is to provide consistent data on the hydrology, including water quality, and related factors in representative undeveloped watersheds nationwide, and to provide analyses on a continuing basis to compare and contrast conditions observed in basins more obviously affected by the activities of man. Hydrologic unit is a geographic area representing part or all of a surface drainage basin or distinct hydrologic feature as delineated by the Office of Water Data Coordination on the State Hydrologic Unit Maps; each hydrologic unit is identified by an eight-digit number. Land-surface datum (LSD) is a datum plane that is approximately at land surface at each ground-water observation well. Measuring point (MP) is an arbitrary permanent reference point from which the distance to the water surface in a well is measured to obtain the water level. Metamorphic stage refers to the stage of development that an organism exhibits during its transformation from an immature form to an adult form. This developmental process exists for most insects, and the degree of difference from the immature stage to the adult form varies from relatively slight to pronounced, with many intermediates. Examples of metamorphic stages of insects are egg-larva-adult or egg-nymph-adult. Methylene blue active substances (MBAS) are apparent detergents. The determination depends on the formation of a blue color when methylene blue dye reacts with synthetic anionic detergent compounds. Micrograms per gram (fig/g) is a unit expressing the concentration of a chemical element as the mass (micrograms) of the element per unit mass (gram) of material analyzed. Micrograms per liter (fiG/L, ug/L) is a unit expressing the concentration of chemical constituents in solution as mass (micrograms) of solute per unit volume (liter) of water. One thousand micrograms per liter is equivalent to one milligram per liter. Milligrams per liter (MG/L, mg/L) is a unit for expressing the concentration of chemical constituents in solution. Milligrams per liter represent the mass of solute per unit volume (liter) of water. Concentration of suspended sediment also is expressed in mg/L, and is based on the mass of sediment per liter of water-sediment mixture. Conversion of chemical concentrations in Mg/L to milliequivalents per liter can be done by using the factors in table 6. 3 4 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Table 5. Factors for conversion of chemical constituents in milligrams per liter to milliequivalents per liter Ion Multiply by Ion Multiply bv Aluminum (Al+3)* ................ Ammonia as NH4+1 .............. Barium (Ba+2) ....................... Bicarbonate (HCO3-1)........... Bromide (Br-1)....................... Calcium (Ca+2)...................... Carbonate (CO3-2)................. Chloride(Cl-l)....................... Chromium (Cr+6)* ................ Cobalt (Co+2)* ...................... Copper (Cu+2)* ..................... Cyanide(CN-l)...................... Fluoride(F-l)......................... Hydrogen (H+l)..................... Hydroxide (OH-1).................. 0.11119 .05544 .01456 .01639 .01251 .04990 .03333 .02821 .11539 .03394 .03148 .03844 .05264 .99209 .05880 Iodide (1-1 .............................. Iron (Fe+3) ............................. Lead (Pb+2) ........................... Lithium (Li+1) ....................... Magnesium (Mg+2) ............... Manganese (Mn+2)*.. ............ Nickel (Ni+2). ....... ................. Nitrate (N03-1)....................... Nitrite (NO2-1 )...................... Phosphate (PO4-3). ................ Potassium (K+l) .................... Sodium (NA+1). .................... Strontium (Sr+2) .................... Sulfate (SO4-2). ................. .... Zinc (Zn+2)*. ......................... 0.00788 .05372 .00965 .14411 .08226 .03640 .03406 .01613 .02174 .03159 .02557 .04350 .02283 .02082 .03060 "Constituent reported in micrograms per liter; multiply by factor and divide results by 1,000. National Stream Quality Accounting Network (NASQAN) is a nationwide data-collection network designed by the U.S. Geological Survey to meet many of the information needs of government agencies and other groups involved in natural or regional water-quality planning and management. The 500 or so sites in NASQAN are generally located at the downstream ends of hydrologic accounting units designated by the U.S. Geological Survey office of Water Data Coordination in consultation with the Water Resources Council. The objectives of NASQAN are (1) to obtain information on the quality and quantity of water moving within and from the United States through a systematic and uniform process of data collection, summarization, analysis, and reporting such that the data may be used for, (2) description of the areal variability of water quality in the Nation's rivers through analysis of description of the areal variability of water quality in the Nation's rivers through analysis of data from this and other programs, (3) detection of changes or trends with time in the pattern of occurrence of water-quality characteristics, and (4) providing a nationally consistent data base useful for water-quality assessment and hydrologic research. National Trends Network (NTN) is a network for sampling atmospheric deposition in the United States. The purpose of the network is to determine the variability, both in location and in time, of the composition of atmospheric deposition, which includes snow, rain, dust particles, aerosols, and gases. The core from which the NTN was built was the already-existing deposition-monitoring network of the National Atmospheric Deposition Program (NADP). Organism is any living entity. Organism count/area refers to the number of organisms collected and enumerated in a sample and adjusted to the number per unit area habitat, usually square meters (m2), acres, or hectare. Periphyton, benthic organisms, and macrophytes are expressed in these terms. Organism count/volume refers to the number of organisms collected and enumerated in a sample and adjusted to the number per sample volume, usually milliliters (mL) or liters (L). Numbers of planktonic organisms can beexpressed in these terms. Total organism count is the total number of organisms collected and enumerated in any particular sample. Parameter Code is a 5-digit number used in the U.S. Geological Survey computerized data system, WATSTORE, to uniquely identify a specific constituent. The codes used in WATSTORE are the same as those used in the U.S. Environmental Protection Agency data system, STORET. The Environmental Protection Agency assigns and approves all requests for new codes. Partial-record station is a particular site where limited streamflow and/or water-quality data are collected systematically over a period of years for use in hydrologic analyses. 35 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Particle-size is the diameter, in millimeters (mm), of a particle determined by either sieve or sedimentation methods. Sedimentation methods (pipet, bottom-withdrawal tube, visual-accumulation tube) determine fall diameter of particles in either distilled water (chemically dispersed) or in native water (the river water at the time and point of sampling). Particle-size classification used in this report agrees with recommendations made by the American Geophysical Union Subcommittee on Sediment Terminology. The classification is as follows: Classification Size (mm) Method of analysis Clay...... 0.00024 - 0.004 Sedimentation Silt...... .004 - .062 Sedimentation Sand...... .062 - 2.0 Sedimentation or sieve Gravel.... 2.0 -64.0 Sieve The particle-size distributions given in this report are not necessarily representative of all particles in transport in the stream. Most of the organic matter is removed and the sample is subjected to mechanical and chemical dispersion before analysis in distilled water. Chemical dispersion is not used for native water analysis. Percent composition is a unit for expressing the ratio of a particular part of a sample or population to the total sample or population, in terms of types, numbers, mass or volume. Periphyton is the assemblage of microorganisms attached to and living upon submerged solid surfaces. While primarily consisting of algae, they also include bacteria, fungi, protozoa, rotifers, and other small organisms. Pesticides are chemical compounds used to control undesirable organisms. Major categories of pesticides include insecticides, miticides, fungicides, herbicides, and rodenticides. Picocurie (PC, pCi) is one trillionth (1 X 10-12) of the amount of ratioactivity represented by a curie (Ci). A curie is the amount of radioactivity that yields 3.7 x 10'° radioactive disintegrations per second. A picocurie yields 2.22 dpm (disintegrations per minute). Plankton is the community of suspended, floating, or weakly swimming organisms that live in the open water of lakes and rivers. Phvtoplankton is the plant part of the plankton. They are usually microscopic and their movement is subject to the water currents. Phvtoplankton growth is dependent upon solar radiation and nutrient substances. Because they are able to incorporate as well as release materials to the surrounding water, the phytoplankton have a profound effect upon the quality of the water. They are the primary food producers in the aquatic environment, and are commonly known as algae. Blue-green algae are a group of phytoplankton organisms having a blue pigment, in addition to the green pigment called chlorophyll. Blue-green algae often cause nuisance conditions in water. Diatoms are the unicellular or colonial algae having a siliceous shell. Their concentrations are expressed as number of cells per milliliter (cells/mL) of sample. Green algae have chlorophyll pigments similar in color to those of higher green plants. Some forms produce algae mats or floating "moss" in lakes. Their concentrations are expressed as number of cells per milliliter (cells/mL) of sample. Zooplankton is the animal part of the plankton. Zooplankton are capable of extensive movements within the water column and are often large enough to be seen with the unaided eye. Zooplankton are secondary consumers feeding upon bacteria, phytoplankton, and detritus. Because they are the grazers in the aquatic environment, the zooplankton are a vital part of the aquatic food web. The zooplankton community is dominated by small crustaceans and rotifers. 36 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Primary productivity is a measure of the rate at which new organic matter is formed and accumulated through photosynthetic and chemosynthetic activity of producer organisms (chiefly, green plants). The rate of primary production is estimated by measuring the amount of oxygen released (oxygen method) or the amount of carbon assimilated by the plants (carbon method). Milligrams of carbon per area or volume per unit time f mg C/fm^.time)! for periphyton and macrophytes and [mg C/(m3.time)1 for phvtoplankton are units for expressing primary productivity. They define the amount of carbon dioxide consumed as measured by radioactive carbon (carbon 14). The carbon 14 method is of greater sensitivity than the oxygen light and dark bottle method, and is preferred for use in unenriched waters. Unit time may be either hour or day, depending on the incubation period. Milligrams of oxygen per area or volume per unit time fmgO / (rrAtime)] for periphyton and macrophytes and FmgO /(m3.time)1 for phvtoplankton are the units for expressing primary productivity. They define production and respiration rates as estimated from changes in the measured dissolved-oxygen concentration. The oxygen light and dark bottle method is preferred if the rate of primary production is sufficient for accurate measurements to be made within 24 hours. Unit time may be either the hour or day, depending on the incubation period. Polychlorinated biphenyls (PCBs) are industrial chemicals that are mixtures of chlorinated biphenyl compounds having various percentages of chlorine. They are similar in structure to organochlorine insecticides. Radiochemical program is a network of regularly sampled water-quality stations where samples are collected to be analyzed for radioisotypes. The streams that are sampled represent major drainage basins in the conterminous United States. Recoverable from bottom material is the amount of a given constituent that is in solution after a representative sample of bottom material has been digested by a method (usually using an acid or mixture of acids) that results in dissolution of readily soluble substances. Complete dissolution of all bottom material is not achieved by the digestion treatment and thus the determination represents less than the total amount (that is, less than 95 percent) of the constituent in the sample. To achieve comparability of analytical data, equivalent digestion procedures would be required of all laboratories performing such analyses because different digestion procedures are likely to produce different analytical results. Return period is the average time interval between occurrences of a hydrological event of a given or greater magnitude, usually expressed in years. May also be called recurrence interval. Runoff in inches (IN, in) shows the depth to which the drainage area would be covered if all the runoff for a given time period were uniformly distributed on it. Sediment is solid material that originates mostly from disintegrated rocks and is transported by, suspended in, or deposited from water; it includes chemical and biochemical precipitates and decomposed organic material, such as humus. The quantity, characteristics, and cause of the occurrence of sediment in streams are influenced by environmental factors. Some major factors are degree of slope, length of slope, soil characteristics, land usage, and quantity and intensity of precipitation. Bed load is the sediment that is transported in a stream by rolling, sliding, or skipping along the bed and very close to it. In this report, bed load is considered to consist of particles in transit within 0.25 ft of the streambed. Bed load discharge (tons per day) is the quantity of bed load measured by dry weight that moves past a section as bed load in a given time. Suspended sediment is the sediment that at any given time is maintained in suspension by the upward components of turbulent currents or that exists in suspension as a colloid. 37 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Suspended-sediment concentration is the velocity-weighted concentration of suspended sediment in the sampled zone (from the water surface to a point approximately 0.3 ft above the bed) expressed as milligrams of dry sediment per liter of water-sediment mixture (mg/L). Mean concentration is the time-weighted concentration of suspended sediment passing a stream section during a 24-hour day. Suspended-sediment discharge (tons/day) is the rate at which dry mass of sediment passes a section of a stream or is the quantity of sediment, as measured by dry mass or volume, that passes a section in a given time. It is calculated in units of tons per day as follows: concentrations (mg/L) x discharge (ftVs) x 0.0027. Suspended-sediment load is a general term that refers to material in suspension. It is not synonymous with either discharge or concentration. Total sediment discharge (tons/day) is the sum of the suspended-sediment discharge and the bed-load discharge. It is the total quantity of sediment, as measured by dry mass or volume, that passes a section during a given time. Total-sediment load or total load is a term which refers to the total sediment (bed load plus suspended-sediment load) that is in transport. It is not synonymous with total-sediment discharge. 7-day 10-year low flow (7Q10) is the discharge at the 10-year recurrence interval taken from a frequency curve of annual values of the lowest mean discharge for 7 consecutive days (the 7-day low flow). Sodium-adsorption-ratio (SAR) is the expression of relative activity of sodium ions in exchange reactions within soil and is an index of sodium or alkali hazard to the soil. Waters range in respect to sodium hazard from those which can be used for irrigation on almost all soils to those which are generally unsatisfactory for irrigation. Solute is any substance that is dissolved in water. Specific conductance is a measure of the ability of a water to conduct an electric current. It is expressed in microsiemens per centimeter at 25°C. Specific conductance is related to the type and concentration of ions in solution and can be used for approximating the dissolved-solids content of the water. Commonly, the concentration of dissolved solids (in milligrams per liter) is about 65 percent of the specific conductance (in micromhos). This relation is not constant from stream to stream, and it may vary in the same source with changes in the composition of the water. Stage-discharge relation is the relation between gage height (stage) and volume of water per unit of time, flowing in a channel. Streamflow is the discharge that occurs in a natural channel. Although the term "discharge" can be applied to the flow of a canal, the word "streamflow" uniquely describes the discharge in a surface stream course. The term "streamflow" is more general than "runoff as streamflow may be applied to discharge whether or not it is affected by diversion or regulation. Substrate is the physical surface upon which an organism lives. Natural substrate refers to any naturally occurring emersed or submersed solid surface, such as a rock or tree, upon which an organism lives. Artificial substrate is a device which is purposely placed in a stream or lake for colonization of organisms. The artificial substrate simplifies the community structure by standardizing the substrate from which each sample is taken. Examples of artificial substrates are basket samplers (made of wire cages filled with clean streamside rocks) and multiplate samplers (made of hardboard) for benthic organism collection, and plexiglass strips for periphyton. 38 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Surface area of a lake is that area outlined on the latest U.S.G.S. topographic map as the boundary of the lake and measured by a planimeter in acres. In localities not covered by topographic maps, the areas are computed from the best maps available at the time planimetered. All areas shown are those for the stage when the planimetered map was made. Surflcial bed material is that part (0.1 to 0.2 ft) of the bed material that is sampled using U.S. Series Bed-Material Samplers. Suspended (as used in tables of chemical analyses) refers to the amount (concentration) of the total concentration in a water-sediment mixture. It is associated with the material retained on a 0.45-micrometer filter. Suspended, recoverable is the amount of a given constituent that is in solution after the part of a representative water-suspended sediment sample that is retained on a 0.45 um membrane filter has been digested by a method (usually using a dilute acid solution) that results in dissolution of only readily soluble substances. Complete dissolution of all the paniculate matter is not achieved by the digestion treatment and thus the determination represents something less than the "total" amount (that is, less than 95 percent) of the constituent present in the sample. To achieve comparability of analytical data, equivalent digestion procedures are required of all laboratories performing such analyses because different digestion procedures are likely to produce different analytical results. Determinations of "suspended, recoverable" constituents are made either by analyzing portions of the material collected on the filter or, more commonly, by difference, based on determinations of (1) dissolved and (2) total recoverable concentrations of the constituent. Suspended, total is the total amount of a given constituent in the pan of representative water-suspended sediment sample that is retained on a 0.45 um membrane filter. This term is used only when the analytical procedure assures measurement of at least 95 percent of the constituent determined. A knowledge of the expected form of the constituent in the sample, as well as the analytical methodology used, is required to determine when the results should be reported as "suspended, total." Determinations of "suspended, total" constituents are made either by analyzing portions of the material collected on the filter or, more commonly, by difference, based on determinations of (1) dissolved and (2) total concentrations of the constituent. Taxonomy is the division of biology concerned with the classification and naming of organisms. The classification of organisms is based upon a hierarchial scheme beginning with Kingdom and ending with Species at the base. The higher the classification level, the fewer features the organisms have in common. For example, the taxonomy of a particular mayfly, Hexagenia limbata, is the following: Kingdom.....................Animal Phylum........................Arthopoda Class...........................Insecta Order...........................Ephemeroptera Family.........................Ephemeridae Genus..........................Hexagenia Species........................Hexagenia limbata Thermograph is an instrument that continuously records variations of temperature on a chart. The more general term "temperature recorder" is used in the table heading and refers to any instrument that records temperature whether on a chart, a tape, or any other medium. Time-weighted average is computed by multiplying the number of days in the sampling period by the concentrations of individual constituents for the corresponding period and dividing the sum of the products by the total number of days. A time- weighted average represents the composition of water that would be contained in a vessel or reservoir that had received equal quantities of water from the stream each day for the year. Tons per acre-foot indicates the dry mass of dissolved solids in 1 acre-foot of water. It is computed by multiplying the concentration of the constituent, in milligrams per liter by 0.00136. 39 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1997 Tons per day (T/DAY) is the quantity of a substance in solution or suspension that passes a stream section during a 24- hour period. Total is the total amount of a given constituent in a representative water-suspended sediment sample, regardless of the constituent's physical or chemical form. This term is used only when the analytical procedure assures measurement of at least 95 percent of the constituent present in both the dissolved and suspended phases of the sample. A knowledge of the expected form of the constituent in the sample, as well as the analytical methodology used, is required to judge when the results should be reported as "total." (Note that the word "total" does double duty here, indicating both that the sample consists of a water- suspended sediment mixture and that the analytical method determined all of the constituent in the sample.) Total discharge is the total quantity of any individual constituent, as measured by dry mass or volume, that passes through a stream cross-section per unit of time. This term needs to be qualified, such as "total sediment discharge," "total chloride discharge," and so on. Total, recoverable is the amount of a given constituent that is in solution after a representative water-suspended sediment sample has been digested by a method (usually using a dilute acid solution) that results in dissolution of only readily soluble substances. Complete dissolution of all paniculate matter is not achieved by the digestion treatment, and thus the determination represents something less than the "total" amount (that is, less than 95 percent) of the constituent present in the dissolved and suspended phases of the sample. To achieve comparability of analytical data, equivalent digestion procedures are required of all laboratories performing such analyses, because different digestion procedures are likely to produce different analytical results. Tritium Network is a network of stations which has been established to provide baseline information on the occurrence of tritium in the Nation's surface waters. In addition to the surface-water stations in the network, tritium data are also obtained at a number of precipitations stations. The purpose of the precipitation stations is to provide an estimate sufficient for hydrologic studies of the tritium input to the United States. Water year in Geological Survey reports dealing with surface water supply is the 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months. Thus, the year ending September 30,1980, is called the "1980 water year." WDR is used as an abbreviation for "Water-Data Report" in the REVISED RECORDS paragraph to refer to State annual hydrologic-data reports (WRD was used as an abbreviation for "Water-Resources Data" in reports published prior to 1976). Weighted average is used in this report to indicate discharge-weighted average. It is computed by multiplying the discharge for a sampling period by the concentrations of individual constituents for the corresponding period and dividing the sum of the products by the sum of the discharges. A discharge- weighted average approximates the composition of water that would be found in a reservoir containing all the water passing a given location during the water year after thorough mixing in the reservoir. WSP is used as an abbreviation for "Water-Supply Paper" in references to previously published reports. 40 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS The U.S. Geological Survey publishes a series of manuals describing procedures for planning and conducting specialized work in water-resources investigations. The material is grouped under major subject headings called books and is further divided into sections and chapters. For example, Section A of Book 3 (Applications of Hydraulics) pertains to surface water. The chapter, the unit of publication, is limited to a narrow field of subject matter. This format permits flexibility in revision and publication as the need arises. The reports listed below are for sale by the U.S. Geological Survey, Branch of Information Services, Box 25286, Federal Center, Denver, Colorado 80225 (authorized agent of the Superintendent of Documents, Government Printing Office). Prepayment is required. Remittance should be sent by check or money order payable to the U.S. Geological Survey. Prices are not included because they are subject to change. Current prices can be obtained by writing to the above address. When ordering or inquiring about prices for any of these publications, please give the title, book number, chapter number, and "U.S. Geological Survey Techniques of Water-Resources Investigations." 1-D1. Water temperature—influential factors, field measurement, and data presentation, by H. H. Stevens, Jr., J. F. Ficke, and G. F. Smoot: USGS-TWRI Book 1, Chapter Dl. 1975. 65 pages. 1-D2. Guidelines for collection and field analysis of ground-water samples for selected unstable constituents, by W. W Wood: USGS-TWRI Book 1, Chapter D2. 1976. 24 pages. 2-D1. Application of surface geophysics to ground-water investigations, by A. A. R. Zohdy, G. P. Eaton, and D. R. Mabey: USGS-TWRI Book 2, Chapter Dl. 1974. 116 pages. 2-D2. Application of seismic-refraction techniques to hydrologic studies, by F. P. Haeni: USGS--TWRI Book 2, Chapter D2. 1988. 86 pages. 2-E1. Application of borehole geophysics to water-resources investigations, by W. S. Keys and L.M. MacCary: USGS—TWRI Book 2, Chapter El. 1971. 126 pages. 2-E2. Borehole geophysics applied to ground-water investigations, by W. S. Keys: USGS-TWRI Book 2, Chapter E2. 1990. 150 pages. 2-F1. Application of drilling, coring, and sampling techniques to test holes and wells, by Eugene Shuter and W. E. Teasdale: USGS-TWRI Book 2, Chapter Fl. 1989. 97 pages. 3-A1. General field and office procedures for indirect discharge measurements, by M. A. Benson and Tate Dalrymple: USGS-TWRI Book 3, Chapter Al. 1967. 30 pages. 3-A2. Measurement of peak discharge by the slope-area method, by Tate Dalrymple and M. A. Benson: USGS--TWRI Book 3, Chapter A2. 1967. 12 pages. 3-A3. Measurement of peak discharge at culverts by indirect methods, by G. L. Bodhaine: USGS--TWRI Book 3, Chapter A3. 1968. 60 pages. 3-A4. Measurement of peak discharge at width contractions by indirect methods, by H. F. Matthai: USGS-TWRI Book 3, Chapter A4.1967. 44 pages. 3-A5. Measurement of peak discharge at dams by indirect methods, by Harry Hulsing: USGS--TWRI Book 3. Chapter A5. 1967. 29 pages. 3-A6. General procedure for gaging streams, by R. W. Carter and Jacob Davidian: USGS-TWRI Book 3, Chapter A6. 1968. 13 pages. 3-A7. Stage measurement at gaging stations, by T. J. Buchanan and W. P. Somers: USGS-TWRI Book 3, Chapter A7. 1968. 28 pages. 3-A8. Discharge measurements at gaging stations, by T. J. Buchanan and W. P. Somers: USGS-TWRI Book 3, Chapter A8. 1969. 65 pages. 3-A9. Measurement of time of travel in streams by dye tracing, by F. A. Kilpatrick and J. F. Wilson, Jr.: USGS--TWRI Book 3, Chapter A9.1989. 27 pages. 3-A10. Discharge ratings at gaging stations, by E. J. Kennedy: USGS-TWRI Book 3, Chapter A10. 1984. 59 pages. 41 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS-Continued 3-A11. Measurement of discharge by the moving-boat method, by G. F. Smoot and C. E. Novak: USGS--TWRI Book 3, Chapter All. 1969. 22 pages. 3-A12. Fluorometric procedures for dye tracing, Revised, by J. F. Wilson, Jr., E. D. Cobb, and F. A. Kilpatrick: USGS- -TWRI Book 3, Chapter A12.1986. 34 pages. 3-A13. Computation of continuous records of streamflow, by E. J. Kennedy: USGS--TWRI Book 3, Chapter A13. 1983. 53 pages. 3-A14. Use of flumes in measuring discharge, by F. A. Kilpatrick and V. R. Schneider: USGS--TWRI Book 3, Chapter A14. 1983.46 pages. 3-A15. Computation of water-surface profiles in open channels, by Jacob Davidian: USGS--TWRI Book 3, Chapter A15.1984. 48 pages. 3-A16. Measurement of discharge using tracers, by F. A. Kilpatrick and E. D. Cobb: USGS--TWRI Book 3, Chapter A16. 1985. 52 pages. 3-A17. Acoustic velocity meter systems, by Antonius Laenen: USGS--TWRI Book 3, Chapter A17.1985. 38 pages. 3-A18. Determination of stream reaeration coefficients by use of tracers, by F. A. Kilpatrick, R. E. Rathbun, Nobuhiro Yotsukura, G. W. Parker, and L. L. DeLong: USGS--TWRI Book 3, Chapter A18. 1989. 52 pages. 3-A19. Levels at streamflow gaging stations, by E.J. Kennedy: USGS-TWRI Book 3, Chapter A19. 1990. 31 pages. 3-A20. Simulation ofsoluable waste transport and buildup in surface waters using tracers, by F. A. Kilpatrick: USGS--TWRI Book 3, Chapter A20.1993. 38 pages. 3-A21 Stream-gaging cableways, by C. Russell Wagner: USGS--TWRI Book 3, Chapter A21. 1995. 56 pages. 3-B1. Aquifer-test design, observation, and data analysis, by R. W Stallman: USGS--TWRI Book 3, Chapter Bl. 1971. 26 pages. 3-B2. Introduction to ground-water hydraulics, a programed text for self-instruction, by G. D. Bennett: USGS-- TWRI Book 3, Chapter B2.1976. 172 pages. 3-B3. Type curves for selected problems of flow to wells in confined aquifers, by J. E. Reed: USGS--TWRI Book 3, Chapter B3. 1980. 106 pages. 3-B4. Regression modeling of ground-water flow, by R. L. Cooley and R. L. Naff: USGS--TWRI Book 3, Chapter B4. 1990. 232 pages. 3-B4. Supplement L Regression modeling of ground-water flow - Modifications to the computer code for nonlinear regression solution of steady-state ground-water flow problems, by R. L. Cooley: USGS--TWRI Book 3, Chapter B4. 1993. 8 pages. 3-B5. Definition of boundary and initial conditions in the analysis of saturated ground-water flow systems--An introduction, by O. L. Franke, T. E. Reilly, and G. D. Bennett: USGS--TWRI Book 3, Chapter B5. 1987. 15 pages. 3-B6. The principle of superposition and its application in ground-water hydraulics, by T. E. Reilly, O. L. Franke, and G. D. Bennett: USGS-TWRI Book 3, Chapter B6. 1987. 28 pages. 3-B7. Analytical solutions for one-, two-, and three-dimensional solute transport in ground-water systems with uniform flow, by E. J. Wexler: USGS--TWRI Book 3, Chapter B7. 1992. 190 pages. 3-C1. Fluvial sediment concepts, by H. P. Guy: USGS--TWRI Book 3, Chapter C1. 1970. 55 pages. 3-C2. Field methods for measurement of fluvial sediment, by H. P. Guy and V. W. Norman: USGS--TWRI Book 3, Chapter C2. 1970. 59 pages. 3-C3. Computation of fluvial-sediment discharge, by George Porterfield: USGS--TWRI Book 3, Chapter C3. 1972. 66 pages. 4-A1. Some statistical tools in hydrology, by H. C. Riggs: USGS--TWRI Book 4, Chapter A1. 1968. 39 pages. 4-A2. Frequency curves, by H. C. Riggs: USGS--TWRI Book 4, Chapter A2. 1968. 15 pages. 4-B1. Low-flow investigations, by H. C. Riggs: USGS--TWRI Book 4, Chapter B1. 1972. 18 pages. 42 PUBLICATIONS ON TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS-Continued 4-B2. Storage analyses for water supply, by H. C. Riggs and C. H. Hardison: USGS--TWRI Book 4, Chapter B2. 1973. 20 pages. 4-B3. Regional analyses ofstreamflow characteristics, by H. C. Riggs: USGS--TWRI Book 4, Chapter B3.1973. 15 pages. 4-D1. Computation of rate and volume of stream depletion by wells, by C. T. Jenkins: USGS--TWRI Book 4, Chapter Dl. 1970.17 pages. 5-A1. Methods for determination of inorganic substances in water and fluvial sediments, by M.J. Fishman and L. C. Friedman, editors: USGS--TWRI Book 5, Chapter Al. 1989. 545 pages. 5-A2. Determination of minor elements in water by emission spectroscopy, by P. R. Barnett and E. C. Mallory, Jr.: USGS-- TWRI Book 5, Chapter A2.1971. 31 pages. 5-A3. Methods for the determination of organic substances in water and fluvial sediments, edited by R. L. Wershaw, M. J. Fishman, R. R. Grabbe, and L. E. Lowe: USGS--TWRI Book 5, Chapter A3. 1987. 80 pages. 5-A4. Methods for collection and analysis of aquatic biological and microbiological samples, by L. J. Britton and P. E. Greeson, editors: USGS--TWRI Book 5, Chapter A4. 1989. 363 pages. 5-A5. Methods for determination of radioactive substances in water and fluvial sediments, by L.L. Thatcher, V. J. Janzer, and K. W. Edwards: USGS--TWRI Book 5, Chapter A5. 1977.95 pages. 5-A6. Quality assurance practices for the chemical and biological analyses of water and fluvial sediments, by L. C. Friedman and D. E. Erdmann: USGS--TWRI Book 5, Chapter A6.1982. 181 pages. 5-C1. Laboratory theory and methods for sediment analysis, by H. P. Guy: USGS-TWRI Book 5, Chapter Cl. 1969. 58 pages. 6-A1. A modular three-dimensional finite-difference ground-water flow model, by M. G. McDonald and A. W. Harbaugh: USGS--TWRI Book 6, Chapter Al. 1988. 586 pages. 6-A2. Documentation of a computer program to simulate aquifer-system compaction using the modular finite-difference ground-water flow model, by S. A. Leake and D. E. Prudic: USGS--TWRI Book 6, Chapter A2. 1991.68 pages. 6-A3. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 1: Model Description and User's Manual, by L. J. Torak: USGS--TWRI Book 6, Chapter A3.1993. 136 pages 6-A4. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 2: Derivation of finite-element equations and comparisons with analytical solutions, by R. L. Cooley: USGS--TWRI Book 6, Chapter A4. 1992. 108 pages. 6-A5. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 3: Design philosophy and programming details, by L. J. Torak: USGS-TWRI Book 6, Chapter A5,1993. 243 pages. 6-A6. A coupled surface-water and ground-water flow model (MODBRANCH) for simulation of stream-aquifer interaction, by Eric D. Swain and Eliezer J. Wexler. 1995. 125 pages. 7-C1. Finite difference model for aquifer simulation in two dimensions with results of numerical experiments, by P. C. Trescott, G. F. Pinder, and S. P. Larson: USGS--TWRI Book 7, Chapter Cl. 1976. 116 pages. 7-C2. Computer model of two-dimensional solute transport and dispersion in ground water, by L. F. Konikow and J. D. Bredehoeft: USGS--TWRI Book 7, Chapter C2. 1978. 90 pages. 7-C3. A model for simulation of flow in singular and interconnected channels, by R. W. Schaffranek, R. A. Baltzer, and D. E. Goldberg: USGS--TWRI Book 7, Chapter C3. 1981. 110 pages. 8-A1. Methods of measuring water levels in deep wells, by M. S. Garber and F. C. Koopman: USGS--TWRI Book 8, Chapter Al. 1968. 23 pages. 8-A2. Installation and service manual for U.S. Geological Survey manometers, by J. D. Craig: USGS--TWRI Book 8, Chapter A2.1983. 57 pages. 8-B2. Calibration and maintenance of vertical-axis type current meters, by G. F. Smoot and C. E. Novak: USGS--TWRI Book 8, Chapter B2.1968. 15 pages. 44 THIS PAGE WAS LEFT BLANK INTENTIONALLY 45 ATLANTIC OCEAN igntou* ond --•» &«dim*ntary rock* v V k 0105 010720 10108 *165 EXPLANATION SURFACE-WATER STATION AND NUMBER QUALITY-OF-WATER STATION AND NUMBER QUALITY-OF-WATER PARTIAL RECORD STATION AND NUMBER LAKE-ELEVATION STATION AND NUMBER WELL AND WELL NUMBER -Mop or«o 01 23456 KILOMETERS |_LTJ__ir_L+_h 01234 MILES Figure 12.--Rfo Guajataca basin. 46 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR LOCATION.—Lat 18°18'01", long 66 0 52'24", Hydrologic Unit 21010001 at bridge on Highway 111, 0.1 mi (0.2 km) upstream from Quebrada Anon, and 0.4 mi (0.6 km) east of Lares. DRAINAGE AREA.—3.16 mi 2 (8.18 km*) . WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1959 to February 1962 (annual low-flow measurements only), January 1963 to April 1969 (monthly measurements only). Hay 1969 to December 1970 (February to Hay 1971 and Harch 1974 to November 1989, monthly measurements only), December 1989 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 935 ft (285 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Small diversion above station for sewage treatment plant; effluent re-enters stream below station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC APR AUG 1 13 12 2 10 9.7 3 31 8.9 4 26 8.1 5 15 7.7 6 12 7.5 7 11 7.4 8 18 6.7 9 10 6.1 10 9.0 31 11 7.9 13 12 8.9 13 13 22 10 14 16 8.6 15 8.5 11 16 7.2 15 17 35 12 18 22 24 19 11 12 20 8.8 13 21 22 11 22 10 13 23 8.6 12 24 7.7 10 25 7.2 9.0 26 21 8.0 27 10 7.7 28 26 7.1 29 23 6.5 30 19 9.2 31 26 TOTAL 482.8 330.2 MEAN 15.6 11.0 MAX 35 31 HIN 7.2 6.1 AC-FT 958 655 CFSM 4.93 3.48 IN. 5.68 3.89 6.8 6.3 5.9 6.1 5.4 5.5 5.1 5.1 5.8 8.1 18 5.5 5.0 4.9 4.4 4.2 4.3 4.3 3.8 4.0 4.3 4.5 3.5 4.0 4.0 3.3 3.2 3.2 3.9 3.1 2.9 158.4 5.11 18 2.9 314 1.62 1.86 STATISTICS OF MONTHLY MEAN DATA MEAN 16.9 8.65 MAX 33.7 16.7 (WY) 1991 1971 HIN 8.52 3.75 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 3.84 7.31 1971 1.35 1991 2.9 13 24 5.6 3.5 2.6 2.5 7.0 3.7 2.0 1.9 3.4 15 11 3.8 2.4 2.2 1.8 5.4 11 56 39 9.6 15 6.4 .9 .3 .3 .2 .0 3.8 276.2 8.91 56 1.8 548 2.82 3.25 4.0 3.6 3.4 3.2 3.2 3.2 3.4 3.2 9.4 4.7 4.0 3.0 2.3 2.3 2.1 2.0 1.9 1.8 1.9 1.7 2.2 1.7 1.6 1.4 1.3 1.1 1.2 1.2 —— 76.0 2.71 9.4 1.1 151 .86 .89 FOR WATER YEARS 1969 3.41 8.91 1997 .66 1991 2.71 7.21 1996 .93 1992 1.2 1.1 1.1 1.3 1.1 .93 1.1 1.2 .87 .90 .73 .65 .65 .65 .79 .70 1.3 2.5 8.5 3.2 2.4 2.1 1.7 1.8 1.6 1.8 1.5 11 4.9 3.3 1.9 64.47 2.08 11 .65 128 .66 .76 - 1997 2.23 6.38 1971 .92 1994 FOR 1996 CALENDAR YEAR 3154.8 8.62 129 1.2 1.4 6260 2.73 37.14 20 4.9 1.9 Sep 10 Jan 13 Jan 7 1.9 1.8 1.8 1.8 1.8 1.7 1.9 1.7 1.6 1.6 1.5 1.8 1.8 1.8 1.8 1.7 1.2 1.2 1.0 .90 1.8 5.1 1.4 .89 .75 .70 .85 .78 .68 .71 —— 45.96 1.53 5.1 .68 91 .48 .54 , BY WATER 3.38 7.63 1993 1.09 1994 FOR 1997 2024 5 88 2110 15 4020 1 23 13 2 .77 .70 .67 1.1 .75 .75 .65 .64 .68 .68 .64 .64 .60 .57 .59 .56 .50 .51 .58 .98 62.2 66.0 e!2 613 el. 8 elO e2.8 e3.5 63.2 e3.0 62.5 73.56 2.37 13 .50 146 .75 .87 YEAR (WY) 9.23 20.2 1995 2.37 1997 62.0 el. 5 el. 2 el. 6 62.1 el. 9 62.0 el. 9 el. 8 el. 6 62.1 el. 9 el. 7 el. 8 el. 6 el. 7 el. 6 el. 3 el. 4 62.8 el. 2 6.90 6.96 6.96 el. 8 62.5 el. 5 6.96 el. 4 63.4 —— 51.08 1.70 3.4 .90 101 .54 .60 7.24 16.4 1995 1.70 1997 WATER YEAR .97 .55 .50 .56 .71 .76 .84 .6 .95 Sep 24 May 17 Hay 13 Sep 24 Sep 24 62.5 el. 7 el. 2 el. 3 62.0 el.O el.O 1.7 1.6 1.3 1.2 1.6 1.4 3.0 5.0 2.2 1.3 1.7 1.5 1.3 1.4 1.4 1.3 1.4 1.4 2.3 1.8 1.4 2.2 1.6 1.9 53.6 1.73 5.0 1.0 106 .55 .63 4.12 9.85 1969 1.73 1997 1.4 1.6 5.9 2.5 1.8 1.7 1.9 5.7 11 8.9 2.5 2.5 2.7 15 3.7 4.0 2.2 2.3 2.4 30 13 4.1 16 8.8 4.0 2.6 2.5 14 5.6 4.6 6.2 191.1 6.16 30 1.4 379 1.95 2.25 6.11 11.1 1996 3.34 1970 WATER YEARS 1969 6.41 9.08 4.13 216 .47 .51 5300 21.30 4640 2.03 27.55 15 3.5 .96 Oct Jan Jan Oct Oct 16 8.8 2.7 3.1 2.5 2.9 2.2 2.0 1.7 1.5 1.4 5.8 3.4 6.9 2.6 2.6 1.1 1.3 1.6 2.2 3.3 7.3 3.8 88 11 4.2 14 5.8 7.2 4.7 —— 221.6 7.39 88 1.1 440 2.34 2.61 11.9 24.7 1996 5.95 1993 - 1997 1996 1994 7 1990 13 1991 9 1991 7 1990 7 1990 e Estimated RIO QUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°18'01", long 66°52'24>, at bridge on Highway 111 (km 32.9), 0.1 ml (0.2 km) upstream from Quebrada Anon, and 0.4 mi (0.6 km) northeast of Lares plaza. DRAINAGE AREA.—3.16 mi* (8.18 km1 ). PERIOD OF RECORD.—Water years 1958-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 47 DATE TIME OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- TUR- OXYGEN, (PER- ICAL BID- DIS- CENT (HIGH ITY SOLVED SATUR- LEVEL) (NTU) (MG/L) ATION) (MG/L) (00076) (00300) (00301) (00340) OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... 1110 1300 0920 1130 11 4.2 2.3 3.9 226 246 231 302 6.7 6.4 7.6 7.8 22.5 21.5 23.5 24.0 7.1 13 8.4 7.3 7.8 8.7 6.6 6.7 89 99 80 82 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K1800 K1300 3500 3200 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 2900 4500 5900 8500 DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... DATE OCT 1996 31... FEB 1997 11... JUN 12... AUG 22... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 85 — 89 68 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.11 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.24 0.22 <0.20 0.26 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 25 — 24 22 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 30 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.5 2.2 0.99 1.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.4 — 6.7 3.1 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 146 — 145 132 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 11 9.7 4.4 6.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 10 — 11 6.2 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.44 — 0.91 1.39 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.030 0.080 0.060 0.030 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.5 0.3 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) <1 18 9 6 ARSENIC TOTAL (UG/L AS AS) (01002) 1 — 1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 — 2.2 2.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 2.30 2.00 0.790 1.20 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 90 94 81 120 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 0.015 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 20 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 2.30 2.00 0.800 1.30 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 6.8 — 9.5 8.0 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 0.030 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 12 8.4 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.22 0.20 <0.20 0.22 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non- ideal count 48 RIO GUAJATACA BASIN 50010500 RIO OUAJATACA AT LARES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 31... FEB 1997 11... JUN 12... AUO 22... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UO/L (UO/L 320 290 MANGA- NESE, MERCURY TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UO/L (UO/L METHY- SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL (UO/L (MO/L BLUE ACTIVE PHENOLS SUB- TOTAL STANCE AS FE) AS PB) AS MN) AS HO) AS SB) AS AO) AS ZN) AS CN) (UO/L) (MO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) 30 <0.10 54 <0.10 <10 <0.010 <1 <0.01 <10 <0.010 <0.01 RIO GUAJATACA BASIN 50010800 LAGO GUAJATACA AT DAMSITE NEAR QUEBRADILLAS, PR 49 LOCATION.—Lat 18°24'02", long 66°55'25", Hydrologic Unit 21010002, on right bank, in a concrete intake tower at Damsite, 5.2 mi (8.4 km) southeast from Quebradillas plaza, 0.5 mi (0.8 km) northeast from Iglesia San Antonio da Padua and 2.8 mi (4.5 km) from Escuela Segunda Unidad Baldorioty de Castro. DRAINAGE AREA.—24.6 mi* (63.71 km*) ELEVATION RECORDS PERIOD OF RECORD.—April 1995 to current year. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Guajataca was completed in 1928. The dam is a semihydraulic earthfill structure about 123 ft (37 m) bight, a top width of 31 ft (9.5 m) at crest elevation of 664 ft (202.5 m), a base width of 623 ft (190 m), a crest lenght of 1,036 ft (316 m) and has a maximum storage capacity of 49,200 acre-feet (60.6 hm3 ). The Guajataca Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and provides water for the municipalities of Aguadilla, Isabela, Moca, Aguada and Quebradillas although its primary purpose is for agricultural irrigation for the flatlands of the area. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 645.48 ft (196.7 m), Oct. 18, 1995; minimum elevation, 611.22 ft (186.3 m) Aug. 16, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 644.46 ft (196.4 m), Jan. 23; minimum elevation, 611.22 ft (186.3 m), Aug. 16. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 593 600 Contents, in acre-feet 0 2,405 Elevation, in feet 625 650 Contents, in acre-feet 15,295 36,403 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES DAY 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT NOV DEC JAN APR JUL AUG 640.27 A 640.36 640.44 640.46 640.43 640.39 640.36 640.30 640.22 640.13 640.05 640.21 640.31 640.29 641.32 641.27 641.22 641.14 641.05 640.96 640.87 640.78 640.68 640.75 640.69 640.77 640.74 640.68 640.75 641.99 641.92 641.98 641.94 641.84 641.75 641.66 641.56 641.44 641.38 641.65 641.60 641.50 641.43 641.38 639.40 639.38 639.70 639.77 639.68 639.57 639.45 639.33 639.22 639.10 638.99 639.00 639.03 639.24 639.24 638.59 638.08 637.86 637.77 637.65 637.55 637.44 637.32 637.24 637.12 637.05 636.92 636.79 636.65 636.51 634.64 634.51 634.38 634.24 634.11 633.97 633.84 633.69 633.56 633.41 633.26 633.10 632.94 632.79 632.64 630.34 630.19 630.00 629.82 629.64 629.53 629.39 629.20 629.02 628.82 628.63 628.42 628.22 628.03 627.83 624.42 624.19 623.98 623.76 623.54 623.39 623.35 623.22 623.12 622.95 623.24 623.17 622.98 622.77 622.56 623.54 623.53 623.46 623.29 623.11 622.93 622.69 622.52 622.37 622.17 621.98 621.79 621.61 621.41 621.21 618.46 618.43 618.19 617.92 617.68 617.39 617.10 616.84 616.54 616.26 615.98 615.69 615.48 615.56 615.97 A A A A A A A A A A A A A 611.44 611.33 617.38 617.43 617.39 617.32 617.21 617.09 616.95 616.85 616.69 616.49 616.27 616.05 615.86 615.64 615.51 640.23 640.59 640.75 640.73 640.69 640.69 640.64 640.67 640.60 640.52 641.06 641.31 641.52 641.60 641.67 641.94 642.85 642.75 642.36 642.23 641.29 641.18 641.06 640.94 640.83 640.73 640.64 640.52 640.41 640.29 639.15 639.04 638.93 638.85 639.19 641.39 644.42 644.28 643.88 643.26 636.37 636.23 636.09 635.96 635.83 635.71 635.57 635.43 635.31 635.19 632.49 632.36 632.23 632.18 632.11 631.97 631.81 631.65 631.49 631.32 627.63 627.42 627.22 627.02 626.81 626.60 626.42 626.23 626.01 625.80 622.34 622.12 621.89 621.66 621.42 621.24 621.12 621.10 621.90 622.54 620.99 620.76 620.52 620.30 620.09 619.87 619.62 619.38 619.36 619.38 640.56 640.64 640.77 641.08 641.25 641.32 642.22 642.18 642.14 642.08 642.05 640.17 640.05 639.93 639.80 639.67 639.55 642.50 641.69 640.85 640.07 639.41 639.03 635.05 634.93 634.78 ___ ___ ___ 631.16 630.99 630.90 630.79 630.64 630.48 625.55 625.33 625.09 624.86 624.64 ___ 622.80 623.53 623.89 623.83 623.71 623.57 619.19 618.97 618.71 618.45 618.24 ___ 641.32 640.05 642.85 640.68 641.99 639.55 644.42 638.85 638.59 634.78 634.64 630.48 630.34 624.64 624.42 621.10 623.54 618.24 616.00 615.79 615.55 615.31 615.09 614.85 614.64 614.39 614.14 613.87 A A A A A A 618.46 613.87 611.54 611.81 611.71 612.57 614.10 614.78 614.91 614.98 615.21 615.19 615.06 615.38 616.64 617.01 617.00 617.21 617.21 611.33 615.33 615.09 614.94 614.76 614.57 614.46 614.30 614.17 614.73 614.84 614.69 614.62 614.51 614.32 614.16 617.43 614.16 CAL YR 1996 WTR YR 1997 MAX 642.99 MAX 644.42 MIN 629.08 MIN 611.33 A No gage-height record so RIO GUAJATACA BASIN 50011000 CANAL PRINCIPAL DE DIVERSIONES AT LAGO DE GUAJATACA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°24'02", long 66°55'27", off Highway 476 at Lago Guajataca outlet, 3.0 mi (4.8 km) southwest of Segunda Unidad Baldorioty de Castro, and 5.3 mi (8.5 km) south of Quebradillas Plaza. DRAINAGE AREA.--Indeterminate. PERIOD OF RECORD.—Water years 1958-64, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 15... FEB 1997 10... MAY 20... AUG 21... DATE NOV 1996 15... FEB 1997 10... MAY 20... AUG 21... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET D0CT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1200 E65 1145 75 1345 65 0800 60 HARD- NESS TOTAL (MG/L AS CAC03) (00900) 140 — 130 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.26 0.29 0.53 0.87 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 49 — 47 50 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 7.2 — 4.9 7.2 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.26 0.61 0.53 0.89 296 306 293 308 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.6 — 4.1 4.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 144 — 164 174 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.1 2.7 2.4 4.0 7.0 7.2 7.8 7.6 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 7.0 — 6.1 5.7 24.0 0 24.0 0 27.0 1 27.5 1 SODIUM AD- SORP- TION RATIO (00931) 0.3 — 0.2 0.2 RESIDUE SOLIDS, TOTAL DIS- AT 105 SOLVED DEG. C, (TONS SUS- PER FENDED DAY) (MG/L) (70302) (00530) E25.2 — 28.7 28.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.030 <0.020 <0.020 3 1 1 5 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ .90 .40 .0 .4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.6 — 2.1 1.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) — 0.320 <0.010 0.020 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 1.0 3.2 2.9 3.6 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 100 140 130 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — 12 38 37 46 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — 0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) <0.020 0.320 <0.020 0.020 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 16 <10 <10 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 7.6 — 13 6.3 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.060 <0.010 0.130 0.380 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — K14 4 K4 97 K4 K12 K80 K99 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 6.9 — 8.9 7.9 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.28 0.40 0.49 COPPER, TOTAL RECOV- ERABLE (UG/L AS CO) (01042) <1.0 — , Hydrologic Unit 21010002 on right bank at abandoned power house at Charco Hondo, 1.5 mi (2.4 km) upstream from mouth, and 4 mi (6 km) south of Arecibo. DRAINAGE AREA.--57.6 mi 2 (149.2 km2 ). PERIOD OF RECORD.—April 1969 to June 1971, October 1981 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 60 ft (18 m), from topographic map. REMARKS.—Records poor. Diversion 0.8 mi (1.3 km) upstream for municipal supply of Arecibo. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 107 DAY OCT NOV DEC JAN APR MAY JDN JUL AtJG SEP 1 145 178 2 113 142 3 126 126 4 123 117 5 116 111 6 150 107 7 130 103 8 101 99 9 105 102 10 96 e225 11 95 e225 12 92 146 13 103 161 14 155 108 15 263 108 16 129 175 17 110 247 18 253 232 19 146 224 20 124 149 21 113 146 22 322 147 23 186 167 24 155 134 25 139 130 26 153 109 27 300 103 28 208 103 29 187 107 30 197 117 31 188 TOTAL 4823 4348 MEAN 156 145 MAX 322 247 MXN 92 99 AC-FT 9570 8620 CFSM 7.01 6.53 IN. 8.08 7.29 STATISTICS OF MONTHLY MEAN MEAN 164 135 MAX 335 260 (WY) 1990 1982 MXN 72.1 50.4 (WY) 1983 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 108 96 93 90 88 85 84 83 80 95 e330 181 123 111 108 106 102 99 96 96 98 103 93 91 114 110 89 90 89 86 85 3302 107 330 80 6550 4.80 5.53 86 99 209 194 105 95 90 89 95 85 84 95 100 e226 e!74 94 88 83 84 264 338 e600 359 304 243 192 169 159 133 117 111 5164 167 600 83 10240 7.50 8.65 DATA FOR WATER 80.3 219 1982 36.4 1989 FOR 60.6 167 1997 22.3 1989 108 107 110 94 91 90 89 86 84 83 79 79 76 73 73 71 70 70 69 68 69 70 64 64 64 63 60 59 —— 2183 78.0 110 59 4330 3.51 3.66 YEARS 1969 50.9 106 1996 16.8 1989 59 59 59 60 59 57 55 55 55 53 51 51 50 49 49 50 48 57 66 93 56 53 50 49 48 48 48 61 70 66 79 1763 56.9 93 48 3500 2.56 2.95 - 1997 42.9 70.0 1971 16.6 1988 1996 CALENDAR YEAR 39552 108 1360 38 41 78450 4. 66. 187 83 49 Sep 10 Jul 27 Jul 22 87 28 56 51 52 50 50 48 48 47 47 48 46 45 45 45 43 44 43 44 46 47 51 73 81 52 46 44 42 39 38 35 —— 1446 48.2 81 35 2870 2.17 2.42 33 39 66 34 33 34 33 35 42 42 40 35 34 33 35 35 33 34 34 33 36 41 79 89 el!7 102 90 78 53 47 70 1539 49.6 117 33 3050 2.24 2.58 112 57 50 47 45 44 42 e37 e35 e35 e38 e40 e39 e38 e37 e35 e34 38 38 e63 69 46 44 42 38 41 64 46 38 39 —— 1371 45.7 112 34 2720 2.06 2.30 48 38 36 e35 e37 e39 e41 e44 e62 e39 37 38 44 46 97 108 62 47 50 43 62 45 40 38 38 56 72 44 65 92 61 1604 51.7 108 35 3180 2.33 2.69 69 47 42 45 45 40 37 58 146 136 113 70 91 157 192 118 134 88 53 89 140 103 97 156 76 60 52 50 91 177 132 2904 93.7 192 37 5760 4.22 4.87 e!31 221 134 90 80 75 73 71 70 68 68 74 87 77 122 82 77 72 71 69 70 78 82 83 109 75 119 127 125 127 —— 2807 93.6 221 68 5570 4.21 4.70 , BY WATER YEAR (WY) 66.9 141 1986 25.9 1989 128 371 1986 15.8 1989 88.2 196 1995 23.3 1989 FOR 1997 WATER YEAR 33254 91.1 600 33 34 2080 10.23 65960 4.10 55.72 158 77 38 Jan 22 May 1 May 14 Sep 1 Sep 1 63.9 120 1969 22.0 1989 WATER 87 124 46 2500 4 5 15000 17 63700 3 53 176 65 29 76.2 125 1991 35.1 1994 YEARS 1969 - .9 .9 Oct 7 .2 May 28 .4 May 22 May 18 .95 May 18 .96 .82 124 269 1996 44.9 1994 1997 1986 1994 1985 1989 1989 1985 1985 e Estimated 108 RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR LOCATION.—Lat 18°27'20", long 66°42'10", Hydrologic Unit 21010002, at bridge on unimproved road, about 500 ft (152 m) upstream from Central Cambalache, near Highway 2, 13.9 mi (22.4 km) downstream from Dos Bocas Reservoir, 1.9 mi (3.1 km) downstream from Rio Tanama, and 1.6 mi (2.6 km) southeast of Arecibo. DRAINAGE AREA.—200 mi 2 (520 km2 ). PERIOD OF RECORD.--January 1963 to January 1965 (monthly measurements only), February 1965 to April 1969 (occasional measurements only). Hay 1969 to Sepetember 1983, October 1996 to September 1997. GAGE.--Water-stage recorder. Datum of gage is 3.73 ft (1.14 m) above mean sea level. REMARKS.--Records poor. Flow regulated by Lago Dos Bocas dam, 13.9 mi (22.4 km) upstream. Gage-height satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges and elevations above mean sea level of major floods at valley cross sections along Expressway PR-22 about 1.0 mi (1.6 km) above gage site are as follows: Aug. 8, 1899, 195,000 ftVs (5,520 mVs), gage-height, 24.4 ft (7.44 m); Sept. 13, 1928, 105,000 ftVs (2,970 mVs), gage-height, 21.6 ft (6.58 m); Oct. 13, 1954, 76,000 ftVs (2,150 mVs), gage-height. 19.1 ft (5.82 m); and Nov. 26, 1968, 21,000 ftVs (595 mVs) gage-height, 16.6 ft (5.06 m) . DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV FEB MAR MAY JUN JUL AUG 1 e963 932 2 e!160 361 3 e!020 292 4 911 515 5 838 352 6 e526 460 7 703 750 8 319 617 9 262 390 10 225 458 11 e!97 624 12 e!87 527 13 e238 695 14 e402 536 15 657 365 16 e682 493 17 e631 456 18 e792 1060 19 e468 1260 20 e321 1160 21 878 704 22 890 771 23 914 896 24 785 485 25 718 671 26 402 633 27 511 623 28 325 348 29 333 459 30 861 373 31 901 —— TOTAL 19020 18266 MEAN 614 609 MAX 1160 1260 MIN 187 292 AC-FT 37730 36230 CFSM 3 . 07 3 . 04 IN. 3.54 3.40 677 759 548 323 601 595 799 347 691 739 672 388 198 494 547 688 456 320 271 259 302 317 369 372 258 590 605 286 211 370 356 14408 465 799 198 28580 2.32 2.68 STATISTICS OF MONTHLY MEAN DATA MEAN 811 755 MAX 1577 1388 (WY) 1971 1978 MIN 404 299 (WY) 1983 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 539 1327 1982 195 1972 220 255 295 558 332 321 e219 e284 e!43 e!30 412 213 300 678 645 472 440 327 347 472 1020 4120 1670 1100 1000 761 820 673 669 650 641 20187 651 4120 130 40040 3.26 3.75 FOR WATER 365 651 1997 155 1973 367 350 395 476 551 511 396 292 253 545 543 566 518 462 287 389 363 311 362 442 529 441 321 385 e330 e482 e535 492 ___ ___ —— 11894 425 566 253 23590 2.12 2.21 YEARS 1969 302 425 1997 152 1974 210 143 381 471 377 388 519 272 137 356 493 404 430 475 353 407 459 386 414 392 293 155 309 345 402 439 476 285 232 280 357 11040 356 519 137 21900 1.78 2.05 - 1997 328 627 1972 141 1977 343 365 186 371 280 225 106 290 364 428 462 198 117 99 253 457 452 502 265 158 182 236 452 444 258 137 456 358 304 386 —— 9134 304 502 99 18120 1.52 1.70 , BY WATER 387 641 1983 196 1975 387 410 291 227 211 274 309 310 175 428 244 314 419 252 386 304 119 307 417 164 103 90 174 203 251 349 369 167 200 194 141 8189 264 428 90 16240 1.32 1.52 YEAR (WY) 564 1192 1980 188 1977 154 101 315 447 412 264 214 140 190 105 244 157 90 81 74 86 122 132 95 94 135 110 211 137 89 85 109 90 81 82 —— 4646 155 447 74 9220 .77 .86 457 1220 1979 139 1977 FOR 1997 WATER YEAR 140534 385 4120 74 96 5750 10 68 278700 1 26 684 347 112 .74 .93 .14 Jan 22 Jun 15 Jun 24 Jan 22 Jan 22 Jun 15 272 464 300 153 101 87 79 107 163 85 116 103 77 74 186 188 123 148 151 128 199 221 170 268 190 102 125 237 448 423 376 5864 189 464 74 11630 .95 1.09 381 854 1979 189 1997 WATER 501 691 290 15900 60 86 26100 13. 50 363100 2. 34. 964 358 139 333 184 167 93 88 106 103 139 202 191 193 212 251 495 819 431 444 400 274 419 340 447 436 365 423 415 468 463 318 292 247 9758 315 819 88 19350 1.57 1.81 421 1269 1979 218 1974 YEARS 1969 Aug Aug Jun Aug 74 Aug Feb 51 05 191 570 668 575 435 452 266 394 471 359 330 200 152 114 149 221 153 147 149 101 143 104 103 120 148 97 128 240 455 493 —— 8128 271 668 97 16120 1.35 1.51 704 1866 1979 271 1997 - 1997 1979 1974 31 1979 4 1982 29 1977 31 1979 31 1979 26 1974 e Estimated RIO GRANDE DE ARECIBO BASIN 109 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAHBALACHE, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°27'20", long 66°42'10", Hydrologic Unit 21010002, at bridge on unimproved road, about 500 ft (152 m) upstream from Central Cambalache, near Highway 2, 8.3 mi (13.4 km) downstream from Dos Bocas Reservoir, 1.9 mi (3.1 km) downstream from Rio Tanama , and 1.6 mi (2.6 km) southeast of Arecibo. DRAINAGE AREA.--200 mi' (520 km2 ), approximately. PERIOD OF RECORD.--Water years 1963-66, 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEE 1997 21... JUN 05... AUG 26... TIME 0930 1230 1145 1050 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 451 214 158 185 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 250 268 271 325 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.2 6.5 7.9 7.6 TEMPER- ATURE WATER (DEG C) (00010) 24.0 23.5 27.5 27.0 TUR- BID- ITY (NTU) (00076) 59 2.6 3.6 8.2 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.5 7.6 7.7 7.1 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 87 86 98 88 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 <10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 3500 K180 40 K690 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 4200 K1100 K80 K130 OCT 30 FEB 21 JUN 05 AUG 26 OCT 30 FEB 21 JUN 05 AUG HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) 1996 100 1997 ... 110 98 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 <0.10 1997 ... ... <0.10 26... <0.10 K - non- ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 34 -- 34 30 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 16 -- 19 18 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.7 -- 6.2 5.5 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 143 -- 160 141 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 8.0 -- 9.6 8.6 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 174 -- 68.2 70.4 SODIUM AD- SORP- TION RATIO (00931) 0.3 -- 0.4 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 72 5 1 15 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 -- 2.0 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.900 0.790 0.400 0.690 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 98 110 110 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 0.020 0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -~ NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.920 0.790 0.420 0.700 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 11 -- 12 11 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.030 0.050 0.030 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 8.6 __ 11 10 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.38 <0.20 0.22 0.24 110 DATE OCT 1996 30... FEB 1997 21... JUN 05... AUG 26... RIO GRANDE DE ARECIBO BASIN 50029000 RIO GRANDE DE ARECIBO AT CENTRAL CAMBALACHE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN/ TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.43 0.22 0.26 0.28 1.3 1.0 0.69 0.98 6.0 0.040 4.5 0.020 3.1 <0.020 4.3 <0.020 <1 <1 <100 <100 20 20 <1 <1 <1 20 DATE OCT 1996 30... FEB 1997 21... JUN 05... AUG 26... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- IiBHE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2000 120 <1 120 25 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 PESTICIDE ANALYSES DATE JUN 1997 05... TIME 1145 PCB, TOTAL (UG/L) ALDRIN, TOTAL CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (UG/L) P,P'- P,P'- ENDO- DDD P,P'- DDT DI- DI- SULFAN, UNFILT DDE, UNFILT AZINON, ELDRIN I RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) luwsii; luw/ii/ luu/ii; iuu/ii; iuw/ii; luw/u; iuu/u/ luu/u; iuu/u/ (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) (39390) (39398) JUN 1997 05... HEPTA- CHLOR, TOTAL (UG/L) (39410) HEPTA- CHLOR EPOXIDE TOTAL (UG/L) (39420) LINDANE TOTAL (UG/L) (39340) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MIREX, TOTAL (UG/L) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE JUN 1997 05... PARA- PCNS THION, UNFILT TOTAL RECOVER (UG/L) (UG/L) (39540) (39250) PER- THANE TOTAL (UG/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) <0.010 <0.100 <0.100 <1.00 TOTAL TRI- THION (UG/L) (39786) <0.010 2,4-D, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) 0.040 <0.010 <0.010 <0.010 111 ATLANTIC OCEAN Drainage bounoan** indeterminate in limestone terrane Ri'o inoBtfn t>4lin 7-r Do«.ft J &0*m EXPLANATION AOSSO SURFACE-WATER STATION AND NUMBER Toso/ QUAUTY-OF-WATER STATION AND NUMBER •210 WELL AND WELL NUMBER |032290 LAKE-ELEVATION STATION rt „ „ „ „ c ft *„ OMPTPPC JL AND NUMBER 0123456 KILOMETERS I I ! I 01234 MtLES Figure 15.—Rio Grande de Manati basin. 112 RIO GRANDE DE MANATI BASIN 50030460 RIO OROCOVXS AT OROCOVIS, PR LOCATION.--Lat 18°13'25", long 66°23'34", Bydrologic Unit 21010001, on right bank, 0.4 mi (0.6 tan) couth of junction of Highway* 155 and 156 in Oroeovic, 2.1 mi (3.38 tan) upctream from Rio Botijai, and 250 ft (76 m) upctream from bridge on Highway 599. DRAINAGE AREA.--5.03 mi* (13.03 tan»). PERIOD OF RECORD.—April 1981 to September 1982, October 1988 to current year. GAGE.—Water-stage recorder. Elevation of gage is 500 ft (152 m), from topographic map. REMARKS.—Records poor. Low flow affected by diversions for water supply. Gage-height and precipitation catellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 3.7 6.2 2 3.1 5.3 3 7.9 4.3 4 4.1 4.3 5 4.0 3.8 6 10 3.6 7 5.1 3.3 8 4.5 4.3 9 4.1 5.0 10 3.6 3.9 11 3.3 5.2 12 3.2 4.0 13 3.2 2.9 14 3.4 2.7 15 3.3 2.6 16 3.1 2.5 17 3.0 2.5 18 2.4 50 19 4.9 8.1 20 3.8 7.1 21 2.7 4.8 22 2.2 5.2 23 2.8 13 24 2.1 26 25 1.7 19 26 15 7.3 27 8.0 4.2 28 11 4.6 29 39 3.9 30 21 21 31 9.3 TOTAL 198.5 240.6 MEAN 6.40 8.02 MAX 39 50 MIN 1.7 2.5 AC-FT 394 477 CFSM 1.27 1.59 IN. 1.47 1.78 STATISTICS OF MONTHLY MEAN MEAN 16.2 6.91 MAX 58.0 15.2 (WY) 1990 1991 MIN 1.95 1.56 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 12 5.9 4.4 3.9 3.3 2.6 2.7 2.5 2.4 2.6 62 23 9.4 5.8 4.5 4.6 3.4 3.1 2.7 3.1 3.1 2.7 3.2 3.0 2.9 2.5 2.7 2.7 4.0 3.5 3.2 197.4 6.37 62 2.4 392 1.27 1.46 DATA 5.16 15.8 1982 .65 1995 2.9 e2.9 e5.8 e5.8 e3.1 e2.7 e2.6 e2.4 e2.4 e2.4 2.8 3.2 3.1 3.3 3.2 2.1 2.2 2.1 3.1 6.2 43 35 24 31 19 9.1 5.6 5.0 3.9 3.4 3.4 246.7 7.96 43 2.1 489 1.58 1.82 3.3 3.2 3.5 3.3 3.7 3.8 2.8 2.8 2.4 2.6 2.2 3.2 1.9 1.9 1.8 1.6 1.7 2.1 e2.9 e2.0 el. 8 el. 7 el. 5 el. 5 el. 5 el. 6 el. 4 el. 3 el. 3 el. 3 el. 3 el. 2 el. 5 el. 4 el. 2 el. 2 el. 2 el. 2 el.l el.l el.l el.l el.O el.O el.O el.O el. 2 el.l el.l el.O el.O e.96 el.l el.l el. 9 el. 9 —— e!5 —— —— 65.0 2.32 3.8 1.3 129 .46 .48 FOR WATER YEARS 1981 6.55 34.3 1992 .77 1995 3.52 15.7 1996 .96 1995 e2.3 el. 2 52.06 1.68 15 .96 103 .33 .39 - 1997 1.82 3.07 1996 .90 1994 FOR 1996 CALENDAR YEAR 4261.2 11.6 1570 1.1 1.2 8450 2.31 31.51 11 2.8 1.4 Sep 10 Mar 31 Aug 26 el. 2 el.l el. 2 e.95 el.O el.l el.l el.l el.l el.l el.O el.O el.l el.O el.O el.O e.98 e.90 e.86 el.O el. 4 1.1 1.2 1.3 1.2 .90 1.0 .95 1.0 1.3 —— 32.14 1.07 1.4 .86 64 .21 .24 .78 .88 1.1 1.1 1.2 .99 .97 .88 .81 1.1 1.0 .83 .86 .81 .79 .78 1.0 .73 .79 .87 .80 .73 .91 1.1 1.0 .76 .68 .63 .63 .61 .62 26.74 .86 1.2 .61 53 .17 .20 .63 .63 .52 .48 .44 .50 .47 .42 .48 .90 .60 .43 .49 .57 .49 .43 .36 .52 .36 .33 .35 .42 .55 .55 .38 .36 1.0 2.8 8.6 6.1 —— 31.16 1.04 8.6 .33 62 .21 .23 1.9 .40 .56 .24 .45 .51 1.3 1.0 .25 .23 .43 .41 .86 .85 .64 .33 .50 1.1 1.6 6.4 1.9 .95 1.0 1.6 2.1 2.1 .95 1.4 1.1 1.2 11 45.26 1.46 11 .23 90 .29 .33 10 6.4 3.7 3.2 1.6 1.4 1.6 1.3 11 9.2 3.0 2.1 12 12 3.2 1.7 3.7 2.4 1.1 1.1 1.6 2.1 1.7 1.7 2.6 1.9 1.6 1.1 .90 .89 1.1 108.89 3.51 12 .89 216 .70 .81 2.1 2.3 .84 .86 .85 .90 1.4 .78 .79 .83 .85 1.5 1.8 1.4 1.0 .81 .97 1.0 1.2 1.2 1.6 2.7 3.4 1.4 1.1 1.7 2.8 2.7 4.1 2.7 47.58 1.59 4.1 .78 94 .32 .35 , BY WATER YEAR (WY) 5.24 21.0 1993 .93 1995 FOR 1997 1292 3 62 388 7 2560 9 6 1 14.0 45.9 1995 .86 1997 WATER YEAR .03 .54 Dec 11 .23 Jul 10 .40 Jun 16 Nov 18 .53 Nov 18 .70 .56 .3 .7 .63 4.38 15.2 1992 .88 1994 3.56 9.07 1996 .88 1994 WATER 7 11 1 1570 8890 17 5370 1 20 11 1 3.67 12.3 1989 1.03 1982 YEARS 1981 .41 .8 .49 .20 .33 .38 .47 .02 .9 .85 Sep Oct Oct Sep Sep 19.5 73.0 1996 .88 1994 - 1997 1996 1994 10 1996 4 1992 11 1992 10 1996 10 1996 e Estimated 113 RIO QRANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR WATER-QUALITY RECORDS LOCATION.—L»t 18°14'20", long 66°22'58", at flat low bridge about 300 ft (91 m) northwest of Highway 568, 1.0 mi (1.6 km) north of Orocovis plaza. DRAINAGE AREA.—10.1 mi 1 (26.2 kma ). PERIOD OF RECORD.—Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... OCT 17 FEB 25 JUN 11 SEP 10 OCT 17 FEB 25 JUN 11 SEP 10 OCT 17 FEB 25 JUN 11 SEP 10 K - DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1100 12 296 7.5 24.0 0.60 7.9 96 <10 K1400 940 0930 10 330 7.6 20.0 2.5 8.0 90 <10 K1300 210 1310 5.3 352 8.4 27.0 0.23 7.0 94 <10 K180 3200 0930 2.3 378 8.2 26.0 0.35 6.8 88 <10 K160 260 ALKA- BARD- MAGNE- SODIUM POT AS- LINITY CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, WAT WH SULFATE RIDE, DATE 1996 ... 1997 ... ... ... DATE 1996 1997 ... ... ... DATE 1996 ... 1997 ... ... ... TOTAL (MG/L AS CACO3) (00900) 120 .. 140 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 0.21 0.23 0.23 DIS- SOLVED (MG/L AS CA) (00915) 28 — 36 41 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 31 29 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.3 1.2 1.3 DIS- SOLVED (MG/L AS MG) (00925) 11 — 13 14 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 180 — 212 224 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.0 5.6 5.2 5.7 DIS- SOLVED (MG/L AS NA) (00930) 13 .. 15 16 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.65 — 3.04 1.42 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.060 0.130 0.070 SORP- TION RATIO (00931) 0.5 — 0.5 0.6 RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 2 <1 <1 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — DIS- SOLVED (MG/L AS K) (00935) 2.1 __ 1.7 1.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.00 1.00 0.940 1.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — TOT FET FIELD MG/L AS CACO3 (00410) 120 130 150 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.00 1.10 0.950 1.10 CADMIUM HATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — DIS- SOLVED (MG/L AS S04) (00945) 8.1 -. 8.3 7.8 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.040 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 .. <1 — DIS- SOLVED (MG/L AS CL) (00940) 15 ._ 17 18 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 0.20 0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 .. <10 — non- ideal count 114 RIO ORANDE DE MANATI BASIN 50030700 RIO OROCOVIS NEAR OROCOVIS, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS H6) (71900) SELE- NIUM, TOTAL (UO/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LBNE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 130 60 <1 <1 20 14 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.02 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR 775 LOCATION.--Lat 18°17'45", long 66°24'47", Hydro!ogic Unit 21010001, on right bank , 0.1 mi (0.2 km) downstream from Quebrada Perchas, 0.8 mi (1.3 km) upstream from Rio Sana Muerto, and 2.2 mi (3.5 km) south of Morovis. DRAINAGE AREA.--55.2 mi* (143.0 km')- PERIOD OF RECORD.—January 1965 to current year. GAGE.--Water-stage recorder and concrete control. Elevation of gage is 440 ft (134 m), from topographic map. Feb. 2, 1966 to Apr. 27, 1967, staff gage read twice daily. REMARKS.--Records poor. Public water-supply pumpage, about 300 ft (91 m) above the station, influences low-flow discharges. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 69 e58 2 66 e52 3 67 e47 4 78 e48 5 63 e45 6 71 045 7 72 045 8 59 49 9 56 54 10 55 57 11 54 55 12 49 65 13 51 59 14 50 54 15 49 52 16 57 41 17 47 40 18 45 e!30 19 44 e!30 20 48 ellO 21 60 e!20 22 59 e!40 23 46 e!70 24 46 0200 25 47 0210 26 0160 0120 27 0210 092 28 0120 094 29 0120 096 30 0140 0150 31 074 —— TOTAL 2232 2628 MEAN 72.0 87.6 MAX 210 210 MIN 44 40 AC -FT 4430 5210 CFSM 1.30 1.59 IN. 1.50 1.77 STATISTICS OF MONTHLY MEAN MEAN 152 143 MAX 1037 491 (WY) 1971 1971 MIN 24.0 11.4 (WY) 1978 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 0160 ellO 090 078 072 064 e60 060 058 e!70 0400 elSO elOO 086 e82 elOO e84 e72 e62 e58 e60 e60 e58 e52 e51 050 e58 056 e80 084 e72 2797 90.2 400 50 5550 1.63 1.88 064 058 0210 0140 090 070 058 054 064 084 058 056 e54 066 e80 e56 e52 049 e54 elSO 0800 02100 0700 0520 0420 e250 e!90 elSO 138 117 110 7062 228 2100 49 14010 4.13 4.76 DATA FOR WATER 108 522 1966 8.65 1995 FOR 82.1 228 1997 10.4 1995 123 121 103 93 95 96 82 80 81 82 74 73 80 74 72 67 66 66 71 79 96 91 71 68 66 65 64 59 ... ... 2258 80.6 123 59 4480 1.46 1.52 YEARS 1965 63.5 179 1969 15.3 1994 57 59 66 74 91 74 60 63 62 53 53 53 54 55 57 57 57 57 52 49 46 46 42 41 39 42 43 61 154 128 62 1907 61.5 154 39 3780 1.11 1.29 - 1997 64.4 226 1972 12.7 1984 1996 CALENDAR YEAR 31831 87. 7500 13 14 63140 1. 21. 140 46 21 0 Sep 10 Jul 6 Jul 1 58 45 51 49 63 851 49 46 41 41 41 39 39 40 39 37 34 34 35 33 32 37 44 42 34 32 32 30 29 32 29 27 --- 1162 38.7 63 27 2300 .70 .78 28 28 28 28 27 26 25 25 25 26 27 24 24 24 23 23 23 25 23 21 22 26 35 080 elSO e94 068 e38 e33 59 35 1143 36.9 150 21 2270 .67 .77 32 28 29 28 26 24 22 21 21 21 19 20 20 21 19 17 17 18 23 23 19 17 16 16 17 16 16 15 14 14 609 20.3 32 14 1210 .37 .41 16 14 13 11 11 11 13 24 11 11 11 12 12 11 10 11 9.7 15 21 21 27 15 12 11 11 11 10 9.3 9.0 9.4 12 405.4 13.1 27 9.0 804 .24 .27 19 11 9.9 17 11 9.7 9.3 8.6 8.6 13 11 10 19 46 15 12 21 47 17 12 11 11 13 12 12 11 9.3 11 13 12 13 455.4 14.7 47 8.6 903 .27 .31 10 9.2 8.2 8.1 8.1 7.7 7.7 7.8 8.4 9.4 7.6 7.4 9.3 9.9 8.7 7.7 7.6 7.2 7.3 7.4 8.3 12 18 9.8 15 16 13 14 10 19 299.8 9.99 19 7.2 595 .18 .20 , BY WATER YEAR (WY) 106 412 1969 8.80 1995 157 915 1985 15.7 1994 60.2 173 1987 6.75 1994 FOR 1997 WATER YEAR 22958.6 62.9 2100 7.2 7.7 unknown unknown 45540 1.14 15.47 113 46 11 Jan 22 Sep 18 Sep 15 Jan 22 Jan 22 45.3 157 1979 5.54 1994 WATER 94. 248 24. 17100 3. 4. 48000 17. 68510 1. 23. 170 48 21 53.9 435 1979 9.70 1984 YEARS 1965 6 2 May 5 May 0 Jul May 89 May 71 28 101 432 1996 6.87 1994 - 1997 1971 1994 18 1985 1 1995 22 1994 18 1985 18 1985 e Estimated 116 PERIOD RIO GRANDE DE MMJATI BASIN 50031200 RIO GRANDE DE HANATI NEAR NOROVIS, PR—Continued MATER-QUALITY RECORDS OF RECORD.—Water years 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- CHARGE, INST. CUBIC FEET TIME PER SPE- CIFIC CON- DUCT- ANCE PH WATER WHOLE FIELD TEMPER- (STAND- ATURE ARD WATER OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- TUR- OXYGEN, (PER- ICAL BID- DIS- CENT (HIGH ITY SOLVED SATUR- LEVEL) OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) 0915 1215 1050 1230 46 63 18 9.4 238 290 304 312 7.0 8.0 8.2 8.2 25.5 25.0 28.5 30.5 0.40 1.5 4.3 6.4 8.1 10.1 8.1 8.6 98 121 105 117 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K120 K10 K49 K140 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 100 K40 K70 K54 OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MO) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS S04) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 110 26 120 28 130 31 11 12 13 13 14 15 0.5 0.5 0.6 2.8 2.1 1.8 150 110 120 130 <0.5 <0.5 8.0 8.7 6.8 16 17 17 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 — SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 191 — SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 23.8 — RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.670 0.710 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 <0.010 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.680 0.720 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.22 0.10 27 0.11 27 180 190 8.65 4.80 0.140 <0.010 0.140 0.030 0.25 DATE OCT 1996 17... FEB 1997 25... JUN 11... SEP 10... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <0.20 0.24 0.28 0.80 0.96 0.42 3.5 4.2 1.9 <0.020 0.030 0.020 <100 <100 30 <1 non-ideal count RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 117 DATE OCT 1996 17... PEB 1997 25... JUN 11... SEP 10... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L 70 230 MANGA- NESE, MERCURY TOTAL TOTAL RECOV- ERABLE RECOV- ERABLE (UG/L (UG/L SILVER, ZINC, SELE- TOTAL TOTAL NIUM, RECOV- RECOV- CYANIDE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 30 <0.10 30 <0.10 <1 <1 <1 <1 <0.010 <1 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 118 RIO GRANDE DE MANATI BASIN 50032290 LAGO EL GUINEO AT DAMSITE NEAR VTLLALBA, PR LOCATION.—Lat 18°09'41", long 66°31'36", Hydrologic Unit 21010001, at damsite on Rio Toro Negro, 3.0 mi (4.8 km) northwest from Vi11alba plaza and 1.9 mi (3.1 km) northeast of Cerro Maravillas. The reservoir itself fixes the territorial limits between the Municipality of Ciales and Orocovis. DRAINAGE AREA.—1.64 mi 2 (4.25 tan1 ). ELEVATION RECORDS PERIOD OF RECORD.—May 1988 to current year. Prior to October 1994, published as Lago El Guineo at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago El Guineo was completed in 1931. It provides a maximum storage of approximately 2,180 ac-ft (2.688 hm3 ) for power and irrigation. Waters are discharged through an outlet power tunnel into the Rio Toro Negro and coveyed to the head water works of Toro Negro Hydroelectric Plant No.2, for energy generation at Toro Negro Hydroelectric plant No.l, and are discharged into the Guayabal Reservoir to be later used for irrigation at South Coast Irrigation System. The dam is rockfill with a vertical concrete corewall, rock toes, and riprap facing of upstream slope, with a total length of 565 ft (172 m), a maximum structural height of 125 ft (38 m) to top of corewall. At a maximum reservoir water surface elevation the uncontrolled morning-glory tunnel spillway crest has an elevation of 2,966 ft (904 m) above mean sea level and a design capacity of 7,000 ftVs. The dam is owned by Puerto Rico Electric Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation 2,961.70 ft (902.73 m), Oct. 21, 1990; rainimun elevation, 2,919.79 ft (899.95 m), May 27, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,961.12 ft (902.55 m), Nov. 23; minimun elevation, 2,927.61 ft (892.34 m). May 23. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 2,872 2,919 2,925 Contents, in acre-feet 0 361 491 Elevation, in feet 2,943 2,950 2,961 Contents, in acre-feet 1,029 1,308 1,852 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT NOV DEC APR MAY JUL AUG SEP 2956.86 2956.43 2956.34 2955.93 2956.14 2956.34 2955.82 2955.28 2954.76 2954.39 2953.91 2954.07 2954.23 2953.76 2953.34 2952.89 2953.15 2953.50 2954.17 2954.68 2954.81 2955.10 2955.34 2955.15 2954.92 2955.71 2955.89 2956.05 2956.08 2955.81 2955.95 2956.10 2956.23 2956.38 2956.70 2957.24 2957.44 2957.13 2957.26 2956.91 2957.04 2958.07 2959.26 2959.56 2959.37 2960.83 2960.65 2960.95 2960.36 2959.80 2959.01 2959.04 2958.88 2959.09 2959.27 2959.32 2959.49 2959.65 2959.62 2959.58 2959.47 2959.07 2958.63 2958.81 2958.97 2959.00 2959.02 2958.99 2958.89 2958.90 2959.04 2959.15 2959.14 2958.94 2959.05 2958.85 2958.69 2958.71 2958.88 2958.99 2959.09 2958.68 2959.22 2958.89 2958.41 2958.54 2958.65 2959.07 2959.53 2959.25 2959.15 2959.28 2959.39 2959.58 2959.72 2960.13 2960.44 2960.53 2959.99 2959.42 2957.93 2958.12 2958.24 2957.87 2957.53 2957.19 2956.86 2956.96 2957.08 2956.64 2956.01 2955.38 2954.90 2954.53 2954.59 2954.68 2954.76 2954.23 2953.70 2953.36 2952.81 2952.90 2952.97 2952.47 2951.93 2950.14 2950.24 2949.66 2949.04 2948.43 2947.99 2948.06 2948.16 2948.24 2947.67 2947.08 2946.47 2945.88 2945.29 2945.38 2945.45 2945.53 2945.11 2944.91 2944.39 2943.92 2943.99 2944.05 2943.52 2942.97 2942.12 2941.58 2941.68 2941.15 2941.25 2941.29 2941.10 2940.79 2940.56 2940.36 2940.21 2940.28 2940.33 2939.65 2938.90 2938.27 2937.63 2937.05 2937.10 2937.16 2937.24 2936.58 2936.66 2936.71 2936.79 2934.31 2933.79 2933.95 2934.01 2933.30 2932.74 2932.46 2932.17 2932.17 2932.35 2932.43 2932.16 2932.24 2931.96 2931.65 2931.34 2931.40 2931.46 2931.25 2930.58 2929.54 2928.36 2928.12 2928.20 2928.27 2932.16 2931.26 2929.88 2928.60 2929.35 2927.90 2928.60 2928.68 2928.76 2928.84 2928.92 2929.00 2929.07 2929.14 2929.20 2929.26 2929.32 2929.38 2929.50 2929.63 2929.69 2929.77 2929.82 2929.87 2929.91 2930.34 2930.39 2930.44 2930.39 2930.46 2930.47 2930.56 2930.62 2930.67 2930.71 2930.67 2930.74 2930.79 2930.62 2930.66 2930.71 2930.75 2930.82 2930.97 2931.36 2931.53 2931.62 2931.54 2931.59 2931.62 2930.67 2930.71 2930.84 2930.89 2930.79 2930.83 2930.86 2932.06 2932.89 2933.72 2933.96 2934.09 2934.98 2937.43 2937.31 2937.54 2937.74 2937.26 2937.26 2936.72 2935.96 2935.29 2935.39 2935.62 2935.15 2936.79 2937.01 2937.16 2937.29 2937.42 2937.51 2937.63 2937.72 2937.50 2937.60 2937.70 2937.89 2937.99 2938.07 2938.15 2938.23 A A 2938.40 2938.51 2938.60 2938.70 2938.63 2938.51 2938.37 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 2955.16 2959.38 2959.16 2959.56 2951.37 2942.41 2936.84 2931.54 2930.00 2931.67 2935.25 2938.45 27 2955.37 28 2955.15 29 2954.93 30 2955.30 31 2955.52 MAX 2956.86 MIN 2952.89 CAL YR 1996 WTR YR 1997 2959.07 2959.36 2958.84 2959.00 —— 2960.95 2955.71 MAX 2961. MAX 2960. 2959.26 2959.37 2959.46 2959.15 2958.76 2959.65 2958.63 05 MIN 95 MIN 2959.06 2958.57 2958.10 2957.65 2957.77 2960.53 2957.65 2936.81 2927.90 2950.78 2950.18 —— 2958.24 2950.18 2942.49 2942.59 2942.81 2942.90 2942.58 2950.24 2942.41 2936.91 2936.21 2935.54 2934.98 2942.12 2934.98 2933.72 2933.30 2932.65 2931.95 2932.06 2934.31 2928.12 2930.10 2930.15 2930.24 2930.30 2932.16 2927.90 2931.71 2931.75 2931.46 2931.51 2931.31 2931.75 2930.34 2934.56 2935.92 2936.25 2936.46 2936.63 2937.74 2930.67 2938.53 2938.61 2939.35 2939.48 —— 2939.48 2936.79 A No gage-height record RIO GRANDE DE MANAT1 BASIN 50032590 LAGO DE MATRULLAS AT DAMSITE NEAR OROCOVIS, PR 119 LOCATION.--Lat 18°12'46", long 66°28'50", Bydrologic Unit 21010001, in shelter house at damsite, and 5.8 mi (9.3 km) southwest of Orocovis. DRAINAGE AREA.--4.46 mi 2 (11.55 km»). ELEVATION RECORDS PERIOD OF RECORD.—Hay 1988 to current year. Prior to October 1994, published as Lago de Matrullas at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Matrullas was completed in 1934. The dam is an earthfill structure about 120 ft (37 m) height, a top width of 30 ft (9 m) and a length of 710 ft (216 m), and has a maximum storage capacity of about 4,274 ac-ft (5.220 hra3 ) at top of dam elevation. The Matrullas Dam is owned by the Puerto Rico Electric Power Authority and is part of the Toro Negro Hydroelectric Project; a project developed by the P.R.E.P.A. for the primary purpose of generating electric power. Discharges from the Power Plants are collected by the Jacaguas River which flows into Guayabal Dam, at which dam they are regulated for irrigation of lands served by the Juana Diaz Canal. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 2,419.90 ft (737.58 m), Sept. 10, 1996; minimum elevation, 2,375.55 ft (724.06 m), Sept. 24, 25, 1994. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,416.16 ft (736.44 m), Jan. 21; minimum elevation, 2,398.96 ft (731.20 m), Aug. 8. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 2,338 2,360 Contents, in acre-feet 2 302 Elevation, in feet 2,399 2,420 Contents, in acre-feet 1,845 3,331 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN 2415.24 A 2415.22 2415.20 2415.47 A 2415.50 2415.37 2415.29 2415.24 2415.18 2415.42 2415.55 2415.41 2415.32 2415.24 2415.24 2415.19 2415.57 2415.91 2415.57 2415.45 2415.41 2415.34 2415.34 2415.70 2415.71 2415.56 2415.93 2415.63 A 2415.93 2415.18 A A A A A A A A A A A A A A A A A A A A A 2415.68 2415.76 2415.65 2415.55 2415.47 2415.43 2415.68 2415.50 2415.74 --- 2415.76 2415.43 2415.73 2415.60 2415.55 2415.54 2415.50 2415.47 2415.66 2415.69 2415.53 2415.50 2415.83 2415.63 2415.57 2415.70 2415.72 2415.60 2415.53 2415.48 2415.45 2415.45 2415.65 2415.69 2415.53 2415.39 2415.47 2415.31 2415.23 2415.49 2415.64 2415.44 2415.32 2415.83 2415.23 2415.46 2415.46 2415.69 2415.68 2415.66 2415.66 2415.47 2415.38 2415.30 2415.19 2415.41 2415.58 2415.80 2415.56 2415.39 2415.29 2415.18 2415.44 2415.78 2415.70 2416.15 2415.82 2415.64 A 2415.51 2415.69 2415.57 2415.53 2415.50 2415.48 2415.47 2416.15 2415.18 2415.67 2415.68 2415.59 2415.58 2415.57 2415.56 2415.55 2415.65 2415.66 2415.56 2415.45 2415.38 2415.40 2415.41 2415.58 2415.63 2415.64 2415.55 2415.56 2415.57 2415.54 2415.62 2415.63 2415.55 2415.50 2415.49 2415.46 2415.44 ___ ___ --- 2415.68 2415.38 2415.58 2415.63 2415.53 2415.48 2415.48 2415.45 2415.41 2415.58 2415.62 2415.50 2415.42 2415.37 2415.31 2415.23 2415.38 2415.34 2415.27 2415.20 2415.14 2415.08 2414.99 2415.12 2415.25 2415.17 2415.09 2415.02 2414.89 2415.07 2415.27 2415.41 2415.25 2415.63 2414.89 2415.07 2414.94 2414.77 2414.63 2414.75 2414.87 2414.68 2414.56 2414.45 2414.33 2414.14 2414.25 2414.35 2414.09 2413.82 2413.60 2413.37 2413.26 2413.35 2413.44 2413.54 2413.33 2413.41 2413.49 2413.57 2413.65 2413.74 2413.52 2413.27 2413.02 --- 2415.07 2413.02 2412.76 2412.47 2412.55 A A A A A A A A A A 2410.80 2410.53 2410.26 2410.35 2410.42 2410.14 2409.85 2409.58 2409.30 2409.03 2409.17 2409.29 2409.90 2409.76 2409.55 2409.28 2409.02 2409.11 2412.76 2409.02 2409.20 2408.86 2408.58 2408.23 2407.94 2407.68 A A A A A A A A A A A A 2405.24 2404.89 2404.81 2404.74 2404.36 2404.06 2403.74 2403.41 2403.01 2403.06 2403.10 2402.90 --- 2409.20 2402.90 2402.73 2402.50 2402.25 2402.27 2402.27 2402.29 2402.02 2401.76 2401.47 2401.20 2400.91 2400.93 2400.95 2400.72 2400.44 2400.19 2399.90 2399.67 2399.80 2399.97 2400.04 2399.95 2399.86 2399.77 2399.81 2399.85 2399.88 2399.92 2399.82 2399.74 2399.67 2402.73 2399.67 2399.52 2399.53 2399.60 2399.46 2399.34 2399.22 2399.10 2400.01 2402.17 2402.39 2402.37 2402.38 2403.25 2403.36 2403.37 2403.49 2403.61 2403.55 2403.50 2403.34 2403.05 2402.89 2402.96 2403.15 2403.10 2403.02 2402.87 2403.76 2403.89 2404.03 2404.23 2404.23 2399.10 2404.37 2407.64 2407.94 2408.01 2408.06 2408.20 2408.32 2408.29 2408.12 2408.08 2408.03 2408.06 2408.17 2408.26 2408.22 2408.15 2408.24 2408.31 2408.37 2408.45 2408.54 2408.55 2408.62 2408.71 2408.74 2408.79 2408.93 2409.02 2409.19 2409.24 —— 2409.24 2404.37 CAL YR 1996 WTR YR 1997 MAX 2416.52 MAX 2416.15 MIN 2411.50 MIN 2399.10 A No gage-height record 120 RIO GRANDE DE MANATI BASIN 50034000 RIO BAUTA NEAR OROCOVXS, PR LOCATION.--Lat 18°14'10", long 66°27'18", Hydrologic Unit 21010001, on left bank, at bridge on Highway 157 (12.1 km), and 4.2 mi (6.8 km) west of Orocovis. DRAINAGE AREA.--16.7 mi 1 (43.3 km 2 ). PERIOD OF RECORD.--February 1959 to April 1966 (annual low-flow measurements only), February to September 1969 (occasional measurements only), October 1969 to September 1982, October 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 772.82 ft (235.556 m) above mean sea level. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV 1 27 19 2 37 17 3 30 16 4 26 14 5 38 13 6 34 13 7 28 13 8 25 13 9 22 17 10 22 26 11 21 29 12 21 27 13 20 19 14 19 16 15 18 15 16 16 16 17 16 18 18 17 88 19 19 72 20 21 58 21 19 56 22 16 62 23 15 94 24 15 109 25 14 81 26 27 51 27 44 38 28 26 37 29 41 34 30 41 61 31 23 TOTAL 758 1142 MEAN 24.5 38.1 MAX 44 109 MIN 14 13 AC-FT 1500 2270 CFSM 1.46 2.28 IN. 1.69 2.54 STATISTICS OF MONTHLY MEAN MEAN 84.5 52.6 MAX 392 205 (WY) 1971 1971 MIN 14.6 7.12 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 61 43 35 31 29 27 26 26 25 25 131 76 49 38 34 34 33 31 29 28 28 27 25 24 24 24 24 23 24 24 24 1082 34.9 131 23 2150 2.09 2.41 DATA 27.9 108 1971 4.29 1995 JAN 23 23 43 43 28 24 23 21 21 21 21 21 21 26 25 21 21 21 35 47 6212 e!77 e!24 elOl 681 659 e44 642 636 634 632 1471 47.5 212 21 2920 2.84 3.28 FEB 633 630 629 628 628 626 626 625 625 625 625 624 625 624 623 622 621 621 24 24 24 22 21 21 20 21 19 19 ___ ___ --- 675 24.1 33 19 1340 1.44 1.50 FOR WATER YEARS 1969 21.2 83.4 1992 3.66 1995 15.1 40.1 1996 5.70 1994 MAR 18 18 18 17 20 19 18 18 18 17 16 16 16 16 15 15 15 15 16 15 15 15 14 14 14 14 14 15 23 18 14 506 16.3 23 14 1000 .98 1.13 - 1997 15.1 59.9 1972 4.18 1994 FOR 1996 CALENDAR YEAR 41802 114 19500 8 8 82920 6 93 76 16 10 .6 Sep 10 .3 Jul 6 .8 Jul 1 .84 .12 APR 14 14 16 612 ell elO 69.5 69.5 69.5 69.4 69.2 69.2 69.4 68.8 68.8 68.7 68.5 68.0 67.5 ell e!3 616 e!4 612 elO 69.0 68.6 68.0 67.6 7.0 --- 309.2 10.3 16 7.0 613 .62 .69 MAY 7.5 12 8.2 7.3 7.3 6.6 7.0 7.2 7.4 7.8 7.7 7.8 8.1 7.7 7.0 7.1 7.7 8.3 7.6 7.4 7.7 7.9 8.5 14 14 13 13 15 9.6 8.3 7.1 272.8 8.80 15 6.6 541 .53 .61 JUN 7.5 7.4 7.4 6.7 6.2 5.7 6.0 66.0 6.2 66.5 66.2 6.4 6.3 6.7 6.2 5.6 5.5 5.3 5.9 6.1 6.1 6.1 5.7 5.7 6.6 6.3 5.9 6.8 11 32 218.0 7.27 32 5.3 432 .44 .49 JUL 15 ell 69.0 65.0 65.0 65.0 66.0 68.8 64.2 64.2 64.2 64.4 64.4 64.2 63.9 65.5 63.9 3.6 4.3 5.1 6.9 4.4 4.1 3.9 3.9 3.8 4.4 4.6 4.6 4.8 9.3 171.4 5.53 15 3.6 340 .33 .38 AUG 6.6 4.6 4.3 5.2 4.3 4.6 4.4 5.0 126 639 e!3 ell 626 625 613 69.5 ell 69.2 69.5 elO 69.4 69.0 69.1 e!2 e!3 7.6 6.7 6.5 7.2 6.8 6.1 434.6 14.0 126 4.3 862 .84 .97 SEP 6.1 37 25 9.5 7.5 6.9 6.3 5.5 5.3 5.3 5.5 6.1 6.7 6.1 5.7 5.7 5.3 5.3 5.3 5.3 5.3 5.5 5.7 5.5 5.3 5.3 5.8 8.1 35 20 272.9 9.10 37 5.3 541 .54 .61 , BY WATER YEAR (WY) 26.1 80.2 1980 4.92 1995 FOR 1997 7312 20 212 3 4 924 10 14510 1 16 37 15 5 48.8 179 1981 4.24 1994 WATER YEAR .9 .0 Jan 21 .6 Jul 18 .2 Jul 22 Aug 9 . 61 Aug 9 .20 .29 .3 18.7 78.6 1979 3.59 1994 16.0 104 1979 3.22 1994 WATER 37 117 6 19500 2 2 25900 25 2 26950 2 30 63 13 5 20.1 152 1979 3.97 1994 YEARS 1969 .2 .56 Sep .8 Jul .8 Jul Sep .14 Sep .6 Jul .23 .26 .3 101 1104 1996 3.55 1994 - 1997 1996 1994 10 1996 23 1994 23 1994 10 1996 10 1996 26 1994 e Estimated RIO GRANDE DE MANATI BASIN 50035000 RIO GRANDE DE MANATI AT CIALES, PR 121 LOCATION.--Lat 18°19'26", long 66°27'36", Hydrologic Unit 21010001, on left bank, 1.6 mi (2.6 km) upstream from Hwy 145 bridge, 0.8 mi (1.3 km) downstream from Quebrada Saliente, 0.9 mi (1.4 km) upstream from Quebrada Cojo Vales, and 1.2 mi (1.9 km) southeast of Ciales. DRAINAGE AREA.--128 mi' (332 km'), excludes 6.0 mi' (15.5 km'), the runoff from which is diverted through El Guineo and de Matrullas reservoirs. PERIOD OF RECORD.--September 1946 to September 1953, May 1956 to December 1957 (unpublished, available in files of Caribbean District Office and in the National Water Data Storage and Retrieval System, Washington, D.C.); February 1959 to September 1960 (monthly discharge measurements only); October 1960 to current year. Equivalent record from January 1971 to December 1972 published as 50035200 Rio Grande de Manati at Highway 145 at Ciales at site 1.6 mi (2.6 km) downstream, drainage area 132 mi 2 (342 km'). GAGE.--Water-stage recorder. Elevation of gage is 140 ft (43 m), from topographic map. Prior to Apr. 1, 1962, staff gage, read twice daily, at site 100 ft (30 m) upstream at same datum. January 1971 to December 1972 at site 1.6 mi (2.6 km) downstream at different datum. REMARKS.—Records fair except those for estimated daily discharges, which are poor, satellite telemetry at station. Gage-height and precipitation EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate gage heights of major floods, pointed out by local residents are as follows: August 1899, 50 ft (15 m), September 1928, 36 ft (11 m), and September 1932, 34 ft (10 m) at site 1.6 mi (2.6 km) upstream. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC MAR APR MAY JUN AUG SEP 1 146 182 2 139 161 3 192 148 4 191 150 5 146 142 6 180 143 7 199 142 8 150 133 9 139 146 10 133 171 11 130 266 12 123 261 13 121 194 14 124 161 15 122 142 16 127 148 17 134 193 18 170 515 19 127 518 20 161 334 21 351 357 22 217 420 23 151 505 24 139 598 25 122 635 26 534 367 27 655 275 28 379 276 29 370 288 30 436 433 31 243 —— TOTAL 6551 8404 MEAN 211 280 MAX 655 635 MIN 121 133 AC-FT 12990 16670 CFSM 1.65 2.19 IN. 1.90 2.44 STATISTICS OF MONTHLY MEAN MEAN 425 341 MAX 2422 1006 (WY) 1971 1971 MIN 91.9 34.7 (WY) 1994 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 491 332 263 232 213 189 181 178 172 640 1200 476 315 258 247 303 247 217 187 172 179 180 171 158 151 149 176 165 235 253 211 8541 276 1200 149 16940 2.15 2.48 DATA 256 1296 1966 29.7 1995 185 171 650 446 269 205 170 157 189 258 172 169 e!60 e200 e240 e!70 e!55 e!45 e!60 eSOO e2500 e4200 elSOO ellOO e900 e550 e400 e340 e300 e260 e240 17061 550 4200 145 33840 4.30 4.96 FOR WATER 195 679 1952 26.2 1995 e230 e250 e220 e200 e!90 e!90 e!80 e!70 e!70 e!70 el55 elSO e!49 e!49 e!40 e!35 e!35 e!35 e!40 e!40 e!45 el55 e!32 e!30 e!30 e!25 el!8 112 ___ ___ 4445 159 250 112 8820 1.24 1.29 YEARS 1946 168 1394 1950 41.6 1957 el!3 e!08 e!23 e!27 e!39 e!34 ellO el!7 el!9 ellO e!06 e96 e98 e98 e94 e92 e90 e90 e92 e87 e80 e82 e76 e77 e78 e77 e!22 e!39 e!41 e365 e!75 3555 115 365 76 7050 .90 1.03 - 1997 137 477 1969 29.7 1994 FOR 1996 CALENDAR YEAR 93630 256 26400 58 60 185700 2. 27. 391 123 68 Sep 10 May 6 May 2 00 21 el!6 e96 ellO elOO e93 e86 e82 e80 e76 e74 e71 e73 e70 e67 e65 e62 e55 50 48 47 72 97 76 68 63 61 61 62 59 56 ___ 2196 73.2 116 47 4360 .57 .64 56 99 119 72 64 60 59 54 54 61 64 56 53 51 50 50 52 53 48 46 45 52 52 177 317 199 134 76 66 81 59 2479 80.0 317 45 4920 .62 .72 55 51 48 e48 e61 e50 e45 e46 e45 e43 e45 e45 e43 e41 e41 e39 e37 e39 47 46 41 35 33 31 36 34 34 43 50 97 —— 1349 45.0 97 31 2680 .35 .39 123 65 47 39 35 36 38 66 49 39 36 34 35 35 35 40 37 37 48 60 89 61 44 36 31 e29 e27 e26 e24 e24 e60 1385 44.7 123 24 2750 .35 .40 e200 e75 e40 e28 e28 24 22 22 369 208 73 50 254 232 138 62 98 141 67 64 73 47 44 39 49 39 31 97 108 53 41 2816 90.8 369 22 5590 .71 .82 38 92 195 73 51 46 41 37 38 38 32 33 42 45 41 38 34 32 30 29 34 40 57 41 54 58 52 65 166 158 1730 57.7 195 29 3430 .45 .50 , BY WATER YEAR (WY) 256 1174 1969 28.5 1984 FOR 1997 60512 166 4200 22 28 e 9800 unknown 21 120000 1 17 308 110 37 414 2293 1985 29.6 1994 WATER YEAR Jan 22 Aug 7 JUl 24 Jan 22 Jan 22 Aug 8 .30 .59 151 458 1979 17.8 1994 105 438 1979 14.1 1994 WATER 242 520 47 42700 8 9 128000 25 8 175500 1 25 438 113 51 148 1212 1979 27.0 1994 YEARS 1946 - .3 May 18 .5 JUl 28 .5 Jul 24 Sep 10 .20 Sep 10 .5 Jul 27 .89 .72 299 1295 1996 23.9 1994 1997 1971 1994 1985 1994 1994 1996 1996 1994 e Estimated 122 RIO GRANDE DE MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, RP WATER-QUALITY RECORDS LOCATION.—Lat 18°20'46", long 66°28'06", at bridge on Highway 149, about 800 ft (244 m) upstream from confluence with Rio Cialitos, 0.5 mi (0.8 km) north of Ciales plaza. DRAINAGE AREA.—136 mi 2 (352 km2 ) this excludes the 6 mi 2 (15.5 km2 ) upstream from Lago El Guineo and Lago de Matrullas, flow from which is diverted to Rio Jacaguas. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 21... FEB 1997 20... JUN 04... AUG 28... TIME 0935 1100 1015 1330 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) TEMPER- ATURE WATER (DEG C) (00010) TUR- BID- ITY (NTU) (00076) OXYGEN, DIS- SOLVED (MG/L) (00300) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 157 191 59 113 226 257 272 243 7.2 7.0 8.1 7.7 27.0 21.5 29.5 29.0 2.0 0.60 1.9 3.3 7.2 8.6 8.4 8.6 88 94 111 111 K1100 310 K1300 580 280 240 410 420 DATE OCT 1996 21... FEB 1997 20... JUN 04... AUG 28... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT PET FIELD MG/L AS CAC03 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS S04) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 85 110 98 22 27 26 7.3 9.5 8.2 13 13 0.5 0.6 0.6 2.2 2.4 2.2 74 100 110 100 <0.5 <0.5 7.9 10 10 11 15 12 OCT 1996 21... FEB 1997 20... JUN 04... AUG 28. .. FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.10 21 0.15 0.15 27 27 127 170 158 53.8 27.2 48.2 0.480 0.010 0.500 0.010 0.310 <0.010 0.090 <0.010 NITRO- NITRO- NITRO- GEN, GEN, GEN, N02+N03 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 0.490 0.050 0.37 0.510 0.030 <0.20 0.320 0.040 0.23 0.100 0.020 0.25 DATE NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) OCT 1996 21... 0.41 FEB 1997 20... <0.20 JUN 04... 0.27 AUG 28... 0.28 K = non- ideal count 0.90 0.64 0.59 0.38 4.0 2.8 2.6 1.7 0.060 0.030 0.040 0.260 <100 <100 20 30 19 RIO GRANDE DE MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 123 DATE IRON, TOTAL RECOV- ERABLE (UQ/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UQ/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 21... FEB 1997 20... JUN 04... AUO 28... 300 200 50 <0.10 56 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 124 RIO GRANDE DE MANATI BASIN 50035950 RIO CIALITOS AT HIGHWAY 649 AT CIALES, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°20'18", long 66°28'28", 100 ft (30 m) upstream from bridge on Highway 649, upstream from mouth, and about 0.4 mi (0.6 km) west of Ciales plaza. DRAINAGE AREA.--17.0 mi* (44.0 km*). PERIOD OF RECORD.--Water years 1969-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 0.7 mi (1.1 km) DATE OCT 1996 21... FEE 1997 13... jtm 04... SEP 10... OCT 21 FEB 13 JUN 04 SEP 10 OCT 21 FEB 13 JUN 04 SEP 10 OCT 21 FEB 13 JUN 04 SEP 10 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1045 17 238 7.8 25.5 0.60 8.6 103 <10 K1600 3500 1135 34 233 6.6 22.0 0.50 9.1 102 <10 K900 310 1300 9.6 247 8.1 28.5 2.0 8.1 105 <10 K80 K120 1510 9.5 237 8.5 30.0 2.8 7.3 97 <10 300 270 ALKA- HARD- MAGNE- SODIUM POT AS- LINITY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... DATE 1996 1997 . . . NESS TOTAL (MG/L AS CACO3) (00900) 92 -- 96 93 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.11 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.32 <0.20 <0.20 0.22 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- 27 27 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 -- 31 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.96 1.0 0.56 0.47 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.6 -- 7.0 6.6 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 151 -- 156 145 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.2 4.5 2.5 2.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- 11 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.16 -- 4.05 3.70 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.050 0.050 0.030 AD- SORP- TION RATIO (00931) 0.5 -- 0.5 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 4 <1 <1 1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 -- 2.0 1.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.630 0.940 0.360 0.250 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 100 97 100 93 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 10 -- 20 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 "" NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.640 0.940 0.370 0.260 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 5.9 -- 6.5 5.5 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 <0.010 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 12 11 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.30 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 11 — K « non-ideal count RIO GRANDE DE MANATI BASIN 50035950 RIO CIALITOS AT HIGHWAY 649 AT CIALES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 125 IRON, TOTAL RECOV- ERABLE (OG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (OG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (OG/L AS HN) (01055) MERCURY TOTAL RECOV- ERABLE (OG/L AS HG) (71900) SELE- NIUM, TOTAL (OG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (OG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (OG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (OG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 21... FEB 1997 13... JON 04... SEP 10... 150 150 <1 <1 20 22 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 126 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR LOCATION.—Lat 18°25'52", long 66°31'37", Hydrologic Unit 21010002, at bridge on Highway 2, and 2.3 mi (3.7 km) west of Manati. DRAINAGE AREA.—197 mi 2 (510 tan*), approximately, of which about 38 mi> (98 km 1 ) is partly or entirely noncontributing, excludes 6.0 mi* (15.5 km1 ) upstream from Lago El Guineo and Lago de Matrullas. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—1963-68 (annual maximum discharge only), February 1970 to current year. REVISED RECORDS.—WRD PR-86-1: 1970-71 (M), 1975, 1979, 1982-85 (P). GAGE.—Water-stage recorder. Elevation of gage is 14 ft (4 m), from topographic map. Prior to 1968 crest-stage gage at same site and datum 3.57 ft (1.09 m) lower. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Possible water extraction about 500 ft (152.4 m) upstream of gage by unknown source affecting low flow. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate gage heights to gage datum of major floods, pointed out by local residents, are as follows: Sept. 13, 1928, 36.6 ft (11.16 m), Sept. 27, 1932, 36.3 ft (11.06 m), and Aug. 4, 1945, 34.3 ft (10.45 m). DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR APR JUL AUG 1 231 274 2 220 224 3 229 192 4 345 181 5 248 180 6 246 176 7 285 167 8 224 170 9 201 169 10 189 189 11 183 252 12 176 259 13 172 309 14 183 204 15 209 183 16 184 165 17 165 189 18 218 390 19 176 978 20 175 494 21 268 450 22 442 689 23 216 840 24 190 855 25 165 1190 26 225 615 27 1390 453 28 488 410 29 561 419 30 617 451 31 360 TOTAL 9181 11717 MEAN 296 391 MAX 1390 1190 MIN 165 165 AC -FT 18210 23240 CFSM 1.50 1.98 IN. 1.73 2.21 735 463 372 326 299 270 251 236 224 216 1690 1270 539 369 323 391 354 292 264 243 241 259 232 220 212 208 286 224 246 340 259 11854 382 1690 208 23510 1.94 2.24 233 221 1150 1310 483 331 276 248 236 221 211 205 200 243 300 216 196 186 205 513 4560 6880 2250 1710 1420 867 630 519 470 400 367 27257 879 6880 186 54060 4.46 5.15 349 386 330 305 295 290 268 259 257 255 238 233 229 227 217 212 209 207 215 216 224 239 206 203 200 192 190 178 __. ___ —— 6829 244 386 178 13550 1.24 1.29 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1970 MEAN 722 536 MAX 2958 1803 (WY) 1971 1971 MIN 154 71.0 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 361 1498 1971 71.8 1995 FOR 270 879 1997 59.1 1995 202 444 1988 72.0 1994 172 173 184 191 185 212 180 177 184 174 168 161 159 156 152 151 149 148 150 150 144 140 138 136 134 136 138 142 207 302 181 5174 167 302 134 10260 .85 .98 - 1997 185 521 1972 56.2 1994 1996 CALENDAR YEAR 153686 420 42000 70 74 304800 2.13 29.02 522 178 95 Sep 10 Jul 6 Jul 1 153 141 151 151 142 136 130 127 125 123 121 120 119 116 112 110 107 106 103 101 108 127 115 105 99 98 97 96 98 94 —— 3531 118 153 94 7000 .60 .67 , BY WATER 353 1037 1993 49.9 1995 93 e96 172 115 94 97 94 87 85 92 105 91 86 81 79 78 78 78 76 71 71 73 81 142 258 384 212 131 119 114 105 3538 114 384 71 7020 .58 .67 YEAR (WY) 654 3178 1985 93.7 1989 96 94 88 82 77 72 67 67 67 66 64 65 65 63 61 62 60 58 66 72 69 64 62 58 61 64 61 62 70 91 —— 2074 69.1 96 58 4110 .35 .39 230 747 1987 63.8 1994 FOR 1997 WATER YEAR 91051 249 6880 50 54 13400 28.58 51 180600 1.27 17.19 428 156 62 Jan 22 Jul 29 Jul 24 Jan 21 Jan 21 Sep 20 121 94 75 62 55 52 55 61 77 59 54 e54 e55 e55 e54 e62 e58 e58 e76 e94 e!40 e94 e72 e56 54 60 55 54 50 51 95 2112 68.1 140 50 4190 .35 .40 155 577 1979 53.0 1994 WATER 364 756 96. 55900 31 33 487 145 81 70 71 60 54 51 203 695 181 120 145 527 260 143 117 293 163 114 146 105 93 86 84 84 73 85 165 116 87 5104 165 695 51 10120 .84 .96 210 1644 1979 67.9 1984 YEARS 1970 - 5 May 18 Jan 24 Jul 23 Not determined Sep 10 36. 28 263800 1. 25. 633 166 84 39 Sep 10 Jan 23 85 11 77 72 266 149 107 90 81 73 74 71 65 61 69 88 69 63 59 57 55 54 56 59 70 e64 e86 e90 e82 e90 e96 287 —— 2680 89.3 287 54 5320 .45 .51 509 2506 1996 67.4 1994 1997 1971 1994 1985 1995 1994 1996 1996 1995 e Estimated RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR—Continued WATER-QUALITY RECORDS 127 PERIOD OF RECORD.—Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 JUN 03 AUG DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. JATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) L996 1050 481 230 7.0 24.0 63 7.2 84 <10 K6500 5400 L997 1010 E199 220 7.0 25.0 5.2 7.5 88 <10 K9100 750 0945 88 334 7.5 28.5 6.0 6.8 87 <10 K7600 640 1125 70 332 7.6 28.5 10 6.6 85 <10 3400 540 ALKA- NOV HARD- NESS TOTAL (MG/L DATE AS CACO3) (00900) 1996 21... 89 FEB 26 JUN 03 AUG 28 NOV 21 FEB 26 JUN 03 AUG 28 NOV 21 FEB 26 JUN 03 AUG 1997 ... 140 . .. 140 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 ... 0.10 1997 ... 0.13 . .. 0.14 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) 1996 0.41 1997 0.28 0.56 28... 0.41 K m E « non-ideal count estimated CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 25 -- 41 43 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 21 -- 20 20 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.0 1.3 1.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.4 — 8.6 7.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 138 -- 192 182 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.6 4.4 5.8 5.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 9.6 — 11 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 179 -- 45.8 34.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.140 0.060 0.080 0.150 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- 0.4 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 60 12 15 20 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 -- 2.2 2.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 0.700 0.730 0.770 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 90 130 140 130 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.030 0.020 0.020 0.023 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 30 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 0.710 0.750 0.790 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.2 — 10 9.2 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.060 0.050 0.040 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 4 — 1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 -- 15 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.35 0.23 0.52 0.37 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 11 — 128 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 21... FEB 1997 26... JUN 03... AUG 28... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) ;01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 3000 540 <1 160 87 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <0.01 <0.01 129 LACUNA TORTUGUERO BASIN 50038200 LAGONA TORTUOUERO OUTLET NEAR VEGA BAJA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°28'29", long 66°26'50", at bridge on Highway 686, 4.2 mi (6.8 km) northeast of 4.4 mi (7.1 km) northwest of Vega Baja plaza. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Water years 1964-66, 1969-71, 1974 to current year. Manati, and DATE NOV 1996 06... FEE 1997 18... MAY 16... SEP 04... TIME 1115 0815 1045 0950 WATER-QUA SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 1130 750 920 1140 LITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PH OXYGEN, OXYGEN COLI- WATER DIS- DEMAND, FORM, WHOLE FIELD (STAND- ARD UNITS) (00400) 6.7 7.0 7.8 7.7 TEMPER- ATURE WATER (DEG C) (00010) 28.5 25.0 29.0 30.5 OXYGEN, DIS- SOLVED (MG/L) (00300) 4.1 4.6 3.6 5.2 SOLVED (PER- CENT SATUR- ATION) (00301) 50 54 46 69 CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 20 14 31 28 FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K660 220 220 420 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 220 200 2700 810 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 140 120 100 DATE NOV 1996 06... FEB 1997 18... MAY 16... SEP 04... SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 4 6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.230 0.580 0.100 0.150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.020 <0.010 0.014 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.240 0.590 0.110 0.170 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.550 0.120 0.180 0.170 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.74 0.76 1.1 1.2 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.3 0.88 1.2 1.4 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.5 1.5 1.4 1.5 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 6.8 6.5 6.0 6.7 DATE NOV 1996 06... FEB 1997 18... MAY 16... SEP 04... PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 0.030 <0.020 <0.020 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 80 — 60 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 12 — IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 70 — 100 — MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) <10 — 11 — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) <10 -- <10 — CYANIDE TOTAL (MG/L AS CN) (00720) <0.010 -- <0.010 — PHENOLS TOTAL (UG/L) (32730) 1 — <1 -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.03 -- 0.07 — K - non-ideal count 130 THIS PAGE WAS LEFT BLANK INTENTIONALLY 131 ATLANTIC OCEAN Drainage boundaries in 1969-76, 1979 to currant year. 133 HATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARQE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 28... 0810 26 309 7.1 23.5 5.6 7.2 83 <10 K890 600 FEB 1997 26... 1430 22 395 7.1 25.0 1.3 7.7 91 <10 >60000 1000 MAY 14... 1140 6.9 387 8.0 27.0 1.7 8.3 105 <10 K1100 380 SEP 08... 0915 4.4 499 7.8 27.5 1.0 6.6 84 <10 K720 470 ALKA- DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 120 -- 140 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.12 0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 29 -- 36 33 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 25 -- 33 34 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 11 — 12 12 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 189 — 225 210 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 -- 21 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 13.1 — 4.16 2.49 SODIUM AD- SORP- TION RATIO (00931) 0.6 -- 0.8 0.8 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 10 3 4 4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.0 — 3.7 3.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.70 2.30 2.70 2.20 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 110 130 130 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.030 0.030 0.066 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.70 2.30 2.80 2.20 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 17 — 13 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.140 0.060 0.060 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 23 — 28 24 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.27 0.32 0.39 0.30 K - non- ideal count 134 RIO CIBUCO BASIN 50038320 RIO CIBUCO BELOW COROZAL, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 28... PEB 1997 26... MAY 14... SEP 08... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.30 0.47 0.46 0.36 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.0 2.8 3.2 2.6 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.8 12 14 12 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.130 0.210 0.340 0.680 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- <1 -- BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 -- CADMIUM MATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 — 1 -- COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 13 — DATE OCT 1996 28... FEB 1997 26... MAY 14... SEP 08... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- ZiENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 480 100 <1 <1 30 50 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.06 RIO CIBUCO BASIN 1 35 50039500 RIO CIBtJCO AT VEGA BAJA, PR LOCATION.--Lat 18°26'53«, long 66°22'29", Hydrologic Unit 21010002, on left bank, at bridge on Bwy 2, 0.6 mi (1.0 km) downstream from Rio Indio, and 0.8 mi (1.3 km) east of Vega Baja. DRAINAGE AREA.—99.1 mi 3 (256.7 km1 ), of which 25.4 mi 3 (65.8 km1 ), does not contribute directly to surface runoff. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1973 to current year. GAGE.—Hater-stage recorder. Datum of gage is 7.79 ft (2.374 m) above mean sea level. REMARKS.—Records fair, except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Dec. 11, 1965 reached a stage of 26.2 ft (7.99 m), datum unknown, discharge about 28,000 ftVs (793 mVs). DISCHARGE, CUBIC FEET PER SECOND, WATER T DAY OCT NOV 1 88 155 2 83 115 3 77 124 4 117 97 5 133 82 6 126 115 7 75 104 8 63 115 9 72 94 10 65 92 11 58 161 12 54 219 13 50 725 14 86 292 15 54 243 16 60 145 17 44 121 18 42 205 19 e42 264 20 e46 324 21 e42 207 22 e42 656 23 e54 871 24 e45 676 25 e56 759 26 e330 335 27 e!20 245 28 e50 256 29 e200 250 30 e!80 423 31 163 —— TOTAL 2717 8470 MEAN 87.6 282 MAX 330 871 MIN 42 82 AC-FT 5390 16800 CFSM .88 2.85 IN. 1.02 3.18 STATISTICS OF MONTHLY MEAN MEAN 155 194 MAX 559 523 (WY) 1986 1980 MIN 45.9 40.0 (WY) 1974 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 359 251 202 183 161 143 132 121 116 113 612 270 136 112 151 518 210 152 125 109 121 133 103 172 134 113 543 230 301 337 223 6586 212 612 103 13060 2.14 2.47 JAN 165 176 291 494 245 208 149 131 117 108 100 95 87 93 112 80 72 67 89 211 1250 2270 815 894 544 382 308 284 247 217 200 10501 339 2270 67 20830 3.42 3.94 DAILY FEB 188 184 161 151 173 144 139 131 153 129 110 114 134 107 102 92 94 86 103 97 225 217 125 128 125 90 80 70 —— 3652 130 225 70 7240 1.32 1.37 DATA FOR WATER YEARS 1973 172 1316 1982 25.1 1995 FOR 103 339 1997 30.2 1995 88.8 190 1988 27.3 1994 BAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN VALUES MAR 64 69 86 134 139 129 85 109 114 83 78 75 73 70 68 66 64 64 64 62 60 54 56 54 45 44 45 63 84 55 47 2303 74.3 139 44 4570 .75 .86 - 1997 83.6 339 1990 20.5 1994 1996 CALENDAR YEAR 55145 151 12800 18 20 109400 1.52 20.70 252 63 28 Sep 10 Jul 5 Jun 30 APR 47 45 52 56 60 58 52 50 50 49 47 45 42 41 39 36 35 36 36 35 45 39 41 35 33 35 34 35 32 32 —— 1272 42.4 60 32 2520 .43 .48 MAY 31 31 30 33 30 31 29 29 29 29 29 29 29 30 29 28 27 24 23 24 25 26 26 133 249 274 224 95 51 46 40 1763 56.9 274 23 3500 .57 .66 JUN 40 36 37 34 31 29 28 27 26 26 25 25 24 22 21 21 20 18 m28 36 25 24 26 34 45 28 25 23 22 22 —— 828 27.6 45 18 1640 .28 .31 JUL 26 27 21 19 19 22 22 25 39 27 22 20 20 20 21 28 31 31 44 46 47 39 28 *[26 25 40 27 23 22 22 36 865 27.9 47 19 1720 .28 .32 AUG 30 28 25 29 29 26 24 •20 •21 •18 •41 •22 •21 •30 •40 •31 •76 e82 48 25 25 •23 •26 •33 •33 •21 •24 •25 •150 •54 •45 1125 36.3 150 18 2230 .37 .42 SEP •28 •26 •22 e24 •21 e20 •20 •20 •94 •40 •21 •21 •70 •60 •38 •24 •22 •21 •20 •19 •35 •34 •54 •38 •210 •110 •60 •45 •35 e38 —— 1290 43.0 210 19 2560 .43 .48 , BY WATER YEAR (WY) 150 667 1987 16.2 1984 FOR 1997 41372 113 2270 18 22 2730 14 82060 1 15 244 54 23 190 655 1985 24.7 1977 WATER YEAR Jan 22 Jun 18 Jun 12 Jan 22 .66 Jan 22 .14 .53 70.3 239 1987 12.5 1994 51.4 162 1979 14.0 1994 78.6 461 1979 21.2 1978 WATER YEARS 1973 - 122 236 38.5 14600 7.2 8.1 34000 19.10 7.2 88060 1.23 16.67 225 58 22 Dec 13 May 3 • Apr 28 Apr 12 Apr 12 May 2 141 690 1996 26.7 1994 1997 1982 1994 1981 1995 1995 1987 1987 1995 e Estimated 136 RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEGA BAJA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. 1ATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1000 99 333 7.2 24.5 63 6.3 74 <10 K7700 K20000 .997 1140 85 448 6.8 23.5 18 7.9 91 <10 K1000 210 1445 28 470 8.0 27.5 3.0 6.6 83 <10 560 330 1200 21 479 7.8 29.5 2.5 5.2 68 <10 K1700 560 ALKA- DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... DATE OCT 1996 28... FEB 1997 18... MAY 16... SEP 04... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 130 -- 200 190 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.14 0.11 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.71 <0.20 0.32 1.4 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 41 — 65 61 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 16 -- 20 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 1.7 2.2 3.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.0 -- 10 9.2 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 188 — 268 257 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 9.2 7.6 9.6 15 SODIUM, DIS- SOLVED (MG/L AS NA) (00.930) 11 -- 18 19 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 50.4 — 20.4 14.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.190 0.080 0.160 0.170 SODIUM AD- SORP- TION RATIO (00931) 0.4 — 0.6 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 84 <1 5 3 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.4 -- 2.7 3.1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.30 1.50 1.80 2.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 180 190 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.020 0.020 0.019 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- <10 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.40 1.60 1.80 2.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 14 — 13 13 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.090 0.030 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 5 — 3 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 17 -- 26 28 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.62 <0.20 0.29 1.4 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 -- K - non- ideal count RIO CIBUCO BASIN 50039500 RIO CIBUCO AT VEQA BAJA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 137 IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) OCT 1996 28... FEB 1997 18... MAY 16... 2800 690 <1 130 110 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 <0.01 04... 138 THIS PAGE WAS LEFT BLANK INTENTIONALLY 139 SAN JUAN igneous and sedimentary rocfc* 8AYAMON / \ i Limestone x igneous ond \ s*dim*nfory rocks v / \ I J fifffrtSO • tf I I I ! I 'j,a,in '"**&,/' ^ 01234 MILES ^ Figure 17.--Rio de la Plata basin. 140 RIO DE LA PLATA BASIN 50039990 LAGO CARITE AT GATE TOWER NEAR CAYEY, PR LOCATION.--Lat 18°03'46", long 66°05'58", Hydrologic Unit 21010005, on top of a concrete tower at diversion tunnel on Carite Reservoir, 0.7 mi (1.1 km) northwest from Escuela Carite Chino, 1.2 mi (1.9 km) northeast from Central Hidroelectrica de Carite Num. 1 and 1.8 mi (2.9 km) northeast from Escuela Segunda Unidad. DRAINAGE AREA.--8.20 mi* (21.24 km2 ). ELEVATION RECORDS PERIOD OF RECORD.--Hay 1989 to current year. Prior to October 1994, published as Lago Carite at Gate Tower. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.--Lago Carite Dam was completed in 1913. The operation of the reservoir is controlled by the utilization of water to meet the demands for domestic, industrial and agricultural purposes in the Guayama Area. The dam is an earthfill with crest elevation of 1,806 ft (550 m) above mean sea level, with a structural height of 104 ft (32 m) and a lenght of 500 ft (152 m). The dam has a capacity of approximately 11,310 acre-feet (13.9 hm3 ). The Dam is operated by the Puerto Rico Electric and Power Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 1,788.73 ft (545.20 m), Sep. 10, 1996; minimum elevation, 1,761.22 ft (536.81 m), May 28, 1995. EXTREMES FOR CURRENT YEAR.--Maximum elevation 1,782.08 ft (543.18 m), Nov. 12; minimum elevation, 1,768.95 ft (539.18 m), Sep. 21. Capacity Table (based on Data from Puerto Rico Electric Power Authority) Contents, in acre-feet Elevation, in feet Elevation, in feet 1,746 0 1,760 2,471 1,769 4,561 1,775 1,780 1,790 Contents, in acre-feet 6,194 7,704 11,048 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT DEC JUN JUL AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN CAL WTR A A A A 1781.52 1781.54 1781.52 1781.49 1781.54 1781.67 1781.63 1781.56 1781.52 1781.52 1781.55 1781.55 1781.49 1781.53 1781.54 1781.50 1781.40 1781.36 1781.38 1781.48 1781.43 1781.47 1781.48 1781.49 1781.45 1781.45 1781.48 1781.67 1781.36 YR 1996 YR 1997 1781.55 1781.51 1781.50 1781.53 1781.51 1781.51 1781.51 1781.52 1781.50 1781.45 1781.91 1782.08 1781.85 1781.68 1781.59 1781.54 1781.54 1781.50 1781.50 1781.56 1781.88 1781.65 1781.62 1781.54 1781.48 1781.46 1781.44 1781.45 1781.44 1781.44 1782.08 1781.44 MAX 1782. MAX 1782. 1781.46 1781.45 1781.43 1781.41 1781.43 1781.46 1781.42 1781.43 1781.40 1781.38 1781.64 1781.55 1781.50 1781.50 1781.51 1781.45 1781.43 1781.43 1781.43 1781.42 1781.34 1781.37 1781.38 1781.37 1781.38 1781.35 1781.35 1781.34 1781.56 1781.56 1781.50 1781.64 1781.34 84 MIN 08 MIN 1781.47 1781.43 1781.48 1781.39 1781.40 1781.39 1781.34 1781.33 1781.31 1781.29 1781.38 1781.34 1781.34 1781.28 1781.25 1781.30 1781.20 1781.18 1781.18 1781.22 1781.36 1781.53 1781.50 1781.50 1781.49 1781.46 1781.42 1781.43 1781.43 1781.37 1781.38 1781.53 1781.18 1779.31 1768.99 1781.61 1781.56 1781.54 1781.49 1781.51 1781.47 1781.48 1781.44 1781.48 1781.44 1781.41 1781.41 1781.55 1781.57 1781.48 1781.49 1781.40 1781.47 1781.44 1781.44 1781.51 1781.53 1781.56 1781.47 1781.48 1781.57 1781.58 1781.51 ___ ___ ___ 1781.61 1781.40 1781.44 1781.47 1781.44 1781.44 1781.41 1781.38 1781.36 1781.40 1781.40 1781.37 1781.30 1781.32 1781.33 1781.29 1781.35 1781.39 1781.37 1781.39 1781.31 1781.37 1781.32 1781.25 1781.21 1781.25 1781.19 1781.10 1781.11 1781.19 1781.15 1781.12 1781.12 1781.47 1781.10 1780.99 1781.51 1781.48 1781.45 1781.41 1781.33 1781.33 1781.28 1781.28 1781.20 1781.17 1781.13 1781.15 1781.05 1781.04 1781.04 1780.98 1780.95 1780.91 1780.89 1780.70 1780.76 1780.68 1780.66 1780.63 1780.43 1780.29 1780.13 1779.99 1779.87 ___ 1781.51 1779.87 1779.70 1779.65 1779.51 1779.35 1779.25 1779.15 1778.99 1778.88 1778.80 1778.69 1778.58 1778.45 177*. 37 1778.28 1778.17 1778.08 1778.03 1777.91 1777.78 1777.67 1777.53 1777.38 1777.23 1777.13 1776.98 1776.82 1776.78 1776.66 1776.56 1776.46 1776.39 1779.70 1776.39 1776.27 1776.23 1776.30 1776.23 1776.12 1775.97 1775.84 1775.72 1775.57 1775.45 1775.31 1775.18 1775.04 1774.94 1774.81 1774.68 1774.55 1774.40 1774.25 1774.12 1774.01 1773.85 1773.73 1773.59 1773.45 1773.33 1773.21 1773.06 1772.92 1772.78 ___ 1776.30 1772.78 1772.63 1772.50 1772.36 1772.22 1772.11 1772.03 1771.92 1771.81 1771.67 1771.55 1771.40 1771.28 1771.17 1771.04 1770.91 1770.85 1770.75 1770.65 1770.64 1770.73 1770.90 1770.81 1770.72 1770.64 1770.52 1770.45 1770.39 1770.40 1770.29 1770.19 1770.24 1772.63 1770.19 1770.20 1770.14 1770.11 1770.09 1770.04 1770.00 1769.97 1769.94 1769.94 1770.02 1770.02 1770.01 1769.96 1769.85 1769.84 1769.76 1769.73 1769.68 1769.60 1769.51 1769.42 1770.85 1770.88 1771.11 1771.12 1771.09 1771.03 1770.96 1770.93 1770.92 1770.89 1771.12 1769.42 1770.81 1770.77 1770.66 1770.54 1770.45 1770.34 1770.22 1770.13 1770.02 1769.90 1769.78 1769.72 1769.67 1769.59 1769.52 1769.39 1769.32 1769.23 1769.11 1768.99 1769.23 1769.36 1769.46 1769.42 1769.44 1769.54 1769.53 1769.48 1769.47 1769.44 ___ 1770.81 1768.99 A No gage-height record RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1958 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 141 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. JATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) L996 1000 55 379 7.8 27.0 1.2 8.0 100 <10 K150 410 L997 1115 19 376 6.9 23.5 1.2 8.7 102 <10 K50 K73 0945 20 393 8.1 27.0 2.4 7.9 101 <10 250 360 1045 77 333 7.8 27.5 2.2 7.0 92 <10 24000 9400 ALKA- DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... DATE OCT 1996 09... FEB 1997 19... MAY 13... SEP 09... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 140 -- 120 110 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.14 0.12 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 0.28 0.48 0.57 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 — 30 31 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 20 -- 22 17 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.4 1.7 1.8 1.8 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- 12 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 265 -- 221 203 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.2 7.5 7.9 7.8 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 28 -- 31 29 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 39.6 -- 12.0 42.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.130 0.170 0.320 0.150 SODIUM AD- SORP- TION RATIO (00931) 1 -- 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 2 <1 1 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 _- 1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 -- 2.5 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.20 1.40 1.30 1.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 160 140 130 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 0.030 0.054 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 _- 60 -- SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 1.40 1.30 1.20 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -_ <1 -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 19 -- 17 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.020 0.040 0.090 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 51 -- 29 36 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.43 0.48 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- 10 — K • non-ideal count 142 RIO DE LA PLATA BASIN 50043000 RIO DE LA PLATA AT PROYECTO LA PLATA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- DATE IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (OG/L (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RECOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (OG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 09... FEE 1997 19... MAY 13... SEP 09... 80 170 <1 <1 20 <0.10 27 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.10 143 RIO DE LA. PLATA BASIN 50043800 RIO BE LA PLATA AT COMERIO, PR LOCATION.--Lat 18e13'23", long 66»13'30", Hydrologic unit 21010005, on right bank 50 ft (15 m) upstream from bridge off Highway 167 in the Town of Comerio, 0.4 mi (0.6 km) southwest of Comerio High School, and 0.2 mi (0.3 km) northeast of Plaza de Comerio. DRAINAGE AREA.--109 mi* (282 km'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 604.2 ft (184.160 m) above mean sea level. REMARKS.—Records fair. Filtration plant more or less 1,000 feet upstream from station. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO DAILY MEAN VALUES DAY OCT NOV JAN MAR APR MAY JUN 1997 JtJL AUQ SEP 1 84 65 2 82 67 3 83 67 4 85 62 5 79 64 6 79 60 7 87 57 8 77 58 9 75 61 10 80 65 11 94 217 12 86 409 13 79 489 14 75 252 15 77 186 16 75 153 17 66 134 18 63 184 19 84 199 20 92 215 21 76 212 22 73 445 23 66 293 24 62 193 25 58 151 26 64 99 27 108 82 28 87 88 29 123 84 30 161 93 31 69 —— TOTAL 2549 4804 MEAN 82.2 160 MAX 161 489 MIN 58 57 AC-FT 5060 9530 CFSM .76 1.48 IN. .87 1.65 STATISTICS OF MONTHLY MEAN MEAN 191 96.3 MAX 866 166 (WY) 1991 1993 MIN 40.6 19.0 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 129 101 84 72 71 65 62 63 57 55 194 153 73 60 55 51 48 46 41 39 34 35 33 33 35 35 36 35 47 64 98 2004 64.6 194 33 3970 .60 .69 56 41 36 34 32 31 30 31 31 29 30 37 33 30 36 33 31 27 29 45 153 627 249 e!90 el49 el!9 e90 e74 76 72 65 2546 82.1 627 27 5050 .76 .87 DATA FOR WATER 54.4 112 1993 17.1 1995 FOR 144 732 1992 21.3 1995 157 168 107 80 70 67 64 60 60 64 59 57 57 75 71 63 61 56 54 57 71 99 76 80 62 74 103 75 —— 2147 76.7 168 54 4260 .71 .74 YEARS 1989 81.6 247 1989 24.4 1990 66 62 62 63 64 60 54 54 54 51 49 44 44 45 45 48 52 47 41 41 39 38 35 31 30 30 29 40 89 66 39 1512 48.8 89 29 3000 .45 .52 - 1997 41.9 75.7 1989 20.6 1993 1996 CALENDAR YEAR 86395 236 32400 13 15 171400 2. 29. 320 66 21 Sep 10 May 5 May 1 18 62 35 33 344 82 60 51 42 38 36 35 34 34 34 33 32 32 31 30 30 29 29 30 30 29 28 28 29 38 41 40 —— 1397 46.6 344 28 2770 .43 .48 35 34 36 34 33 33 33 33 33 48 52 39 36 36 37 39 46 59 41 35 34 35 48 292 75 47 42 37 33 37 44 1496 48.3 292 33 2970 .44 .51 36 33 32 43 37 30 27 26 24 22 21 20 20 20 21 22 18 e!9 22 19 23 21 18 20 23 20 17 19 18 16 —— 707 23.6 43 16 1400 .22 .24 16 16 15 14 14 14 24 25 19 17 15 15 14 14 13 15 19 35 24 23 56 116 42 28 26 22 21 22 42 32 33 801 25.8 116 13 1590 .24 .27 31 24 19 16 14 12 12 12 12 13 14 13 13 14 14 13 18 20 19 23 15 222 261 54 359 56 28 24 40 24 16 1425 46.0 359 12 2830 .42 .49 14 14 14 12 11 11 11 14 141 31 16 16 20 26 19 18 14 12 12 11 12 23 51 37 32 49 78 31 20 16 —— 786 26.2 141 11 1560 .24 .27 , BY WATER YEAR (WY) 53.3 162 1993 22.3 1991 FOR 1997 22174 60 627 11 12 1750 6 43980 7 107 39 16 90.0 263 1992 19.7 1994 WATER YEAR .8 Jan 22 Sep 5 Sep 1 Aug 22 .19 Aug 22 .56 .60 77.5 213 1996 13.2 1994 97.0 291 1993 10.4 1994 WATER 113 239 35 32400 5 7 127000 29 81770 1 14 159 35 15 75.9 193 1996 12.7 1994 YEARS 1989 - .3 Sep 10 .8 Jun 25 .3 Jul 31 Jan 5 .22 Jan 5 .04 .13 382 1433 1996 26.2 1997 1997 1996 1994 1996 1994 1994 1992 1992 e Estimated 144 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COHERIO, PR—Continued WATER-QUALITY RECORDS PERIOD or RECORDS.-- Water years 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1989 to current year. INSTRUMENTATION.— USD-77 sediment sampler since 1989. Automatic sediment sampler since 1989. REMARKS.—Sediment samples were collected by a local observer on a week basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 8,800 mg/L Jan. 05, 1992; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 950,000 tons (862,000 tonnes) Jan. 05, 1992; Minimum daily mean, 0.04 tons (0.04 tonne) November 28, 1994. EXTREMES FOR WATER YEARS 1997.— SEDIMENT CONCENTRATION: Maximun daily mean, 494 mg/1 May 24, 1997; Minimun daily mean, 1 mg/L April 18, 1997. SEDIMENT LOADS: Maximun daily mean, 611 tons (554 tonnes) January 22, 1997; Minimun daily mean .11 tons (.10 tonnes) April 18, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 84 82 83 85 79 79 87 77 75 80 94 86 79 75 77 75 66 63 84 92 76 73 66 62 58 64 108 87 123 161 69 10 11 11 10 9 8 39 17 7 10 14 18 18 18 16 11 8 6 24 16 6 11 18 19 19 23 57 47 18 83 31 2.3 2.3 2.4 2.2 1.9 1.7 9.5 3.6 1.4 2.0 3.5 4.3 3.9 3.6 3.3 2.3 1.4 1.0 6.3 4.2 1.3 2.2 3.1 3.1 3.0 4.1 17 11 8.8 53 5.8 65 67 67 62 64 60 57 58 61 65 217 409 489 252 186 153 134 184 199 215 212 445 293 193 151 99 82 88 84 93 65 67 67 62 64 60 57 58 61 65 217 409 489 252 186 153 134 184 199 215 212 445 293 193 151 99 82 88 84 93 19 14 10 8 10 11 13 14 21 20 111 228 347 121 51 24 22 64 116 243 375 239 163 168 61 22 45 79 59 42 3.2 2.5 1.8 1.4 1.7 1.9 2.0 2.2 3.6 3.7 228 267 481 85 26 10 8.1 45 65 163 228 329 134 90 26 6.0 9.9 19 13 11 TOTAL 2549 175.5 4804 2268.0 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 129 101 84 72 71 65 62 63 57 55 194 153 73 60 55 51 48 46 41 39 34 35 33 33 35 35 36 35 47 64 98 2004 38 21 11 6 6 7 7 7 8 8 82 47 30 21 15 11 8 6 5 4 4 5 5 6 7 8 9 12 23 17 19 —— 13 5.6 2.4 1.2 1.2 1.2 1.2 1.2 1.2 1.2 57 22 5.9 3.5 2.3 1.5 1.0 .73 .57 .47 .39 .44 .48 .54 .66 .76 .93 1.1 3.3 2.9 5.9 141.77 RIO DE IA PLATA BASIN 50043800 RIO DE IA PIATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 745 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS/DAY) (CFS) (MO/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 56 41 36 34 32 31 30 31 31 29 30 37 33 30 36 33 31 27 29 45 153 627 249 e!90 e!49 el!9 e90 e74 76 72 65 8 7 9 10 13 15 18 20 17 14 12 17 10 23 90 20 23 20 15 23 71 338 133 55 23 10 4 3 8 7 5 1.2 .82 .85 .96 1.1 1.2 1.5 1.7 1.4 1.1 .99 1.8 .90 3.2 9.7 1.8 2.0 1.5 1.2 2.9 69 611 95 e22 e7.8 e2.7 e.96 e.61 1.8 1.3 .93 FEBRUARY 157 168 107 80 70 67 64 60 60 64 59 57 57 75 71 63 61 56 54 57 71 99 76 80 62 74 103 75 ___ 56 94 21 19 18 17 15 13 11 11 12 12 12 11 11 11 10 10 12 13 23 51 41 9 5 10 19 12 —— 64 51 6.2 4.0 3.4 3.2 2.6 2.0 1.8 2.0 1.9 1.8 1.8 2.3 2.1 1.8 1.7 1.6 1.7 2.1 4.8 14 8.4 2.1 .84 2.6 5.9 2.4 —— —— CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH TOTAL 2546 850.92 2147 200.04 66 62 62 63 64 60 54 54 54 51 49 44 44 45 45 48 52 47 41 41 39 38 35 31 30 30 29 40 89 66 39 1512 11 11 12 18 22 18 14 12 15 20 22 17 13 11 13 15 18 18 19 19 19 19 21 23 24 23 23 25 55 46 39 2.0 1.9 2.0 3.0 3.8 2.9 2.0 1.7 2.2 2.7 2.9 2.0 1.5 1.3 1.5 2.0 2.5 2.3 2.1 2.1 2.0 2.0 2.0 1.9 1.9 1.9 1.8 3.2 17 8.3 4.1 90.5 e Estimated 146 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CPS) (MG/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 35 33 344 82 60 51 42 38 36 35 34 34 34 33 32 32 31 30 30 29 29 30 30 29 28 28 29 38 41 40 APRIL 31 22 159 50 39 31 24 19 17 18 19 18 15 13 9 4 2 1 3 7 11 11 10 9 11 12 14 19 16 13 —— MAY 2.9 1.9 227 11 6.3 4.2 2.8 2.0 1.6 1.7 1.7 1.7 1.4 1.1 .78 .36 .16 .11 .23 .51 .90 .88 .80 .73 .82 .95 1.1 1.9 1.7 1.4 —— 35 34 36 34 33 33 33 33 33 48 52 39 36 36 37 39 46 59 41 35 34 35 48 292 75 47 42 37 33 37 44 12 11 11 10 11 13 14 13 12 23 29 28 29 37 49 56 45 29 12 13 14 16 95 494 42 34 41 36 32 29 29 1.1 1.0 1.0 .96 1.0 1.1 1.2 1.1 1.0 3.3 4.1 2.9 2.8 3.6 5.0 6.0 5.6 4.7 1.3 1.2 1.3 1.5 25 387 8.9 4.3 4.6 3.6 2.8 2.9 3.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 36 33 32 43 37 30 27 26 24 22 21 20 20 20 21 22 18 »19 22 19 23 21 18 20 23 20 17 19 18 16 28 26 20 103 139 93 61 41 28 19 14 13 12 12 18 26 20 18 65 55 47 41 35 22 12 10 8 9 10 9 2.8 2.3 1.8 14 14 7.5 4.4 2.8 1.8 1.1 .80 .72 .67 .64 1.1 1.6 .99 el.l 3.8 2.9 3.0 2.3 1.7 1.2 .78 .54 .38 .46 .47 .39 TOTAL 1397 280.63 1496 495.26 707 78.04 e Estimated RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 147 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 16 16 15 14 14 14 24 25 19 17 15 15 14 14 13 15 19 35 24 23 56 116 42 28 26 22 21 22 42 32 33 801 22174 JULY 8 7 7 6 6 7 12 14 13 11 10 9 8 7 6 7 9 18 13 12 26 61 22 15 14 13 12 11 20 16 16 —— AUGUST .32 .29 .26 .24 .22 .26 .85 .96 .64 .50 .41 .34 .29 .25 .22 .29 .49 1.7 .82 .73 4.0 23 2.6 1.2 1.0 .75 .68 .63 2.7 1.4 1.4 49.44 5540.07 31 24 19 16 14 12 12 12 12 13 14 13 13 14 14 13 18 20 19 23 15 222 261 54 359 56 28 24 40 24 16 1425 15 12 9 8 7 6 6 6 6 7 7 6 6 7 7 7 9 11 10 10 7 109 136 28 183 29 14 12 26 25 28 —— 1.3 .74 .46 .32 .24 .20 .20 .20 .20 .24 .25 .22 .22 .26 .27 .27 .44 .60 .52 .64 .29 370 154 4.2 282 4.8 1.1 1.0 3.3 1.6 1.2 831.28 SEPTEMBER 14 14 14 12 11 11 11 14 141 31 16 16 20 26 19 18 14 12 12 11 12 23 51 37 32 49 78 31 20 16 —— 786 26 21 17 14 14 15 15 13 72 22 15 11 11 17 18 19 18 13 9 7 6 11 26 20 17 25 41 16 11 9 —— —— .97 .78 .63 .47 .44 .45 .43 .47 38 1.8 .66 .46 .64 1.2 .91 .90 .68 .44 .30 .20 .19 1.1 3.6 2.1 1.5 7.4 9.6 1.4 .59 .38 —— 78.69 148 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE MAY 1997 24... TIME 0645 DIS- CHARGE, INST. CUBIC PER SECOND (00061) 67 SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. PALL DIAM. SED. SUSP. FALL DIAM. SED. SUSP. PALL DIAM. (T/DAY) (80155) * FINER * FINER * FINER THAN THAN THAN .002 MM .004 MM .008 MM (70326) (70327) (70328) 4230 788 44 56 67 DATE MAY 1997 24... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 81 89 99 100 100 100 100 RIO DE LA PLATA BASIN 50043800 RIO DE LA PLATA AT COMERIO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 149 NOV 13 JAN 23 MAY 24 SEP 09 DATE 1996 ... 1997 ... ... ... TIME 1910 0745 0630 0715 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 555 289 67 248 SEDI- MENT, SUS- PENDED (MG/L) (80154) 699 2370 318 129 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1050 1850 57 86 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 100 100 100 91 150 RIO DE LA PLATA BASIN 50044000 RIO DE LA PLATA NEAR COMERIO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°14'33", long 66°12'28", at bridge on Highway 156, 0.56 mi (0.9 km) upstream from dam, about 2.0 mi (3.2 km) northeast of Comerio plaza. DRAINAGE AREA.--139 mi 1 (360 tan'), excludes 8.2 mi' (21.1 tan1 ) upstream from Carite Reservoir, the flow of which is diverted to Rio Guamani. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DATE OCT 1996 08... FEB 1997 24... JUN 06... SEP 05... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEW- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1230 91 0935 110 1105 36 1100 19 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 160 — 150 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 ~ 0.16 0.13 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.23 0.30 0.38 0.30 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 39 — 34 34 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 23 ~ 29 26 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.4 1.5 0.91 0.82 432 424 408 390 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 15 — 16 14 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 256 — 238 227 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 6.0 6.5 4.0 3.6 7.7 7.7 8.1 8.2 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 23 — 25 24 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 63.2 — 23.4 11.8 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.090 0.080 0.080 0.110 28.0 1 22.0 1 28.0 4 29.5 3 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 3 <1 3 10 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 1 __ .0 .2 .3 .1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.9 — 2.3 2.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 1.20 0.520 0.500 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 __ 7.6 8.2 7.8 9.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 180 140 150 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.020 0.018 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — 60 — 95 93 99 123 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 1.20 0.530 0.520 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 K8600 K1500 11 <10 <10 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 17 — 15 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.070 0.030 0.040 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — 510 380 590 250 470 260 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 28 — 27 26 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.34 0.26 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — non-ideal count 151 RIO DE LA PLATA BASIN 50044000 RIO DE LA PLATA NEAR COMERIO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS UN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1996 08... FEE 1997 24... JUN 06... SEP 05... 100 200 <1 <1 30 37 <0.10 <0.10 <1 <1 <1 <1 <0.010 <10 <0.010 <1 <1 0.03 0.03 752 RIO DE LA PLATA BASIN 50044850 RIO GUADIANA NEAR NARANJITO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°18'39", long 66°13'28", at steel-cross-bridge 0.8 mi (1.3 km) northwest of Highway 164, 1.2 mi (1.9 km) upstream from mouth and about 2.0 mi (3.2 km) northeast of Naranjito plaza. DRAINAGE AREA.--4.0 mi 2 (10.3 km2 ). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DZS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - ZNST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCZ CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. HATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEO C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 0850 8.6 338 7.4 26.0 19 7.2 87 <10 K14000 4900 .997 1145 13 390 7.5 23.0 26 8.0 91 <10 5800 K1800 1000 4.5 385 8.0 27.5 0.32 9.2 116 <10 5000 360 1225 3.4 445 7.9 32.0 0.52 7.3 101 <10 260 330 ALKA- DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... DATE OCT 1996 15... FEB 1997 24... MAY 12... SEP 05... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 140 -- 160 180 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 -- 0.13 0.14 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.31 0.40 <0.20 0.21 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 30 -- 38 43 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 24 -- 27 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.0 2.2 1.2 1.6 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 15 -- 16 17 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 204 -- 239 254 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.7 9.6 5.3 6.9 SODIUM, Dis- SOLVED (MG/L AS NA) (00930) 16 __ 18 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.75 -- 2.91 2.31 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.170 0.140 0.100 0.130 SODIUM AD- SORP- TION RATIO (00931) 0.6 — 0.6 0.7 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 50 37 <1 2 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- 2 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 _- 2.6 2.4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) -- 1.70 1.00 1.30 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 130 160 150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) •eO.010 0.020 0.020 0.031 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 30 -- SULFIDE TOTAL (MG/L AS S) (00745) 2.6 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.70 1.80 1.00 1.40 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 16 -- 16 26 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.040 0.020 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 4 -- <1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 22 -- 25 29 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.28 0.36 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 -- K » non- ideal count RIO DE LA PLATA BASIN 50044850 RXO GUADXANA NEAR NARANJITO, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 15$ DATE OCT 1996 15... FEE 1997 24... MAY 12... SEP 05... IRON, TOTAL RECOV- ERABLE (UO/L AS FB) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2100 90 160 <0.10 100 <0.10 <1 <1 <1 <1 80 <0.010 <0.010 <1 <0.01 0.02 754 RIO DE LA PLATA BASIN 50045000 LAGO LA PLATA AT DAHSITE NEAR TOA ALTA, PR LOCATION.--Lat 18°20'40", long 66°14'10", Hydrologic Unit 21010005, 2.9 ml (4.7 km) at northeast of Plaza de Naranjito, 2.7 ml (4.3 km) West of Road 167, km 15.3, Buena Vista, Bayamon, 5.2 ml (8.4 km) east of Plaza de Corozal. DRAINAGE AREA.--181 ml 2 (469 km2 ). ELEVATION RECORDS PERIOD OF RECORD.--February 1989 to current year. Prior to October 1994, published as Lago La Plata at Damsite. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.--Lago La Plata first construction phase was completed in 1974 and the second construction phase to provide the spillway with bascule gates was completed in October 1989. The maximum storage is 37,000 ac-ft (45.6 hm3 ) and its purpose is the supply of water for domestic and industrial use. La Plata Dam is a concrete gravity structure located across the Rio de la Plata, the dam has an overall length of 774 ft (236 m) and a maximum height of about 131 ft (40 m). The dam spillway is provided with 6 bascule gates. The spillway crest has a total clear length of 690 ft (210 m), an elevation of 155 ft (47 m). The Dam is owned and operated by Puerto Rico Aqueduct and Sewer Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 170.90 ft (52.09 m), Sept. 10, 1996; minimum elevation, 107.95 ft (32.90 m), Feb. 21, 1995. EXTREMES FOR CURRENT YEAR.--Maximum elevation, 166.90 ft (50.87 m), Feb. 16; minimum elevation, 128.95 ft (39.30 m), Sept. 30. Capacity Table (based on data from Puerto Rico Aqueduct and Sewer Authority) Elevation, in feet 98.43 131.24 154.60 Contents, in acre-feet 2,760 11,360 22,720 Elevation, in feet 164.05 170.61 175.52 Contents, in acre-feet 28,550 33,160 37,040 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN OCT 166.30 A 166.29 165.90 165.98 166.06 166.14 166.18 166.22 166.28 166.36 165.84 165.90 165.92 165.93 165.94 165.93 165.88 165.90 165.99 166.01 166.01 166.01 165.98 165.93 NOV 165.87 165.86 165.88 165.87 165.94 165.94 165.93 165.94 166.00 166.10 166.34 166.00 165.89 165.70 165.95 166.09 166.24 165.81 166.01 166.28 166.32 166.05 166.40 165.79 165.99 DEC 166.12 165.81 166.05 166.22 165.88 165.61 165.69 165.75 165.78 165.84 166.07 165.68 165.99 166.30 165.86 165.97 165.74 165.85 165.93 165.97 166.03 166.04 166.06 166.10 166.12 JAN 165.81 165.92 166.00 166.03 166.06 166.06 166.03 165.99 165.94 165.89 165.86 165.82 165.83 165.78 165.82 165.81 165.77 165.75 165.80 165.95 166.73 166.65 166.65 166.64 166.58 FEB 166.69 166.64 166.69 166.62 166.74 166.70 166.61 166.69 166.56 166.63 166.68 166.75 166.58 166.67 166.73 166.71 166.56 166.60 166.64 166.70 166.78 166.60 166.69 166.72 166.61 MAR 166.61 166.62 166.69 166.72 166.64 166.66 166.67 166.70 166.68 166.63 166.57 166.51 166.44 166.37 166.30 166.23 166.16 166.12 166.04 165.93 165.80 165.68 165.57 165.43 165.29 APR 165.08 165.00 165.69 165.78 165.73 165.65 165.56 165.43 165.28 165.12 164.97 164.80 164.62 164.44 164.24 164.04 163.87 163.71 163.53 163.32 163.13 162.89 162.67 162.43 162.19 MAY 160.87 160.65 160.51 160.29 160.07 159.84 159.62 159.39 159.14 158.93 158.79 158.58 158.36 158.14 157.90 157.69 157.48 157.34 157.11 156.87 156.62 156.36 156.37 158.47 159.43 JUN 159.13 159.07 159.02 158.85 158.67 158.43 158.10 157.85 157.62 157.37 157.13 156.89 156.62 156.32 156.04 155.75 155.46 155.18 155.06 154.81 154.53 154.26 154.01 153.74 153.47 JUL 151.70 151.37 151.02 150.67 150.31 149.96 149.60 149.29 148.98 148.65 148.31 147.96 147.59 147.21 146.85 146.49 146.12 145.84 145.76 145.55 145.41 145.57 145.46 145.20 144.96 AUG 142.88 142.55 142.19 141.86 141.50 141.14 140.78 140.46 140.09 139.77 139.52 139.20 138.88 138.55 138.23 137.83 137.70 137.43 137.09 136.75 136.40 136.15 137.53 137.95 139.09 SEP 137.55 137.23 136.88 136.53 136.12 135.71 135.39 134.95 134.98 134.81 134.44 134.08 133.82 133.56 133.23 132.83 132.43 132.05 131.60 131.15 130.78 130.67 130.44 130.38 130.13 166.10 165.97 165.89 165.95 165.72 165.79 166.30 165.82 166.18 165.71 165.84 ___ 166.20 165.76 165.91 165.68 166.09 165.60 166.75 166.68 166.78 166.73 166.72 166.64 166.67 166.66 166.63 ___ ___ ___ 165.17 165.03 164.96 165.18 165.27 165.16 161.96 161.73 161.50 161.28 161.08 ___ 159.65 159.61 159.47 159.41 159.27 159.16 153.21 152.91 152.61 152.33 152.03 ___ 144.65 144.33 144.00 143.66 143.42 143.19 139.16 138.94 138.62 138.44 138.16 137.87 129.86 129.93 129.70 129.36 128.95 ___ 166.40 165.70 166.30 165.60 166.78 165.75 166.78 166.56 166.72 164.96 165.78 161.08 160.87 156.36 159.13 152.03 151.70 143.19 142.88 136.15 137.55 128.95 A No gage-height record RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR 755 LOCATION.--Lat 18°20'45", long 66°14'17», Hydrologic Unit 21010005, 2.8 mi (4.5 km) west of Road 167, km 15.3, Buena Vista, Bayamon, 5.0 mi (8.0 km) east of Plaza de Corozal, 3.0 mi (4.8 km) northeast of Plaza de Naranjito. DRAINAGE AREA.--173 mi 2 (448 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—July 1989 to current year. GAGE.—Water-stage recorder. Elevation of gage is 164 ft (30 m), from topographic map. REMARKS.--Records poor. Regulation at all stages by Puerto Rico Aqpieduct and Sewer Authority reservoir upstream from gage. Gage-height satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT DEC JAN FEB MAR APR MAY JUN AUG SEP 1 e8.4 e!4 2 e8.0 e6.6 3 e8.2 e8.2 4 elO e8.0 5 e7 . 8 e6 . 6 6 e7.2 e5.8 7 e8.4 e7.2 8 e6.8 e6.2 9 e5.8 eS.O 10 e5 . 3 e7 . 6 11 e5 . 0 e7 . 4 12 e4.9 e50 13 e4.8 e!70 14 eS.l e38 15 e5.5 e49 16 eS.O elO 17 e4 . 8 e7 . 0 18 e4.7 e23 19 e4.5 e60 20 e4.4 e!6 21 e4.7 e40 22 e4.4 e!20 23 e6.3 e!30 24 e4.9 e220 25 e4.2 elOO 26 eS.O e42 27 e76 e49 28 e32 e!5 29 elOO e26 30 e26 e68 31 e40 —— TOTAL 431.1 1315.6 MEAN 13.9 43.9 MAX 100 220 MIN 4.2 5.0 AC-FT 855 2610 CFSM .08 .25 IN. .09 .28 e64 e45 e23 elO e7.4 e44 ell e6.8 e5.8 e5.4 e68 e50 e25 e6.2 e31 e24 e42 eS.O e6.2 e5.2 e5.8 e5.2 e4.9 e!5 e9.0 e25 e80 e!3 e30 e46 elO 731.9 23.6 80 4.9 1450 .14 .16 STATISTICS OF MONTHLY MEAN DATA MEAN 187 74.8 MAX 1107 225 (WY) 1991 1993 MIN .048 .004 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 39.8 161 1993 .000 1995 e!2 e4.3 e7.8 e4.0 e2.2 e2.3 el. 8 el. 7 el. 6 el. 5 el. 5 el. 4 el. 4 el. 3 el. 3 el. 3 el. 2 el. 3 el. 6 el. 9 e35 e!20 e66 e60 e30 e20 e9.8 ell e8.2 e6.2 e3.3 422.9 13.6 120 1.2 839 .08 .09 eS.O ell e3.3 e3.5 e4.4 e2.9 e2.4 e2.8 el. 9 e3.5 el. 7 e2.2 e2.5 e3.5 el. 7 el. 7 e4.5 el. 7 el. 5 el. 4 e6.6 eS.O e4.0 e2.9 e2.5 e2.9 el. 4 e2.8 ___ ___ —— 91.2 3.26 11 1.4 181 .02 .02 FOR WATER YEARS 1989 242 1581 1992 .19 1990 37.2 222 1991 .14 1995 FOR 1996 CALENDAR YEAR 258269.20 706 141000 .40 .49 Sep 10 Jul 4 Jun 30 el. 5 el.l e.90 el. 9 e3.1 e4.1 e2.1 e2.1 el. 7 el. 5 el. 3 el. 3 el. 2 el. 2 el.l el.l el.l el. 2 el.l el.l el.O el.O .98 .92 .88 .84 .80 .88 .96 .82 .72 .70 .78 .80 .82 .80 .76 .78 .76 .74 .74 .80 .80 .78 .72 .70 .72 .76 .80 .82 .82 .82 .82 .70 .66 .62 .70 .72 .66 .64 .76 41.54 22.46 1.34 .75 4.1 .82 .76 .62 82 45 .01 .00 .01 .00 e.64 e.62 el.l el.O e.74 e.69 e.64 e.58 e.52 e.50 e.52 e.54 e.56 e.61 e.66 e.92 e.64 e.42 .34 .28 .35 .35 .34 2.6 1.4 .92 .53 .34 .32 .48 .29 20.44 .66 2.6 .28 41 .00 .00 .28 .22 .25 .23 .28 .30 .30 .24 .21 .25 .31 .36 .40 .45 .53 .63 .71 .93 1.5 1.3 .84 .14 .02 .02 .01 .01 .01 .01 .00 .00 —— 10.74 .36 1.5 .00 21 .00 .00 .00 .00 .00 .00 .01 .04 .07 .09 .03 .03 .02 .02 .02 .02 .06 .11 .14 .18 .40 .42 .34 .30 .23 .19 .16 .17 .16 .17 .15 .15 .26 3.94 .13 .42 .00 7.8 .00 .00 .32 .31 .29 .29 .30 .29 .28 .24 .26 .32 .46 .58 .65 .50 .45 .39 .41 .60 .49 .46 .48 .89 1.1 1.7 1.4 .82 .69 .63 .60 .91 1.1 18.21 .59 1.7 .24 36 .00 .00 .88 .82 .73 .73 .73 .73 .99 .97 1.1 1.1 .93 1.0 1.6 1.8 1.6 1.1 1.0 1.1 1.2 1.1 1.3 1.7 1.5 1.4 1.3 1.3 1.3 1.3 1.4 1.5 —— 35.21 1.17 1.8 .73 70 .01 .01 - 1997, BY WATER YEAR (WY) 17.8 34.7 83.2 231 1990 1993 .022 .011 1995 1995 FOR 1997 3145 8 220 123 494 1993 .000 1994 WATER YEAR .24 .62 Nov 24 .00 Jun 29 .00 Jun 28 43.0 220 1993 .002 1994 unknown Nov 24 unknown Nov 24 512300 4.08 55.60 116 3.8 .60 6240 24 1 .050 .68 .2 .23 72.7 384 1993 .037 1994 WATER 170 714 8 141000 197000 42 122900 13 159 1 29.8 129 1996 .020 1989 YEARS 1989 .62 Sep .00 Jul .00 Jul Sep .26 Sep .98 .34 .0 .00 1127 8046 1996 .001 1991 - 1997 1996 1997 10 1996 14 1989 14 1989 10 1996 10 1996 e Estimated 755 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA AT BELOW LA PLATA DAM, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1989 to current year. INSTRUMENTATION.-- Automatic sediment sampler since 1989. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 4,390 mg/L September 10, 1996; Minimum daily mean, <.05 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 1,810,000 tons (1,640,,000 tonnes) September 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 181 mg/L January 16, 1997; Minimum daily mean, 1 mg/L July 1, 1997. SEDIMENT LOADS: Maximum daily mean, e!4 tons (e!3 tonnes) January 22, 1997; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e8.4 e8.0 e8.2 elO e7.8 e7.2 e8.4 e6.8 e5.8 e5.3 e5.0 e4.9 e4.8 e5.1 e5.5 e5.0 e4.8 e4.7 e4.5 e4.4 e4.7 e4.4 e6.3 e4.9 e4.2 e8.0 e76 e32 elOO e26 e40 13 .30 13 14 14 14 13 13 13 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 12 .29 .30 .37 .30 .26 .29 .24 .20 .18 .16 .16 .16 .16 .18 .16 .16 .15 .15 .14 .15 .14 .20 .16 .14 14 e.28 18 e3.2 18 el. 8 19 e4.7 18 el. 7 17 el. 8 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER e!4 e6.6 e8.2 e8.0 e6.6 e5.8 e7.2 e6.2 e5.0 e7.6 e7.4 e50 e!70 e38 e49 elO eV.O e23 e60 el 6 e40 e!20 e!30 e220 elOO e42 e49 el5 e26 668 ___ 17 14 13 13 13 13 13 13 13 13 13 15 20 21 19 16 14 14 17 17 16 18 20 23 23 20 18 16 16 19 ___ .75 .28 .28 .28 .24 .21 .25 .22 .18 .25 e.26 el. 8 e8.4 62.9 62.4 e.59 e.28 6.81 62.6 e.94 el. 6 65.3 67.0 613 66.9 62.6 62.3 e.79 el.l 63.1 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 664 645 623 elO 67.4 644 ell 66.8 65.8 65.4 668 650 625 66.2 631 624 642 68.0 66.2 65.2 65.8 65.2 64.9 615 69.0 625 680 613 630 646 elO 19 18 16 15 14 15 17 15 14 13 16 19 16 14 14 15 17 17 14 13 13 12 12 13 15 17 19 17 15 17 17 63.3 62.2 el.l 6.46 e.28 el. 6 e.65 e.30 e.22 6.19 62.5 62.6 el. 2 6.30 el.O el.O el. 8 .50 .25 .19 .19 .18 .16 .47 .38 el.O e3.7 e.88 el.l e2.0 e.62 TOTAL 431.1 18.58 1315.6 67.61 731.9 32.32 e Estimated RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 157 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN DISCHARGE (CPS) e!2 e4.3 e7.8 e4.0 e2.2 e2.3 el. 8 el. 7 el. 6 el. 5 el. 5 el. 4 el. 4 el. 3 el. 3 el. 3 el. 2 el. 3 el. 6 el. 9 e35 e!20 e66 e60 e30 e20 e9.8 ell e8.2 e6.2 e3.3 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 16 .48 14 13 12 11 12 16 21 28 37 50 67 89 119 159 181 103 53 27 14 .19 .25 .14 .07 .07 .08 .10 .12 .15 .20 .25 .34 .42 .56 .64 .34 .18 .12 .07 17 el. 4 45 e!4 68 e!3 63 elO 59 e5.3 55 e3.2 50 el. 5 36 el.l 26 e.60 18 e.32 13 e.13 MEAN DISCHARGE (CPS) eS.O ell e3.3 e3.5 e4.4 e2.9 e2.4 e2.8 el. 9 e3.5 el. 7 e2.2 e2.5 e3.5 el. 7 el. 7 e4.5 el. 7 el. 5 el. 4 e6.6 eS.O e4-0 e2.9 e2.5 e2.9 el. 4 e2.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 12 .15 13 14 13 12 12 11 11 10 10 10 10 11 11 11 11 12 12 12 13 13 13 12 11 11 10 9 9 .36 .15 .12 .14 .10 .08 .08 .05 .09 .05 .06 .07 .10 .06 .05 .13 .06 .05 .05 .20 .18 .13 .09 .07 .08 .04 .06 —— —— MEAN DISCHARGE (CPS) el. 5 el.l e.90 el. 9 e3.1 e4.1 e2.1 e2.1 el. 7 el. 5 el. 3 el. 3 el. 2 el. 2 el.l el.l el.l el. 2 el.l el.l el.O el.O .98 .92 .88 .84 .80 .88 .96 .82 .76 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 8 .05 8 7 7 7 7 8 8 8 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 .03 .02 .03 .05 .07 .06 .05 .04 .04 .03 .03 .03 .03 .03 .03 .03 .03 .03 .03 .03 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 422.9 55.32 91.2 2.85 41.54 0.97 Estimated 158 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN DISCHARGE DAY (CFS) 1 .72 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 .70 .78 .80 .82 .80 .76 .78 .76 .74 .74 .80 .80 .78 .72 .70 .72 .76 .80 .82 .82 .82 .82 .70 .66 .62 .70 .72 .66 .64 31 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 9 .02 9 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .01 .01 .02 .02 .02 .02 .02 .02 .02 .01 .01 .01 .01 .01 .01 —— —— MEAN DISCHARGE (CFS) e.64 e.62 el.l el.O e.74 e.69 e.64 e.58 e.52 e.50 e.52 e.54 e.56 e.61 e.66 e.92 e.64 e.42 .34 .28 .35 .35 .34 2.6 1.4 .92 .53 .34 .32 .48 .29 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 8 .01 8 8 8 8 8 8 8 8 8 8 8 8 8 17 23 23 14 .01 .02 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .03 .05 .05 .02 8 .01 14 .01 27 .03 17 .02 9 .01 13 .10 10 .04 7 .02 5 .01 6 <.01 7 .01 13 .02 23 .02 MEAN DISCHARGE (CFS) .28 .22 .25 .23 .28 .30 .30 .24 .21 .25 .31 .36 .40 .45 .53 .63 .71 .93 1.5 1.3 .84 .14 .02 .02 .01 .01 .01 .01 .00 .00 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 27 29 31 29 15 9 14 20 16 11 7 4 6 8 7 7 6 6 5 5 5 6 8 11 14 19 25 31 30 29 .02 .02 .02 .02 .01 .01 .01 .01 .01 .01 .01 •c.Ol .01 .01 .01 .01 .01 .01 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 TOTAL 22.46 0.52 20.44 0.62 10.74 0.26 e Estimated RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY}, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 759 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR .00 .00 .00 .00 .01 .04 .07 .09 .03 .03 .02 .02 .02 .02 .06 .11 .14 .18 .40 .42 .34 .30 .23 .19 .16 .17 .16 .17 .15 .15 .26 3.94 3145.24 JULY <1 .01 26 24 23 20 17 10 £ £ £ 3 2 g 35 28 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 21 .01 39 .01 81 .04 75 .08 61 .07 72 .07 69 .06 24 .01 8 <.01 3 <.01 1 <.01 5 <.01 19 .01 12 <.01 5 <.01 7 <.01 0.36 180.66 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST .32 .31 .29 .29 .30 .29 .28 .24 .26 .32 .46 .58 .65 .50 .45 .39 .41 .60 .49 .46 .48 .89 1.1 1.7 1.4 .82 .69 .63 .60 .91 1.1 18.21 12 15 19 24 29 31 31 24 18 13 11 16 22 16 10 8 6 4 2 3 5 5 5 4 3 2 2 9 34 17 19 —— .01 .01 .01 .02 .02 .02 .02 .02 .01 .01 .01 .03 .04 .02 .01 .01 .01 .01 <.01 <.01 .01 .01 .01 .02 .01 <.01 <.01 .01 .05 .04 .05 0.50 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) .88 .82 .73 .73 .73 .73 .99 .97 1.1 1.1 .93 1.0 1.6 1.8 1.6 1.1 1.0 1.1 1.2 1.1 1.3 1.7 1.5 1.4 1.3 1.3 1.3 1.3 1.4 1.5 SEPTEMBER 20 12 7 3 2 1 4 8 3 1 2 4 3 2 5 9 8 6 8 8 5 4 6 12 14 14 12 11 16 20 35.21 .05 .03 .01 .01 .01 .02 .01 .01 .01 .01 .01 .02 .03 .02 .02 .02 .02 .02 .02 .03 .05 .05 .05 .04 .04 .06 .08 0.75 160 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE JAN 1997 27... JUN 30... JDL 02... 18... AUG 29... TIME 1045 0815 0830 1430 1400 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) e9.8 <0.01 <0.01 0.15 0.60 SEDI- MENT, SUS- FENDED (MQ/L) (80154) 52 77 66 95 48 SEDI- MENT, DIS- CHARGE, SUS- FENDED (T/DAY) (80155) el. 4 <0.01 <0.01 0.04 0.08 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 86 99 98 93 90 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HIGHWAY 2 NEAR TOA ALTA, PR 161 LOCATION.--Lat 18°24'41", long 66°15'39", Hydrologic Unit 21010005, on left bank, at downstream side of bridge on Highway 2, 1.3 mi ( 2.1 km) downstream from Rio Lajas, and 1.6 mi (2.6 km) northwest of Toa Alta, 11.3 mi (18.2 km) downstream from Puerto Rico Aqueduct and Sewer Authority reservoir. DRAINAGE AREA.--208 mi 2 (539 km2 ), excludes 8.2 mi 1 (21.2 km2 ) upstream from Lago Carite, flow from which is diverted to Rio Guamani. Area at site used prior to September 25, 1984, 200 mi 2 (518 km 2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1959 (measurement only), January 1960 to current year. Prior to October 1984, published as Rio de la Plata at Toa Alta, PR; October 1984 to September 1988 published as 50046900. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 9.15 ft (2.789 m), above mean sea level, to October, 1984, at site about 1.0 mi (1.6 km) upstream at mean sea level datum. Prior REMARKS.—Records poor. Regulation at all stages by Puerto Rico Aqueduct and Sewer Authority reservoir upstream from gage. Gage-height and precipitation satellite telemetry at station. Flow affected by bridge construction about 1.0 mi (1.6 km) upstream from station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges and elevations of major floods, as pointed out by local residents are as follows: Sept. 13, 1928, 120,000 ftVs (3,400 mVs), gage height, 37.4 ft (11.40 m); June 16, 1943, 82,000 ftVs (2,322 mVs), gage height, 34.4 ft (10.48 m), at site 1.0 mi upstream and different datum. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC JAN MAR JUN JUL AUG SEP 1 e65 59 2 e60 50 3 e65 63 4 e80 63 5 e55 50 6 e56 45 7 e65 57 8 e50 47 9 e45 38 10 e40 59 11 e39 56 12 e38 605 13 e37 1330 14 e40 289 15 e43 379 16 e40 58 17 e36 52 18 36 87 19 34 464 20 34 120 21 36 230 22 33 e963 23 49 elOOO 24 34 1710 25 32 684 26 60 311 27 603 e382 28 243 112 29 801 142 30 196 532 31 327 TOTAL 3372 10037 MEAN 109 335 MAX 801 1710 MIN 32 38 AC -FT 6690 19910 CFSM .54 1.67 IN. .63 1.87 STATISTICS OF MONTHLY MEAN MEAN 457 422 MAX 4813 2015 (WY) 1971 1985 MIN 18.8 18.4 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 496 305 153 71 64 350 64 55 53 50 615 403 221 55 263 190 336 56 47 45 47 46 43 137 e76 128 779 116 221 438 199 6122 197 779 43 12140 .99 1.14 232 82 151 108 44 44 35 33 31 30 30 28 27 26 26 24 23 23 30 32 1420 2680 1240 1130 682 386 178 200 159 146 94 9374 302 2680 23 18590 1.51 1.75 DATA FOR WATER 316 1352 1971 14.8 1995 FOR 187 929 1992 16.9 1984 149 366 109 112 149 96 79 95 62 121 57 e72 e74 126 56 55 e!71 e55 55 51 193 171 149 97 82 97 50 106 —— 3055 109 366 50 6060 .55 .57 YEARS 1960 126 409 1989 16.0 1983 48 48 53 58 103 149 75 75 62 50 43 45 43 41 40 40 39 41 39 38 36 36 34 32 30 29 27 28 33 29 25 1469 47.4 149 25 2910 .24 .27 - 1997 98.4 468 1969 8.31 1986 1996 CALENDAR YEAR 139193 380 68100 13 18 276100 1. 25. 445 50 22 Sep 10 May 15 May 12 90 92 25 25 27 27 28 28 26 27 26 26 25 28 27 27 25 24 25 26 27 28 29 29 29 24 23 21 24 25 23 22 —— 776 25.9 29 21 1540 .13 .14 22 21 39 37 24 24 22 20 20 21 21 21 21 21 22 24 24 21 22 22 29 23 23 e!46 e!09 75 57 35 28 28 29 1051 33.9 146 20 2080 .17 .20 34 35 31 31 32 31 25 26 26 28 25 25 24 22 22 23 22 e22 e80 49 28 26 54 47 35 40 55 47 41 39 —— 1025 34.2 80 22 2030 .17 .19 34 32 27 25 27 34 32 27 27 27 27 33 35 24 22 40 50 64 41 31 36 20 18 17 26 22 18 18 17 19 38 908 29.3 64 17 1800 .15 .17 33 20 19 18 17 17 15 15 27 45 53 74 62 62 51 74 143 121 48 33 74 134 89 199 212 53 35 28 24 23 26 1844 59.5 212 15 3660 .30 .34 25 18 16 13 12 11 12 12 11 12 12 12 61 176 68 30 22 20 20 20 50 60 44 86 65 37 31 27 36 60 —— 1079 36.0 176 11 2140 .18 .20 , BY WATER YEAR (WY) 181 723 1987 5.07 1984 FOR 1997 40112 110 2680 11 12 4350 10 11 79560 7 216 40 21 339 1939 1985 7.63 1984 WATER YEAR Jan 22 Sep 6 Sep 5 Jan 22 .80 Jan 22 Sep 6 .55 .47 160 847 1970 11.4 1977 146 690 1961 13.2 1994 242 1677 1979 16.5 1976 WATER YEARS 1960 - Not 254 824 31.5 68100 2.7 2.9 determined 27.33 184100 1.27 17.28 476 83 17 Sep 10 Apr 17 Apr 15 Sep 10 Sep 10 399 3173 1996 19.2 1991 1997 1971 1994 1996 1984 1984 1996 1996 e Estimated 162 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HWY 2 NR TOA ALTA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°24'41", long 66°15'39", at Highway 2, 1.3 mi (2.1 km) downstream from Rio Lajas, and 1.6 mi (2.6 km) northwest of Toa Alta, 11.3 mi (18.2 km) downstream from Puerto Rico A fa10123456 KILOMETERS 01234 MILES Figure 18.-Rio Hondo to Rio Puerto Nuevo basins. 166 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATANO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°26'13", long 66 009'36", at Rio Hondo Channel, 800 ft (245 m) below junction with Rio Hondo, 0.9 mi (1.5 km) downstream from bridge on de Diego Expressway and 1.1 mi (1.8 km) above mouth. DRAINAGE AREA.—Indeterminate. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... TIME 0800 0930 1045 1330 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) TEMPER- ATURE WATER (DEG C) (00010) TUR- BID- ITY (NTU) (00076) OXYGEN, DIS- SOLVED (MG/L) (00300) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 380 17500 3690 39000 7.2 6.9 7.7 7.8 25.0 25.0 30.5 32.0 73 1.6 43 17 4.2 4.2 2.9 7.6 50 53 38 96 27 89 36 92 K5600 4100 K71000 2100 450 500 4200 K70 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS SO4) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 310 49 45 360 360 39 63 553 4500 320 902 7500 13 49 16 26 290 130 150 66 170 <0.5 95 620 <0.5 130 1000 1900 14000 DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.16 0.52 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 9.6 — 5.1 1.8 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 1270 — 1860 24900 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 72 17 39 38 NITRO GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.530 0.280 0.247 — NITRO- NITRO- NITRO- NITRO- GEN, GEN, GEN, GEN, NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) (00615) (00630) (00610) (00605) 0.080 0.600 0.460 0.70 0.080 0.370 0.860 0.59 0.043 0.290 0.400 0.90 <0.010 0.020 0.030 1.2 NITRO- GEN, AM- MONIA + ORGANIC TOTAL DATE (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... 1.2 1.5 1.3 1.2 0.150 0.200 0.120 0.070 <100 <100 180 290 <1 <1 K - non-ideal count Discharge measurement values not available due to ponded conditions. DATE NOV 1996 14... MAR 1997 07... JUN 24... SEP 09... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 400 910 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATANO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 167 MANGA- LEAD, NESE, MERCURY SILVER, TOTAL TOTAL TOTAL SELE- TOTAL RECOV- RECOV- RECOV- NIUM, RECOV- ERABLE ERABLE ERABLE TOTAL ERABLE (UG/L (UG/L (UG/L (UG/L (UG/L ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL PHENOLS (UG/L (MO/L TOTAL AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 140 120 <0.10 <0.10 <1 <1 <1 <1 30 <0.010 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 0.08 0.12 168 RIO DE BAYAMON BASIN 50047535 RIO DE BAYAMON AT ARENAS, PR LOCATION.--Lat 18°10'11", long 66°07'18", Bydrologic Unit 21010005, at left bank, 2.61 ml (4.20 ka) southeast of plaza de Cldra, 0.56 ml (0.90 km) southwest from Escuela Segunda Unidad de Bayam6n, and 2.70 ml (4.34 km) northeast from Central Cayey. DRAINAGE AREA.--0.45 ml 2 (1.16 km2 ). PERIOD OF RECORD.--July 1992 to September 1993, October 1995 to current year. GAGE.—Water-stage recorder. Elevation of gage Is 1,378 ft (420 m), from topographic map. REMARKS.--Records fair. DISCHARGE, CUBIC FEET PER SECOND, MATER YEAR OCTOBER 1996 TO S DAY OCT NOV 1 .28 .28 2 .30 .31 3 .29 .24 4 .25 .25 5 .26 .24 6 .24 .23 7 .26 .26 8 .27 .24 9 .30 .26 10 .33 .25 11 .29 .66 12 .26 1.5 13 .25 .81 14 .24 .41 15 .25 .28 16 .24 .21 17 .24 .19 18 .24 .23 19 .24 .21 20 .24 .35 21 .24 .30 22 .25 .30 23 .24 .35 24 .24 .46 25 .24 .50 26 .36 .26 27 .40 .32 28 .38 .37 29 .79 .29 30 .46 1.1 31 .31 TOTAL 9.18 11.66 MEAN .30 .39 MAX .79 1.5 MIN .24 .19 AC-FT 18 23 CFSM .66 .86 IN. .76 .96 STATISTICS OF MONTHLY MEAN MEAN .31 .78 MAX .34 1.30 (WY) 1996 1993 MIN .30 .39 (WY) 1997 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC .62 .67 .37 .32 .27 .23 .32 .24 .20 .20 .70 .37 .24 .21 .20 .21 .19 .18 .19 .21 .19 .18 .17 .17 .21 .18 .18 .24 .29 .84 .69 9.48 .31 .84 .17 19 .68 .78 JAN .36 .27 .23 .22 .19 .16 .15 .14 .14 .15 .29 .22 .18 .15 .18 .19 .16 .16 .19 .27 1.3 3.2 1.8 2.1 1.4 .73 .48 .51 .60 .41 .35 16.88 .54 3.2 .14 33 1.21 1.40 DATA FOR WATER .36 .63 1993 .16 1996 FOR .60 .63 1996 .54 1997 DAILY FEB 1.5 .73 .41 .25 .25 .28 .28 .25 .52 .32 .29 .31 .55 .48 .38 .25 .20 .20 .39 .36 1.3 .75 1.5 .50 .37 .34 .27 .25 ___ ___ —— 13.48 .48 1.5 .20 27 1.07 1.11 YEARS 1992 .29 .48 1997 .16 1993 EjrTBHhBR 1997 MEAN VALUES MAR .25 .23 .35 .31 .28 .21 .16 .29 .27 .21 .15 .11 .12 .09 .12 .13 .11 .12 .12 .12 .12 .12 .11 .12 .12 .12 .12 .15 .25 .22 .15 5.35 .17 .35 .09 11 .38 .44 - 1997 .14 .17 1997 .097 1993 1996 CALENDAR YEAR 421. 1. 141 . . 835 2. 34. 1. . . 09 15 Sep 10 03 May 2 04 Apr 28 56 81 5 24 07 APR .15 .26 .29 .15 .10 .09 .08 .08 .08 .07 .11 .09 .10 .09 .08 .07 .07 .07 .07 .07 .07 .08 .07 .07 .07 .07 .06 .06 .07 .06 —— 2.85 .095 .29 .06 5.7 .21 .24 MAY .07 .07 .07 .06 .06 .06 .06 .06 .07 .09 .06 .08 .07 .06 .07 .10 .32 .09 .07 .06 .08 .06 .06 .14 .08 .07 .08 .07 .22 .32 .33 3.16 .10 .33 .06 6.3 .23 .26 JUN .22 .31 .61 .22 .14 .11 .10 .09 .09 .09 .10 .09 .09 .21 .09 .07 .06 .05 .07 .09 .06 .05 .28 .21 .07 .09 .06 .04 .04 .03 —— 3.83 .13 .61 .03 7.6 .28 .32 JUL .03 .03 .02 .02 .04 .38 .08 .04 .06 .07 .05 .03 .03 .03 .02 .39 .16 .16 .14 .29 1.2 .60 .63 .50 .23 .26 .11 .72 .27 .12 .09 6.80 .22 1.2 .02 13 .49 .56 AUG .09 .04 .07 .07 .04 .04 .03 .04 .02 .05 .06 .03 .03 .03 .04 .07 .37 .17 .51 .10 .06 4.8 .66 14 1.8 .33 .15 .11 .09 .09 .24 24.23 .78 14 .02 48 1.74 2.00 SEP .22 .31 .18 .16 .15 .15 .24 1.0 .52 .12 .08 .32 .14 .17 .11 .10 .09 .11 .09 .07 .17 .16 .16 .22 .11 .35 .16 .11 .10 .09 —— 5.96 .20 1.0 .07 12 .44 .49 , BY WATER YEAR (WY) .22 .45 1993 .095 1997 FOR 1997 112 14 228 5 224 9 .75 2.02 1993 .10 1997 WATER YEAR .86 .31 Aug 24 . 02 Jul 3 .03 Jun 28 Aug 24 .21 Aug 24 .02 Jul 15 .69 .33 .51 .19 .06 .97 1.79 1996 .13 1997 1.31 2.12 1993 .22 1997 WATER 1 141 885 7 561 1 23 1 .96 1.87 1996 .46 1992 YEARS 1992 - .77 .16 .31 Sep 10 . 02 Jul 3 .03 Jun 28 Sep 10 .34 Sep 10 .02 Jul 15 .72 .36 .1 .18 .07 2.20 6.38 1996 .20 1997 1997 1996 1997 1996 1997 1997 1996 1996 1997 RIO DE BAYAMON BASIN 50047540 RIO SABANA AT VISTA MONTE, PR 169 LOCATION.—Lat 18°10'28", long 66°08'38", Hydrologic Unit 21010005, at left bank, 1.2 mi (1.9 km) southeast of Plaza de Cidra, 1.2 ml (1.9 km) southwest from Escuela Segunda Unidad de Bayamon, and 0.4 ml (0.6 km) upstream from Lago de Cidra. DRAINAGE AREA.--0.80 ml 2 (2.07 km2 ). PERIOD OF RECORD.—August 1992 to September 1993, October 1995 to current year. GAGE.—Hater-stage recorder and crest-stage gage. Elevation of gage is 1,345 ft (410 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV 1 1.0 .66 2 .93 .72 3 .91 .56 4 .81 .58 5 .80 .56 6 .82 .54 7 .76 .60 8 .69 .56 9 .81 .60 10 .75 .58 11 .67 el. 5 12 .68 e3.5 13 .63 e2.7 14 .60 el. 5 15 .59 el.O 16 .60 e.72 17 .60 e.64 18 .62 e.76 19 .63 e.78 20 .64 1.0 21 .61 1.3 22 .60 .99 23 .60 1.0 24 .57 1.1 25 .55 1.1 26 .73 .90 27 .85 1.2 28 .75 1.4 29 el. 8 .96 30 el.l 1.6 31 e.74 —— TOTAL 23.44 31.48 MEAN .76 1.05 MAX 1.8 3.5 MIN .55 .45 AC-FT 46 62 CFSM .95 1.31 IN. 1.09 1.46 DEC 1.1 1.1 .93 .95 .87 .84 .83 .79 .78 .75 1.1 .84 .79 .79 .80 .76 .75 .72 .70 .71 .74 .67 .68 .72 .72 .72 .73 .85 .78 1.1 1.9 26.51 .86 1.9 .67 53 1.07 1.23 STATISTICS OF MONTHLY MEAN DATA MEAN .79 1.22 MAX .86 1.56 (WY) 1993 1993 MIN .76 1.05 (WY) 1997 1997 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .82 1.11 1993 .48 1996 FOR JAN .86 .79 .74 .71 .68 .66 .63 .64 .63 .66 .66 .62 .63 .64 .64 .64 .62 .63 .68 .70 1.4 4.4 1.8 1.9 1.8 1.3 1.1 1.1 1.1 1.1 .99 31.45 1.01 4.4 .62 62 1.27 1.46 FEB 2.0 1.4 1.2 1.0 1.1 1.1 .97 .94 1.1 .96 .94 .97 1.1 1.1 1.0 .94 .93 .91 1.1 1.0 1.6 1.1 1.5 .82 .73 .72 .66 .64 ___ —— 29.53 1.05 2.0 .64 59 1.32 1.37 FOR WATER YEARS 1992 .86 1.01 1997 .72 1993 .68 1.05 1997 .33 1993 MAR .62 .64 .72 .66 .70 .64 .61 .76 .60 .58 .56 .56 .58 .58 .63 .57 .56 .56 .56 .56 .55 .56 .56 .55 .56 .55 .56 3.1 .76 .53 .51 21.04 .68 3.1 .51 42 .85 .98 - 1997 .41 .68 1997 .15 1993 1996 CALENDAR YEAR 834.37 2.28 401 .23 .23 1650 2.85 38.80 1.6 .68 .34 Sep 10 Apr 11 Apr 17 APR .47 .60 .63 .49 .47 .46 .44 .44 .44 .44 .47 .44 .45 .43 .43 .47 .45 .44 .43 .44 .45 .46 .45 .44 .43 .44 .49 .48 .48 .43 —— 13.88 .46 .63 .43 28 .58 .65 MAY .42 .42 .42 .42 .41 .41 .42 .47 .46 .46 .44 .47 .45 .43 .43 .43 .77 .43 .38 .37 .35 .34 .39 .38 .34 .33 .40 .34 .38 .45 .42 13.03 .42 .77 .33 26 .53 .61 JUN .32 .41 .43 .28 .27 .25 .24 .23 .21 .21 .23 .21 .22 .24 .20 .20 .19 .20 .24 .19 .19 .19 .67 .24 .21 .22 .20 .19 .19 .19 —— 7.46 .25 .67 .19 15 .31 .35 JUL .19 .19 .19 .21 .21 .42 .25 .24 .25 .24 .28 .24 .23 .23 .24 1.0 .27 .20 .24 .28 .55 .29 .44 .26 .30 .25 .21 .35 .22 .20 .19 8.86 .29 1.0 .19 18 .36 .41 AUG .19 .18 .24 .20 .18 .18 .18 .18 .18 .25 .20 .21 .19 .18 .19 .20 .36 .23 .29 .20 .19 1.9 .31 6.6 .53 .26 .21 .19 .18 .19 .20 14.97 .48 6.6 .18 30 .60 .70 SEP .20 .22 .19 .19 .19 .19 .20 .83 .26 .26 .30 .32 .21 .26 .21 .21 .19 .19 .18 .18 .26 .27 .33 .24 .18 .21 .19 .36 .19 .19 7.40 .25 .83 .18 15 .31 .34 , BY WATER YEAR (WY) .69 1.23 1993 .37 1996 FOR 1997 229 6 46 2 454 10 1 1.05 2.26 1993 .42 1997 WATER YEAR .05 .63 .6 Aug 24 . 18 Aug 2 .19 Jun 27 Aug 24 .41 Aug 24 .16 Aug 7 .78 .65 .1 .55 .19 .78 1.21 1996 .25 1997 1.82 3.02 1993 .29 1997 WATER 1. 2. . 401 . . 2380 12. . 979 1. 22. 1. . . 1.19 2.15 1996 .48 1997 YEARS 1992 - 35 25 63 Sep 10 11 Mar 25 12 Jun 6 Sep 10 02 Sep 10 11 Mar 23 69 96 3 49 19 4.79 16.7 1996 .25 1997 1997 1996 1997 1996 1993 1993 1996 1996 1993 e Estimated 170 RIO DE BAYAMON BASIN 50047550 LAGO CIDRA AT DAMSITE NEAR CIDRA, PR LOCATION.--Lat 18°11'57", long 66°08'29", Rydrologic Unit 21010005, at Lago de Cidra Dan on Rio de Bayamon, 1.9 mi (3.0 km) northeast of Plaza de Cidra and 1.8 mi (2.9 km) northwest of Escuela Segunda Unidad de Bayamon. DRAINAGE AREA.--8.26 mi 2 (21.39 km2 ). ELEVATION RECORDS PERIOD OF RECORD.—January 1988 to current year. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago de Cidra was completed in 1946. The maximum storage is 5,300 ac-ft (6.53 bra5 ) and provides supple- mental water to metropolitan San Juan. The dam is a concrete gravity and earthfill structure approximately 541 ft (165 m) long between abutments with a maximum structural height of about 78.7 ft (24.0 m). The spillway portion of the dam, length 131 ft (40 m) and crest elevation 1,322 ft (403 m), is an ungated ogee crest located 131 ft (40 m) from the right abutment. This dam is owned by Puerto Rico Aqueduct and Sewer Authority. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 1,328.09 ft (404.80 m), Sep. 10, 1996; minimum elevation 1,295.86 ft (394.98 m), April 22,1995. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 1,322.06 ft (402.96 m), Oet.l; minimum elevation, 1,308.84 ft (398.93 m), Jan. 20,21. DAY MAX MXN Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 1,295 1,305 1,309 1,312 Contents, in acre-feet 860 1,970 2,610 3,100 Elevation, in feet 1,319 1,322 1,328 Contents, in acre-feet 4,400 5,200 6,920 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG 1321.90 1321.80 1321.80 1321.70 1321.57 1321.40 1321.30 1321.20 1321.09 1321.01 1320.90 1320.77 1320.65 1320.52 1320.38 1320.22 1320.06 1319.80 1319.69 1319.48 1319.30 1319.14 1318.96 1318.74 1318.51 1318.09 1317.91 1317.74 1317.54 1317.36 1317.17 1317.01 1316.83 1316.64 1316.44 1316.33 1316.34 1316.31 1316.18 1316.01 1315.83 1315.65 1315.47 1315.26 1315.09 1314.97 1314.81 1314.63 1314.49 1314.34 1313.63 1313.48 1313.29 1313.14 1312.95 1312.74 1312.55 1312.34 1312.11 1311.89 1311.90 1311.88 1311.74 1311.52 1311.34 1311.17 1310.96 1310.76 1310.59 1310.54 1310.48 1310.42 1310.33 1310.16 1309.98 1309.85 1309.84 1309.75 1309.68 1309.60 1309.48 1309.36 1309.26 1309.23 1309.19 1309.18 1309.17 1309.16 1309.07 1309.05 1308.99 1308.94 1308.90 1308.86 1308.84 1308.97 1309.16 1309.29 1309.39 1309.50 1309.93 1309.98 1310.03 1310.07 1310.11 1310.15 1310.18 1310.21 1310.25 1310.27 1310.31 1310.34 1310.38 1310.35 1310.34 1310.32 1310.29 1310.26 1310.23 1310.20 1310.19 1310.17 1310.17 1310.15 1310.13 1310.04 1310.01 1309.99 1309.97 1309.94 1309.90 1309.87 1309.84 1309.81 1309.77 1309.73 1309.69 1309.68 1309.68 1309.69 1309.67 1309.64 1309.63 1309.62 1309.50 1309.47 1309.47 1309.47 1309.47 1309.49 1309.68 1309.72 1309.75 1309.78 1309.81 1309.84 1309.87 1309.89 1309.91 1309.92 1309.93 1309.94 1309.95 1309.96 1309.98 1309.98 1310.00 1310.01 1310.02 1310.02 1310.02 1310.02 1310.02 1310.00 1310.00 1309.94 1309.93 1309.92 1309.85 1309.76 1309.70 1309.65 1309.60 1309.55 1309.52 1309.48 1309.45 1309.46 1309.49 1309.52 1309.56 1309.60 1309.63 1309.66 1309.69 1309.72 1309.76 1309.79 1309.82 1309.85 1309.98 1309.99 1309.98 1309.99 1309.99 1309.99 1310.09 1310.09 1310.09 1310.10 1310.10 1310.11 1310.11 1310.12 1310.12 1310.12 1310.12 1310.12 1309.90 1309.90 1309.90 1309.89 1309.87 1309.87 1309.80 1309.90 1309.89 1309.90 1309.89 1309.82 1309.77 1309.72 1309.72 1309.73 1309.74 1309.75 1309.76 1309.78 1309.79 1309.81 1309.84 1309.87 1309.91 1309.93 1309.98 1310.03 1310.08 1310.13 1310.18 1310.23 1310.55 1310.59 1310.63 1310.67 1310.70 1310.74 1310.78 1310.80 1310.83 1310.86 1310.87 1310.87 1310.86 1310.86 1310.84 1310.84 1310.85 1310.85 1310.85 1310.85 1310.85 1310.88 1310.90 1310.97 1312.79 1313.08 1313.12 1313.16 1313.19 1313.22 1313.24 1313.27 1313.29 1313.32 1313.34 1313.34 1313.31 1313.29 1313.26 1313.25 1313.22 1313.20 1313.17 1313.10 1313.11 1313.08 1313.06 1313.03 1313.01 1312.98 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 1318.36 1314.17 1309.81 1309.58 1310.11 1309.51 1309.99 1309.88 1309.80 1310.28 1312.84 1312.96 27 1318.21 28 1318.13 29 1318.20 30 1318.29 31 1318.26 1314.05 1314.01 1313.80 1313.70 1309.72 1309.69 1309.66 1309.68 1309.77 1309.65 1309.71 1309.77 1309.83 1309.88 1310.09 1310.07 ._. —— 1309.52 1309.55 1309.59 1309.62 1309.65 1309.98 1309.97 1309.96 1309.95 —— 1309.90 1309.93 1309.95 1309.96 1309.97 1309.89 1309.89 1309.89 1309.90 —— 1310.33 1310.38 1310.42 1310.47 1310.50 1312.88 1312.92 1312.96 1313.00 1313.04 1312.93 1312.91 1312.89 1312.85 1321.90 1318.13 1318.09 1313.70 1313.63 1309.66 1309.88 1308.84 1310.38 1309.93 1310.04 1310.02 1309.97 1310.12 1310.50 1313.04 1313.34 1309.47 1309.68 1309.45 1309.80 1309.72 1310.55 1312.85 WTR YR 1997 MAX 1321.90 MIN 1308.84 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR 171 LOCATION.--Lat 18°12'04", long 66°08'26", Hydrologic Unit 21010005, 0.2 ml (0.3 tan) downstream of Lago Cidra Dam on right bank, 2.1 mi (3.4 tan) northwest of Plaza de Cidra. DRAINAGE AREA.—8.31 mi 2 (21.5 tan2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1990 to current year. GAGE.—Hater-stage recorder. Elevation of gage is 1,279 ft (390 m), from topographic map. REMARKS.—Records poor. Regulation at all stages by Puerto Rico Acxueduct and Sewer Authority reservoir upstream from gage. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR JUN JUL AUG SEP 1 18 26 2 18 26 3 18 26 4 19 26 5 22 26 6 21 26 7 21 25 8 21 26 9 21 26 10 21 25 11 21 25 12 21 25 13 21 22 14 20 19 15 22 22 16 24 24 17 23 23 18 26 27 19 29 30 20 30 29 21 26 29 22 22 29 23 25 28 24 29 28 25 29 24 26 29 19 27 29 28 28 24 34 29 17 33 30 16 33 31 20 TOTAL 703 789 MEAN 22.7 26.3 MAX 30 34 MIN 16 19 AC-FT 1390 1560 CFSM 2.73 3.16 IN. 3.14 3.53 STATISTICS OF MONTHLY MEAN MEAN 14.6 22.8 MAX 22.7 41.2 (WY) 1997 1992 MIN 3.74 8.85 (WY) 1995 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 33 30 29 29 28 28 27 28 28 29 19 12 18 21 20 20 21 20 20 19 19 19 20 22 22 21 21 21 21 18 16 699 22.5 33 12 1390 2.71 3.13 17 19 19 19 e!6 el 5 e!4 e!3 e!4 e!4 e!3 e!3 e!4 e!2 e!3 e!2 ell e!2 e!2 ell e!2 e!2 6.4 5.8 5.4 4.9 6.9 9.1 7.2 10 13 375.7 12.1 19 4.9 745 1.46 1.68 DATA FOR HATER 15.3 30.4 1992 4.36 1994 FOR 18.4 59.6 1992 5.45 1995 13 12 12 11 15 20 16 10 12 13 13 13 18 24 27 27 26 21 16 13 13 14 14 21 23 20 17 15 ___ —— 469 16.8 27 10 930 2.01 2.10 YEARS 1991 17.6 36.5 1991 7.24 1994 15 17 17 16 15 15 16 16 16 16 16 16 18 19 20 18 19 16 23 16 11 10 10 8.6 7.8 8.6 9.3 9.2 9.4 8.7 9.0 441.6 14.2 23 7.8 876 1.71 1.97 - 1997 16.2 23.7 1992 11.4 1994 1996 CALENDAR YEAR 14121. 38. 5420 3. 4. 28010 4. 63. 32 19 11 7 6 Sep 10 4 Jul 24 1 Jun 8 64 14 8.3 7.9 7.9 7.8 7.6 7.6 5.5 4.3 4.8 5.0 5.1 5.2 5.2 5.1 4.8 4.4 4.3 6.0 7.6 7.4 7.3 5.7 5.3 5.4 5.3 5.3 5.1 4.0 3.2 3.2 —— 171.6 5.72 8.3 3.2 340 .69 .77 4.7 7.1 7.2 7.2 6.3 5.5 5.3 5.2 5.3 5.1 5.2 3.7 2.7 2.7 2.7 2.7 4.8 6.0 4.9 3.0 2.9 2.9 4.5 5.6 5.7 5.8 5.7 4.1 3.1 3.3 3.3 144.2 4.65 7.2 2.7 286 .56 .64 3.3 8.5 9.6 6.6 6.5 6.5 6.5 6.8 4.9 3.1 3.1 3.0 4.5 5.3 5.7 4.8 3.4 3.3 3.3 5.2 6.6 6.7 4.3 3.3 3.4 3.6 3.7 3.7 3.8 3.8 —— 146.8 4.89 9.6 3.0 291 .59 .66 3.8 4.1 6.7 6.7 7.2 7.7 6.5 .0 .1 .3 .1 .2 .1 .2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 193.3 6.24 8.8 3.8 383 .75 .86 7.1 7.3 7.3 7.8 7.3 7.2 7.6 7.5 7.7 8.1 7.2 7.1 7.1 8.7 6.7 7.2 7.0 7.1 8.0 7.2 7.1 7.8 7.1 8.1 7.5 8.5 8.4 7.1 8.7 8.4 8.8 235.7 7.60 8.8 6.7 468 .91 1.05 8.7 10 14 14 13 11 8.8 10 11 11 8.6 7.0 5.8 5.8 5.9 7.2 8.0 8.0 8.1 8.2 8.5 8.7 8.5 8.1 8.0 8.1 8.5 8.2 8.0 8.2 —— 266.9 8.90 14 5.8 529 1.07 1.19 , BY HATER YEAR (WY) 13.1 24.5 1996 5.72 1997 FOR 1997 4635 12 34 2 3 72 9 9200 1 20 26 8 4 9.49 17.0 1996 4.13 1993 HATER YEAR .8 .7 Nov 28 .7 May 13 .5 May 11 Aug 24 .74 Aug 24 .53 .73 .8 .2 9.97 17.8 1992 3.47 1994 14.6 39.6 1993 1.56 1994 HATER 17 36 5 5420 15000 27 12340 2 27 27 11 2 13.5 29.2 1996 1.18 1995 YEARS 1991 .0 .1 .93 Sep . 60 Aug .80 May Sep .34 Sep .05 .82 .5 41.9 233 1996 1.64 1994 - 1997 1996 1994 10 1996 6 1992 1 1995 10 1996 10 1996 e Estimated 172 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1991 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: November 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 3,670 mg/L Jan. 05, 1992; Minimum daily mean, 3 mg/L November 27, 1993 and June 27-28, 1997. SEDIMENT LOADS: Maximum daily mean, 27,700 tons (25,100 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.02 tonne) November 21, 1993. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 256 mg/L August 25, 1997; Minimum daily mean, 3 mg/L June 27-28, 1997. SEDIMENT LOADS: Maximum daily mean, 13 tons (12 tonnes) several days; Minimum daily mean, 0.03 ton (0.03 tonne) June 28, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 (AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 18 18 18 19 22 21 21 21 21 21 21 21 21 20 22 24 23 26 29 30 26 22 25 29 29 29 29 24 17 16 20 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 18 18 18 19 22 21 21 21 21 21 21 21 21 20 22 24 23 26 29 30 26 22 25 29 29 29 29 24 17 16 20 206 219 233 244 223 197 177 178 184 169 142 161 180 182 180 179 174 168 163 158 153 148 143 139 134 130 126 122 120 128 140 9.7 11 11 13 13 11 10 10 11 9.6 7.9 9.2 10 10 11 11 11 12 13 13 11 8.8 9.7 11 10 10 9.7 7.9 5.4 5.5 7.7 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 26 26 26 26 26 26 25 26 26 25 25 25 22 19 22 24 23 27 30 29 29 29 28 28 24 19 28 34 33 33 149 134 116 101 101 105 109 103 94 86 79 72 66 60 55 50 45 41 38 35 26 22 21 23 23 23 26 34 30 31 11 9.3 8.2 7.1 7.1 7.4 7.5 7.2 6.6 5.9 5.3 4.8 3.8 3.1 3.2 3.2 2.8 3.1 3.1 2.8 2.1 1.8 1.6 1.8 1.5 1.2 2.0 3.1 2.7 2.8 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 33 30 29 29 28 28 27 28 28 29 19 12 18 21 20 20 21 20 20 19 19 19 20 22 22 21 21 21 21 18 16 32 31 30 30 27 24 24 24 26 28 34 41 44 25 11 6 6 7 8 13 21 35 36 31 28 24 23 21 20 18 17 2.9 2.6 2.3 2.4 2.1 1.8 1.8 1.9 2.0 2.2 1.7 1.3 2.1 1.5 .60 .36 .35 .38 .47 .67 1.1 1.8 1.9 1.8 1.7 1.4 1.3 1.2 1.2 .91 .73 TOTAL 703 314.1 789 133.1 699 46.47 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 173 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 17 19 19 19 e!6 e!5 e!4 e!3 e!4 e!4 e!3 e!3 e!4 e!2 e!3 e!2 ell e!2 e!2 ell e!2 e!2 6.4 5.8 5.4 4.9 6.9 9.1 7.2 10 13 19 23 28 21 15 9 7 7 9 11 14 16 19 23 27 38 56 83 124 183 249 162 87 47 28 41 71 97 15 19 21 .90 1.2 1.5 1.1 e.79 .41 .26 .26 .33 .43 .50 .57 .70 .79 .92 el. 3 el. 7 e2.6 e4.0 e5.7 e7.7 e3.6 1.5 .72 .41 .55 1.4 2.3 .33 .70 .77 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 13 12 12 11 15 20 16 10 12 13 13 13 18 24 27 27 26 21 16 13 13 14 14 21 23 20 17 15 14 11 8 8 8 8 10 12 17 34 86 194 147 78 45 40 37 35 33 32 30 17 9 4 5 9 11 12 .49 .35 .28 .23 .33 .48 .41 .32 .58 1.2 3.0 6.9 6.7 5.0 3.3 2.9 2.6 2.0 1.4 1.1 1.1 .64 .36 .24 .35 .50 .52 .49 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (HG/L) (TONS/DAY) TOTAL 375.7 45.94 469 43.77 15 17 17 16 15 15 16 16 16 16 16 16 18 19 20 18 19 16 23 16 11 10 10 8.6 7.8 8.6 9.3 9.2 9.4 8.7 9.0 441.6 MARCH 12 12 15 14 14 18 27 34 27 19 15 23 44 91 66 33 18 13 13 10 11 10 11 11 11 12 12 11 13 9 10 .50 .57 .69 .62 .62 .79 1.1 1.5 1.2 .84 .67 1.0 2.2 4.6 3.5 1.6 .92 .59 .86 .43 .34 .28 .31 .25 .24 .30 .30 .28 .34 .23 .25 27.92 e Estimated 174 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 8.3 7.9 7.9 7.8 7.6 7.6 5.5 4.3 4.8 5.0 5.1 5.2 5.2 5.1 4.8 4.4 4.3 6.0 7.6 7.4 7.3 5.7 5.3 5.4 5.3 5.3 5.1 4.0 3.2 3.2 APRIL 8 8 10 15 18 15 11 11 12 15 18 16 13 12 10 10 9 10 11 11 10 10 9 8 8 7 7 6 5 6 —— MAY .19 .18 .22 .31 .37 .32 .17 .13 .16 .21 .25 .23 .19 .16 .13 .12 .11 .17 .23 .23 .20 .16 .13 .13 .12 .11 .09 .07 .05 .06 —— 4.7 7.1 7.2 7.2 6.3 5.5 5.3 5.2 5.3 5.1 5.2 3.7 2.7 2.7 2.7 2.7 4.8 6.0 4.9 3.0 2.9 2.9 4.5 5.6 5.7 5.8 5.7 4.1 3.1 3.3 3.3 6 7 9 9 9 12 15 19 16 13 10 8 8 8 6 6 6 7 5 8 12 21 36 20 18 15 10 7 10 17 27 .08 .15 .18 .18 .16 .18 .22 .27 .23 .18 .14 .08 .06 .07 .05 .05 .09 .12 .07 .07 .09 .17 .44 .30 .27 .23 .16 .08 .09 .15 .23 3.3 8.5 9.6 6.6 6.5 6.5 6.5 6.8 4.9 3.1 3.1 3.0 4.5 5.3 5.7 4.8 3.4 3.3 3.3 5.2 6.6 6.7 4.3 3.3 3.4 3.6 3.7 3.7 3.8 3.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 20 8 8 9 8 8 10 12 12 9 8 6 7 7 8 8 8 9 11 12 13 8 6 5 6 6 3 3 4 4 .18 .21 .21 .16 .14 .15 .19 .22 .16 .08 .07 .05 .09 .11 .12 .11 .08 .08 .10 .17 .23 .16 .07 .05 .06 .06 .04 .03 .04 .05 TOTAL 171.6 5.20 144.2 4.84 146.8 3.47 RZO OB BAYAMON BASIN 50047560 RZO OB BAYAMON BELOW LACK) CZDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 175 DISCHARGE DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR (CFS) 3.8 4.1 6.7 6.7 7.2 7.7 6.5 4.0 4.1 4.3 4.1 4.2 4.1 4.2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 193.3 4635.8 MEAN CONCEN- TRATION DISCHARGE (MG/L) (TOMS/DAY) JULY MEAN DISCHARGE (CP8) 3.8 4.1 6.7 6.7 7.2 7.7 6.5 4.0 4.1 4.3 4.1 4.2 4.1 4.2 5.9 8.8 6.8 6.8 7.0 7.3 7.3 7.3 7.6 6.7 7.4 6.9 7.2 7.5 7.0 7.0 7.1 7 14 36 82 51 21 9 4 4 4 3 4 4 5 5 6 8 6 7 17 58 176 82 20 6 5 8 13 14 14 16 .08 .16 .65 1.5 .98 .44 .18 .05 .05 .05 .04 .05 .05 .06 .09 .13 .14 .12 .13 .35 1.1 3.5 1.7 .36 .13 .11 .17 .27 .28 .27 .32 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 7.1 7.3 7.3 7.8 7.3 7.2 7.6 7.5 7.7 8.1 7.2 7.1 7.1 8.7 6.7 7.2 7.0 7.1 8.0 7.2 7.1 7.8 7.1 8.1 7.5 8.5 8.4 7.1 8.7 8.4 8.8 15 16 16 17 22 32 46 48 45 43 41 38 37 40 45 49 28 13 7 8 16 34 69 140 256 134 43 18 19 17 17 .28 .32 .33 .36 .43 .61 .93 .96 .94 .94 .79 .74 .70 .95 .83 .96 .52 .27 .16 .17 .32 .71 1.3 3.1 5.3 3.2 .94 .35 .45 .38 .41 MEAN DISCHARGE (CFS) 8.7 10 14 14 13 11 8.8 10 11 11 8.6 7.0 5.8 5.8 5.9 7.2 8.0 8.0 8.1 8.2 8.5 8.7 8.5 8.1 8.0 8.1 8.5 8.2 8.0 8.2 MEAN CONCEN- TRATION (MG/L) SEPTEMBER 19 22 25 30 37 44 33 21 14 14 16 18 17 13 13 15 21 28 28 23 20 18 16 13 11 11 10 16 28 47 SEDXtfiENT DISCHARGE (TONS/DAY) .44 .61 .95 1.1 1.2 1.3 .78 .60 .42 .41 .38 .35 .27 .21 .20 .31 .44 .61 .60 .51 .46 .44 .37 .29 .25 .24 .24 .35 .61 1.1 13.51 683.01 235.7 28.65 266.9 16.04 176 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE SEP 1997 21... TIME 1626 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 8.6 671 15 80 84 88 DATE SEP 1997 21... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 89 91 97 98 99 100 100 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW XAQO CIDRA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 177 DATE OCT 1996 10... FEB 1997 12... MAR 14... MAY 28... TIME 1507 1608 1738 1100 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 22 13 18 3.2 SEDI- MENT, SUS- PENDED (MG/L) (80154) 191 243 114 57 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 11 8.5 5.5 0.49 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 100 58 86 97 RIO DE BAYAMON BASIN 50047600 RIO DE BAYAHON NEAR AGUAS BUENAS, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°14'39", long 66°08'39", at bridge on Highway 156, and 2.9 mi (4.7 km) west of Aguas Buenas plaza. DRAINAGE AREA.—18.5 mi 2 (47.9 km2 ). PERIOD OF RECORD.—Hater years 1958-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 08... FEB 1997 19... MAY 13... SEP 09... OCT 08 FEB 19 MAY 13 SEP 09 OCT DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1010 30 173 7.4 24.0 0.30 8.0 93 <10 K700 K1900 0820 27 289 6.5 21.5 1.7 7.6 85 <10 590 K1300 1320 9.2 336 8.3 27.0 0.55 8.2 105 <10 K91 580 1305 14 299 8.2 28.0 0.89 7.8 103 <10 230 300 ALKA- HARD- MAGNE- SODIUM POT AS- LINITY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 08... FEB 19 MAY 13 09 OCT 08 FEB 19 MAY 13 SEP 09 1997 ... ... ... DATE 1996 ... 1997 . . . . . . NESS TOTAL (MG/L AS CACO3) (00900) 75 — 130 99 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.28 0.24 0.22 0.24 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 18 — 30 23 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 18 — 29 26 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.0 0.99 0.68 0.86 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.4 — 14 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 134 — 203 175 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.5 4.4 3.0 3.8 SODIUM, DIS-' SOLVED (MG/L AS NA) (00930) 8.2 — 18 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 10.8 -- 5.06 6.62 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.030 0.030 <0.020 AD- SORP- TION RATIO (00931) 0.4 — 0.7 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 52 <1 <1 14 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 — 1.7 2.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.720 0.750 0.450 0.620 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 100 110 130 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.030 <0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) 0.5 — <0.5 *.. NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 0.750 0.750 0.460 0.630 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.2 — 11 6.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.010 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 3 -- 1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 — 22 15 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.25 0.23 0.20 0.21 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 11 — K » non-ideal count DATE OCT 1996 08... FEB 1997 19... MAY 13... SEP 09... RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AGUAS BUENAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 179 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 2700 100 <1 100 32 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 0.03 180 RIO DB BAYAMON BASIN 50047850 RIO BAYAMON NR BAYAMON, PR LOCATION.--Lat 18»20'08", long 66°08'13", Hydrologic Unit 21010005, on left bank, at rock 50000 7.6 29.0 28.0 6.6 85 K91 230 160 24 SEP 09... 1140 28000 7.6 33.0 13.0 9.8 73 2600 79000 170 32 NITRO- DATE OCT 1996 21... MAR 1997 06... JUN 23... SEP 09... NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) <0.010 -- 0.310 0.020 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 0.170 0.014 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) <0.020 <0.020 <0.020 0.030 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 1.40 8.70 3.00 0.600 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.83 1.8 0.45 1.6 GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 2.2 10 3.4 2.2 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.3 10 3.9 2.3 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 10 46 17 10 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.280 1.30 0.590 0.220 CARBON, ORGANIC TOTAL (MG/L AS C) (00680) 7.2 13 9.6 8.4 193 ATLANTIC OCEAN / L-Drc^noge bouftdar . vjwnrnwf vvn A 0509 AND NUMBER ETERS 0 222 WELL AND WELL NUMBER Figure 19.--Rfo Grande de Lofza basin. 194 RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°23'27", long 65°58'28", at bridge on Highway 3, 1.4 mi (2.3 km) south of Valle Arriba Heights housing area, and 1.2 mi (1.9 km) west-southwest of Carolina plaza. DRAINAGE AREA.—2.96 mi 2 (7.67 km2 ). PERIOD OF RECORD.--Water years 1973 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP- INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1300 6.8 526 7.1 28.0 4.4 5.7 72 <10 27000 2700 1300 7.6 495 6.5 24.5 2.2 5.9 70 13 49000 310000 1145 2.7 625 7.0 28.0 1.2 3.6 46 13 32000 71000 1200 4 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 200 — 28 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 -- <0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.73 0.90 3.4 0.89 .2 505 7 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 64 — 6.3 49 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 28 — 17 22 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 2.2 3.9 2.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 10 — 3.0 8.0 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 305 -- 160 253 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 9.2 9.7 17 9.5 .3 28 SODIUM, pis- SOLVED (MG/L AS NA) (00930) 31 — 7.4 29 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.56 — 1.17 2.87 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.120 0.200 0.590 0.200 .5 3. SODIUM AD- SORP- TION RATIO (00931) 1 — 0.6 0.8 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 9 3 <1 7 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — 1 __ 2 5. POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.7 — 0.62 4.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.10 1.00 0.310 1.10 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 4 70 <10 5500 K1600 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 190 200 190 210 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.230 0.260 0.170 0.170 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 60 — 70 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.40 1.30 0.480 1.30 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 17 — 2.0 34 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.560 0.590 3.00 0.390 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 37 — 9.6 33 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.31 0.45 0.50 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K » non-ideal count RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR—Continued MATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 30... FEB 1997 19... JUN 06... SEP 10... 420 470 MANGA- IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RECOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 <1 170 430 <0.10 <0.10 <1 <1 <1 <1 20 <0.010 <0.010 <1 METHY- TtffNE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.06 0.07 195 196 RIO GRANDE DE LOIZA BASIN 50050900 RIO GRANDE DE LOIZA AT QUEBRADA ARENAS, PR LOCATION.--Lat 18°07'10", long 65°59'22", Hydrologic Unit 21010005, at intersection of Highways 181 and 9990, 0.2 mi (0.3 km) upstream from confluence with Rio Emajagua and about 7.1 mi (11.4 km) southwest of San Lorenzo. DRAINAGE AREA.—6.00 mi 2 (15.54 km2 ). PERIOD OF RECORD.--October 1977 to current year. GAGE.—Water-stage recorder. Elevation of gage is 640 ft (195 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV JAN APR JUN JUL AUG SEP 1 29 49 2 e30 31 3 e45 19 4 29 32 5 26 23 6 e26 25 7 26 53 8 e25 23 9 33 41 10 62 21 11 39 59 12 27 205 13 24 128 14 28 35 15 40 27 16 25 23 17 21 21 18 23 20 19 22 39 20 20 29 21 19 44 22 19 48 23 18 35 24 18 e24 25 17 21 26 20 20 27 20 19 28 19 19 29 18 19 30 17 22 31 19 TOTAL 804 1174 MEAN 25.9 39.1 MAX 62 205 MIN 17 19 AC-FT 1590 2330 CFSM 4.32 6.52 IN. 4.98 7.28 STATISTICS OF MONTHLY MEAN MEAN 39.6 44.4 MAX 123 122 (WY) 1986 1988 MIN 13.1 8.34 (WY) 1990 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 19 18 17 17 17 16 17 15 15 15 26 15 14 14 14 14 13 13 12 12 12 12 12 13 14 13 12 12 62 28 16 519 16.7 62 12 1030 2.79 3.22 DATA 25.0 55.2 1988 6.65 1990 13 12 12 12 12 11 11 11 11 11 111 14 11 10 9.7 9.5 9.3 8.9 9.0 11 19 71 14 14 12 13 10 11 9.8 11 10 514.2 16.6 111 8.9 1020 2.76 3.19 116 100 25 18 29 28 20 18 29 19 25 23 41 29 22 22 18 18 17 17 25 22 36 19 18 50 18 16 --. --. —— 838 29.9 116 16 1660 4.99 5.20 FOR WATER YEARS 1978 19.4 56.1 1992 8.16 1990 19.0 38.0 1982 6.36 1979 15 15 15 15 14 14 13 15 13 12 12 13 14 15 19 15 12 12 11 10 9.9 9.7 9.1 8.7 8.4 8.3 8.2 9.0 8.5 7.6 8.8 370.2 11.9 19 7.6 734 1.99 2.30 - 1997 13.8 34.4 1996 5.07 1979 FOR 1996 CALENDAR YEAR 19708 53.8 3740 10 11 39090 8.97 122.19 98 24 13 Sep 10 May 28 May 25 7.3 333 37 15 12 11 10 10 9.8 9.5 9.4 9.3 9.7 9.2 8.8 8.5 8.5 8.3 8.2 8.1 8.1 8.0 7.9 7.7 7.7 7.6 7.5 7.4 7.3 7.2 --- 619.0 20.6 333 7.2 1230 3.44 3.84 7.0 6.9 6.9 7.0 6.8 6.6 7.6 7.8 7.3 23 12 17 14 12 13 12 17 12 9.8 9.7 9.6 9.4 8.5 8.7 10 9.0 17 18 32 22 13 372.6 12.0 32 6.6 739 2.00 2.31 15 42 64 e24 e22 e23 e20 e!8 e!7 e!6 e!6 e!6 e26 e20 e!5 ell e!2 e!2 ell e!2 11 9.8 11 11 9.6 10 9.2 8.7 8.3 8.0 --- 508.6 17.0 64 8.0 1010 2.83 3.15 7.8 7.5 7.4 7.5 9.9 11 8.8 9.8 10 8.3 7.7 8.2 13 8.0 7.7 14 13 9.9 27 47 145 35 48 24 20 20 17 164 28 64 30 838.5 27.0 164 7.4 1660 4.51 5.20 22 19 18 18 17 16 16 17 20 69 35 29 23 20 21 27 25 110 27 21 21 352 46 126 46 31 63 32 31 26 44 1388 44.8 352 16 2750 7.46 8.61 26 26 22 21 20 19 18 19 18 17 16 16 16 18 33 17 16 21 16 15 71 169 48 40 24 59 28 22 24 66 —— 941 31.4 169 15 1870 5.23 5.83 , BY WATER YEAR (WY) 13.7 27.1 1985 4.64 1979 FOR 1997 8887 24 352 6 6 3620 9 6 17630 4 55 41 17 8 30.3 77.5 1985 9.56 1988 WATER YEAR .1 .3 Aug 22 .6 May 6 .9 Apr 30 Apr 2 .84 Apr 2 .3 May 5 .06 .10 .3 38.7 122 1979 11.3 1985 37.6 92.3 1993 12.5 1986 WATER 30 54 14 3740 3 3 44000 25 2 21880 5 68 50 15 7 33.9 90.0 1979 9.30 1991 YEARS 1978 - .2 .1 .5 Sep 10 .1 May 7 .6 May 1 Sep 10 .93 Sep 10 .8 May 5 .03 .39 .1 46.9 202 1996 11.8 1981 1997 1996 1990 1996 1979 1979 1996 1996 1979 e Estimated 197 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR LOCATION.--Lat 18°09'40", long 65°58'58", Hydrologic Unit 21010005, 0.1 mi (0.2 km) upstream from bridge on Highway 181, and 2.8 mi (4.5 km) southwest of San Lorenzo. DRAINAGE AREA. —3.25 mi* (8.42 tan1 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—October 1984 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 459 ft (140 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC JAN FEB MAR JUL AUG SEP 1 8.7 9.4 2 16 13 3 7.1 7.5 4 6.3 6.7 5 6.2 6.7 6 6.2 6.6 7 6.6 17 8 6.7 18 9 13 14 10 25 9.9 11 15 18 12 12 44 13 10 34 14 9.2 20 15 9.3 16 16 9.4 14 17 8.5 14 18 8.2 12 19 8.5 17 20 8.6 14 21 7.8 12 22 7.9 10 23 7.9 12 24 7.3 11 25 7.2 9.0 26 8.2 7.7 27 13 7.0 28 9.9 7.3 29 8.9 6.4 30 7.5 7.1 31 6.9 TOTAL 293.0 401.3 MEAN 9.45 13.4 MAX 25 44 MIN 6.2 6.4 AC-FT 581 796 CFSM 2.91 4.12 IN. 3.35 4.59 6.2 5.6 4.9 4.7 4.3 4.5 9.1 5.2 4.4 4.4 28 12 8.9 7.5 7.2 6.9 5.7 5.1 4.9 4.8 4.6 4.5 4.4 4.6 6.4 4.4 4.5 4.2 7.4 11 4.7 205.0 6.61 28 4.2 407 2.03 2.35 4.0 3.8 3.7 3.7 3.6 3.5 3.3 3.3 3.2 3.1 9.0 3.8 3.4 3.0 3.0 3.0 2.8 2.6 3.0 4.6 12 24 6.4 4.4 3.9 3.6 3.0 7.4 4.1 3.5 3.4 149.1 4.81 24 2.6 296 1.48 1.71 16 17 9.2 5.8 9.7 7.5 6.3 5.1 14 5.5 6.9 9.6 11 9.9 6.3 5.0 4.4 4.0 3.9 3.9 4.8 4.7 11 4.4 4.6 4.6 4.0 3.8 -__ —— 202.9 7.25 17 3.8 402 2.23 2.32 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1984 MEAN 10.0 15.0 MAX 47.8 36.9 (WY) 1986 1985 MZN 2.75 2.49 (WY) 1993 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 6.80 30.1 1988 1.49 1990 FOR 4.81 9.94 1992 1.74 1995 4.20 8.21 1989 1.32 1985 3.6 3.6 3.8 3.8 3.6 3.3 3.1 3.2 3.4 3.2 2.9 2.9 2.9 2.9 4.1 3.4 3.0 3.2 3.0 2.7 2.6 2.6 2.5 2.5 2.3 2.3 2.2 2.2 2.3 2.3 2.4 91.8 2.96 4.1 2.2 182 .91 1.05 - 1997 3.93 20.7 1989 1.64 1993 1996 CALENDAR YEAR 3797.7 10.4 326 1.3 1.5 7530 3.19 43.47 21 6.0 1.7 Sep 10 Apr 2 Mar 27 2.3 24 13 4.0 3.1 2.6 2.4 2.4 2.3 2.2 2.2 2.2 2.8 2.2 2.0 1.9 2.0 2.0 2.0 1.9 1.9 1.9 1.8 2.1 1.9 1.6 1.7 1.8 1.8 1.8 —— 97.8 3.26 24 1.6 194 1.00 1.12 1.8 1.6 1.4 1.3 1.3 1.4 1.4 1.8 2.0 3.7 3.0 3.3 2.3 2.2 3.3 3.2 12 3.1 2.5 2.8 2.6 2.1 1.9 1.9 1.9 1.9 3.4 5.0 3.3 3.6 3.1 86.1 2.78 12 1.3 171 .85 .99 2.7 4.6 7.3 4.3 3.8 4.0 3.5 3.1 3.0 2.7 2.7 2.7 4.3 3.4 2.6 1.9 2.0 2.0 1.9 2.0 1.9 2.0 2.6 2.7 1.8 1.8 1.6 1.5 1.5 1.5 —— 83.4 2.78 7.3 1.5 165 .86 .95 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 135.4 4.37 34 1.1 269 1.34 1.55 1.9 1.4 1.6 2.6 2.0 1.7 1.4 1.7 1.7 2.6 3.9 2.6 2.3 1.8 1.6 2.5 2.5 5.1 4.1 2.6 4.9 39 12 el02 21 8.4 23 15 7.4 5.5 17 302.8 9.77 102 1.4 601 3.01 3.47 6.6 6.0 3.8 3.0 2.5 2.2 2.1 5.3 3.5 2.1 1.7 2.9 2.4 7.1 11 3.6 2.8 11 4.0 3.3 12 17 23 28 12 18 9.2 5.1 4.1 6.6 —— 221.9 7.40 28 1.7 440 2.28 2.54 , BY WATER YEAR (WY) 2.32 4.88 1989 .75 1994 FOR 1997 2270 6 102 1 1 1530 8 4500 1 25 13 3 1 6.72 31.5 1985 .62 1994 WATER YEAR .5 .22 Aug 24 .1 Jul 3 .3 Jul 9 Aug 24 .76 Aug 24 .96 Jul 15 .91 .99 .8 .8 6.24 21.3 1987 2.12 1994 6.31 15.0 1993 2.02 1986 WATER 6. 12. 2. 457 . . 7610 14. . 5030 2. 29. 12 2. 1. 7.15 20.2 1988 1.95 1994 YEARS 1984 - 94 3 50 Dec 7 33 May 20 37 Apr 26 Sep 10 64 Sep 10 30 May 21 13 00 6 0 9.67 27.7 1996 1.36 1990 1997 1988 1990 1987 1994 1994 1996 1996 1994 e Estimated 198 RIO GRANDE DB LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1985 to 1986 and water year 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDBD-SBDIHENT DISCHARGE: October 1984 to September 1986 and from October 1989 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1989. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,300 mg/L Oct. 06, 1985; Minimum daily mean, <1 mg/L several days in 1996. SEDIMENT LOADS: Maximum daily mean, 4,940 tons (4,480 tonnes) May 17, 1985; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,260 mg/L August 24, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,270 tons (1,150 tonnes) August 24, 1997; Minimum daily mean, 0.01 ton (0.01 tonnes) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 8.7 16 7.1 6.3 6.2 6.2 6.6 6.7 13 25 15 12 10 9.2 9.3 9.4 8.5 8.2 8.5 8.6 7.8 7.9 7.9 7.3 7.2 8.2 13 9.9 8.9 7.5 6.9 8 75 32 14 13 12 12 15 55 124 17 8 5 4 5 5 16 79 43 27 6 5 .19 9.5 .63 .25 .21 .21 .22 .26 2.7 8.5 .73 .25 .15 .10 .12 .12 .10 .09 .09 .09 .09 .09 .09 .08 .08 .49 3.3 1.3 .68 .13 .09 NOVEMBER 9.4 13 7.5 6.7 6.7 6.6 17 18 14 9.9 18 44 34 20 16 14 14 12 17 14 12 10 12 11 9.0 7.7 7.0 7.3 6.4 7.1 —— 6 68 37 35 35 35 92 112 68 25 80 247 149 33 11 62 68 12 78 35 20 13 12 30 15 7 5 6 7 7 .15 2.8 .74 .64 .63 .62 5.9 7.3 2.8 .66 5.7 35 16 1.9 .47 2.5 2.9 .39 4.1 1.4 .61 .35 .38 1.1 .39 .15 .10 .12 .12 .14 —— DECEMBER 6.2 5.6 4.9 4.7 4.3 4.5 9.1 5.2 4.4 4.4 28 12 8.9 7.5 7.2 6.9 5.7 5.1 .9 .8 .6 .5 .4 .6 .4 .4 .5 .2 7.4 11 4.7 7 8 16 25 13 6 47 13 3 3 327 5 2 2 2 2 4 8 11 12 7 4 2 2 10 6 6 6 28 63 17 .12 .12 .21 .32 .15 .07 1.4 .18 .04 .04 79 .17 .05 .04 .04 .04 .06 .11 .14 .16 .09 .05 .03 .03 .23 .07 .07 .07 .79 2.2 .22 293.0 30.93 401.3 96.06 205.0 86.31 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 199 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JANUARY 4.0 3.8 3.7 3.7 3.6 3.5 3.3 3.3 3.2 3.1 9.0 3.8 3.4 3.0 3.0 3.0 2.8 2.6 3.0 4.6 12 24 6.4 4.4 3.9 3.6 3.0 7.4 4.1 3.5 3.4 11 10 12 14 13 13 11 5 2 2 62 10 3 5 10 5 2 2 3 3 38 173 32 9 8 10 12 50 9 4 3 .12 .11 .12 .14 .13 .12 .10 .04 .02 .02 2.4 .10 .03 .04 .09 .04 .02 .02 .02 .04 2.2 19 .61 .10 .09 .10 .10 1.8 .11 .04 .03 MEAN DISCHARGE (CFS) CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 16 17 9.2 5.8 9.7 7.5 6.3 5.1 14 5.5 6.9 9.6 11 9.9 6.3 5.0 4.4 4.0 3.9 3.9 4.8 4.7 11 4.4 4.6 4.6 4.0 3.8 82 100 17 4 49 43 28 26 81 43 30 50 64 31 24 10 4 3 2 4 7 7 48 10 13 18 9 4 6.2 7.4 .49 .07 3.2 1.0 .53 .36 4.9 .65 .66 3.1 2.2 .91 .42 .13 .05 .03 .03 .04 .09 .09 2.2 .12 .16 .23 .10 .04 DISCHARGE (CFS) 3.6 3.6 3.8 3.8 3.6 3.3 3.1 3.2 3.4 3.2 2.9 2.9 2.9 2.9 4.1 3.4 3.0 3.2 3.0 2.7 2.6 2.6 2.5 2.5 2.3 2.3 2.2 2.2 2.3 2.3 2.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 3 2 2 6 13 13 12 12 11 10 10 10 14 19 24 10 3 3 3 2 2 4 6 10 11 10 9 42 33 21 14 .03 .02 .03 .06 .12 .12 .10 .10 .10 .09 .08 .08 .11 .15 .28 .09 .03 .03 .02 .02 .02 .03 .04 .06 .07 .06 .05 .25 .20 .13 .09 TOTAL 149.1 27.90 202.9 35.40 91.8 2.66 200 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAOUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 2.3 24 13 4.0 3.1 2.6 2.4 2.4 2.3 2.2 2.2 2.2 2.8 2.2 2.0 1.9 2.0 2.0 2.0 1.9 1.9 1.9 1.8 2.1 1.9 1.6 1.7 1.8 1.8 1.8 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 13 134 86 37 25 17 14 21 30 20 14 13 14 15 24 33 20 12 13 14 16 18 16 6 2 2 2 3 8 19 .08 29 4.4 .40 .22 .12 .09 .14 .18 .12 .08 .08 .10 .09 .13 .17 .10 .06 .07 .07 .08 .09 .08 .03 .01 .01 .01 .01 .04 .09 MEAN DISCHARGE (CFS) 1.8 1.6 1.4 1.3 1.3 1.4 1.4 1.8 2.0 3.7 3.0 3.3 2.3 2.2 3.3 3.2 12 3.1 2.5 2.8 2.6 2.1 1.9 1.9 1.9 1.9 3.4 5.0 3.3 3.6 3.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 7 2 2 2 2 2 2 6 12 20 10 5 3 3 11 35 78 11 3 3 4 3 3 3 2 1 11 36 17 32 27 .04 .01 .01 .01 .01 .01 .01 .03 .06 .22 .08 .05 .02 .02 .09 .31 4.3 .10 .02 .03 .03 .02 .01 .01 .01 .01 .27 .51 .16 .31 .23 i TO aEPTrln MEAN DISCHARGE (CFS) 2.7 4.6 7.3 4.3 3.8 4.0 3.5 3.1 3.0 2.7 2.7 2.7 4.3 3.4 2.6 1.9 2.0 2.0 1.9 2.0 1.9 2.0 2.6 2.7 1.8 1.8 1.6 1.5 1.5 1.5 BER 1997 MEAN CONCEN- TRATION (MO/L) JUNE 20 53 42 9 3 2 2 2 2 2 2 2 6 2 4 8 9 8 6 3 2 1 13 14 3 6 14 8 4 2 SEDIMENT DISCHARGE (TONS/DAY) .14 .75 .91 .11 .04 .02 .02 .02 .02 .01 .01 .01 .09 .02 .03 .04 .05 .04 .03 .02 .01 .01 .11 .11 .01 .03 .06 .03 .02 .01 TOTAL 97.8 36.15 86.1 7.00 83.4 2.78 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAQUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 201 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 TOTAL 135.4 YEAR • 2270.5 Estimated MEAN CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) JULY 1.6 1.3 1.1 1.1 2.2 12 3.9 1.9 2.0 1.3 1.2 1.1 1.2 1.1 1.1 2.2 2.5 2.4 1.9 9.7 34 18 5.6 4.3 2.0 1.7 1.3 7.0 2.5 3.8 2.4 3 4 2 3 16 75 17 10 25 19 11 9 7 6 7 8 4 9 28 118 189 79 97 30 10 7 6 80 5 33 18 .01 .01 .01 .01 .10 3.1 .20 .05 .13 .07 .04 .03 .02 .02 .02 .04 .03 .09 .15 3.8 19 4.8 1.8 .56 .05 .03 .02 3.0 .04 .39 .12 37.74 1770.08 MEAN DISCHARGE (CFS) 1.9 1.4 1.6 2.6 2.0 1.7 1.4 1.7 1.7 2.6 3.9 2.6 2.3 1.8 1.6 2.5 2.5 5.1 4.1 2.6 MEAN CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) AUGUST 302.8 6 7 9 10 3 1 4 10 11 9 7 3 1 1 1 1 2 12 7 7 .03 .03 .04 .07 .02 .01 .01 .05 .05 .07 .08 .02 .01 .01 .01 .01 .01 .26 .08 .05 4.9 39 12 •102 21 8.4 23 15 7.4 5.5 17 26 347 151 1260 86 41 202 115 12 8 87 .88 45 5.9 •1270 5.7 .95 19 5.6 .24 .12 5.1 1359.39 i TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) SI 6.6 6.0 3.8 3.0 2.5 2.2 2.1 5.3 3.5 2.1 1.7 2.9 2.4 7.1 11 3.6 2.8 11 4.0 3.3 12 17 23 28 12 18 9.2 5.1 4.1 6.6 MEAN CONCEN- TRATION (MO/L) 10 9 13 8 4 4 3 22 29 4 3 14 12 47 55 20 16 65 14 9 63 50 149 105 22 93 57 22 14 51 SEDIMENT DISCHARGE (TONS/DAY) .19 .14 .13 .06 .03 .02 .02 .75 .32 .02 .01 .17 .09 1.2 2.5 .20 .13 2.9 .16 .08 2.8 2.4 12 11 .79 6.4 , 1.6 .30 .15 1.2 221.9 47.76 202 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGOAL, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE AUG 1997 24... TIME 1801 1070 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED* SUSP. FALL DIAH. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAH. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAH. % FINER THAN .008 MM (70328) 11000 31700 23 28 33 DATE AOG 1997 24... SED. SUSP. FALL DIAM. *» FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAH. % FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 43 57 79 94 98 99 100 203 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 13... DEC 11... JAN 1997 11... 22. . . JUN 02... JUL 28... AUG 22... 27. .. TIME 1010 0501 1030 1040 1045 1130 1100 1040 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 34 203 18 22 4.0 19 53 24 SEDI- MENT, SUS- PENDED (MG/L) (80154) 124 8700 143 147 309 412 756 626 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 11 4770 6.9 8.7 3.3 21 108 41 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 78 72 98 90 98 100 99 10Q 204 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR LOCATION.--Lat 18°10'24", long 65°58'38", Hydrologic Unit 21010005, on left downstream side of bridge on Highway 181, 0.2 mi (0.3 km) upstream from Rio Grande de Loiza, and 1.5 mi (2.4 km) southwest of San Lorenzo. DRAINAGE AREA.--3.74 mi 2 (9.69 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--January 1984 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 330 ft (100 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV JAN FEB MAY JUN JUL AUG SEP 1 5.4 4.2 2 5.1 4.0 3 4.8 3.6 4 4.8 3.4 5 4.8 3.7 6 4.8 4.6 7 5.0 6.3 8 5.1 8.7 9 6.1 4.2 10 8.6 3.1 11 6.2 4.2 12 5.3 32 13 5.1 15 14 5.1 6.2 15 5.0 5.0 16 4.9 4.1 17 .6 9.7 18 .3 5.2 19 .6 7.9 20 .6 5.8 21 .3 5.0 22 .1 11 23 3.8 5.6 24 3.8 4.3 25 3.5 3.8 26 3.5 3.3 27 4.0 3.0 28 4.6 3.7 29 4.5 3.4 30 3.9 3.9 31 3.8 TOTAL 148.0 187.9 MEAN 4.77 6.26 MAX 8.6 32 MIN 3.5 3.0 AC-FT 294 373 CFSM 1.28 1.67 IN. 1.47 1.87 STATISTICS OF MONTHLY MEAN MEAN 8.68 12.1 MAX 36.2 33.4 (WY) 1986 1988 MIN 2.31 2.72 (WY) 1987 1990 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 3.6 4.0 3.3 3.0 3.3 3.3 3.9 3.3 2.8 2.8 48 7.4 5.7 5.0 4.1 4.1 3.8 3.6 3.5 3.4 3.4 3.4 3.3 3.1 3.5 3.1 3.0 2.8 3.3 14 3.7 168.5 5.44 48 2.8 334 1.45 1.68 DATA 5.11 22.8 1988 1.17 1990 2.7 2.7 2.6 2.6 2.5 2.5 2.5 2.4 2.3 2.3 3.6 2.6 2.3 2.2 2.3 2.2 2.2 2.2 2.4 3.8 13 47 7.7 5.6 5.6 4.5 3.9 4.2 4.3 3.8 3.5 154.0 4.97 47 2.2 305 1.33 1.53 21 12 6.4 4.5 6.4 6.2 5.0 3.9 17 5.1 3.6 3.0 3.5 3.0 2.4 2.5 2.4 2.3 2.5 2.4 3.2 2.9 5.9 2.6 2.6 2.6 2.3 2.2 ___ ___ --- 139.4 4.98 21 2.2 276 1.33 1.39 FOR WATER YEARS 1984 4.93 23.4 1992 1.16 1990 3.32 10.3 1984 1.23 1990 2.2 2.3 2.6 2.5 2.3 2.1 2.1 2.2 2.0 2.0 1.9 2.0 2.1 2.1 2.3 2.4 2.2 2.2 2.2 2.0 2.0 1.9 1.8 1.8 1.8 1.8 1.8 1.9 2.1 2.0 1.8 64.4 2.08 2.6 1.8 128 .56 .64 - 1997 3.02 17.4 1989 1.15 1992 FOR 1996 CALENDAR YEAR 4668 12 1750 9260 3 46 14 3 1 .25 .8 Sep 10 . 93 May 5 .99 May 1 .41 .43 .3 .2 1.8 28 12 3.0 2.2 1.9 1.9 1.6 1.6 1.6 1.5 1.5 1.7 1.5 1.4 1.5 1.5 1.4 1.3 1.3 1.3 1.3 1.2 1.2 1.1 1.1 1.1 .98 1.1 1.0 —— 81.58 2.72 28 .98 162 .73 .81 , BY WATER 2.41 6.60 1985 .66 1995 .95 .90 .89 .91 .85 .79 .78 1.0 1.4 1.7 3.7 1.3 1.1 .94 .94 1.1 2.0 1.1 .90 .90 1.1 1.0 1.0 1.1 1.1 1.1 1.4 2.9 2.0 2.6 1.6 41.05 1.32 3.7 .78 81 .35 .41 YEAR (WY) 6.20 35.8 1985 .86 1995 1.6 2.5 2.5 1.5 1.3 1.3 1.1 .88 .90 .78 .78 .70 .98 .85 .66 .56 .50 .52 .56 .60 .57 .53 .63 1.2 .66 .62 .59 .55 .53 .52 --- 27.47 .92 2.5 .50 54 .24 .27 6.53 17.5 1996 .92 1997 FOR 1997 WATER YEAR 1436.82 3.94 88 .48 .51 962 8.14 .47 2850 1.05 14.29 6.2 2.3 .85 Aug 24 Jul 2 Jun 28 Aug 24 Aug 24 Jul 2 .51 .48 .48 .48 .59 1.2 .74 .61 .62 .60 .53 .48 .58 .55 .58 .93 .99 .94 .91 1.0 9.2 8.0 2.7 3.8 1.6 1.4 1.2 2.3 1.5 1.7 1.2 48.40 1.56 9.2 .48 96 .42 .48 5.68 20.5 1993 1.45 1994 WATER 6. 12. 3. 1750 . . 15000 20. . 4830 1. 24. 10 2. . .99 .85 .94 1.3 1.4 1.5 .90 .87 .88 1.3 2.3 1.5 1.2 1.1 1.0 1.1 1.0 1.2 1.3 1.0 1.4 40 5.5 88 37 7.8 14 12 6.0 4.6 19 258.93 8.35 88 .85 514 2.23 2.58 6.20 14.5 1996 1.51 1994 YEARS 1984 66 4 19 29 41 87 26 78 20 0 92 Sep Sep May Sep Sep May 8.3 5.4 4.5 2.5 1.5 1.4 1.4 38 7.3 2.1 1.5 1.5 1.6 1.4 8.6 1.3 1.1 3.8 1.3 1.0 2.0 1.6 1.4 3.3 1.1 8.0 1.3 .92 e.97 el.l —— 117 . 19 3.91 38 .92 232 1.04 1.17 15.8 76.5 1996 1.88 1990 - 1997 1996 1990 10 1996 12 1990 19 1990 10 1996 10 1996 30 1990 e Estimated RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR—Continued HATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1984 to 1986 and water years 1989 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1984 to September 1986 and from October 1989 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1989. REMARKS.— Sediment samples were collected by local observer on a weekly basis. During high flow sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,300 mg/L Oct. 06, 1985; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 33,000 tons (29,900 tonnes) Sep. 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 502 mg/L August 24, 1997; Minimum daily mean, 1.0 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 475 tons (431 tonnes) August 24, 1997; Minimum daily mean, <0.01 ton (<0.01 tonne) several days. 205 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 5.4 5.1 4.8 4.8 4.8 4.8 5.0 5.1 6.1 8.6 6.2 5.3 5.1 5.1 5.0 .9 .6 .3 .6 .6 .3 .1 3.8 3.8 3.5 3.5 4.0 4.6 4.5 3.9 3.8 5 8 12 17 16 14 11 5 2 11 2 3 8 14 4 1 1 1 1 1 1 1 1 1 1 2 2 2 1 1 1 .07 .11 .16 .22 .21 .19 .15 .06 .04 .32 .04 .04 .11 .19 .05 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 .02 .01 .01 NOVEMBER 4.2 4.0 3.6 3.4 3.7 4.6 6.3 8.7 4.2 3.1 4.2 32 15 6.2 5.0 4.1 9.7 5.2 7.9 5.8 5.0 11 5.6 4.3 3.8 3.3 3.0 3.7 3.4 3.9 1 1 1 1 1 7 21 51 13 6 8 223 124 53 17 13 48 19 32 15 10 45 18 17 15 13 12 10 9 9 .01 .01 .01 .01 .01 .10 .41 2.7 .16 .05 .13 31 5.3 .91 .23 .15 3.5 .27 .75 .24 .14 8.0 .28 .19 .15 .12 .09 .10 .08 .09 ___ DECEMBER 3.6 4.0 3.3 3.0 3.3 3.3 3.9 3.3 2.8 2.8 48 7.4 5.7 5.0 4.1 4.1 3.8 3.6 3.5 3.4 3.4 3.4 3.3 3.1 3.5 3.1 3.0 2.8 3.3 14 3.7 8 7 5 3 2 1 2 4 8 9 426 7 3 3 3 3 5 7 3 1 1 4 10 12 13 9 6 7 8 102 27 .08 .08 .04 .02 .01 .01 .02 .04 .06 .06 308 .14 .05 .04 .03 .04 .05 .06 .03 .01 .01 .03 .09 .10 .12 .08 .05 .05 .07 7.6 .33 148.0 2.15 187.9 55.19 168.5 317.40 206 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 2.7 2.7 2.6 2.6 2.5 2.5 2.5 2.4 2.3 2.3 3.6 2.6 2.3 2.2 2.3 2.2 2.2 2.2 2.4 3.8 13 47 7.7 5.6 5.6 4.5 3.9 4.2 4.3 3.8 3.5 9 6 7 9 10 10 10 8 6 5 4 2 2 9 14 11 8 8 8 13 58 262 22 10 6 3 3 10 24 8 2 .06 .05 .05 .06 .07 .07 .07 .05 .04 .03 .04 .01 .01 .05 .09 .07 .05 .05 .05 .13 5.0 109 .46 .16 .09 .04 .03 .12 .28 .08 .02 FEBRUARY 21 12 6.4 4.5 6.4 6.2 5.0 3.9 17 5.1 3.6 3.0 3.5 3.0 2.4 2.5 2.4 2.3 2.5 2.4 3.2 2.9 5.9 2.6 2.6 2.6 2.3 2.2 ___ ___ ___ 127 49 48 10 19 22 10 10 78 14 11 9 6 5 7 11 15 7 4 8 13 9 26 17 8 4 3 2 ___ ___ ___ 20 2.2 .88 .12 1.2 .47 .13 .10 8.4 .20 .11 .08 .06 .04 .05 .08 .10 .04 .03 .05 .12 .07 .52 .12 .05 .03 .02 .01 ___ ___ ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) MARCH 2.2 2.3 2.6 2.5 2.3 2.1 2.1 2.2 2.0 2.0 1.9 2.0 2.1 2.1 2.3 2.4 2.2 2.2 2.2 2.0 2.0 1.9 1.8 1.8 1.8 1.8 1.8 1.9 2.1 2.0 1.8 6 15 24 7 3 6 7 4 3 3 7 17 19 19 17 15 12 5 2 2 2 2 3 3 6 10 6 2 2 2 2 .03 .09 .16 .05 .02 .03 .04 .02 .01 .01 .04 .09 .10 .10 .10 .09 .07 .03 .01 .01 .01 .01 .01 .02 .03 .05 .03 .01 .01 .01 .01 TOTAL 154.0 116.38 139.4 35.28 64.4 1.30 207 RIO GRANDE DB LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1.8 28 12 3.0 2.2 1.9 1.9 1.6 1.6 1.6 1.5 1.5 1.7 1.5 1.4 1.5 1.5 1.4 1.3 1.3 1.3 1.3 1.2 1.2 1.1 1.1 1.1 .98 1.1 1.0 —— APRIL 4 211 298 117 50 22 11 12 15 21 27 19 13 9 9 8 4 2 3 6 8 7 5 4 3 4 4 5 3 2 .02 68 12 .96 .30 .11 .06 .05 .06 .09 .11 .08 .06 .04 .04 .03 .02 .01 .01 .02 .03 .02 .02 .01 .01 .01 .01 .01 .01 .01 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) .95 .90 .89 .91 .85 .79 .78 1.0 1.4 1.7 3.7 1.3 1.1 .94 .94 1.1 2.0 1.1 .90 .90 1.1 1.0 1.0 1.1 1.1 1.1 1.4 2.9 2.0 2.6 1.6 MAY 5 8 7 5 4 5 6 5 5 5 10 3 3 5 4 3 17 21 13 5 2 2 3 3 4 4 5 6 4 4 5 .01 .02 .02 .01 .01 .01 .01 .01 .02 .02 .16 .01 .01 .01 .01 .01 .11 .06 .03 .01 .01 .01 .01 .01 .01 .01 .03 .05 .02 .03 .02 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 1.6 2.5 2.5 1.5 1.3 1.3 1.1 .88 .90 .78 .78 .70 .98 .85 .66 .56 .50 .52 .56 .60 .57 .53 .63 1.2 .66 .62 .59 .55 .53 .52 .02 .04 .03 .02 .02 .03 .01 .01 <.01 .01 .01 .01 .02 .01 .01 t.Ol .01 .01 .01 t.Ol .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 TOTAL 81.58 82.21 41.05 0.77 27.47 0.28 208 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY DISCHARGE (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 .51 .48 .48 .48 .59 1.2 .74 .61 .62 .60 .53 .48 .58 .55 .58 .93 .99 .94 .91 1.0 9.2 8.0 2.7 3.8 1.6 1.4 1.2 2.3 1.5 1.7 1.2 TOTAL 48.40 YEAR • 1436.82 Estimated MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JULY 3 4 3 3 3 2 2 2 2 1 1 1 1 1 2 4 5 11 10 7 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .03 .02 .02 47 36 8 14 5 4 3 12 9 4 3 3.5 1.6 .06 .20 .02 .02 .01 .09 .04 .02 .01 5.67 1313.97 MEAN DISCHARGE (CFS) .99 .85 .94 1.3 1.4 1.5 .90 .87 .88 1.3 2.3 1.5 1.2 1.1 1.0 1.1 1.0 1.2 1.3 1.0 1.4 40 5.5 88 37 7.8 14 12 6.0 4.6 19 258.93 CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST 3 3 4 4 4 3 3 2 2 3 4 3 3 2 2 2 3 3 2 1 4 201 18 502 93 14 49 57 6 4 88 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 59 .03 » .32 475 18 .30 3.0 2.2 .10 .05 6.8 564.99 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 8.3 5.4 4.5 2.5 1.5 1.4 1.4 38 7.3 2.1 1.5 1.5 1.6 1.4 8.6 1.3 1.1 3.8 1.3 1.0 2.0 1.6 1.4 3.3 1.1 8.0 1.3 .92 • .97 •1.1 117.19 6 2 1 1 2 2 2 254 25 7 5 4 4 4 65 9 4 11 5 4 10 9 5 18 5 32 6 5 5 4 121 .15 .03 .01 .01 .01 .01 .01 L .71 .04 .02 .02 .02 .01 i.O .03 .01 .22 .02 .01 .08 .04 .02 .20 .02 4.6 .02 .01 • .01 • .01 132.35 209 RIO QRANDE DE LOXZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE DEC 1996 11... TXME 0529 DIS- CHARGE, XNST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DXAM. \ FINER THAN .002 MM (70326) SED. SUSP. FALL DXAM. * FINER THAN .004 MM (70327) SED. SUSP. FALL DXAM. * FINER THAN .008 MM (70328) 382 7430 7660 25 35 49 DATE DEC 1996 11... SED. SUSP. FALL DIAM. \ FINER THAN .016 MM (70329) SED. SUSP. FALL DXAM. \ FINER THAN .031 MM (70330) SED. SUSP. SIEVE DXAM. \ FINER THAN .062 MM (70331) SED. SUSP. SIEVE DXAM. \ FINER THAN .125 MM (70332) SED. SUSP. SIEVE DXAM. \ FINER THAN .250 MM (70333) SED. SUSP. SIEVE DXAM. * FINER THAN .500 MM (70334) SED. SUSP. SIEVE DXAM. \ FINER THAN 1.00 MM (70335) 63 74 93 98 99 99 100 210 RIO ORANDE DE LOIZA BASIN 50051180 QUEBRADA 8ALVATIERRA NEAR SAN IXXRENZO—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 13... DEC 11... 11... 30... JAN 1997 22... APR 04... SEP 08... 18... TIME 0950 0500 0614 1030 1010 1000 1626 1011 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 20 34 40 10 58 3.0 117 10 SEDI- MENT, SUS- PENDED (MO/L) (80154) 190 4050 3180 91 282 98 1050 353 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 10 372 343 2.4 44 0.80 332 9.5 SED. SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) 99 89 97 98 99 30 98 98 RIO GRANDE DE LOIZA BASIN 50051310 RIO CAYAGUAS AT CERRO GORDO, PR LOCATION.—Lat 18°09'13", long 65°57'20", Hydrologic Unit 21010005, at downstream side of bridge on Highway 912, at Barrio Cerro Gordo, 2.8 mi (4.5 km) south of San Lorenzo. DRAINAGE AREA.—10.2 mi* (26.4 km1 ). PERIOD OF RECORD.--October 1977 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 490 ft (150 m), from topographic map. Prior to Oct. 1, 1983, at site 2,000 ft (610 m) downstream at different datum. REMARKS.—Records poor. Sand removal at a commercial level is practiced at times during the year. This takes place about one hundred feet downstream from the low water control. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 211 OCT NOV JAN FEB MAY JUL AUG SEP 1 e60 61 2 e55 56 3 e67 41 4 64 73 5 61 43 6 52 54 7 56 185 8 48 56 9 55 61 10 103 56 11 71 121 12 44 239 13 41 226 14 40 85 15 52 46 16 41 73 17 37 48 18 36 45 19 37 144 20 36 96 21 36 76 22 35 78 23 35 77 24 34 49 25 34 55 26 41 39 27 39 44 28 36 50 29 40 38 30 38 37 31 39 TOTAL 1463 2352 MEAN 47.2 78.4 MAX 103 239 MIN 34 37 AC-FT 2900 4670 CFSM 4.63 7.69 IN. 5.34 8.58 STATISTICS OF MONTHLY MEAN MEAN 58.9 69.1 MAX 176 196 (WY) 1986 1988 MIN 14.4 19.2 (WY) 1992 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 28 30 30 36 33 39 59 42 43 44 42 26 24 25 24 24 24 21 24 24 23 21 18 22 19 18 14 17 34 75 17 920 29.7 75 14 1820 2.91 3.36 DATA 44.5 163 1988 12.5 1992 16 17 18 17 19 17 17 20 21 20 114 25 21 21 18 20 18 19 20 25 40 102 16 22 17 25 21 22 22 23 18 811 26.2 114 16 1610 2.56 2.96 162 371 124 63 60 91 45 39 84 64 98 84 113 94 72 82 57 37 34 32 47 40 50 23 23 50 19 16 ___ —— 2074 74.1 371 16 4110 7.26 7.56 FOR WATER YEARS 1977 30.0 50.0 1993 14.6 1990 29.3 74.1 1997 11.0 1992 21 25 27 29 26 23 24 25 20 21 21 28 32 34 40 52 29 32 27 24 24 26 36 32 32 28 30 26 23 24 27 868 28.0 52 20 1720 2.75 3.17 - 1997 22.2 45.4 1989 11.3 1992 FOR 1996 CALENDAR YEAR 24058 65.7 5120 13 14 47720 6.44 87.74 102 35 17 Sep 10 May 29 May 25 26 244 182 32 19 16 17 16 617 19 18 21 22 18 16 16 16 15 12 12 11 11 13 18 e!4 12 10 elO e!2 e!3 —— 878 29.3 244 10 1740 2.87 3.20 13 12 11 12 9.3 8.4 10 12 10 31 31 27 14 14 24 20 89 13 11 17 17 12 11 10 11 13 29 35 23 23 19 591.7 19.1 89 8.4 1170 1.87 2.16 22 38 41 16 16 14 14 11 11 11 11 9.9 13 17 11 11 11 9.6 16 14 12 9.6 16 21 13 17 13 13 13 16 461.1 15.4 41 9.6 915 1.51 1.68 15 12 9.7 12 13 24 11 11 15 10 10 12 20 11 10 31 18 13 15 44 399 100 30 22 12 14 11 247 39 178 33 1401.7 45.2 399 9.7 2780 4.43 5.11 14 14 16 23 21 19 18 26 23 128 82 59 28 27 64 80 81 332 96 35 35 489 147 394 151 32 158 166 30 29 79 2896 93.4 489 14 5740 9.16 10.56 33 43 31 28 27 29 29 37 37 25 23 29 28 86 181 34 28 95 33 29 116 359 157 150 28 207 60 26 34 195 —— 2217 73.9 359 23 4400 7.25 8.09 , BY WATER YEAR (WY) 20.4 46.0 1985 10.7 1980 FOR 1997 16933 46 489 8 10 1690 11 33590 4 61 95 27 12 43.3 155 1985 9.68 1990 WATER YEAR .5 .4 Aug 22 . 4 May 6 May 3 Feb 2 .40 Feb 2 .55 .76 45.4 140 1979 10.9 1994 44.0 118 1979 15.4 1994 WATER 43 89 18 5120 7 8 13200 9 31700 4 58 69 24 12 48.8 202 1979 14.5 1991 YEARS 1977 - .8 .7 .6 Sep 10 . 1 Feb 4 .5 Jun 19 Aug 31 .44 Aug 31 .29 .28 68.7 298 1996 16.9 1980 1997 1979 1990 1996 1981 1994 1979 1979 e Estimated 212 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR LOCATION.--Lat 18°11'09", long 65°57'42", Hydrologic Unit 21010005, at upstream side of bridge on Highway 183 by-pass, 0.4 mi (0.6 km) south from Plaza de San Lorenzo, 1.4 mi (2.2 km), southwest from Escuela Rafael Colon Garcia and 2.0 mi (3.2 km) northwest from Escuela Segunda Unidad de Carlos Zayas. DRAINAGE AREA.--25.0 mi 2 (64.8 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--February 1990 to current year. GAGE.—Water-stage recorder. Elevation of gage is 262 ft (80 m), from topographic map. REMARKS.—Records fair except those for estimated discharges, which are poor. Water purification plant located about 0.2 mi (0.3 km) upstream from gage. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES NOV DEC JAN FEB APR MAY JUN ADG SEP 1 e200 141 2 elBO 135 3 e!70 94 4 el60 130 5 elSO 91 6 e!40 104 7 e!30 274 8 6130 175 9 166 147 10 317 116 11 232 240 12 160 735 13 141 583 14 144 239 15 177 174 16 155 151 17 131 162 18 124 133 19 129 223 20 119 168 21 111 172 22 106 161 23 102 159 24 99 127 25 94 113 26 98 104 27 129 100 28 103 104 29 96 99 30 86 107 31 84 —— TOTAL 4363 5461 MEAN 141 182 MAX 317 735 MIN 84 91 AC-FT 8650 10830 CFSM 5.63 7.28 IN. 6.49 8.13 STATISTICS OF MONTHLY MEAN MEAN 122 131 MAX 266 223 (WY) 1991 1992 MIN 77.6 69.2 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 102 97 89 89 87 83 106 83 78 77 230 101 86 80 77 81 75 72 69 67 67 65 63 67 76 67 66 63 92 157 90 2702 87.2 230 63 5360 3.49 4.02 DATA 89.3 110 1993 69.7 1994 72 65 64 66 61 59 57 58 57 56 197 94 68 64 61 53 49 49 47 69 113 294 83 70 61 65 52 61 53 47 51 2316 74.7 294 47 4590 2.99 3.45 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 _-_ —— —— 3031 108 465 58 6010 4.33 4.51 FOR WATER YEARS 1990 101 192 1992 50.1 1995 72.4 108 1997 21.0 1992 FOR 1996 CALENDAR YEAR 60107 164 10000 22 26 119200 6 89 269 100 44 Sep 10 May 30 May 25 .57 .44 55 54 58 61 55 54 54 61 59 54 62 56 56 57 75 80 58 59 58 49 48 47 43 53 37 36 39 40 46 43 45 1652 53.3 80 36 3280 2.13 2.46 - 1997, 49.9 76.5 1995 17.4 1992 42 439 252 88 72 62 56 54 51 51 48 48 55 48 44 41 41 38 34 35 34 32 30 30 30 30 31 29 29 28 --- 1902 63.4 439 28 3770 2.54 2.83 BY WATER 36.4 63.4 1997 16.8 1992 27 31 28 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 1536 49.5 114 24 3050 1.98 2.29 YEAR (WY) 63.4 186 1992 25.2 1995 60 89 167 88 66 63 54 47 45 41 42 41 51 70 47 38 36 36 44 49 37 33 37 46 36 38 33 28 27 25 1514 50.5 167 25 3000 2.02 2.25 116 290 1992 42.3 1994 FOR 1997 WATER YEAR 33325 91.3 735 21 24 3420 12.93 66100 3.65 49.59 160 68 34 NOV 12 Jul 3 Jun 28 Aug 24 Aug 24 23 23 21 21 32 47 32 30 32 29 25 23 35 28 22 36 53 36 40 109 337 148 93 75 56 54 46 237 89 155 90 2077 67.0 337 21 4120 2.68 3.09 101 208 1993 42.3 1994 WATER 102 154 67. 10000 6. 7. 56800 35. 74220 4. 55. 173 61 24 68 59 58 59 55 54 49 56 63 109 93 81 67 59 61 70 69 203 87 66 66 588 150 476 205 118 203 159 110 95 135 3791 122 588 49 7520 4.89 5.64 108 196 1996 39.3 1994 YEARS 1990 - 8 Sep 10 3 Apr 29 4 Apr 25 Sep 10 62 Sep 10 10 68 98 98 87 83 79 73 71 89 79 68 65 73 67 92 161 82 73 101 76 66 117 233 153 155 88 148 101 81 81 142 2980 99.3 233 65 5910 3.97 4.43 200 631 1996 59.7 1990 1997 1996 1994 1996 1992 1992 1996 1996 e Estimated RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: February 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,530 mg/L September 10, 1996; Minimum daily mean, 5 mg/L Several days. SEDIMENT LOADS: Maximum daily mean, 80,600 tons (73,100 tonnes) September 10, 1996; Minimum daily mean, 0.20 ton (0.18 tonne) May 05, 1992. EXTREMES FOR CURRENT YEAR 1997-- SEDIMENT CONCENTRATION: Maximum daily mean, 1,650 mg/L August 22, 1997; Minimum daily mean, 8 mg/L April 17-18, 1997. SEDIMENT LOADS: Maximum daily mean, 4,040 tons (3,665 tonnes) November 12, 1996; Minimum daily mean, 0.76 ton (0.69 tonne) April 18, 1997. 213 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e200 e!80 e!70 e!60 e!50 e!40 e!30 e!30 166 317 232 160 141 144 177 155 131 124 129 119 111 106 102 99 94 98 129 103 96 86 84 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 60 61 64 55 66 84 103 118 150 432 285 159 99 63 139 127 182 134 105 82 70 80 93 104 112 105 185 189 197 206 215 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 4363 e32 e31 e30 e24 e28 e33 e38 e41 70 453 186 69 38 25 71 53 64 45 37 27 21 23 26 28 29 28 64 52 51 48 49 1814 141 135 94 130 91 104 274 175 147 116 240 735 583 239 174 151 162 133 223 168 172 161 159 127 113 104 100 104 99 107 217 107 62 100 77 61 435 179 135 97 323 1560 780 171 76 99 132 64 236 118 163 143 137 58 37 63 96 63 42 56 82 39 16 39 19 17 728 89 61 32 472 4040 1710 114 36 41 64 23 204 54 98 66 61 20 11 18 26 17 11 16 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 102 97 89 89 87 83 106 83 78 77 230 101 86 80 77 81 75 72 69 67 67 65 63 67 76 67 66 63 92 157 90 82 117 156 184 131 87 86 85 78 73 179 54 45 58 78 85 35 15 18 23 19 16 14 17 23 30 38 38 63 570 59 22 31 37 44 31 19 25 19 16 15 207 15 11 13 16 19 7.2 2.9 3.4 4.1 3.5 2.8 2.4 3.2 4.8 5.4 6.7 6.4 20 285 14 5461 8224 2702 911.8 e Estimated 214 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 72 65 64 66 61 59 57 58 57 56 197 94 68 64 61 53 49 49 47 69 113 294 83 70 61 65 52 61 53 47 51 MEAN CONCEN- TRATION (MG/L) JANUARY 67 77 70 60 44 31 26 42 64 60 1480 1110 431 183 89 108 133 92 59 38 92 483 74 70 65 61 58 57 61 82 111 SEDIMENT DISCHARGE (TONS/DAY) 13 14 12 11 7.3 5.0 4.0 6.7 9.8 8.9 1130 294 80 32 15 15 18 12 7.4 7.2 45 800 17 13 11 11 8.1 9.4 8.7 10 15 MEAN DISCHARGE (CFS) 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 ___ —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 271 465 152 91 93 132 84 75 122 83 93 84 128 106 84 78 69 63 63 60 81 79 112 70 67 101 67 58 514 732 117 54 52 217 176 135 133 79 89 94 76 54 47 42 42 64 88 73 59 51 78 28 22 184 96 82 843 2250 53 13 20 78 39 28 47 18 23 23 26 15 11 8 7 11 15 12 13 11 25 5 4 77 17 13 .9 .7 .3 .0 55 54 58 61 55 54 54 61 59 54 62 56 56 57 75 80 58 59 58 49 48 47 43 53 37 36 39 40 46 43 45 85 90 91 82 78 99 113 84 60 50 82 129 150 163 150 135 125 136 146 141 136 132 128 126 101 81 67 60 53 46 40 13 13 14 14 12 14 17 14 9. 7. 14 20 23 25 30 29 19 22 23 19 17 17 15 20 10 7. 7. 6. 6. 5. 4. 4 4 9 0 5 6 4 9 2316 2650.5 3031 3706.9 1652 469.1 215 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 42 439 252 88 72 62 56 54 51 51 48 48 55 48 44 41 37 34 32 33 32 30 29 28 29 28 30 29 28 28 APRIL 33 741 321 78 41 22 12 10 9 10 10 12 14 15 12 10 8 8 18 42 68 30 13 10 9 15 27 37 21 12 ___ 3.7 3170 364 19 8.0 3.7 1.9 1.5 1.3 1.3 1.3 1.5 2.1 2.0 1.5 1.1 .82 .76 1.6 3.8 5.8 2.5 .98 .73 .71 1.2 2.2 2.8 1.6 .93 26 30 27 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 26 30 27 29 25 24 26 31 38 62 66 61 47 41 58 53 114 64 45 43 51 43 40 36 42 40 45 90 89 86 61 16 22 31 43 56 55 54 61 76 129 229 339 251 167 101 62 202 285 271 258 246 234 207 120 65 43 66 139 155 173 164 1.1 1.8 2.3 3.3 3.7 3.5 3.8 5.1 7.8 22 40 56 32 19 16 8.9 73 49 33 30 34 27 22 12 7.5 4.8 9.4 34 38 40 27 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 60 89 167 88 66 63 54 47 45 41 42 41 51 70 47 38 36 36 44 49 37 33 37 46 36 38 33 28 27 25 151 136 139 67 42 33 41 55 69 67 62 33 66 42 48 47 62 87 127 174 104 47 26 39 69 144 232 146 82 51 24 32 66 16 7.5 5.5 6.0 7.0 8.4 7.4 6.9 3.7 11 8.1 6.1 4.7 5.8 7.8 15 23 11 4.2 2.6 4.8 6.7 15 20 11 5.9 3.4 TOTAL 1878 3610.33 1533 667.0 1514 356.5 216 RIO GRANDE DB LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR MEAN DISCHARGE (CFS) 23 23 21 21 32 47 32 30 32 29 25 23 35 28 22 36 53 36 40 109 337 148 93 75 56 54 46 237 89 155 90 2077 33298 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 53 59 66 73 82 92 96 71 51 36 31 59 122 190 97 54 82 63 47 75 779 346 93 54 22 17 15 453 51 345 124 3.3 3.6 3.8 4.1 7.1 12 8.4 5.7 4.4 2.8 2.0 3.6 12 14 5.8 5.5 11 6.0 5.1 31 1100 187 25 11 3.4 2.5 1.8 849 13 190 31 2564.9 34597.53 MEAN DISCHARGE (CFS) 68 59 58 59 55 54 49 56 63 109 93 81 67 59 61 70 69 203 87 66 66 588 150 476 205 118 203 159 110 95 135 3791 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 81 84 91 91 58 34 17 9 31 177 252 66 19 19 21 22 26 268 34 16 31 1650 157 852 282 47 334 565 42 22 86 15 13 14 14 8.5 5.0 2.3 1.4 5.1 59 65 15 3.4 2.9 3.5 4.2 5.1 237 8.1 2.9 5.7 3910 66 3150 223 15 263 269 13 5.6 34 8438.7 i TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) HI 98 98 87 83 79 73 71 89 79 68 65 73 67 92 161 82 73 101 76 66 117 233 153 155 88 148 101 81 81 142 MEAN CONCEN- TRATION (MG/L) 21 13 13 39 98 111 114 141 145 105 130 162 160 154 194 137 120 111 94 65 93 286 145 217 109 131 129 118 107 132 SEDIMENT DISCHARGE (TONS/DAY) 5.7 3.4 3.0 8.7 21 22 22 37 32 19 23 32 29 39 90 30 24 31 19 12 38 235 72 97 26 65 35 26 23 64 2980 1183.8 217 RIO ORANDE DE LOIZA BASIN 50051800 RIO ORANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. * FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) DATE TIME NOV 1996 12... 0800 1580 7010 29900 13 16 21 JAN 1997 24... 1135 69 1320 246 41 51 61 FEB 26... 0915 206 2590 1440 11 13 17 JUL 21... 1010 776 4140 8680 34 39 48 28... 1000 625 4620 7800 34 40 50 AUO 27... 1000 304 940 771 69 79 81 SED. SED. SED. SED. SED. SED. SED. SUSP. SUSP. SUSP. SUSP. SUSP. SUSP. SUSP. FALL FALL SIEVE SIEVE SIEVE SIEVE SIEVE DIAM. DIAM. DIAM. DIAM. DIAM. DIAM. DIAM. % FINER % FINER % FINER % FINER % FINER % FINER % FINER DATE THAN THAN THAN THAN THAN THAN THAN .016 MM .031 MM .062 MM .125 MM .250 MM .500 MM 1.00 MM (70329) (70330) (70331) (70332) (70333) (70334) (70335) NOV 1996 12... 30 48 72 94 99 100 100 JAN 1997 24... 79 82 99 100 100 100 100 FEB 26... 28 47 78 98 100 100 100 JUL 21... 61 74 94 98 99 100 100 28... 64 79 93 98 100 100 100 AUO 27... 88 90 97 99 99 100 100 218 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE TIME DIS- CHARGE, INST. CUBIC FEET PER SECOND SEDI- MENT, SUS- PENDRD (MO/L) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (00061) (80154) (80155) (70331) NOV 1996 12... DEC 30... JAN 1997 11... MAR 17... MAY 12... JUL 30... AUO 25... 1445 1250 0940 1030 0950 1030 1030 526 134 340 57 83 151 189 900 853 3090 122 379 397 142 1280 308 2840 19 85 162 72 96 94 93 82 99 96 98 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR LOCATION.--Lat 18°09'35", long 66°02'26", Hydrologic Unit 21010005, on left bank at Highway 765, 1.2 mi (1.9 km) south of villa Borinquen, 8.1 mi (13.0 km) upstream from Rio Grande de Loiza. DRAINAGE AREA.--7.14 mi' (18.49 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 492 ft (150 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 219 DAY OCT NOV JAN FEB MAY JUN JUL AUG SEP 1 28 20 2 27 22 3 28 17 4 26 18 5 25 17 6 24 17 7 24 28 8 25 27 9 29 21 10 58 17 11 29 49 12 23 137 13 22 90 14 22 38 15 23 26 16 21 22 17 19 28 18 19 22 19 20 25 20 19 24 21 18 44 22 17 28 23 17 24 24 16 22 25 15 19 26 21 18 27 31 17 28 23 21 29 18 18 30 17 26 31 17 —— TOTAL 721 902 MEAN 23.3 30.1 MAX 58 137 MIN 15 17 MED 22 22 AC-FT 1430 1790 CFSM 3.26 4.21 IN. 3.76 4.70 STATISTICS OF MONTHLY MEAN MEAN 23.9 23.6 MAX 48.2 37.9 (WY) 1991 1992 MIN 10.3 18 . 6 (WY) 1994 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 25 19 17 16 16 el7 24 17 16 15 115 32 26 23 22 21 19 18 17 17 17 16 16 17 17 16 17 16 26 44 22 716 23.1 115 15 17 1420 3.23 3.73 DATA 17.6 23.1 1991 10.6 1994 21 21 32 28 24 23 22 22 21 21 49 26 23 21 21 20 20 20 21 31 60 94 27 26 23 21 17 26 19 17 17 834 26.9 94 17 22 1650 3.77 4.35 FOR WATER 22.6 47.5 1992 7.85 1990 54 63 29 21 21 20 20 18 28 20 23 22 38 28 23 22 19 18 19 18 27 24 27 19 20 24 18 17 ___ ___ --- 700 25.0 63 17 22 1390 3.50 3.65 YEARS 1990 17.1 25.0 1997 8.93 1990 16 16 17 17 16 16 15 16 16 15 14 14 14 13 17 21 15 15 15 13 13 12 12 12 11 11 11 13 13 12 11 442 14.3 21 11 14 877 2.00 2.30 - 1997 12.0 18.8 1996 7.35 1993 FOR 1996 CALENDAR YEAR 14079. 38. 1940 7. 7. 27930 5. 73. 68 17 9. 8 5 Sep 10 2 May 31 6 May 28 39 36 1 11 69 31 15 13 12 11 11 11 10 11 10 11 10 9.7 9.4 9.2 9.1 8.8 8.6 8.5 8.4 8.1 8.1 8.2 7.8 8.3 8.4 8.3 8.1 —— 373.0 12.4 69 7.8 9.5 740 1.74 1.94 7.9 7.7 7.6 7.7 7.6 7.6 7.7 8.6 7.9 14 9.0 11 8.7 8.0 12 11 33 11 8.5 8.5 9.2 7.8 7.6 7.8 7.9 7.2 11 13 24 17 12 329.5 10.6 33 7.2 8.5 654 1.49 1.72 12 26 54 19 13 12 11 9.9 9.7 9.2 9.9 9.2 12 19 9.7 8.6 8.1 8.8 12 9.8 8.5 7.8 9.0 11 8.5 8.3 7.6 7.3 7.1 7.1 —— 365.1 12.2 54 7.1 9.7 724 1.70 1.90 6.9 6.7 6.5 6.3 8.0 14 8.0 7.6 9.1 7.8 7.2 6.8 7.3 6.6 6.5 17 12 9.0 13 36 90 26 20 14 11 10 9.4 43 15 19 14 473.7 15.3 90 6.3 9.4 940 2.14 2.47 11 10 9.6 10 9.2 8.7 8.3 8.6 9.0 13 11 10 9.6 8.6 8.8 11 9.8 25 13 9.4 9.9 166 25 102 45 24 22 18 16 15 17 673.5 21.7 166 8.3 11 1340 3.04 3.51 15 16 13 13 12 12 12 29 15 12 11 12 11 14 14 11 11 14 11 10 29 35 26 27 16 19 15 13 13 13 474 15.8 35 10 13 940 2.21 2.47 , BY WATER YEAR (WY) 8.77 12.4 1997 6.18 1990 FOR 1997 7003 19 166 6 6 1020 10 2 13890 2 36 28 16 8 14.6 31.9 1993 6.11 1994 WATER YEAR .8 .2 Aug 22 .3 Jul 4 .8 Jun 28 Aug 24 .81 Aug 24 .6 Jul 17 .69 .49 .1 27.0 67.9 1996 9.59 1991 23.8 54.6 1993 8.42 1995 WATER 22 38 12 1940 3 3 15200 22 2 16090 3 42 34 11 5 21.7 41.4 1996 6.98 1994 YEARS 1990 - .2 .1 .1 Sep 10 .3 Aug 17 .8 Aug 11 Sep 10 .60 Sep 10 .6 Jul 17 .11 .26 .9 43.8 123 1996 14.1 1990 1997 1996 1994 1996 1994 1994 1996 1996 1997 e Estimated 220 RZO GRANDE DE LOIZA BASIN 50053025 RIO TORABO ABOVE BORINQUEN, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: January 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 9,230 mg/L September 10, 1996; Minimum daily mean, 1 mg/L Several years. SEDIMENT LOADS: Maximum daily mean, 80,900 tons (73,400 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) Several days. EXTREMES FOR CURRENT YEAR 1997. SEDIMENT CONCENTRATION: Maximum daily mean, 693 mg/L August 22, 1997; Minimum daily mean, 1 mg/L July 13-15, 1997. SEDIMENT LOADS: Maximum daily mean, 732 tons (664 tonnes) August 22, 1997; Minimum daily mean, 0.02 ton (0.02 tonne) July 13-15, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 28 27 28 26 25 24 24 25 29 58 29 23 22 22 23 21 19 19 20 19 18 17 17 16 15 21 31 23 18 17 17 30 30 30 30 30 30 30 30 40 162 179 83 48 30 18 15 14 13 11 8 7 5 4 3 3 19 57 74 70 33 24 2.3 2.2 2.2 2.1 2.0 1.9 2.0 2.0 3.3 39 15 5.2 2.8 1.7 1.1 .84 .73 .65 .58 .43 .32 .24 .18 .14 .12 3.6 9.1 6.0 3.5 1.5 1.2 NOVEMBER 20 22 17 18 17 17 28 27 21 17 49 137 90 38 26 22 28 22 25 24 44 28 24 22 19 18 17 21 18 26 ___ 35 35 25 24 24 23 67 53 34 25 166 427 222 80 68 61 71 33 68 29 125 99 41 36 21 17 15 22 16 38 ___ 2.0 2.2 1.1 1.2 1.1 1.0 9.1 5.8 2.0 1.2 54 225 69 8.7 4.7 3.6 7.5 1.9 4.8 1.9 33 7.7 2.7 2.3 1.1 .83 .71 1.3 .79 2.9 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 25 19 17 16 16 el7 24 17 16 15 115 32 26 23 22 21 19 18 17 17 17 16 16 17 17 16 17 16 26 44 22 26 11 9 8 8 8 21 9 10 12 346 43 18 16 18 20 22 23 23 15 9 6 4 4 3 4 5 7 40 103 27 2.0 .55 .43 .36 .32 e.35 1.6 .42 .44 .49 264 3.9 1.2 .96 1.0 1.1 1.1 1.1 1.1 .70 .41 .24 .19 .17 .15 .17 .24 .28 4.7 22 1.6 TOTAL 721 113.93 902 461.13 716 313.27 e Estimated 221 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 21 21 32 28 24 23 22 22 21 21 49 26 23 21 21 20 20 20 21 31 60 94 27 26 23 21 17 26 19 17 17 25 30 55 39 29 32 35 36 37 37 99 41 35 28 22 21 23 25 28 51 201 231 42 53 71 47 30 55 28 25 24 1.4 1.7 5.5 3.0 1.9 2.0 2.1 2.1 2.1 2.1 19 2.9 2.1 1.6 1.2 1.2 1.2 1.3 1.7 4.8 65 106 3.1 4.2 4.4 2.7 1.4 5.6 1.5 1.1 1.1 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 54 63 29 21 21 20 20 18 28 20 23 22 38 28 23 22 19 18 19 18 27 24 27 19 20 24 18 17 135 212 154 115 115 108 58 28 36 7 27 23 139 116 94 94 98 100 65 34 26 30 39 13 22 35 20 16 39 53 13 6.6 6.4 5.8 3.0 1.4 3.4 .35 1.8 1.6 15 8.9 5.8 5.6 5.1 5.0 3.3 1.7 2.0 2.0 3.0 .68 1.3 2.6 .96 .73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 16 16 17 17 16 16 15 16 16 15 14 14 14 13 17 21 15 15 15 13 13 12 12 12 11 11 11 13 13 12 11 13 10 9 9 8 8 7 7 7 7 7 8 9 12 25 30 9 13 30 27 24 21 18 13 9 6 6 6 6 6 6 .55 .45 .44 .41 .36 .34 .29 .30 .31 .28 .26 .31 .35 .42 1.2 1.8 .39 .57 1.2 .98 .81 .68 .56 .40 .28 .19 .19 .20 .21 .19 .18 TOTAL 834 257.0 700 199.02 442 15.10 222 i 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CPS) (MG/L) (TONS/DAY) APRIL 11 69 31 15 13 12 11 11 11 10 11 10 11 10 9.7 9.4 9.2 9.1 8.8 8.6 8.5 8.4 8.1 8.1 8.2 7.8 8.3 8.4 8.3 8.1 6 442 103 11 21 26 28 30 31 32 30 13 4 1 1 2 4 7 13 23 26 26 25 25 25 25 24 24 24 25 .17 380 12 .47 .72 .85 .87 .91 .90 .89 .86 .35 .13 .04 .04 .05 .09 .17 .31 .55 .59 .58 .55 .55 .55 .52 .55 .55 .54 .54 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 7.9 7.7 7.6 7.7 7.6 7.6 7.7 8.6 7.9 14 9.0 11 8.7 8.0 12 11 33 11 8.5 8.5 9.2 7.8 7.6 7.8 7.9 7.2 11 13 24 17 12 MAY 25 25 20 14 10 9 9 9 10 9 3 15 8 4 14 14 34 7 6 7 11 9 8 9 9 8 15 29 41 25 15 .54 .53 .40 .29 .22 .19 .18 .22 .22 .35 .06 .49 .18 .09 .48 .43 8.0 .19 .14 .18 .28 .19 .17 .18 .18 .16 .78 1.1 3.8 1.2 .47 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 12 26 54 19 13 12 11 9.9 9.7 9.2 9.9 9.2 12 19 9.7 8.6 8.1 8.8 12 9.8 8.5 7.8 9.0 11 8.5 8.3 7.6 7.3 7.1 7.1 16 47 101 30 18 14 12 11 9 9 10 11 16 31 12 10 9 9 15 12 8 8 10 57 15 5 9 13 18 25 .50 4.9 18 1.6 .65 .46 .35 .28 .24 .23 .27 .26 .58 2.1 .31 .22 .20 .21 .54 .33 .18 .17 .26 1.7 .37 .10 .18 .26 .35 .48 TOTAL 373.0 405.89 329.5 21.89 365.1 36.28 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 223 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CPS) (MO/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 6.9 6.7 6.5 6.3 8.0 14 8.0 7.6 9.1 7.8 7.2 6.8 7.3 6.6 6.5 17 12 9.0 13 36 90 26 20 14 11 10 9.4 43 15 19 14 473.7 7003.8 JULY 33 37 40 38 10 19 10 8 11 7 4 2 1 1 1 27 21 12 24 85 252 41 43 45 38 27 18 99 9 28 13 —— .63 .68 .71 .65 .22 .80 .22 .17 .27 .14 .07 .04 .02 .02 .02 3.1 .79 .29 1.3 18 100 3.5 2.4 1.7 1.1 .76 .46 28 .37 1.6 .49 168.52 3120.42 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) 11 10 9.6 10 9.2 8.7 8.3 8.6 9.0 13 11 10 9.6 8.6 8.8 11 9.8 25 13 9.4 9.9 166 25 102 45 24 22 18 16 15 17 5 4 5 5 6 6 7 8 8 15 15 13 12 12 13 13 12 43 17 13 13 693 38 329 95 34 30 13 10 10 14 .15 .12 .12 .14 .14 .15 .16 .17 .20 .64 .44 .35 .31 .28 .30 .37 .32 5.2 .63 .32 .37 732 2.8 309 14 2.3 1.8 .64 .43 .39 .70 SEPTEMBER 673.5 1074.94 15 16 13 13 12 12 12 29 15 12 11 12 11 14 14 11 11 14 11 10 29 35 26 27 16 19 15 13 13 13 474 10 19 5 6 9 13 15 70 12 7 9 11 11 19 21 11 6 16 21 15 58 57 41 67 36 28 22 15 11 8 16 .41 .86 .17 .22 .30 .43 .48 .54 .23 .26 .33 .33 .78 .86 .34 .18 .67 .64 .43 10 5.7 3.1 5.0 1.6 1.5 .91 .52 .38 .28 53.45 224 RIO ORANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN,PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OD SUSPENDED-SEDIMENT DATE AUO 1997 22... TIME 0445 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (HO/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SBD. SUSP. FALL DIAM. * FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. \ FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. \ FINER THAN .008 MM (70328) 482 9750 12700 22 26 43 DATE AUO 1997 22... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 59 SKD. SUSP. FALL DIAM. * FINER THAN SED. SUSP. SIEVE DIAM. * FINER THAN .031 MM .062 MM (70330) (70331) SED. SED. SUSP. SUSP. SIEVE SIEVE DIAM. DIAM. * FINER * FINNER THAN THAN .125 MM .250 MM (70332) (70333) 77 90 98 100 SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) 100 SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 100 RZO QRANDE DE LOZZA BASIN 50053025 RZO TDRABO ABOVE BORZNQUEN,PR—Continued 225 iTER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 3 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DZS- SEDZ- SED. DATE OCT 1996 12... APR 1997 02... 17... AUG 22... 25... SEP 24... TIME 1505 1745 1347 1546 1300 1500 CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 22 364 9.6 201 38 21 SEDI- MENT, SUS- PENDED (MG/L) (80154) 73 6940 83 77 75 64 MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4.3 6820 2.2 42 7.7 3.7 SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) 97 94 98 99 98 97 226 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR LOCATION.--Lat 18°14'33", long 66°00'34", Hydrologic Unit 21010005, on right bank 250 ft (76 m) upstream from bridge on Highway 189, 1.2 mi (1.9 km) downstream from Rio Turabo, and 1.8 mi (2.9 km) east of Plaza de Caguas. DRAINAGE AREA.—89.8 mi 2 (232.6 km2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—1959 (low-flow measurement only), February to November 1959 (monthly measurements only). December 1959 to current year. GAGE.—Hater-stage recorder. Datum of gage is 143.28 ft (43.672 m) above mean sea level. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e320 317 2 e309 349 3 e320 273 4 e300 293 5 e286 258 6 e278 279 7 e275 520 8 e290 373 9 e340 361 10 e650 325 11 e457 438 12 363 1260 13 326 1050 14 326 345 15 350 249 16 331 210 17 291 263 18 280 215 19 289 336 20 275 285 21 264 296 22 254 509 23 251 327 24 249 248 25 240 222 26 265 191 27 355 180 28 285 208 29 294 194 30 274 234 31 242 —— TOTAL 9629 10608 MEAN 311 354 MAX 650 1260 HIN 240 180 AC-FT 19100 21040 CFSH 3.46 3.94 IN. 3.99 4.39 STATISTICS OF MONTHLY MEAN MEAN 355 315 MAX 1910 1131 (WY) 1971 1988 HIN 44.2 64.9 (WY) 1968 1968 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 4849 156 538 93 9620 1.74 2.01 132 106 102 107 92 89 83 84 87 79 290 161 95 87 82 84 77 72 71 114 e250 e400 224 182 168 128 99 105 112 86 86 3934 127 400 71 7800 1.41 1.63 625 782 258 124 117 225 153 133 212 151 146 109 208 152 120 98 87 81 84 82 129 120 171 106 95 140 102 83 ___ ___ 4893 175 782 81 9710 1.95 2.03 DATA FOR HATER YEARS 1960 220 714 1988 33.6 1968 FOR 145 559 1992 45.3 1968 109 291 1984 35.6 1968 78 78 79 97 83 80 75 88 84 74 71 75 85 87 116 136 111 98 113 88 84 79 74 . 73 75 63 67 71 89 82 75 2628 84.8 136 63 5210 .94 1.09 - 1997 91.2 306 1989 23.2 1968 1996 CALENDAR YEAR 121761 333 20000 30 34 241500 3.70 50.44 555 151 57 Sep 10 May 31 May 26 76 823 691 158 124 103 91 88 82 81 77 72 82 78 69 63 62 61 58 55 60 50 43 41 40 40 40 33 30 30 ___ 3401 113 823 30 6750 1.26 1.41 29 30 34 34 30 28 28 40 55 98 137 89 87 74 75 80 171 117 57 44 57 48 43 45 43 39 45 118 114 162 102 2153 69.5 171 28 4270 .77 .89 73 85 288 178 98 79 e66 e56 e54 e52 e54 e53 e65 el08 e54 e42 e37 36 38 69 51 38 49 100 55 45 46 36 32 29 2066 68.9 288 29 4100 .77 .86 29 25 26 23 29 59 75 38 42 49 35 29 42 45 30 37 110 58 63 146 679 471 191 178 120 93 87 444 199 246 146 3844 124 679 23 7620 1.38 1.59 96 76 79 75 66 64 52 56 62 129 157 103 87 64 62 78 82 315 154 88 70 1420 344 1200 613 199 274 292 156 126 195 6834 220 1420 52 13560 2.45 2.83 145 126 114 95 90 86 88 295 179 87 69 85 99 109 239 113 79 113 103 67 126 348 344 236 116 225 177 120 97 205 —— 4375 146 348 67 8680 1.62 1.81 , BY HATER YEAR (WY) 89.7 355 1978 30.6 1995 FOR 1997 59214 162 1420 23 28 7780 12 18 117500 1 24 325 102 43 227 863 1985 33.7 1974 HATER YEAR Aug 22 Jul 4 Jun 29 Aug 24 .78 Aug 24 Jul 5 .81 .53 247 1283 1979 34.1 1975 229 660 1961 21.8 1974 HATER 215 526 82 25300 11 11 83000 32 17 156000 2 32 360 106 39 266 949 1979 51.4 1994 YEARS 1960 - .3 Sep 6 Apr 8 Apr 8 Sep 10 .32 Sep 10 Aug 18 .40 .58 317 1438 1960 37.4 1967 1997 1979 1967 1960 1968 1968 1996 1996 1994 e Estimated RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1959 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1983 to current year. INSTRUMENTATION.— USD-49 sediment sampler since October 1983. Automatic sediment sampler since 1984. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean,14,500 rag/L Nov 27, 1987; Minimum daily mean, 8 mg/L January 23, 1992. SEDIMENT LOADS: Maximum daily mean, 396,000 tons (359,000 tonnes) September 10, 1996; Minimum daily mean, 0.65 tons (0.59 tonnes) May 25,1995. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,610 mg/L April 2, 1997 ; minimum daily mean, 11 mg/L April 27, 1997. SEDIMENT LOADS: Maximum daily mean, 14,600 tons (13,300 tonnes) April 2, 1997; minimum daily 1.0 ton (0.90 tonnes) May 1-2,1997. 227 WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... NOV 20 MAR 04 MAY 20 SEP 04 NOV 20 MAR 04 MAY 20 SEP 04 K - DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CREM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1015 378 248 6.9 25.5 80 6.2 74 <10 41000 25000 0830 103 258 6.9 24.5 18 7.0 83 <10 K9100 750 0930 45 272 6.8 28.5 20 6.5 82 <10 560 K110 0950 95 239 6.9 29.5 6.5 6.4 84 <10 3900 240 ALKA- HARD- NESS TOTAL (MG/L DATE AS CACO3) (00900) 1996 61 1997 ... 78 69 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1996 0.10 1997 ... 0.15 0.11 non- ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 16 -- 20 18 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 27 -- 32 32 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.1 -- 6.6 5.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 130 -- 171 156 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 16 -- 21 18 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 133 -- 20.7 40.1 SODIUM AD- SORP- TION RATIO (00931) 0.9 -- 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 124 25 31 15 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.3 -- 2.3 2.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.590 0.410 0.470 0.360 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 67 84 86 85 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.020 0.040 0.040 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.640 0.430 0.520 0.400 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 9.2 -- 16 10 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.130 0.070 0.010 0.140 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 14 -- 21 18 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.57 0.24 0.33 0.28 228 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.70 0.32 0.43 0.42 NITRO- GEN, TOTAL (HG/L AS N) (00600) 1.3 0.75 0.94 0.82 NITRO- GEN, TOTAL (HG/L AS N03) (71887) 5.9 3.3 4.2 3.6 PHOS- PHORUS TOTAL (HG/L AS P) (00665) 0.160 0.090 0.080 0.050 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- 100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 _- 30 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — DATE NOV 1996 20... MAR 1997 04... MAY 20... SEP 04... IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L AS FE) AS PB) (01045) (01051) 4200 870 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) 310 230 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) <0.10 <0.10 SILVER, SELE- TOTAL NIUM, RECOV- TOTAL ERABLE (UG/L (UG/L AS SE) AS AG) (01147) (01077) <1 <1 <1 <1 ZINC, TOTAL RECOV- CYANIDE ERABLE TOTAL (UG/L (MG/L AS ZN) AS CN) (01092) (00720) 20 <0.010 10 <0.010 METHY- LENE BLUE ACTIVE PHENOLS SUB- TOTAL STANCE (UG/L) (MG/L) (32730) (38260) <1 <1 <0.01 <0.01 non-ideal count RIO GRANDE DE LOIZA BASIN 50055000 RIO ORANDE DE LOIZA AT CAGDAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 229 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 •320 •309 •320 •300 •286 •278 •275 •290 e340 e650 e457 363 326 326 350 331 291 280 289 275 264 254 251 249 240 265 355 285 294 274 242 175 228 152 189 263 253 248 242 189 189 520 397 359 362 388 264 376 356 173 75 105 166 216 262 268 293 389 196 331 121 70 elSl •194 •129 •158 •208 •193 e!85 e!85 e!60 e261 •688 390 316 319 371 237 295 270 134 56 75 114 147 176 174 214 378 154 265 92 46 NOVEMBER 1 317 349 273 293 258 279 520 373 361 325 438 1260 1050 345 249 210 263 215 336 285 296 509 327 248 222 191 180 208 194 234 —— 312 323 117 230 159 237 488 409 408 362 420 1150 681 304 136 126 186 250 313 287 269 499 327 180 184 205 211 101 40 179 ___ 286 310 87 197 111 183 912 426 408 327 693 5160 2390 281 93 73 193 147 334 225 281 936 294 121 110 106 103 55 21 129 —— 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) 222 216 172 165 158 147 193 154 139 135 538 178 123 115 109 116 107 101 99 97 97 96 93 94 130 104 102 103 129 405 212 99 218 98 44 41 48 141 52 46 53 513 254 97 42 19 18 22 23 24 23 21 20 19 20 130 118 110 118 141 389 237 62 129 46 20 18 19 80 22 17 19 1120 130 33 13 5.6 5.7 6.4 6.4 6.3 5.9 5.6 5.3 4.8 5.0 47 33 30 33 55 445 139 TOTAL 9629 6735 10608 14992 4849 2567.0 • Estimated 230 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGDAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 132 106 102 107 92 89 83 84 87 79 290 161 95 87 82 84 77 72 71 114 e250 6400 224 182 168 128 99 105 112 86 86 111 35 28 30 29 29 29 32 36 36 290 169 61 62 73 90 79 70 63 70 113 357 261 279 194 115 65 97 132 102 96 41 9. 7. 8. 7. 6. 6. 7. 8. 7. 331 81 16 15 16 20 16 14 12 22 e43 e399 161 138 91 40 17 31 41 24 22 9 8 5 3 8 4 3 5 7 625 782 258 124 117 225 153 133 212 151 146 109 208 152 120 98 87 81 84 82 129 120 171 106 95 140 102 83 592 730 261 139 138 250 186 134 204 173 184 114 221 166 139 106 65 56 52 89 173 142 216 121 148 220 271 92 2120 3710 211 47 44 167 80 50 151 73 77 35 127 68 46 28 15 12 12 20 66 47 113 35 39 101 77 21 MEAN DISCHARGE (CPS) 78 78 79 97 83 80 75 88 84 74 71 75 85 87 116 136 111 98 113 88 84 79 74 73 75 63 67 71 89 82 75 MEAN CONCEN- TRATION (MG/L) MARCH 91 90 90 169 146 136 101 96 83 52 63 82 88 88 123 137 116 64 122 109 114 115 111 91 72 64 74 87 101 43 35 SEDIMENT DISCHARGE (TONS/DAY) 19 19 19 44 33 29 21 23 19 10 12 17 20 21 40 53 36 17 38 26 26 24 22 18 15 11 14 17 24 9.5 7.2 3934 1661.2 4893 7592 2628 703.7 e Estimated 231 MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) MAY JUKE TOTAL RIO ORAKDE DE LOIZA BASIN 50055000 RIO ORANOE DE LOIZA AT CAGUAS, W--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN DISCHARGE (CFS) 73 85 288 178 98 79 •66 •56 •54 •52 •54 •S3 •65 •108 •54 •42 •37 36 38 69 51 38 49 100 55 45 46 36 32 29 2066 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 76 823 691 158 124 103 91 88 82 81 77 72 82 78 69 63 62 61 58 55 60 50 43 41 40 40 40 33 30 30 APRIL 32 1610 512 191 93 37 26 20 20 21 19 16 15 17 22 19 16 16 17 18 16 13 14 15 14 12 11 15 22 18 6.7 14600 1440 83 32 11 6.3 4.8 4.4 4.5 3.9 3.2 3.2 3.6 4.0 3.3 2.6 2.6 2.7 2.8 2.5 1.7 1.6 1.7 1.5 1.3 1.1 1.3 1.8 1.5 SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) 3401 16240.6 29 30 34 34 30 28 28 40 55 98 137 89 87 74 75 80 171 117 57 44 57 48 43 45 43 39 45 118 114 162 102 2153 13 13 38 37 37 39 30 34 58 113 133 97 76 54 74 89 213 189 63 40 65 89 70 48 40 43 58 142 157 173 113 1.0 1.0 3.5 3.5 3.0 2.9 2.2 3.8 10 33 50 24 18 11 15 19 137 65 9.9 4.7 10 11 8.1 5.8 4.6 4.6 7.3 48 49 76 31 672.9 78 102 353 194 81 76 94 112 104 90 66 49 63 96 146 193 146 99 48 59 41 38 50 95 51 47 51 39 35 33 16 24 283 99 22 16 •16 •18 •15 •13 •9.4 •7.0 •10 •22 •30 •25 •16 9.6 5.0 11 5.6 3.9 8.2 26 7.7 5.8 6.3 3.7 3.1 2.6 739.9 • Estimated 232 RIO GRANDE KB LOZZA BASIN 50055000 RIO ORANDB KB LOZZA AT CAOOAS, PR—Continued SEDIMENT DZSCBAROB, SUSPENDED (TONS/DAY), KATBR YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY DISCHARGE (CFS) CQMCEN** TRATZON DZSCHAROE (MO/L) (TOMS/DAY) JULY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 29 25 26 23 29 59 75 38 42 49 35 29 42 45 30 37 110 58 63 146 679 471 191 178 120 93 87 444 199 246 146 3844 35 28 28 24 33 63 73 40 34 S3 34 26 30 75 100 60 124 68 70 159 772 475 165 62 40 30 29 402 230 217 143 2.7 1.9 2.0 1.5 2.7 11 15 4.1 3.9 7.0 3.3 2.0 3.6 9.0 8.0 6.0 39 11 12 67 1910 729 83 30 13 7.6 6.8 1010 131 174 57 4364.1 DZSCHARQE (CPS) 96 76 79 75 66 64 52 56 62 129 157 103 87 64 62 78 82 315 154 88 70 1420 344 1200 613 199 274 292 156 126 195 6834 CONCEN- SEDIMENT TRATZON DISCHARGE (MO/L) (TONS/DAY) DISCHARGE (CPS) CONCBN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST SEPTEMBER 46 31 51 29 22 23 19 16 15 97 79 43 36 28 31 86 38 343 121 44 22 1080 292 569 332 45 215 441 175 144 208 12 6.4 11 5.8 3.9 3.9 2.7 2.4 2.5 49 36 12 8.5 4.8 5.6 19 9.0 411 55 11 4.1 6710 330 7320 840 25 230 375 74 49 120 16748.6 145 126 114 95 90 86 88 295 179 87 69 85 99 109 239 113 79 113 103 67 126 348 344 236 116 225 177 120 97 205 4375 107 108 25 15 15 37 76 233 195 S3 34 59 110 120 364 117 44 95 128 76 137 303 350 196 107 250 201 135 55 192 43 38 7.7 3.9 3.7 10 19 486 113 13 6.3 16 30 39 279 38 9.4 40 37 14 57 348 406 140 34 209 107 47 14 153 2761.0 YEAR 59214 75778.0 233 RIO ORMJDE DB LOIZA BASIN 50055000 RIO QRANDE DB LOIZA AT CAOUAS, PR—Continued WATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE APR 1997 02... 02... JUL 21... AUO 22... 22... TIME 2015 2115 1445 1050 0900 1700 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 4270 4510 SEDI- MENT, SUS- PENDED (MO/L) (80154) 17000 6750 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 196000 82200 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 23 28 SED. SUSP. FALL DIAM. \ FINER THAN .004 MM (70327) 32 33 SED. SUSP. FALL DIAM. \ FINER THAN .008 MM (70328) 46 49 2210 3130 2680 7600 2450 14600 2830 23900 60 45 51 72 54 58 80 62 64 DATE APR 1997 02... 02... JUL 21... AUO 22... 22... SED. SUSP. FALL DIAM. \ FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. \ FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. \ FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP SIEVE DIA \ FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. \ FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. \ FINER THAN 1.00 MM (70335) 65 64 88 80 77 82 81 90 87 86 95 94 99 98 99 99 98 100 100 100 100 99 100 100 100 100 100 100 100 100 100 100 100 100 100 234 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS—Continued HATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 06... DEC 12... 30... APR 1997 03... 03... 03... JUN 03... JUL 22... 28... AUG 25... 28... SEP 26... TIME 1410 0653 1205 0030 0330 1630 1515 0215 1630 0315 1515 16CO DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) £27 8 193 443 2850 1240 75 258 1100 902 1030 225 285 SEDI- MENT, SUS- PENDED (MG/L) (80154) 248 300 267 1560 789 325 431 899 882 736 593 177 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) E186 156 319 12000 2640 66 300 2670 2150 2050 360 136 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 96 90 90 98 100 98 100 100 100 100 100 99 235 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AQUAS BUENAS, PR LOCATION.--Lat 18°14'48", long 66°05'37», Hydrologic Unit 21010005, on right bank 450 ft (137 m) upstream from bridge on Highway 777, 1.0 mi (1.6 km) southeast from Aguas Buenas, 3.9 mi (6.3 km) northwest from Caguas, and 2.1 mi (3.4 km) southwest from Las Carolinas. DRAINAGE AREA.--5.30 mi 1 (13.72 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 394 ft (120 m), from topographic map. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN PEB MAR APR MAY JUN JUL AUG SEP 1 9.6 6.8 2 10 7.0 3 8.2 5.6 4 8.0 6.0 5 7.6 6.5 6 7.9 5.9 7 7.4 8.9 8 7.1 5.1 9 7.1 4.6 10 8.1 3.5 11 7.4 5.2 12 6.8 9.0 13 6.9 9.1 14 6.8 5.0 15 6.2 4.0 16 5.9 3.6 17 5.6 5.0 18 5.6 5.0 19 5.4 4.7 20 5.2 5.2 21 5.3 14 22 5.2 9.1 23 5.2 7.8 24 5.2 6.7 25 5.0 7.3 26 8.4 5.4 27 6.7 8.6 28 16 12 29 10 7.4 30 7.8 19 31 6.2 TOTAL 223.8 213.0 MEAN 7.22 7.10 MAX 16 19 MIN 5.0 3.5 AC-FT 444 422 CFSM 1.36 1.34 IN. 1.57 1.50 14 12 8.3 8.2 6.5 7.7 8.3 6.2 4.2 3.5 8.0 4.9 4.2 3.9 4.1 4.8 3.9 3.6 3.3 3.1 3.4 3.3 3.1 3.1 4.3 3.8 3.4 2.8 6.6 6.1 4.4 167.0 5.39 14 2.8 331 1.02 1.17 3.3 3.5 2.9 2.7 2.5 2.6 2.6 2.4 2.4 2.7 3.6 2.4 2.4 2.3 2.5 2.6 2.4 3.3 4.8 3.6 46 64 16 34 25 10 6.8 9.8 6.7 6.1 6.2 288.1 9.29 64 2.3 571 1.75 2.02 7.4 6.8 4.3 4.8 5.4 5.0 5.1 3.9 5.5 3.9 3.5 4.0 7.6 4.3 3.5 2.9 2.7 2.8 3.3 3.8 13 6.9 5.6 5.1 4.7 5.4 4.9 4.4 ___ ___ --- 140.5 5.02 13 2.7 279 .95 .99 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1990 MEAN 7.93 7.21 MAX 20.9 12.3 (WY) 1991 1993 MIN 3.17 2.66 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 6.43 13.4 1993 2.34 1995 FOR 8.54 16.7 1992 2.48 1995 4.81 8.00 1991 2.96 1995 4.1 4.3 5.0 3.8 5.9 4.1 3.4 5.0 3.4 3.0 2.6 2.7 2.4 1.9 2.0 2.0 1.8 1.8 1.8 1.8 1.9 1.9 1.8 1.8 1.8 1.8 3.4 6.8 4.3 2.7 2.2 93.2 3.01 6.8 1.8 185 .57 .65 - 1997 4.56 8.87 1990 2.09 1996 1996 CALENDAR YEAR 3361.5 9.18 1260 1.2 1.2 6670 1.73 23.59 11 3.3 1.6 Sep 10 May 1 Apr 30 2.1 2.5 3.2 2.7 2.5 2.3 2.3 2.3 2.1 1.9 1.9 1.9 1.7 1.7 1.7 1.8 1.8 1.7 1.7 1.8 1.9 2.3 2.4 2.1 1.8 1.6 2.2 2.3 2.2 2.1 --- 62.5 2.08 3.2 1.6 124 .39 .44 , BY WATER 4.58 13.1 1993 1.84 1995 2.0 1.9 2.3 2.1 2.0 2.0 2.0 2.0 2.0 2.5 2.4 2.0 2.3 2.0 1.8 1.6 2.0 1.7 1.7 1.6 1.9 1.4 1.6 2.2 1.9 1.4 1.3 1.8 3.4 2.8 2.3 61.9 2.00 3.4 1.3 123 .38 .43 YEAR (WY) 5.35 18.0 1993 2.00 1997 2.0 2.1 2.9 2.2 1.9 1.9 1.8 2.0 2.2 1.8 1.8 1.8 2.6 1.6 1.6 1.6 1.8 1.9 1.7 1.2 1.2 1.1 1.3 2.7 2.1 1.8 2.0 1.7 1.8 1.8 --- 55.3 1.84 2.9 1.1 110 .35 .39 4.23 8.05 1993 1.84 1997 FOR 1997 WATER YEAR 1574.0 4.31 64 1.0 1.3 217 11.45 .82 3120 .81 11.05 7.8 2.7 1.6 jan 22 Aug 1 Sep 5 Jan 21 Jan 21 Jul 29 2.0 2.0 1.9 1.8 1.9 2.2 5.1 3.2 1.9 1.8 2.0 2.5 1.8 1.5 1.3 1.5 1.5 6.5 7.7 3.3 5.2 3.7 1.7 2.2 1.5 1.4 1.8 1.9 1.3 2.1 1.3 77.5 2.50 7.7 1.3 154 .47 .54 5.92 18.6 1993 1.86 1994 1.0 1.5 25 9.4 4.2 2.8 2.5 1.9 1.6 2.4 1.9 1.7 1.8 1.8 1.4 1.4 2.3 2.6 1.5 1.3 1.4 8.3 2.8 14 9.1 2.9 2.2 1.9 1.7 1.8 2.2 118.3 3.82 25 1.0 235 .72 .83 6.09 11.2 1993 1.85 1994 WATER YEARS 1990 - 6.68 11.1 4.31 1260 1.0 1.2 4490 21.22 .82 4840 1.26 17.13 9.2 4.1 1.9 Sep 10 Aug 1 Apr 30 Sep 10 Sep 10 Jul 29 1.8 1.8 1.7 1.6 1.5 1.4 1.3 1.1 1.3 1.2 1.1 7.8 3.5 2.2 1.8 1.5 1.3 2.2 1.5 2.3 3.9 2.6 2.8 1.8 1.5 6.3 2.4 6.5 2.9 2.3 72.9 2.43 7.8 1.1 145 .46 .51 12.9 52.9 1996 2.43 1997 1997 1993 1997 1996 1997 1996 1996 1996 1997 236 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: February 1990 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 5,300 mg/L September 10, 1996; Minimum daily mean, 1 mg/L July 16-17, 1997. SEDIMENT LOADS: Maximum daily mean, 24,500 tons (22,200 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) July 16-17, 1997. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,580 mg/L August 03, 1997; Minimum daily mean, 1 mg/L July 16-17, 1997. SEDIMENT LOADS: Maximum daily mean, 443 tons (401 tonnes) August 3, 1997; Minimum daily mean, <0.01 ton «.01 tonne) July 16-17, 1997 . SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.6 10 8.2 8.0 7.6 7.9 7.4 7.1 7.1 8.1 7.4 6.8 6.9 6.8 6.2 5.9 5.6 5.6 5.4 5.2 5.3 5.2 5.2 5.2 5.0 8.4 6.7 16 10 7.8 6.2 53 40 30 22 17 12 9 7 5 5 5 5 7 9 11 7 4 2 2 2 2 3 3 4 6 78 59 315 49 72 50 1.4 1.0 .68 .48 .34 .27 .19 .13 .10 .11 .10 .09 .13 .16 .18 .11 .06 .03 .03 .03 .03 .04 .05 .06 .09 2.6 1.1 40 1.9 1.6 .83 NOVEMBER 6.8 7.0 5.6 6.0 6.5 5.9 8.9 5.1 4.6 3.5 5.2 9.0 9.1 5.0 4.0 3.6 5.0 5.0 4.7 5.2 14 9.1 7.8 6.7 7.3 5.4 8.6 12 7.4 19 37 34 32 30 28 25 51 47 45 180 191 142 107 85 70 55 100 164 131 80 587 65 98 85 73 53 94 100 53 259 .69 .64 .48 .49 .49 .41 1.5 .66 .57 1.9 2.6 3.4 2.7 1.2 .75 .53 1.6 2.2 1.7 1.1 87 1.8 2.0 1.5 1.4 .76 4.5 3.5 1.0 18 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 14 12 8.3 8.2 6.5 7.7 8.3 6.2 4.2 3.5 8.0 4.9 4.2 3.9 4.1 4.8 3.9 3.6 3.3 3.1 3.4 3.3 3.1 3.1 4.3 3.8 3.4 2.8 6.6 6.1 4.4 76 42 32 24 16 10 7 12 24 48 74 27 7 6 7 8 13 20 34 82 222 500 224 59 24 17 34 27 63 53 36 2.8 1.3 .72 .54 .28 .21 .16 .19 .27 .47 1.7 .38 .08 .06 .08 .10 .13 .19 .29 .69 2.1 4.5 1.9 .49 .31 .20 .31 .20 1.7 .93 .51 TOTAL 223.8 53.92 213.0 147.07 167.0 23.79 237 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3.3 3.5 2.9 2.7 2.5 2.6 2.6 2.4 2.4 2.7 3.6 2.4 2.4 2.3 2.5 2.6 2.4 3.3 4.8 3.6 46 64 16 34 25 10 6.8 9.8 6.7 6.1 6.2 31 26 12 7 7 9 12 15 19 29 188 166 147 130 115 111 111 120 47 33 736 703 157 370 178 94 73 114 44 25 17 .28 .25 .10 .05 .05 .07 .08 .10 .12 .28 1.8 1.1 .94 .80 .79 .78 .70 1.9 .94 .37 240 165 7.9 56 15 2.6 1.3 5.2 .82 .42 .28 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 7.4 6.8 4.3 4.8 5.4 5.0 5.1 3.9 5.5 3.9 3.5 4.0 7.6 4.3 3.5 2.9 2.7 2.8 3.3 3.8 13 6.9 5.6 5.1 4.7 5.4 4.9 4.4 89 148 132 86 52 31 16 9 5 6 9 14 58 15 10 14 22 33 42 52 133 52 18 7 12 32 75 45 2.1 2.7 1.5 1.1 .74 .43 .21 .09 .07 .06 .09 .16 1.5 .17 .10 .11 .16 .25 .37 .54 5.6 1.0 .28 .09 .15 .48 .99 .54 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 4.1 4.3 5.0 3.8 5.9 4.1 3.4 5.0 3.4 3.0 2.6 2.7 2.4 1.9 2.0 2.0 1.8 1.8 1.8 1.8 1.9 1.9 1.8 1.8 1.8 1.8 3.4 6.8 4.3 2.7 2.2 17 7 7 7 8 12 20 28 18 10 6 5 5 5 5 5 5 4 4 4 7 13 21 15 8 4 22 73 46 14 9 .19 .08 .09 .07 .13 .13 .18 .39 .17 .08 .04 .04 .03 .03 .03 .03 .02 .02 .02 .02 .04 .07 .10 .07 .04 .02 .78 2.8 .70 .11 .05 TOTAL 288.1 506.02 140.5 21.58 93.2 6.57 238 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AQUAS BDENAS , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 2.1 2.5 3.2 2.7 2.5 2.3 2.3 2.3 2.1 1.9 1.9 1.9 1.7 1.7 1.7 1.8 1.8 1.7 1.7 1.8 1.9 2.3 2.4 2.1 1.8 1.6 2.2 2.3 2.2 2.1 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 7 15 28 9 4 4 4 4 5 6 8 9 9 10 10 11 9 8 8 7 5 4 3 5 7 11 11 11 10 10 .04 .15 .25 .06 .03 .03 .03 .03 .03 .03 .04 .04 .04 .05 .05 .05 .05 .04 .04 .03 .03 .03 .02 .03 .04 .05 .06 .07 .06 .06 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) MAY 2.0 1.9 2.3 2.1 2.0 2.0 2.0 2.0 2.0 2.5 2.4 2.0 2.3 2.0 1.8 1.6 2.0 1.7 1.7 1.6 1.9 1.4 1.6 2.2 1.9 1.4 1.3 1.8 3.4 2.8 2.3 10 10 9 9 9 9 9 9 8 8 8 11 16 22 16 9 6 8 12 18 23 27 31 19 9 5 5 7 29 25 11 .05 .05 .06 .05 .05 .05 .05 .05 .04 .05 .05 .06 .10 .12 .08 .04 .03 .04 .05 .08 .11 .10 .14 .12 .05 .02 .02 .03 .57 .21 .07 2.0 2.1 2.9 2.2 1.9 1.9 1.8 2.0 2.2 1.8 1.8 1.8 2.0 1.6 1.6 1.6 1.8 1.9 1.7 1.2 1.2 1.1 1.3 2.7 2.1 1.8 2.0 1.7 1.8 1.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 3 3 8 9 7 5 7 9 20 23 16 11 12 16 21 .05 .04 .05 .03 .03 .03 .02 .02 .03 .02 .02 .02 .02 .02 .01 .01 .01 .08 .04 .02 .02 .02 .03 .24 .13 .08 .06 .06 .08 .11 TOTAL 62.5 1.56 61.9 2.59 55.3 1.40 239 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGtflTAS NEAR AQUAS BDENAS , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 2.0 2.0 1.9 1.8 1.9 2.2 5.1 3.2 1.9 1.8 2.0 2.5 1.8 1.5 1.3 1.5 1.5 6.5 7.7 3.3 5.2 3.7 1.7 2.2 1.5 1.4 1.8 1.9 1.3 2.1 1.3 77.5 1574.0 JULY 27 20 12 8 6 5 37 29 17 12 9 6 4 3 2 1 1 75 634 35 47 26 22 29 35 27 19 13 9 6 4 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) AUGUST .14 .10 .06 .04 .03 .03 1.1 .28 .09 .06 .05 .04 .02 .01 .01 <.01 <.01 4.3 52 .34 .79 .28 .10 .16 .14 .10 .09 .06 .03 .03 .01 60.49 1459.97 1.0 1.5 25 9.4 4.2 2.8 2.5 1.9 1.6 2.4 1.9 1.7 1.8 1.8 1.4 1.4 2.3 2.6 1.5 1.3 1.4 8.3 2.8 14 9.1 2.9 2.2 1.9 1.7 1.8 2.2 118.3 4 4 1580 324 35 16 8 7 10 19 19 15 14 14 13 13 19 30 15 14 16 176 33 620 448 84 58 40 28 19 14 —— .01 .02 443 10 .40 .12 .05 .04 .04 .19 .10 .07 .07 .07 .05 .05 .22 .24 .06 .05 .06 8.0 .25 79 14 .67 .34 .21 .13 .09 .08 557.68 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1.8 1.8 1.7 1.6 1.5 1.4 1.3 1.1 1.3 1.2 1.1 7.8 3.5 2.2 1.8 1.5 1.3 2.2 1.5 2.3 3.9 2.6 2.8 1.8 1.5 6.3 2.4 6.5 2.9 2.3 12 11 10 11 11 12 10 9 8 9 10 494 48 91 71 49 35 31 30 29 29 29 29 26 18 76 67 241 144 95 .06 .05 .05 .05 .04 .04 .04 .03 .03 .03 .03 49 .61 .55 .34 .20 .12 .18 .12 .18 .31 .20 .22 .13 .07 2.4 .44 20 1.2 .58 72.9 77.30 240 RIO ORANDE DC LOIZA BASIN 50055100 RIO CAO0ITAS NEAR AGRJAS BUENAS, PR—Continued HATER QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DIS- CHARGE, INST. CUBIC SEDI- DATE NOV 1996 21... AUO 1997 03... TIME 1700 1745 PER SECOND SUS- PENDED (MO/L) SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. PALL DIAM. SED. SED. SUSP. SUSP. PALL PALL DIAM. DIAM. (T/DAY) % FINER % FINER % FINER THAN THAN THAN .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 92 167 7660 1900 19000 8570 29 28 37 33 52 46 DATE NOV 1996 21... AUO 1997 03... SED. SUSP. PALL DIAM. % FINER THAN .016 MM (70329) 67 60 SED. SUSP. PALL DIAM. % FINER THAN .031 MM (70330) 77 73 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 95 91 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 97 97 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 jog. M MM M A M0> M O 242 RIO GRANDE OB LOXZA BASIN 50055170 RIO CAGUITAS NEAR CAOOAS, PR LOCATION.--Lat 18°13'59", long 66«02'53", Bydrologic Unit 21010005, on l«£t bank, 0.9 mi (1.4 km) southwest from Plaza da Caguas, 0.6 mi (1.0 km) northeast from Escuela Bunker, and 1.2 mi (1.9 km) northwest from Escuela Antonio S. Pedreira. DRAINAGE AREA.—8.27 mi* (21.42 k»»). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—May 1992 to September 30, 1997. (discontinued) GAGE.—Water-stage recorder and erect-stage gage. Elevation of gage is 216 ft (66 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV JAN MAR APR MAY JUN JUL AUG SEP 1 e!2 ell 2 e!3 ell 3 ell e8.6 4 elO e9.4 5 e9.8 elO 6 elO e9.0 7 e9.7 e!4 8 e9.2 e7.6 9 e9.2 e7.0 10 ell e6.0 11 e9.6 e9.2 12 e8.8 el4 13 e9 . 0 e!4 14 e8.8 e8.0 15 e8.2 e5.8 16 e7.7 e5.6 17 e7 . 2 e7 . 6 18 e7.2 e7.6 19 e7.0 e7.0 20 e6.8 e7.8 21 e7.0 e23 22 e6.7 e!7 23 e6.7 18 24 e6.7 15 25 e6.4 13 26 e!2 9.9 27 elO 14 28 e22 21 29 e!7 16 30 e!2 38 31 e9.4 TOTAL 301.1 365.1 MEAN 9.71 12.2 MAX 22 38 MIN 6.4 5.6 AC-FT 597 724 CFSM 1.17 1.47 IN. 1.35 1.64 STATISTICS OF MONTHLY MEAN MEAN 11.0 17.9 MAX 16.0 37.4 (WY) 1994 1993 MIN 7.35 5.14 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 20 20 14 13 11 10 9.6 8.5 8.5 8.5 13 11 8.5 8.5 8.6 9.2 8.6 7.8 7.7 7.8 7.5 7.5 7.2 7.0 9.7 8.2 8.4 8.3 13 13 16 319.6 10.3 20 7.0 634 1.25 1.44 10 13 9.7 8.8 8.3 8.6 8.1 8.2 8.0 8.5 10 7.9 7.8 7.4 7.2 7.4 7.0 7.7 12 10 77 141 31 64 52 21 14 15 13 10 9.6 623.2 20.1 141 7.0 1240 2.43 2.80 18 11 10 11 11 14 15 13 16 12 11 11 15 11 9.7 8.9 8.5 8.7 9.5 9.3 18 13 11 10 9.8 11 9.8 9.2 —— —— —— 325.4 11.6 18 8.5 645 1.41 1.46 DATA FOR WATER YEARS 1992 13.7 37.0 1993 4.17 1995 FOR 14.1 20.6 1996 1.90 1995 1996 CALBffi 6230.6 17.0 1320 2.4 3.1 12360 2.06 28.03 24 8.4 4.2 7.56 11.6 1997 2.45 1995 MR YEAR Sep 10 May 5 Apr 30 9.2 9.1 9.3 9.5 9.8 9.0 8.5 11 9.2 8.6 8.2 8.6 8.4 7.8 8.0 8.2 8.3 8.5 8.0 7.7 7.2 7.2 7.1 6.9 6.9 6.8 8.3 14 13 9.7 8.1 270.1 8.71 14 6.8 536 1.05 1.21 - 1997, 6.06 8.71 1997 1.75 1995 7.7 10 10 8.4 8.2 8.2 8.2 8.5 8.3 8.0 8.2 7.3 6.4 6.0 6.0 6.1 6.1 6.0 5.6 5.3 5.8 6.3 5.7 5.6 5.7 5.5 5.6 5.6 6.1 5.5 —— 205.9 6.86 10 5.3 408 .83 .93 5.5 5.6 6.2 6.7 6.8 6.7 6.9 7.2 6.9 7.2 7.5 6.7 6.7 7.0 8.2 8.4 7.9 7.0 6.3 5.8 6.2 6.6 6.4 7.4 7.2 7.2 8.3 11 12 15 11 235.5 7.60 15 5.5 467 .92 1.06 9.6 8.5 9.2 8.5 7.5 7.5 7.5 6.9 7.5 6.9 6.3 6.0 7.1 7.5 6.9 6.3 6.5 8.5 7.8 7.7 7.2 6.6 7.7 9.9 8.4 7.5 7.1 6.5 6.4 6.5 —— 224.0 7.47 9.9 6.0 444 .90 1.01 6.9 6.7 6.0 6.1 6.6 8.6 12 12 9.1 8.2 7.5 6.6 6.9 6.0 5.4 6.5 6.7 8.9 14 16 17 16 11 10 8.9 8.0 9.6 13 9.6 9.4 11 290.2 9.36 17 5.4 576 1.13 1.31 8.1 7.0 43 26 11 9.0 7.6 7.0 6.3 8.1 8.6 6.5 5.7 5.5 5.5 5.5 5.8 7.5 5.9 5.2 5.5 29 14 33 32 12 9.7 8.2 7.2 6.3 7.2 358.9 11.6 43 5.2 712 1.40 1.61 5.8 6.7 6.5 6.3 5.6 6.4 7.1 7.5 8.3 6.9 5.4 14 14 10 8.9 8.2 6.9 8.1 7.6 6.4 9.0 9.3 8.3 6.5 6.0 34 15 14 16 10 284.7 9.49 34 5.4 565 1.15 1.28 BY WATER YEAR (WY) 9.48 27.8 1993 1.16 1995 FOR 1997 - 3803 10 141 5 5 395 19 7540 1 17 14 8 6 12.0 41.2 1993 2.31 1994 WATER YEAR .7 .4 Jan 22 .2 Aug 20 .6 Apr 26 Jan 21 .07 Jan 21 .26 .11 .3 .1 8.31 15.8 1996 1.71 1994 14.5 45.5 1993 2.65 1995 11.9 20.2 1993 4.63 1995 WATER YEARS 1992 13.6 24.5 8.33 1320 .72 .77 9040 31.60 9870 1.65 22.39 21 7.0 2.2 Sep Apr Apr sep Sep 32.9 70.6 1996 9.49 1997 - 1997 1993 1994 10 1996 30 1995 27 1995 10 1996 10 1996 e Estimated RIO GRANDE DE LOIZA BASIN 243 50055170 RIO CAGUITAS NEAR CAGUAS, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1992 to 1997. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: June 1992 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1992. REMARKS.-- Sediment Samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,820 mg/L September 10, 1996; Minimum daily mean, 1 mg/L July 18-19, 1994. SEDIMENT LOADS: Maximum daily mean,19,100 tons (17,300 tonnes) September 10, 1996; Minimum daily mean, eO.Ol ton (eO.Ol tonne) several days. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 699 mg/L January 22, 1997; Minimum daily mean, 7 mg/L March 4, 1997. SEDIMENT LOADS: Maximum daily mean, 456 tons (413 tonnes) January 21, 1997; Minimum daily mean, 0.16 ton (0.14 tonne) May 22, September 21, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e!2 e!3 ell elO e9.8 elO e9.7 e9.2 e9.2 ell e9.6 e8.8 e9.0 e8.8 e8.2 e7.7 e7.2 e7.2 e7.0 e6.8 e7.0 e6.7 e6.7 e6.7 e6.4 e!2 elO e22 e!7 e!2 e9.4 301.1 11 11 12 12 12 13 13 14 14 14 15 15 16 16 16 17 17 18 18 19 19 20 21 21 22 25 31 61 59 51 45 ___ e.36 e.40 e.35 e.33 e.33 e.35 e.34 e.34 e.35 e.43 e.38 e.36 e.38 e.38 e.38 e.35 e.34 e.35 e.35 e.35 e.37 e.36 e.37 e.38 e.38 e.80 e.83 e3.6 e2.7 el. 7 el.l 19.79 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER ell ell e8.6 e9.4 elO e9.0 e!4 e7.6 e7.0 e6.0 e9.2 e!4 e!4 e8.0 e5.8 e5.6 e7.6 e7.6 e7.0 e7.8 e23 e!7 18 15 13 9.9 14 21 16 38 --- 365.1 40 35 31 29 30 31 42 37 29 23 27 43 36 28 23 20 20 21 23 25 27 28 29 48 68 72 52 98 59 119 --- ___ el. 2 el.O e.72 e.74 e.81 e.75 el. 6 e.77 6.55 e.37 a. 68 el. 6 el. 4 6.60 e.37 6.31 6.41 6.44 6.44 e.53 el. 6 el. 4 1.4 2.0 2.3 1.9 2.3 5.7 2.5 16 52.39 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 20 20 14 13 11 10 9.6 8.5 8.5 8.5 13 11 8.5 8.5 8.6 9.2 8.6 7.8 7.7 7.8 7.5 7.5 7.2 7.0 9.7 8.2 8.4 8.3 13 13 16 319.6 77 64 83 110 59 29 29 32 40 52 67 80 57 38 29 47 82 49 21 24 30 37 42 31 34 43 66 47 53 48 94 ___ 4.2 3.4 3.3 3.8 1.8 .83 .75 .74 .93 1.2 2.4 2.2 1.3 .86 .66 1.2 1.9 1.0 .44 .49 .61 .75 .82 .59 .93 .95 1.5 1.1 2.2 1.8 5.3 49.95 e Estimated 244 RIO GRANDE BE LOZZA BASIN 50055170 RIO CAG0ITAS NEAR CAOUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 10 13 9.7 8.8 8.3 8.6 8.1 8.2 8.0 8.5 10 7.9 7.8 7.4 7.2 7.4 7.0 7.7 12 10 77 141 31 64 52 21 14 15 13 10 9.6 134 113 122 96 54 43 57 59 42 32 31 32 40 30 20 25 33 30 42 31 588 699 96 229 160 80 59 58 27 17 15 3.6 4.5 3.2 2.3 1.2 1.0 1.2 1.3 .92 .78 .84 .68 .85 .59 .39 .50 .62 .67 1.4 .85 456 365 8.3 60 28 4.5 2.3 2.6 .98 .47 .40 18 11 10 11 11 14 15 13 16 12 11 11 15 11 9.7 8.9 8.5 8.7 9.5 9.3 18 13 11 10 9.8 11 9.8 9.2 —— —— —— 57 34 22 14 12 43 49 58 233 103 26 20 43 26 12 12 12 13 13 14 51 51 43 40 34 30 37 47 3.9 1.0 .61 .40 .38 1.6 2.1 2.1 12 3.5 .80 .60 1.8 .77 .32 .28 .28 .30 .34 .34 3.1 1.8 1.3 1.1 .91 .87 .97 1.2 MEAN DISCHARGE (CFS) 9.2 9.1 9.3 9.5 9.8 9.0 8.5 11 9.2 8.6 8.2 8.6 8.4 7.8 8.0 8.2 8.3 8.5 8.0 7.7 7.2 7.2 7.1 6.9 6.9 6.8 8.3 14 13 9.7 8.1 MEAN CONCEN- TRATION (MG/L) MARCH 45 36 15 7 16 41 42 32 18 10 11 12 15 18 27 35 21 13 28 63 34 12 11 13 21 34 27 88 45 24 24 SEDIMENT DISCHARGE (TONS/DAY) 1.1 .87 .37 .17 .41 1.0 .95 .92 .44 .23 .23 .29 .33 .37 .59 .76 .46 .31 .61 1.3 .67 .23 .21 .24 .40 .62 .62 3.5 1.6 .67 .51 TOTAL 623.2 955.94 325.4 44.67 270.1 20.98 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 245 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) 7.7 10 10 8.4 8.2 8.2 8.2 8.5 8.3 8.0 8.2 7.3 6.4 6.0 6.0 6.1 6.1 6.0 5.6 5.3 5.8 6.3 5.7 5.6 5.7 5.5 5.6 5.6 6.1 5.5 APRIL 31 39 42 20 13 24 41 24 14 29 54 22 12 11 11 13 18 37 66 42 23 13 11 12 16 20 14 12 32 77 MAY .65 1.2 1.2 .46 .29 .54 .90 .55 .31 .62 1.2 .44 .21 .18 .18 .21 .30 .60 1.0 .60 .35 .22 .18 .17 .24 .29 .20 .18 .53 1.1 5.5 5.6 6.2 6.7 6.8 6.7 6.9 7.2 6.9 7.2 7.5 6.7 6.7 7.0 8.2 8.4 7.9 7.0 6.3 5.8 6.2 6.6 6.4 7.4 7.2 7.2 8.3 11 12 15 11 84 73 35 18 34 64 32 18 35 68 47 26 41 74 77 72 67 63 59 50 18 9 16 30 52 63 35 35 42 30 35 1.2 1.1 .58 .32 .63 1.1 .59 .34 .65 1.3 .95 .48 .75 1.4 1.7 1.6 1.4 1.2 1.0 .77 .30 .16 .27 .58 1.0 1.2 .86 1.2 1.4 1.3 1.1 JUNE 9.6 8.5 9.2 8.5 7.5 7.5 7.5 6.9 7.5 6.9 6.3 6.0 7.1 7.5 6.9 6.3 6.5 8.5 7.8 7.7 7.2 6.6 7.7 9.9 8.4 7.5 7.1 6.5 6.4 6.5 ___ 24 15 13 13 16 21 19 16 12 10 11 11 12 13 12 11 11 21 15 12 11 10 15 32 11 18 19 29 34 21 —— .60 .35 .32 .29 .34 .41 .38 .30 .24 .19 .18 .18 .23 .25 .22 .19 .18 .85 .32 .25 .21 .17 .35 .88 .26 .36 .37 .50 .58 .37 TOTAL 205.9 15.10 235.5 28.43 224.0 10.32 246 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE THAT ION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 6.9 6.7 6.0 6.1 6.6 8.6 12 12 9.1 8.2 7.5 6.6 6.9 6.0 5.4 6.5 6.7 8.9 14 16 17 16 11 10 8.9 8.0 9.6 13 9.6 9.4 11 290.2 3803.7 JULY 14 13 14 15 17 16 32 42 36 22 18 15 13 12 13 32 30 31 49 55 53 58 39 32 29 27 33 48 32 41 36 —— .26 .24 .22 .25 .29 .38 1.4 1.4 .90 .49 .37 .28 .23 .19 .19 .71 .54 .86 2.1 2.5 2.6 2.5 1.1 .89 .71 .59 .93 2.0 .84 1.2 1.0 28.16 1398.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 8.1 7.0 43 26 11 9.0 7.6 7.0 6.3 8.1 8.6 6.5 5.7 5.5 5.5 5.5 5.8 7.5 5.9 5.2 5.5 29 14 33 32 12 9.7 8.2 7.2 6.3 7.2 26 21 150 86 29 17 21 15 12 20 23 17 14 12 12 14 16 17 14 12 11 94 43 111 95 38 31 28 23 22 29 .57 .40 63 7.5 .89 .40 .43 .29 .20 .53 .54 .30 .21 .18 .17 .20 .25 .34 .22 .17 .16 12 1.9 27 10 1.3 .84 .63 .45 .38 .60 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 358.9 132.05 5.8 6.7 6.5 6.3 5.6 6.4 7.1 7.5 8.3 6.9 5.4 14 14 10 8.9 8.2 6.9 8.1 7.6 6.4 9.0 9.3 8.3 6.5 6.0 34 15 14 16 10 284.7 20 12 13 13 14 22 26 26 28 24 20 48 51 35 30 27 24 27 26 21 30 32 27 21 19 103 52 49 55 33 .31 .22 .22 .23 .21 .49 .51 .59 .65 .45 .30 2.4 2.2 .99 .74 .61 .46 .62 .53 .36 .76 .81 .62 .36 .31 17 2.2 2.3 2.6 .90 40.95 RXO GRANDE DE LOIZA BASIN 50055170 RIO CAGUXTAS NEAR CAGUAS, PR—Continued MATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 247 DATE DEC 1996 04... JAN 1997 21... 22... FEB 09... MAR 28... TIME 1330 2220 0845 1405 0800 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 13 393 323 17 10 SEDI- MENT, SUS- FENCED (MO/L) (80154) 127 4520 2730 367 123 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4.5 4800 2380 17 3.3 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 57 99 98 99 96 248 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR LOCATION.—Lat 18°14'55", long 66°01'40", Bydrologic Unit 21010005, on left bank, at C. 4 street Villa Blanca housing area at Caguas, 1.8 mi (2.9 km) upstream from Rio Grande de Loiza, and 0.95 mi (1.53 km) northeast from caguas Plaza. DRAINAGE AREA.—11.71 mi 2 (30.33 km*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1990 to current year. GAGE.—Water-stage recorder. Elevation of gage is 164 ft (50 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Low-flow affected by pluvial discharge about 50 ft upstream from station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 e42 e31 2 e42 629 3 e36 e28 4 636 e27 5 e35 628 6 635 628 7 634 6158 8 e31 675 9 e31 e46 10 e35 636 11 633 644 12 631 641 13 631 637 14 631 627 15 e28 e21 16 626 21 17 625 21 18 625 22 19 624 21 20 623 22 21 624 e45 22 623 e36 23 623 625 24 623 623 25 622 621 26 e37 620 27 e30 e22 28 668 28 29 645 25 30 635 44 31 628 —— TOTAL 992 1052 MEAN 32.0 35.1 MAX 68 158 MIN 22 20 MED 31 28 AC-FT 1970 2090 CFSM 2.73 2.99 IN. 3.15 3.34 STATISTICS OF MONTHLY MEAN MEAN 24.8 33.9 MAX 32.0 56.8 (WY) 1997 1993 MIN 18.7 12.2 (WY) 1996 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e23 e20 617 e23 622 618 618 e!8 e!7 618 24 18 19 19 18 19 16 17 17 16 18 19 17 19 30 19 18 18 24 25 35 619 20.0 35 16 18 1230 1.71 1.97 DATA 22.2 58.4 1993 8.87 1995 21 46 26 22 20 30 e20 e!8 e!8 621 e29 el 8 e!8 e!7 e20 19 18 21 25 24 80 157 49 75 59 34 32 32 30 25 25 1049 33.8 157 17 25 2080 2.89 3.33 FOR WATER 38.0 120 1992 14.2 1995 46 25 23 23 25 26 31 24 40 32 31 28 44 30 26 19 19 21 22 19 45 23 17 18 18 30 20 20 —— 745 26.6 46 17 25 1480 2.27 2.37 YEARS 1991 18.9 26.6 1997 10.8 1992 20 20 23 24 28 24 19 33 28 26 22 25 25 30 25 24 22 21 21 24 23 27 25 24 34 28 33 50 71 38 35 872 28.1 71 19 25 1730 2.40 2.77 - 1997 14.8 28.1 1997 7.54 1994 FOR 1996 CALENDAR YEAR 21075. 57. 8600 7. 8. 41800 4. 66. 69 20 12 2 6 Sep 10 5 May 31 3 May 28 92 95 631 e77 30 22 19 23 27 29 28 21 27 23 18 19 19 18 17 15 13 14 14 14 14 13 12 12 16 14 14 14 —— 627 20.9 77 12 18 1240 1.78 1.99 12 13 12 12 ell ell e9.7 614 615 620 619 e!5 618 615 614 615 614 e!3 e!3 614 14 14 17 15 17 14 22 21 20 15 18 466.7 15.1 22 9.7 14 926 1.29 1.48 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 643 e30 e24 e28 638 623 e!6 e!3 ell 69.5 e!2 ell 533.5 17.8 46 9.5 14 1060 1.52 1.69 69.4 68.4 69.7 69.4 e!2 el 8 e25 el 8 el 8 614 613 elO e!3 elO e8.7 620 614 e!5 621 630 e53 638 617 624 e!3 e!2 623 e45 ell 619 614 565.6 18.2 53 8.4 14 1120 1.56 1.80 ell e9.7 6121 661 e24 e!7 619 e!7 614 626 e20 e!2 e!3 e!3 614 e!3 e20 e!7 e9.5 e9.4 612 189 33 166 88 27 35 615 615 612 e29 1081.6 34.9 189 9.4 17 2150 2.98 3.44 612 612 e20 613 e!2 e!2 ell e9.4 elO e9.3 e8.9 85 70 20 21 14 13 621 615 e22 638 625 628 617 615 e60 e23 660 628 622 726.6 24.2 85 8.9 19 1440 2.07 2.31 , BY WATER YEAR (WY) 16.5 39.8 1993 5.49 1994 24.2 59.8 1993 3.35 1994 22.6 45.6 1996 2.86 1994 FOR 1997 WATER YEAR 9330.0 25.6 189 8.4 9.9 1060 11.37 18510 2.18 29.64 40 21 12 Aug 22 Jul 2 Jun 28 Aug 22 Aug 22 29.7 74.6 1993 4.13 1994 WATER 32 55 11 8600 1 1 25000 23 23250 2 37 42 16 6 33.0 58.0 1995 3.82 1994 YEARS 1991 .1 .2 .9 Sep .3 Jun .4 Jun Sep . 89 Sep .74 .24 .0 85.5 364 1996 8.82 1994 - 1997 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 e Estimated 249 RIO QRANDB DE LOIZA BASIN 50055225 RIO CAOVITAS AT VILLA BLANCA AT CAOUAS, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1991 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCBAROE: December 1990 to current year. INSTRUMENTATION.-- USDB-48 sediment sanpler and automatic sediment sampler since 1991. REMARKS.— Sediment samples collected by local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,5700 mg/L September 10, 1996; Minimum daily mean, 3 mg/L August 2, 1997. SEDIMENT LOADS: Maximum daily mean, e34,700 tons (e31,500 tonnes) September 10, 1996; Minimum daily mean, eO.03 ton (eO.02 tonne) June 15, 1994. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 450 mg/L February 2, 1997; Minimum daily mean, 3 mg/L August 2, 1997. SEDIMENT LOADS: Maximum daily mean, e388 tons (e352 tonnes) November 7 , 1996; Minimum daily mean, eO.08 ton (eO.07 tonne) August 2, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCBAROE (MG/L) (TONS/DAY) OCTOBER DISCBAROE (CFS) TRATION DISCBAROE (MG/L) (TONS/DAY) DISCBAROE (CFS) TRATION DISCBAROE (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL e42 e42 e36 e36 e35 e35 e34 e31 e31 e35 e33 e31 e31 e31 e28 e26 e25 e25 e24 e23 e24 e23 e23 e23 e22 e37 e30 e68 e45 e35 e28 992 31 33 35 37 39 41 43 46 48 47 44 43 47 52 58 65 73 80 65 49 38 41 48 53 47 40 34 80 48 43 51 e3.5 e3.7 e3.4 e3.6 e3.7 e3.9 e4.0 e3.8 e4.0 e4.4 e4.0 e3.6 e3.9 e4.4 e4.4 e4.6 e4.9 e5.4 e4.2 e3.1 e2.5 e2.6 e3.0 e3.3 e2.8 e4.0 e2.7 e!5 e5.9 e4.1 e3.9 e31 e29 e28 e27 e28 e28 e!58 e75 e46 e36 e44 e41 e37 e27 e21 21 21 22 21 22 e45 e36 e25 e23 e21 e20 e22 28 25 44 NOVEMBER 60 64 67 71 78 88 319 146 127 121 119 117 114 90 85 84 83 83 82 81 108 82 74 46 41 40 59 97 86 135 130.3 1052 eS.O eS.O e5.2 e5.2 e5.9 e6.6 B388 e30 el6 el2 el7 el3 ell e6.6 e4.9 e4.7 e4.7 e4.8 e4.6 e4.8 el9 e8.6 eS.O e2.9 e2.3 e2.2 e4.0 7.3 5.8 22 634.1 e23 e20 el7 e23 e22 el8 el8 el8 el7 el8 24 18 19 19 18 19 16 17 17 16 18 19 17 19 30 19 18 18 24 25 35 119 79 50 32 39 57 70 61 70 47 93 93 86 79 73 87 75 73 139 78 79 60 41 55 113 89 75 95 100 85 83 e7.5 e4.4 e2.3 e2.0 e2.2 e2.9 e3.5 e3.0 e3.2 e2.2 6.1 4.6 4.3 4.0 3.5 4.5 3.3 3.4 6.5 3.5 3.9 3.1 1.9 2.9 9.6 4.5 3.6 4.9 6.9 5.9 10 619 134.1 e Estimated 250 RIO GRANDE DE LOZZA BASIN 50055225 RIO CAGOITAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MEAN MEAN iN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT iRGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE !) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 21 46 26 22 20 30 e20 e!8 e!8 a21 e29 e!8 e!8 a 17 e20 19 18 21 25 24 80 157 49 75 59 34 32 32 30 25 25 86 119 64 25 20 63 59 55 65 77 92 111 134 161 188 146 99 81 89 93 166 271 125 161 159 106 78 84 106 93 90 4.8 21 4.6 1.5 1.1 7.5 e3.0 e2.7 e3.2 e4.4 e7.2 e5.4 e6.5 e7.4 elO 7.5 4.7 4.8 6.0 6.1 62 144 17 39 27 9.7 6.7 7.5 8.6 6.2 6.1 FEBRUARY 46 25 23 23 25 26 31 24 40 32 31 28 44 30 26 19 19 21 22 19 45 23 17 18 18 30 20 20 ___ ___ ___ 299 450 406 380 360 306 128 96 68 21 55 34 108 93 33 29 39 50 75 80 87 61 61 60 60 130 130 107 ___ --_ 46 31 26 23 24 22 11 6.2 7.5 1.8 4.8 2.5 14 7.8 2.3 1.5 2.0 2.9 4.5 4.2 11 3.8 2.7 2.9 2.9 11 6.9 5.9 —— ___ _-_ MARCH 20 20 23 24 28 24 19 33 28 26 22 25 25 30 25 24 22 21 21 24 23 27 25 24 34 28 33 50 71 38 35 90 84 145 144 117 100 86 106 86 67 54 70 99 84 50 41 34 28 23 20 21 23 25 24 75 32 76 120 150 103 110 4.8 4.6 8.9 9.3 8.9 6.5 4.3 9.8 6.4 4.8 3.2 4.9 6.6 6.7 3.4 2.6 2.0 1.6 1.3 1.3 1.3 1.7 1.7 1.6 7.6 2.4 7.1 17 32 11 10 1049 453.2 745 292.1 872 195.3 a Estimated RXO GRANDE DE LOXZA BASIN 50055225 RXO CAGUXTAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 251 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATXON DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e31 e77 30 22 19 23 27 29 28 21 27 23 18 19 19 18 17 15 13 14 14 14 14 13 12 12 16 14 14 14 —— APRXL 103 168 131 85 57 80 83 23 16 17 55 73 40 23 27 37 47 38 28 21 19 18 18 17 16 16 36 47 29 24 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATXON DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CPS) MAY e8.7 e77 11 5.0 2.9 5.1 6.3 1.7 1.2 .95 4.5 4.6 1.9 1.2 1.3 1.8 2.1 1.5 .96 .79 .73 .70 .69 .62 .54 .49 1.9 1.8 1.1 .91 ___ 12 13 12 12 ell ell e9.7 e!4 elS e20 e!9 elS e!8 elS e!4 e!5 el4 e!3 e!3 e!4 14 14 17 15 17 14 22 21 20 15 18 22 30 17 18 18 19 20 65 102 81 92 60 88 54 62 225 31 15 13 12 14 15 39 67 71 24 51 77 62 57 75 .73 1.2 .57 .57 e.55 e.54 e.50 e5.7 e!2 e4.3 elO e2.6 ell e6.8 e2.8 e!55 e!8 e2.8 e2.3 el. 3 .51 .59 2.7 2.8 3.4 .93 5.2 5.2 4.2 2.3 4.1 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 e43 e30 e24 e28 e38 e23 e!6 e!3 ell e9.5 e!2 ell—— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 11 10 12 12 11 13 14 15 17 15 11 12 14 10 13 18 21 e46 e43 e30 e24 828 838 823 e!6 e!3 ell e9.5 e!2 ell 97 91 85 73 60 53 69 94 128 155 184 211 187 155 128 98 72 125 115 57 84 97 108 123 119 110 101 91 81 72 2.8 2.5 2.9 2.3 1.7 1.9 2.5 3.8 5.8 6.3 5.5 6.8 6.9 4.3 4.5 4.7 4.5 e!9 e!4 e4.9 e5.7 e6.9 e!2 e7.6 e5.1 e3.8 e3.0 e2.3 e2.6 e2.1 TOTAL 627 149.98 466.7 271.19 533.5 158.7 e Estimated 252 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) e9.4 e8.4 e9.7 e9.4 e!2 e!8 e25 e!8 e!8 e!4 e!3 elO e!3 elO e8.7 e20 e!4 e!5 e21 e30 e53 e38 e!7 e24 e!3 e!2 e23 e45 ell e!9 e!4 JULY 55 38 40 42 38 71 70 85 105 99 89 53 29 15 8 34 63 70 82 82 124 90 35 72 25 20 76 124 41 62 26 TOTAL 565.6 —— YEAR e 9330.0 Estimated el e el el el e4 e7 e4 e5 e3 e3 .4 .86 .1 .1 .2 .2 .8 .1 .0 .6 .2 el. 5 el e e e3 e2 e3 e5 e7 e25 e!4 .0 .42 .19 .7 .4 .2 .2 .3 el. 9 e6 e e e6 e35 el e4 e 154 3995 .1 .94 .63 .2 .2 .1 .93 .47 .86 MEAN DISCHARGE (CFS) ell e9.7 e!21 e61 e24 e!7 e!9 e!7 e!4 e26 e20 e!2 e!3 e!3 e!4 e!3 e20 e!7 e9.5 e9.4 e!2 189 33 166 88 27 35 e!5 e!5 e!2 e29 1081.6 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST ell e9.7 •121 e61 e24 e!7 e!9 e!7 e!4 e26 e20 e!2 e!3 e!3 e!4 e!3 e20 e!7 e9.5 e9.4 e!2 189 33 166 88 27 35 elS elS e!2 e29 5 3 358 158 84 65 67 100 64 86 142 138 135 134 135 138 162 195 222 134 67 243 103 168 199 96 99 66 68 43 85 e.14 e.08 e295 e33 eS.S e2.9 e3.7 e4.7 e2.4 e8.7 e7.5 e4.5 e4.7 e4.8 eS.l e4.8 e8.8 e8.8 e5.7 e3.4 e2.0 314 9.6 163 55 7.1 16 e2.8 e3.1 el. 4 eS.S 996.72 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) ( (MG/L) (TONS/DAY) SEPTEMBER e!2 e!2 e20 e!3 e!2 e!2 ell e9.4 elO e9.3 e8.9 85 70 20 21 14 13 e21 elS e22 e38 e25 e28 e!7 elS e60 e23 e60 e28 e22 45 37 66 82 62 52 66 87 91 50 32 335 286 81 68 47 62 71 40 40 39 38 38 49 103 80 50 50 56 61 el. 4 el. 2 e4.4 e3.3 el. 9 el. 7 e2.0 e2.4 e2.6 el. 3 el. 2 208 126 4.5 4.3 1.7 2.2 e4.0 el. 4 e2.4 e4.0 e2.6 e2.8 e2.2 e4.2 e!3 e3.1 eS.l e4.2 e3.6 726.6 425.7 RIO GRANDE DE LOIZA BASIN 253 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGOAS, PR—Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE JUL 1997 28... AU6 22... DIS- CHARGE, INST. CUBIC FEET TIME PER SECOND (00061) 1002 287 1315 872 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1760 1940 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1370 4570 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 48 41 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 54 50 SED. SUSP. FALL DIAM. H FINER THAN .008 MM (70328) 58 56 DATE JUL 1997 28... AUG 22... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 70 71 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 81 81 SED. SUSP. SIEVE DZAM. % FINER THAN .062 MM (70331) 93 95 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 100 SED* SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 SED. SUSP. SIEVE DZAM. % FINER THAN 1.00 MM (70335) 100 100 254 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE NOV 1996 10... FEB 1997 03... AUG 03... 03... 19... 24... 25... SEP 13... TIME 1431 1528 1845 2300 1500 1830 0030 1645 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 30 26 391 218 8.1 877 223 SEDI- MENT, SUS- PENDED (MG/L) (80154) 122 398 900 2500 241 225 314 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 9.9 28 950 1470 5.3 533 189 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 96 99 98 100 86 96 99 304 1590 1300 99 RIO GRANDE DE LOIZA BASIN 50055250 RIO CAGUITAS AT HIGHWAY 30 AT CAGUAS, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°15'11", long 66°01'26", at Highway 30 bridge, and 0.8 mi (1.3 km) east of Caguas plaza. DRAINAGE AREA.—14.1 mi 2 (36.5 km2 ). PERZOD OF RECORD.—Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 255 DATE NOV 1996 07... PEB 1997 10... MAY 16... SEP 02... NOV 07 PEB 10 MAY 16 SEP 02 NOV 07 PEB 10 MAY 16 SEP 02 NOV 07 FEB 10 MAY DZS- PH OXYGEN, OXYGEN COLZ- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - INST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FZELD TEMPER- TOR- OXYGEN, (PER- ZCAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BZD- DZS- CENT (HIGH UM-MF (COLS. TZME PER ANCE ARD WATER ZTY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATZON) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0945 20 446 6.9 26.0 5.3 6.3 77 16 36000 4600 0850 19 499 6.7 22.5 14 4.0 45 19 K170000 27000 1025 14 509 6.8 26.5 72 3.5 43 65 47000 77000 0755 9.8 514 6.9 27.0 5.9 3.9 49 <10 K8100 2900 ALKA- HARD- MAGNE- SODIUM POTAS- LINZTY CHLO- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... ... DATE 1996 ... 1997 ... 16... SEP 02 K = ... NESS TOTAL (MG/L AS CACO3) (00900) 160 — 160 160 FLUO- RZDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.17 0.14 NZTRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.50 2.3 3.4 1.8 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 44 -- 43 44 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 28 — 29 36 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.2 3.1 3.6 2.2 SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- 13 13 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 274 — 307 314 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.2 14 16 9.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 25 -- 34 31 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 15.1 — 11.3 8.34 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.140 0.370 0.600 0.310 AD- SORP- TION RATIO (00931) 0.9 — 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 26 16 186 12 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.5 — 3.4 3.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.570 0.730 0.120 0.290 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 141 190 160 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.110 0.140 0.050 0.160 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 60 -- 40 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.680 0.880 0.170 0.450 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 43 — 52 39 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.330 1.70 2.00 1.00 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- 1 — RIDE, DIS- SOLVED (MG/L AS CL) (00940) 34 — 36 39 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.60 1.5 0.71 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — 20 — non-ideal count 256 RIO ORANDE DE LOIZA BASIN 50055250 RIO CAOUITAS AT BIOBMAY 30 AT CAOUAS, PR—Continued MATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 07... FEB 1997 10... MAY 16... SEP 02... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 960 780 320 210 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 20 <0.010 0.03 <0.01 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR 257 LOCATION.--Lat 18°15'32", long 66°02'24", Bydrologic Unit 21010005, on left bank, in the Bairoa Housing Area, 1.6 mi (2.6 Ion) northwest of Plaza de Caguas, 4.1 mi (6.6 Ion) east of Plaza de Aguas Buenas, and 0.9 mi (1.4 km) northwest of Escuela Pepita Garriga. DRAINAGE AREA.—5.08 mi 2 (13.15 km2 ). MATER-DISCHARGE RECORDS PERIOD OF RECORD.—November 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. Mean daily discharge affected by domestic discharge from nearby station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEE MAR MAY JUN JUL AUG SEP 1 ell e7 . 0 2 elO e8.0 3 ell e6.2 4 e9.8 e6.4 5 e9.4 e6.2 6 e9.0 e6.2 7 e9.0 elO 8 e9.4 e9.6 9 ell e7 . 2 10 e20 e6.0 11 ell e25 12 e8.4 e47 13 e8.0 e30 14 e8.0 e!2 15 e8.2 e9.4 16 e7.4 e8.2 17 e7 . 0 elO 18 e7 . 0 e8 . 0 19 e7.2 e8.8 20 e6.6 e8.6 21 e6.4 e!6 22 e6.2 elO 23 e6.0 e8.4 24 e5.6 e7.4 25 e5.4 e6.8 26 e8.8 e6.4 27 ell e6.0 28 e7.8 e7.4 29 e6.4 e6.6 30 e6.2 e9.2 31 e6.4 TOTAL 264.6 324.0 MEAN 8.54 10.8 MAX 20 47 MIN 5.4 6.0 AC-FT 525 643 CFSM 1.68 2.13 IN. 1.94 2.37 e9.0 e7.0 e6.2 e5.8 e5.8 e6.2 e8.6 e6.0 e5.6 e5.2 e39 ell elO e8.6 e7.6 e7.4 e7.0 e6.6 e6.2 e6.0 e6.0 e5.6 e5.8 e6.1 e6.0 e5.8 e6.0 e5.6 elO e!5 e8.0 254.7 8.22 39 5.2 505 1.62 1.87 67.4 68.0 ell 69.2 68.4 68.0 67.8 67.6 67.4 e7.4 e!7 e9.0 e8.0 e7.4 e7.4 e7.0 e7.2 e7.3 e7.4 613 e22 e32 e9.8 e9.4 68.6 67.6 66.2 69.0 67.0 66.2 66.0 296.7 9.57 32 6.0 589 1.88 2.17 e!9 622 e9.0 e7.6 e7.4 67.2 67.0 66.4 69.8 67.2 68.2 68.0 e!4 elO e8.2 e8.0 e7.0 e6.2 e6.6 e6.4 a9.2 a8.6 a9.2 66.8 e7.2 e8.2 e6.4 e6.0 —— —— 246.8 8.81 22 6.0 490 1.74 1.81 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1991 MEAN 9.61 10.1 MAX 25.3 22.2 (WY) 1991 1993 MIN 4.30 5.71 (WY) 1992 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 8.84 19.7 1993 4.63 1992 FOR 9.10 14.7 1996 4.12 1995 5.63 8.81 1997 3.42 1994 e5.6 e5.6 66.0 e6.0 65.8 65.8 65.4 65.8 65.8 65.4 64.9 65. 0 64.9 64.6 e6.6 67.2 65.2 65.2 65.4 64.8 64.6 64.3 64.2 64.2 63.9 63.9 63.9 64.7 e4.7 e4.3 e4.0 157.7 5.09 7.2 3.9 313 1.00 1.15 - 1997 4.31 5.53 1996 2.87 1994 1996 CALENDAR YEAR 5356.9 14.6 1700 2.9 3.1 10630 2.88 39.23 19 6.1 3.5 Sep 10 Jul 6 Jul 1 64.0 625 elO e7.8 66.6 66.0 65.4 65.4 65.4 65.0 65.6 65. 0 65.6 65. 1 64.9 e4.8 eS.O e4.8 e4.8 a4.6 e4.8 e4.6 e4.5 e4.5 64.5 e4.4 e4.7 64.8 e4.2 64.1 ___ 175.9 5.86 25 4.0 349 1.15 1.29 64.0 63.9 e3.9 63.9 a3. 8 63.8 63.9 64.4 64.0 67.0 e4.6 e5.6 a4.5 e4.1 e6.0 e5.8 e!9 e5.2 e4.4 e4.4 e4.7 e4.0 a3.9 e4.0 a3.9 e3.7 e5.6 e6.6 612 eS.O e6.2 168.8 5.45 19 3.7 335 1.07 1.24 e6.2 e!2 627 e9.0 e6.6 e6.0 e5.6 65. 0 64.9 64.6 65. 0 64.6 66.6 69.6 66.0 64.3 64.1 64.5 64.3 64.3 64.1 64.1 64.1 64.3 64.1 64.0 64.0 63.9 63.8 64.0 —— 180.6 6.02 27 3.8 358 1.19 1.32 63.7 a3. 4 63.3 63.3 63.3 63.2 63.3 63.8 63.7 63.5 63.3 63.4 63.5 63.3 63.2 63.5 63.3 a20 e24 elO 616 e!2 e5.4 e6.8 e4.7 e4.4 e5.6 e5.8 64.1 66.4 65. 0 188.2 6.07 24 3.2 373 1.20 1.38 e3.8 64.6 688 629 615 68.9 e7.8 e6.0 eS.O e7.4 e6.0 e5. 0 e4.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO a54 e8.1 e33 e!2 e7.6 e6.8 e5.6 eS.O e4.7 e5.4 371.6 12.0 88 3.8 737 2.36 2.72 e4.8 65.2 64.1 64.1 63.8 63.8 63.8 69.2 64.5 63.8 63.5 63.8 63.5 64.0 63.5 a4.9 4.2 5.6 3.4 4.7 10 6.9 5.0 3.6 3.3 10 6.7 7.8 6.6 5.5 153.6 5.12 10 3.3 305 1.01 1.12 , BY WATER YEAR (WY) 4.93 9.23 1996 2.61 1992 FOR 1997 2783 7 88 3 3 260 9 5520 1 20 11 6 3 6.05 12.5 1993 2.91 1994 WATER YEAR .2 .63 Aug 3 .2 Jul 6 .4 Jul 1 Aug 3 .25 Aug 3 .50 .38 .0 .9 5.28 8.64 1993 2.72 1995 8.06 16.5 1991 4.35 1994 WATER 8 14 4 1700 1 1 6190 18 6100 1 22 12 4 2 8.78 17.7 1996 4.09 1991 YEARS 1991 .42 .5 .52 Sep .3 Jul .6 Jun Sep .16 Sep .66 .51 .6 .8 20.3 76.9 1996 4.50 1991 - 1997 1996 1994 10 1996 2 1995 30 1995 10 1996 10 1996 e Estimated 258 RIO ORANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1991 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1991. REMARKS:-- Sediment samples were collected by a local observer on a weekly. During high flows events sediment samples were collected and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 7,040 mg/L September 10, 1996; Minimum daily mean, 2 mg/L Several years. SEDIMENT LOADS: Maximum daily mean, 37,900 tons (34,300 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.01 tonne) Several years. EXTREME FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 336 mg/L January 24, 1997; Minimum daily mean, 3 mg/L Several days. SEDIMENT LOADS: Maximum daily mean, 31 tons (28 tonnes) August 4, 1997; Minimum daily mean, 0.03 ton (0.03 tonne) Several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ell elO ell e9.8 e9.4 e9.0 e9.0 e9.4 ell e20 ell e8.4 eS.O e8.0 e8.2 e7.4 e7.0 e7.0 e7.2 e6.6 e6.4 e6.2 e6.0 e5.6 e5.4 e8.8 ell e7.8 e6.4 e6.2 e6.4 22 .67 18 12 14 18 12 7 4 3 17 24 17 13 11 11 10 17 34 39 42 .52 .35 .40 .47 .30 .17 .11 .09 .77 .99 .45 .28 .25 .23 .22 .34 .63 .76 .77 54 e.94 71 el. 2 84 el. 4 94 el. 5 77 el.l 57 el.l 42 el.l 35 e.86 44 e.83 53 e.90 49 e.83 e7.0 e8.0 e6.2 e6.4 e6.2 e6.2 elO e9.6 e7.2 e6.0 e25 e47 e30 e!2 e9.4 e8.2 elO eB.O e8.8 e8.6 e!6 elO e8.4 e7.4 e6.8 e6.4 e6.0 e7.4 e6.6 e9.2 ___ CONCEN- TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER e7.0 eS.O e6.2 e6.4 e6.2 e6.2 elO e9.6 e7.2 e6.0 e25 e47 e30 e!2 e9.4 e8.2 elO eB.O e8.8 e8.6 e!6 elO e8.4 e7.4 e6.8 e6.4 e6.0 e7.4 e6.6 e9.2 45 44 45 63 89 82 66 54 44 36 59 182 284 115 52 58 74 51 34 37 45 56 68 75 49 31 21 30 51 59 e.82 e.90 e.86 el.l el. 5 el. 4 el. 4 el. 4 e.99 e.63 e2.5 el 8 e29 e6.6 el. 5 el. 4 el. 8 el. 3 e.78 e.87 el. 5 el. 9 el. 7 el. 6 e.95 e.55 e.34 e.55 e.95 el. 2 e9.0 e7.0 e6.2 e5.8 e5.8 e6.2 e8.6 e6.0 e5.6 e5.2 e39 ell elO e8.6 •7.6 e7.4 e7.0 e6.6 e6.2 e6.0 e6.0 e5.6 e5.8 e6.1 e6.0 e5.8 e6.0 e5.6 elO elS eB.O 61 55 48 42 24 12 10 21 13 8 71 28 11 12 13 10 7 6 6 7 8 9 11 12 14 17 19 2? 49 103 82 el. 5 el. 2 e.86 e.68 e.38 e.20 e.20 e.41 e.21 e.12 e4.9 e2.3 e.30 e.30 e.29 e.20 e.13 e.ll e.10 e.ll e.13 e.14 e.16 e.20 e.23 e.26 e.31 e.36 el.l e3.5 e2.5 TOTAL 264.6 20.53 324.0 85.99 254.7 23.39 e Estimated RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 259 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e7.4 eS.O ell e9.2 e8.4 eS.O e7.8 e7.6 e7.4 e7.4 e!7 e9.0 eS.O e7.4 e7.4 e7.0 e7.2 e7.3 e7.4 e!3 e22 e32 e9.8 e9.4 e8.6 e7.6 e6.2 e9.0 e7.0 e6.2 e6.0 55 37 25 17 12 9 7 7 7 7 32 45 8 5 4 5 6 7 8 13 50 196 299 336 129 34 43 75 73 68 61 el. 2 .77 .63 .46 .29 .20 .15 .14 .14 .14 el. 2 el. 6 .18 .10 .08 .09 .11 .13 .17 .35 e2.5 e!5 e!5 e8.7 e3.2 e.74 e.79 el. 5 el. 6 el. 2 el.O e!9 e22 e9.0 e7.6 e7.4 e7.2 e7.0 e6.4 e9.8 e7.2 e8.2 eS.O e!4 elO e8.2 eS.O e7.0 e6.2 e6.6 e6.4 e9;2 e8.6 e9.2 e6.8 e7.2 e8.2 e6.4 e6.0 —— e!9 e22 e9.0 e7.6 e7.4 e7.2 e7.0 e6.4 e9.8 e7.2 e8.2 eS.O e!4 elO e8.2 eS.O e7.0 e6.2 e6.6 e6.4 e9;2 e8.6 e9.2 e6.8 e7.2 e8.2 e6.4 e6.0 55 49 43 26 14 16 22 42 65 28 10 9 10 11 13 16 18 18 20 44 101 64 29 42 82 88 76 50 el. 7 e2.7 el. 7 e.59 e.29 e.31 e.43 e.75 el. 4 e.66 e.21 e.19 e.29 e.37 e.33 e.34 e.36 e.33 e.35 e.77 e2.1 el. 5 e.70 e.89 el. 5 el. 8 el. 5 e.83 296.7 59.36 246.8 24.89 MEAN DISCHARGE (CFS) e5.6 e5.6 e6.0 e6.0 e5.8 e5.8 e5.4 e5.8 e5.8 e5.4 e4.9 eS.O e4.9 e4.6 e6.6 e7.2 e5.2 e5.2 e5.4 e4.8 e4.6 e4.3 e4.2 e4.2 e3.9 e3.9 e3.9 e4.7 e4.7 e4.3 e4.0 157.7 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 30 «.47 21 «.32 35 e.55 62 el.O 75 el. 2 79 «1.2 74 el.l 67 el.O 60 51 30 16 11 8 7 8 7 6 8 , 11 10 8 6 7 8 5 3 5 15 31 27 .94 .77 .41 .22 .14 .10 .11 .14 .12 .09 .12 .15 .13 .09 .07 .08 .09 .05 .03 .06 .19 .38 .30 11.62 e Estimated 260 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY}, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e4.0 e25 elO e7.8 e6.6 e6.0 e5.4 e5.4 e5,4 eS.O e5.6 eS.O e5.6 eS.l e4.9 e4.8 eS.O e4.8 e4.8 e4.6 e4.8 e4.6 e4.5 e4.5 e4.5 e4.4 e4.7 e4.8 e4.2 e4.1 ___ APRIL 23 e.25 78 e3.0 39 e2.1 10 9 9 9 10 9 8 9 10 11 10 9 14 27 25 17 11 5 3 5 13 14 12 15 18 9 6 .23 .18 .15 .14 .14 .13 .12 .13 .14 .15 .14 .12 .19 .37 .32 .21 .14 .07 .03 .06 .16 .17 .14 .20 .23 .10 .07 —— —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY e4.0 e3.9 e3.9 e3.9 e3.8 e3.8 e3.9 e4.4 e4.0 e7.0 e4.6 e5.6 e4.5 e4.1 e6.0 e5.8 e!9 e5.2 e4.4 e4.4 e4.7 e4.0 e3.9 e4.0 e3.9 e3.7 e5.6 e6.6 e!2 eS.O e6.2 5 8 17 37 68 111 83 49 38 31 28 33 41 40 38 54 89 53 51 73 50 27 23 22 22 21 20 22 23 21 17 e.05 e.08 e.18 e.39 e.71 el.l e.86 e.55 e.43 e.45 e.42 e.46 e.55 e.46 e.51 e.69 e2.5 el. 7 e.65 e.87 e.61 e.32 e.24 e.24 e.23 e.21 e.25 e.35 e.57 e.55 e.33 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE e6.2 e!2 e27 e9.0 e6.6 e6.0 e5.6 eS.O e4.9 e4.6 eS.O e4.6 e6.6 e9.6 e6.0 e4.3 e4.1 e4.5 e4.3 e4.3 e4.1 e4.1 e4.1 e4.3 e4.1 e4.0 e4.0 e3.9 e3.8 e4.0 ___ 14 13 28 83 19 15 16 19 19 19 14 9 9 10 11 12 10 9 10 12 11 9 8 7 7 9 12 11 8 19 e.24 e.30 el. 7 e4.1 e.41 e.25 e.26 e.26 e.26 e.25 e.18 e.12 e.13 e.21 e.22 e.16 e.12 e.ll e.12 e.13 e.12 e.10 e.09 e.09 e.08 e.10 e.13 e.ll e.09 e.26 175.9 9.58 168.8 17.51 180.6 10.70 e Estimated RIO ORANDE DE LOIZA BASIN 261 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) AUGUST DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) e3.7 e3.4 e3.3 e3.3 e3.3 e3.2 e3.3 e3.8 e3.7 e3.5 e3.3 e3.4 e3.5 e3.3 e3.2 e3.5 e3.3 e20 e24 elO el6 el2 e5.4 e6.8 e4.7 e4.4 e5.6 e5.8 e4.1 e6.4 eS.O JULY 18 10 12 12 10 9 8 7 10 5 5 6 7 5 3 17 10 10 54 82 26 17 13 9 7 7 10 16 77 319 203 TOTAL 188.2 —— YEAR e 2783.2 Estimated e.18 e.09 e.ll e.10 e.09 e.08 e.07 e.08 e.10 e.05 e.05 e.05 e.06 e.04 e.03 e.16 e.09 6.13 e2.3 e3.8 6.87 6.64 e.28 6.15 e.10 e.09 6.13 e.25 e.96 64.6 e3.2 18.93 394.98 MEAN DISCHARGE (CFS) 63.8 64.6 688 629 e!5 e8.9 e7.8 e6.0 eS.O e7.4 66.0 65.0 64.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO e54 68.1 e33 e!2 e7.6 e6.8 e5.6 eS.O 64.7 65.4 371.6 e3.8 e4.6 e88 e29 e!5 e8.9 e7.8 e6.0 eS.O e7.4 e6.0 eS.O e4.3 4.1 3.9 3.9 4.6 4.4 3.9 3.8 elO e54 e8.1 e33 e!2 e7.6 e6.8 e5.6 eS.O e4.7 e5.4 78 47 208 174 25 6 4 4 5 7 9 13 23 18 9 8 18 13 5 4 19 162 86 37 96 18 14 17 15 12 10 e.93 e.54 e26 e31 el. 5 e.20 e.09 e.08 e.07 e.ll e.15 e.19 e.28 e.20 e.10 e.08 e.24 e.16 e.05 e.04 e.41 e!4 e8.4 e2.7 e6.1 e.48 e.26 e.28 e.22 e.16 e.13 MEAN DISCHARGE (CFS) k>i e4.8 e5.2 e4.1 e4.1 e3.8 e3.8 e3.8 e9.2 e4.5 e3.8 e3.5 e3.8 e3.5 e4.0 e3.5 e4.9 4.2 5.6 3.4 4.7 10 6.9 5.0 3.6 3.3 10 6.7 7.8 6.6 5.5 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 8 .11 6 5 5 4 4 3 11 23 4 13 81 88 56 37 .09 .06 .05 .04 .04 .03 .24 .44 .04 .12 .81 .86 .57 .37 29 e.36 24 .27 49 1.0 22 .21 27 .48 57 2.2 36 .93 31 .44 11 .11 9 .08 107 4.7 42 .77 46 1.3 24 .47 10 .14 95.15 153.6 17.33 262 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 24... NOV 13... JAN 1997 28... FEE 09... MAY 06... JUL 30... AUG 04... SEP 26... TIME 1545 1640 1633 1118 1610 1530 1245 1700 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) e5.6 e30 e9.0 e9.8 83.8 e6.4 e29 14 SEDI- MENT, SUS- PENDED (MG/L) (80154) 99 302 854 81 129 458 95 212 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) el. 5 825 e21 e2.1 el. 3 e7.9 e7.4 8.0 SED. SUSP. SIEVE DIAM. «6 FINER THAN .062 MM (70331) 96 98 99 91 99 100 96 98 e Estimated RIO ORANDE DE LOIZA BASIN 263 50055400 RIO BAIROA NEAR CAGUAS, PR MATER-QUALITY RECORDS LOCATION.—Lat 18°15'28", long 66°02'13", at bridge on Highway 1, about 2.5 mi (4.0 km) upstream from Rio Orande de Loiza, and 1.4 mi (2.3 km) north of Caguas plaza. DRAINAGE AREA.—5.4 mi' (14.0 km2 ). PERIOD OF RECORD.—Water years 1958, 1962-66, 1973-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PB OXYGEN, OXYGEN COLI- CHAROE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CBEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. HATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1200 -- 386 7.0 25.5 4.5 8.4 101 <10 2700 7200 .997 1035 6.1 395 6.7 23.0 1.2 5.1 57 14 21000 2200 1100 3.1 482 7.0 26.0 20 2.8 34 11 K7100 670 0930 2.8 454 6.8 27.0 17 3.2 40 <10 K63000 2800 ALKA- DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 150 — 160 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.21 0.16 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.83 0.76 1.2 0.80 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 — 39 39 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 27 -- 31 30 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.1 1.9 2.3 1.9 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 14 -- 16 15 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 238 — 283 263 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 9.4 8.6 10 8.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 23 — 26 25 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) -- — 2.34 1.97 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.340 0.270 0.380 0.310 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 20 6 30 25 ARSENIC TOTAL (UG/L AS AS) (01002) 2 __ <1 -- POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.8 _- 4.4 4.1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.20 1.10 0.890 0.980 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 __ <100 — LINXTY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 142 180 190 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.100 0.180 0.100 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 1.20 1.10 1.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 _- <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 — 15 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.200 0.330 0.800 0.260 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 2 — 1 -- CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 31 -- 38 35 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.62 0.43 0.45 0.54 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — 10 — K » non- ideal count 264 RIO GRANDE DE LOIZA BASIN 50055400 RIO BAIROA NEAR CAGUAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 07... FEB 1997 10... MAY 20... SEP 02... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UQ/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 660 510 150 <0.10 130 <0.10 <1 <1 <1 <1 20 <0.010 10 <0.010 0.05 0.03 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR 265 LOCATION.--Lat 18°14'02", long 65°53'07", Hydrologic Unit 21010005, on left bank, 2.43 ml (3.91 km) northeast of Plaza de Juncos, 1.3 mi (2.1 km) southeast of Escuela La Placita and 0.35 ml (0.56 km ) southwest of El Mango. DRAINAGE AREA.--22.3 mi 2 (57.8 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—March 1990 to current year. GAGE.--Water-stage recorder. Elevation of gage is 230 ft (70 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Low-flow is affected by sewage discharges from a water treatment plant, 0.60 mi (0.96 m) upstream from gaging station since 1990. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT JAN MAR APR JUL AUG SEP 1 20 28 2 18 51 3 17 22 4 22 19 5 21 19 6 17 30 7 25 414 8 21 46 9 22 40 10 41 26 11 31 132 12 19 506 13 17 231 14 16 43 15 15 30 16 15 32 17 14 47 18 13 45 19 13 70 20 13 43 21 12 40 22 12 57 23 12 39 24 12 60 25 20 34 26 49 21 27 32 18 28 37 19 29 51 18 30 19 39 31 15 —— TOTAL 661 2219 MEAN 21.3 74.0 MAX 51 506 MIN 12 18 AC-FT 1310 4400 CFSM .96 3.32 IN. 1.10 3.70 STATISTICS OF MONTHLY MEAN MEAN 43.7 66.7 MAX 161 109 (WY) 1991 1992 MIN 4.01 13 . 6 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 31 27 22 20 19 18 17 17 16 16 38 27 18 16 15 16 16 15 14 14 14 14 14 13 15 14 15 16 29 46 27 609 19.6 46 13 1210 .88 1.02 17 15 14 13 12 12 12 13 14 12 12 11 10 10 9.8 9.5 9.1 8.8 8.8 13 23 elOS 632 633 620 el2 e9.7 619 615 68.4 68.6 521.7 16.8 105 8.4 1030 .75 .87 DATA FOR WATER 29.8 59.0 1991 12.0 1994 FOR 38.8 103 1996 6.34 1995 6270 6210 656 616 621 652 639 624 628 625 620 621 668 640 626 el 8 621 e!7 e!7 e!4 621 623 647 e!7 626 628 e!3 11 ___ ___ —— 1189 42.5 270 11 2360 1.90 1.98 YEARS 1990 32.3 66.7 1995 10.4 1993 11 11 15 19 17 13 12 12 13 11 10 11 11 10 10 12 12 11 11 9.9 9.5 9.6 9.1 8.8 8.6 8.6 8.0 8.5 13 11 9.5 346.1 11.2 19 8.0 686 .50 .58 - 1997 12.1 18.1 1991 5.63 1993 1996 CALENDAR YEAR 20769. 56. 4040 4. 5. 41200 2. 34. 80 15 5. 5 7 Sep 10 1 Aug 13 1 May 24 54 65 7 9.5 53 39 10 8.0 7.8 6.9 6.7 6.5 6.3 6.0 6.1 6.2 6.1 6.1 5.8 5.8 5.8 5.7 5.7 5.6 5.5 .9 .8 .8 .9 .8 5.2 5.3 5.0 --- 263.8 8.79 53 4.8 523 .39 .44 .6 .6 .4 .1 .2 4.3 5.8 16 13 13 8.3 6.8 6.8 12 8.0 7.4 7.6 7.2 6.0 6.2 6.6 5.8 5.4 5.1 5.3 5.0 6.3 16 8.9 16 8.0 238.7 7.70 16 4.1 473 .35 .40 7.2 10 23 12 8.7 7.2 6.7 6.3 6.4 6.1 5.6 5.2 5.0 4.8 5.7 4.8 5.5 8.2 16 33 41 49 156 216 150 56 9.5 7.3 6.6 6.4 885.2 29.5 216 4.8 1760 1.32 1.48 5.6 5.4 4.8 4.5 4.3 4.8 5.0 4.9 6.5 8.0 6.4 5.1 6.5 5.9 6.3 7.1 7.8 8.8 8.2 40 171 95 35 23 11 18 13 72 24 76 21 714.9 23.1 171 4.3 1420 1.03 1.19 14 10 14 14 10 7.6 6.3 6.3 69.3 632 612 ell 620 613 68.0 632 613 670 618 elO 646 6440 646 6650 670 e!6 ell 619 e!4 67.0 638 1687.5 54.4 650 6.3 3350 2.44 2.82 e!3 e!2 e8.5 67.5 67.3 6.7 6.2 6.1 7.1 5.7 5.0 6.1 6.9 8.3 27 9.5 6.3 8.0 5.8 4.7 7.9 11 18 8.0 5.8 308 39 14 18 46 643.4 21.4 308 4.7 1280 .96 1.07 , BY WATER YEAR (WY) 8.62 11.0 1993 5.29 1995 FOR 1997 9979 27 650 4 4 3570 15 19790 1 16 46 13 5 26.7 123 1992 4.83 1990 WATER YEAR .3 .3 Aug 24 .1 May 4 .5 Apr 30 Nov 12 .79 Nov 12 .23 .65 .6 48.9 117 1992 14.7 1991 48.9 147 1993 6.74 1994 WATER 40. 52. 22. 4040 1. 1. 19100 24. 29200 1. 24. 69 11 4. 35.8 54.4 1997 10.2 1993 YEARS 1990 3 3 0 Sep 1 Oct 4 Oct Sep 12 Sep 81 55 4 77.1 189 1996 21.4 1997 - 1997 1992 1994 10 1996 27 1992 22 1992 10 1996 10 1996 e Estimated 266 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water year 1990 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: March 1990 to current year. INSTRUMENTATION.—USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,490 mg/L September 10, 1996; Minimum daily mean, 2 mg/L May 5,1997. SEDIMENT LOADS: Maximum daily mean, 17,900 tons (16,200 tonnes) September 10, 1996; Minimum daily mean, 0.05 ton (0.3 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 775 mg/L November 07, 1996; Minimum daily mean, 2 mg/L May 5, 1997. SEDIMENT LOADS: Maximum daily mean, 1,880 tons (1,710 tonnes) January 22, 1997; Minimum daily mean, 0.90 ton (0.82 tonne) May 5, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 20 18 17 22 21 17 25 21 22 41 31 19 17 16 15 15 14 13 13 13 12 12 12 12 20 49 32 37 51 19 15 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 20 18 17 22 21 17 25 21 22 41 31 19 17 16 15 15 14 13 13 13 12 12 12 12 20 49 32 37 51 19 15 88 85 83 91 105 109 110 111 112 117 98 58 47 45 43 42 40 42 86 172 247 313 238 167 126 141 74 107 135 59 35 137 144 149 148 157 85 125 45 35 27 17 9.1 13 17 47 63 40 58 35 72 376 425 368 219 163 65 50 23 38 85 52 28 51 22 19 19 30 414 46 40 26 132 506 231 43 30 32 47 45 70 43 40 57 39 60 34 21 18 19 18 39 47 92 41 34 35 58 775 91 72 54 251 640 436 83 51 57 89 87 125 91 72 103 74 122 61 39 33 33 33 69 75 37 16 29 14 39 720 91 38 40 208 423 476 77 27 48 39 158 287 202 92 181 116 76 73 45 37 17 28 35 MEAN DISCHARGE (CFS) DI 31 27 22 20 19 18 17 17 16 16 38 27 18 16 15 16 16 15 14 14 14 14 14 13 15 14 15 16 29 46 27 MEAN CONCEN- TRATION (MG/L) SCEMBER 60 45 41 38 35 34 33 32 31 30 67 49 36 30 28 27 27 26 26 25 25 25 26 26 26 26 27 28 52 83 51 SEDIMENT DISCHARGE (TONS/DAY) 73 64 40 21 41 37 50 25 40 40 75 28 11 29 28 37 23 16 14 13 14 14 19 18 11 31 31 14 21 84 31 TOTAL 661 3287.1 2219 3744 609 993 RIO ORANDE DE LOIZA BASIN 50055750 RIO ODRABO BELOW EL MANGO, PR—Continued 267 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) DISCHARGE (CTS) MEAN ___ CONCEN • 8EPIJUBNT TRATION DISCHARGE (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL 17 15 14 13 12 12 12 13 14 12 12 11 10 10 9.8 9.5 9.1 8.8 8.8 13 23 •105 •32 •33 •20 •12 •9.7 •19 •15 •8.4 •8.6 521.7 JANUARY 31 26 25 23 22 21 20 24 26 22 21 20 19 18 17 17 16 16 17 24 41 205 58 58 37 21 19 37 24 20 16 12 11 11 23 12 11 8.4 17 8.8 5.2 18 7.0 11 22 19 15 14 10 11 17 101 •1880 •163 •106 •67 •29 •28 •53 •29 •23 •19 2761.4 •270 •210 •56 •16 •21 •52 •39 •24 •28 •25 •20 •21 •68 •40 •26 •18 •21 •17 •17 •14 •21 •23 •47 •17 •26 •28 •13 11 FEBRUARY 299 306 58 31 35 71 56 42 39 37 36 36 83 58 44 39 35 31 28 26 31 37 56 24 16 10 9 8 •113 •174 •41 •28 •36 •68 •38 •22 •19 •39 •37 •40 •78 •50 •21 •31 •22 •18 •19 •22 •31 •30 •27 •17 elO 1189 •9.6 •8.5 7.1 1056.2 i TO SEVTEM MEAN DISCHARGE (CFS) 11 11 15 19 17 13 12 12 13 11 10 11 11 10 10 12 12 11 11 9.9 9.5 9.6 9.1 8.8 8.6 8.6 8.0 8.5 13 11 9.5 BER 1997 MEAN CONCEN- TRATION (MG/L) MARCH 8 8 17 69 36 16 11 24 25 7 8 14 8 8 12 15 11 7 7 8 10 11 10 12 16 21 19 16 19 26 24 SEDIMENT DISCHARGE (TONS/DAY) 2.8 2.0 13 60 26 11 11 8.3 5.7 4.5 7.9 11 6.7 7.4 7.5 13 9.2 4.8 5.6 5.8 5.3 2.9 6.2 8.7 13 19 18 7.8 7.6 14 17 346.1 342.7 e Eitinated 268 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGEE TRATION DISCHARGE DAY (CFS) (M6/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.5 53 39 10 8.0 7.8 6.9 6.7 6.5 6.3 6.0 6.1 6.2 6.1 6.1 5.8 5.8 5.8 5.7 5.7 5.6 5.5 4.9 4.8 4.8 4.9 4.8 5.2 5.3 5.0 APRIL 25 99 111 27 13 11 11 10 9 8 7 8 10 14 21 15 8 7 10 14 18 17 16 18 22 22 20 12 6 5 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MAY 17 68 37 20 7.6 4.1 2.0 6.3 7.1 7.4 6.6 3.0 1.9 2.4 12 13 6.7 7.4 3.6 3.3 6.6 6.3 14 15 10 4.0 19 8.0 3.3 4.2 —— .6 .6 .4 .1 .2 4.3 5.8 16 13 13 8.3 6.8 6.8 12 8.0 7.4 7.6 7.2 6.0 6.2 6.6 5.8 5.4 5.1 5.3 5.0 6.3 16 8.9 16 8.0 6 5 4 3 2 4 8 28 23 25 11 9 8 17 11 10 10 9 8 10 11 10 10 9 9 9 11 35 16 29 13 4.5 4.2 2.3 1.2 .90 2.3 5.5 16 6.9 18 6.2 6.0 7.4 8.6 9.3 6.8 2.7 6.2 6.9 4.1 2.8 2.1 3.4 4.2 4.4 6.5 7.5 7.2 6.1 8.9 2.2 7.2 10 23 12 8.7 7.2 6.7 6.3 6.4 6.1 5.6 5.2 5.0 4.8 5.7 4.8 5.5 8.2 16 33 41 49 156 216 150 56 9.5 7.3 6.6 6.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 21 37 42 25 32 48 30 15 18 24 17 11 11 12 12 13 13 12 27 40 26 45 289 168 36 24 28 34 29 24 2.0 3.4 11 21 24 35 14 2.9 6.6 3.3 7.1 2.3 1.2 1.1 1.0 1.6 2.6 2.0 2.4 3.5 2.0 6.4 174 41 3.7 2.4 2.3 2.8 2.6 2.4 263.8 326.8 238.7 181.30 885.2 387.6 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 269 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 5.6 5.4 4.8 4.5 4.3 4.8 5.0 4.9 6.5 8.0 6.4 5.1 6.5 5.9 6.3 7.1 7.8 8.8 8.2 40 171 95 35 23 11 18 13 72 24 76 21 JULY 20 17 18 20 23 26 32 38 29 21 20 19 20 21 18 15 17 39 16 75 147 171 116 97 39 34 27 113 37 147 40 TOTAL 714.9 —— YEAR e 9979.3 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 10 12 9.3 3.8 2.5 2.6 3.1 7.7 5.8 2.1 4.4 2.9 2.0 2.0 5.9 2.9 2.5 8.5 4.4 13 41 51 25 35 12 3.9 2.8 54 29 76 28 465.1 14997.70 14 10 14 14 10 7.6 6.3 6.3 e9.3 e32 e!2 ell e20 e!3 e8.0 e32 e!3 e70 e!8 elO e46 e440 e46 e650 e70 e!6 ell e!9 e!4 e7.0 e38 1687.5 43 28 25 23 22 21 29 43 47 45 24 218 29 55 57 48 54 27 12 23 49 206 76 360 130 43 13 13 15 14 207 —— 26 9.1 6.6 2.6 2.2 3.7 6.0 11 e8.8 e8.5 e4.2 e!54 elS eSO e90 e36 e34 elS eS.S e22 e!7 e!67 eSl e88 e90 e24 elO ell e6.0 e3.8 e26 1004.0 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER e!3 e!2 e8.5 e7.5 e7.3 6.7 6.2 6.1 7.1 5.7 5.0 6.1 6.9 8.3 27 9.5 6.3 8.0 5.8 4.7 7.9 11 18 8.0 5.8 308 39 14 18 46—— 643.4 22 98 27 32 22 15 14 14 18 24 21 18 14 20 50 16 13 15 16 22 30 21 36 30 30 473 73 37 36 77 —— —— e4.9 e74 e35 e29 e!4 9.7 3.8 10 17 14 12 5.2 2.5 2.6 6.5 6.6 3.2 3.7 3.7 2.8 6.7 2.3 3.7 5.3 3.8 47 9.5 12 48 50—— 448.5 270 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE NOV 1996 07... AUO 1997 12... 31... SEP 02... TIME 0336 1470 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. PALL DIAM. % PINER THAN .002 MM (70326) SED* SUSP. PALL DIAM. * PINER THAN .004 MM (70327) SED. SUSP. PALL DIAM. * FINER THAN .008 MM (70328) 2215 1507 1651 ell e38 el2 5600 22200 1698 eSO 2560 e262 1810 e58 32 70 66 60 41 74 68 67 51 76 73 72 DATE NOV 1996 07... AUO 1997 12... 31... SEP 02... SED. SUSP. PALL DIAM. % PINBR THAN .016 MM (70329) 65 80 78 SED. SUSP. PALL DIAM. % PINER THAN .031 MM (70330) 78 86 84 86 SED. SUSP. SIEVE DIAM. % PINER THAN .062 MM (70331) 93 98 99 98 SED. SUSP. SIEVE DIAM. % PINER THAN .125 MM (70332) 98 99 100 99 SUSP. SIEVE DIAM. % PINER THAN .250 MM (70333) 99 100 100 100 SUSP. SIEVE DIAM. % PINER THAN .500 MM (70334) 100 100 100 100 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 e - estimate RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 271 DATE OCT 1996 24... NOV 07... 07... MAR 1997 20... JUN 30... JUL 24... TIME 1801 1245 1445 1830 1200 1200 DIS- CHARGE, XNST. CUBIC FEET PER SECOND (00061) 12 1234 361 9.6 6.3 56 SEDI- MENT, SUS- PENDED (MG/L) (80154) 2200 1270 1260 109 229 2010 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 71 4230 1230 2.8 3.9 304 SED. SUSP. SIEVE DIAM. «s FINER THAN .062 MM (70331) 14 94 99 98 76 99 272 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR LOCATION.—Lat 18°12'58", long 65°55'34", Hydrologic Unit 21010005, on left bank at Highway 919, 0.5 mi (0.8 km) upstream from Quebrada Don Victor, 1.7 mi (2.7 km) upstream from Rio Gurabo and 1.0 mi (1.6 km) south of Juncos. DRAINAGE AREA.—16.4 mi* (42.5 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1971 to current year. GAGE.—Water-stage recorder. Elevation of gage is 320 ft (98 m), from topographic map. REMARKS.—Records poor. Minor diversion from public water supply tank, 0.5 mi upstream, during low flow. Gage-height and precipitation satellite telemetry at station. EXTREMES OUTSIDE PERIOD OF RECORD.—Approximate discharges (no stages were recorded) of major floods are as follows: Sept. 6, 1960, 37,100 ftVs (1,050 m'/S), Oct. 9, 1970, 18,200 ftVs (515 mVs) . DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR MAY JUN JUL 1 38 e34 2 38 e68 3 36 e30 4 34 e25 5 37 e25 6 31 ellO 7 44 308 8 32 68 9 e34 49 10 e65 49 11 e44 161 12 e25 543 13 e23 203 14 e22 65 15 e20 58 16 e20 40 17 e!9 59 18 e!7 54 19 e!7 311 20 e!7 91 21 e!6 97 22 e!6 60 23 e!6 52 24 e!6 51 25 e30 36 26 e65 29 27 e42 24 28 e50 28 29 e68 29 30 e25 32 31 e20 TOTAL 977 2789 MEAN 31.5 93.0 MAX 68 543 MIN 16 24 AC-FT 1940 5530 CFSM 1.92 5.67 IN. 2.22 6.33 STATISTICS OF MONTHLY MEAN MEAN 71.6 87.1 MAX 293 461 (WY) 1986 1988 MIN 19.9 16.8 (WY) 1993 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 24 22 18 18 17 16 27 16 15 14 e!6 e!2 12 12 11 13 17 16 16 16 15 14 14 13 31 13 13 13 21 63 37 575 18.5 63 11 1140 1.13 1.30 16 14 13 12 13 11 10 10 10 10 e!9 9.6 8.8 8.9 8.8 8.2 7.6 7.5 7.8 13 21 128 17 26 12 12 9.8 15 8.8 6.7 6.9 481.4 15.5 128 6.7 955 .95 1.09 DATA FOR WATER 52.8 550 1988 11.0 1990 FOR 24.6 77.0 1992 11.4 1976 217 174 46 23 27 43 32 19 23 20 16 17 55 32 22 15 17 14 14 11 17 19 38 14 21 22 e!7 e9.0 —— 994.0 35.5 217 9.0 1970 2.16 2.25 YEARS 1971 19.5 47.9 1984 7.21 1974 e9.0 e9.0 e!3 e!6 e!4 ell 69.8 12 9.0 8.3 8.4 8.9 8.9 8.1 7.9 17 11 9.7 10 8.6 7.9 7.6 7.5 7.7 7.3 7.6 8.5 8.1 17 12 9.7 310.5 10.0 17 7.3 616 .61 .70 - 1997 18.5 39.7 1973 7.01 1977 1996 CALENDAR YEAR 24930. 68. 5000 4. 5. 49450 4. 56. 116 27 11 9 1 Sep 10 1 May 28 5 May 22 15 55 9.2 271 90 24 18 15 15 14 13 13 11 12 10 10 8.5 7.8 8.1 7.7 7.1 7.0 7.6 7.6 5.8 5.7 5.8 5.5 5.6 6.6 6.3 6.1 —— 634.0 21.1 271 5.5 1260 1.29 1.44 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 445.9 14.4 39 4.4 884 .88 1.01 20 25 37 20 15 11 8.4 8.0 8.0 6.9 8.3 6.1 9.9 5.6 5.0 4.4 4.3 3.9 8.2 7.9 4.9 4.4 50 48 12 11 7.8 5.8 5.0 4.8 —— 376.6 12.6 50 3.9 747 .77 .85 4.9 4.7 4.0 4.0 4.9 20 6.7 5.4 7.4 5.8 5.0 4.8 16 7.9 7.1 9.1 12 24 15 25 498 160 26 60 17 12 19 100 23 68 18 1194.7 38.5 498 4.0 2370 2.35 2.71 17 12 14 11 9.3 8.7 7.7 10 12 40 15 14 26 16 10 41 17 87 22 12 e62 6900 57 795 125 34 23 40 31 15 81 2564.7 82.7 900 7.7 5090 5.04 5.82 27 26 19 14 12 10 11 69 26 12 11 24 15 39 72 20 15 17 12 10 44 25 37 69 19 146 34 18 16 62 ___ 931 31.0 146 10 1850 1.89 2.11 , BY WATER YEAR (WY) 15.2 41.7 1985 5.17 1995 FOR 1997 12273 33 900 3 4 6290 12 24350 2 27 60 15 6 47.3 268 1985 5.02 1990 WATER YEAR .8 .6 Aug 22 .9 JUn 18 .6 Jun 29 Aug 24 .37 Aug 24 .05 .84 .5 51.6 188 1979 4.95 1994 47.8 163 1981 4.61 1994 WATER 48 121 17 9100 1 1 40000 25 35230 2 40 71 18 6 61.7 231 1979 4.71 1994 YEARS 1971 - .6 .1 Dec 8 .4 JUl 15 .7 JUl 10 Dec 8 .63 Dec 8 .97 .29 .9 83.6 255 1979 10.8 1987 1997 1988 1990 1987 1994 1994 1987 1987 e Estimated 273 RIO GRANDE DE LOZZA BASIN 50056400 RZO VALENCZANO NEAR JUNCOS, PR—Continued WATER-QUALITY RECORDS PERZOD OF RECORDS.— Water years 1983 to 1986 and water year 1989 to current year. PERZOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.— Automatic sediment sampler since 1984. REMARKS:— Sediment samples ware collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERZOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 8,340 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 263,000 tons (238,000 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) several days. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,300 mg/L February 1, 1997; Minimum daily mean, 5 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 6,930 tons (6,290 tonnes) August 24, 1997; Minimum daily mean, 0.06 tons (0.05 tonne) May 3, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 38 38 36 34 37 31 44 32 e34 e65 e44 e25 e23 e22 e20 e20 e!9 e!7 e!7 e!7 e!6 e!6 e!6 e!6 e30 e65 e42 eSO e68 e25 e20 36 36 35 32 56 37 152 157 72 24 18 18 18 17 18 21 24 28 33 39 45 53 62 72 109 222 58 134 286 98 34 3.7 3.6 3.5 3.0 6.1 3.1 21 13 e9.5 e4.2 e2.1 el. 6 el. 2 el.l el.O el.l el. 2 el. 3 el. 5 el. 8 el. 9 e2.3 e2.7 e3.1 e6.8 e39 e8.7 e!7 e46 e!4 el. 8 NOVEMBER e34 e68 e30 e25 e25 ellO 308 68 49 49 161 543 203 65 58 40 59 54 311 91 97 60 52 51 36 29 24 28 29 32 —— 48 170 225 140 128 488 1120 722 214 160 649 1040 664 307 304 179 272 142 896 480 425 170 39 131 145 76 74 118 131 103 —— e3.5 e25 e30 elO e8.6 e393 1560 137 29 25 386 2810 464 55 50 20 57 22 978 127 126 29 5.6 22 14 5.9 4.8 9.4 11 11—— DECEMBER 24 22 18 18 17 16 27 16 15 14 e!6 e!2 12 12 11 13 17 16 16 16 15 14 14 13 31 13 13 13 21 63 37 120 98 93 89 84 80 139 77 70 63 58 53 48 44 40 35 20 14 28 58 95 78 59 44 111 70 74 78 104 1230 192 7.8 5.8 4.7 4.2 3.9 3.5 12 3.4 2.8 2.4 e2.5 el. 9 1.6 1.4 1.2 1.3 .89 .61 1.2 2.5 3.9 3.0 2.2 1.6 11 2.5 2.6 2.9 6.6 290 26 TOTAL 977 227.9 2789 7428.8 575 417.90 e Estimated 274 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MO/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 16 14 13 12 13 11 10 10 10 10 •19 9.6 8.8 8.9 8.8 8.2 7.6 7.5 7.8 13 21 128 17 26 12 12 9.8 15 8.8 6.7 6.9 67 28 15 14 27 17 15 14 13 12 83 55 42 28 24 42 59 41 28 19 81 612 131 126 63 55 47 69 46 37 37 2.9 1.1 .53 .47 .93 .52 .41 .38 .35 .33 •4.4 1.4 1.0 .67 .56 .92 1.2 .83 .58 .65 8.4 410 6.3 12 2.1 1.7 1.3 3.2 1.1 .67 .68 (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CrS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) FEBRUARY 217 174 46 23 27 43 32 19 23 20 16 17 55 32 22 15 17 14 14 11 17 19 38 14 21 22 •17 •9.0 ... —— 1300 598 220 125 114 233 184 267 110 82 68 97 250 160 103 74 89 90 76 53 85 96 218 90 110 96 93 28 ... —— 2010 577 29 7.9 18 44 21 14 7.2 4.4 2.9 5.6 42 14 6.3 3.0 4.2 3.4 3.0 1.6 4.5 5.2 32 3.6 7.2 6.7 6.1 .68 —— MARCH •9.0 •9.0 •13 •16 •14 •11 •9.8 12 9.0 8.3 8.4 8.9 8.9 8.1 7.9 17 11 9.7 10 8.6 7.9 7.6 7.5 7.7 7.3 7.6 8.5 8.1 17 12 9.7 10 9 10 13 17 17 17 48 43 30 21 17 15 17 18 58 16 12 12 11 11 10 10 9 9 11 13 13 62 58 27 .25 .23 .29 .51 .67 .48 .42 1.8 1.1 .68 .47 .40 .37 .36 .38 3.6 .47 .32 .32 .26 .23 .21 .20 .19 .19 .23 .30 .28 4.9 1.9 .70 TOTAL 481.4 467.58 994.0 2884.48 310.5 22.71 • Estimated RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 275 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 ^ 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.2 271 90 24 18 15 15 14 13 13 11 12 10 10 8.5 7.8 8.1 7.7 7.1 7.0 7.6 7.6 5.8 5.7 5.8 5.5 5.6 6.6 6.3 6.1 APRIL 15 353 85 15 14 13 13 12 9 8 7 7 9 12 11 10 40 45 38 31 26 23 18 10 7 8 11 11 7 5 .36 1360 56 .99 .69 .54 .50 .44 .34 .27 .21 .22 .25 .33 .25 .21 .91 .94 .72 .60 .54 .47 .28 .16 .10 .12 .16 .20 .12 .08 —— MEAN DISCHARGE (CFS) 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 5.1 5.1 4.4 5.2 5.8 4.6 4.8 5.5 15 33 39 24 18 13 27 20 14 9.3 7.8 7.3 12 7.4 7.0 6.5 6.7 6.4 29 37 24 16 26 5 5 5 20 15 13 13 13 62 163 184 127 117 72 71 55 31 34 52 43 37 15 9 9 10 10 154 308 106 84 125 .07 .07 .06 .35 .24 .16 .17 .19 3.9 18 34 9.3 6.2 2.8 6.0 3.3 1.2 .85 1.1 .88 1.3 .30 .17 .16 .17 .17 83 64 9.2 3.8 14 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 20 25 37 20 15 11 8.4 8.0 8.0 6.9 8.3 6.1 9.9 5.6 5.0 4.4 4.3 3.9 8.2 7.9 4.9 4.4 50 48 12 11 7.8 5.8 5.0 4.8 104 175 101 94 54 70 54 36 27 21 36 31 48 24 13 7 6 7 28 36 25 21 375 213 40 18 15 13 11 9 7.2 13 11 5.5 2.4 2.0 1.2 .79 .58 .40 .95 .52 1.4 .37 .17 .09 .08 .07 .86 .77 .33 .24 142 39 1.3 .53 .31 .20 .14 .12 TOTAL 634.0 1427.00 445.9 265.11 376.6 233.52 276 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) .9 .7 .0 .0 .9 20 6.7 5.4 7.4 5.8 5.0 4.8 16 7.9 7.1 9.1 12 24 15 25 498 160 26 60 17 12 19 100 23 68 18 JULY 8 8 8 8 21 88 50 32 38 33 28 23 78 29 24 22 21 259 313 97 1140 329 93 223 51 42 89 346 123 284 91 TOTAL 1194.7 —— YEAR e 12273.8 Estimated MEAN DISCHARGE (CPS) MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) AUGUST .11 .10 .09 .09 .29 6.5 .93 .46 .83 .51 .38 .30 4.3 .63 .46 .54 .68 36 13 9.2 5020 236 6.8 62 2.4 1.4 5.0 182 8.5 78 4.4 5681.90 28585.81 17 12 14 11 9.3 8.7 7.7 10 12 40 15 14 26 16 10 41 17 87 22 12 e62 e900 57 795 125 34 23 40 31 15 81 2564.7 98 59 74 39 23 20 18 44 61 200 54 34 137 109 109 232 111 295 69 48 61 630 339 1030 414 90 96 126 211 303 392 —— 4.8 1.8 3.0 1.2 .58 .47 .38 1.2 2.1 26 2.3 3.6 14 5.4 3.0 44 5.8 93 4.1 1.5 e6.4 e937 58 6930 188 8.1 5.9 21 23 12 111 8518.63 SEPTEMBER 27 26 19 14 12 10 11 69 26 12 11 24 15 39 72 20 15 17 12 10 44 25 37 69 19 146 34 18 16 62 —— 931 105 95 106 36 11 8 8 360 131 17 15 105 92 198 220 17 15 103 138 86 281 140 139 298 105 372 158 54 43 261 —— —— 8.6 12 5.7 1.3 .33 .22 .23 307 12 .54 .43 13 4.2 33 64 .94 .59 5.3 4.5 2.3 51 10 17 77 5.6 281 16 2.7 1.8 72—— 1010.28 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 277 DATE NOV 1996 07... 12... 19... DEC 30... JAN 1997 22... FEB 01... MAY 27... JUL 21... 30... AUG 22... SEP 26... TIME 1400 1600 0545 0630 0710 1215 2245 1145 0734 1900 1325 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1270 195 658 39 284 1170 231 405 95 331 370 SEDI- MENT, SUS- PENDED (MG/L) (80154) 4510 2570 1850 6600 2270 9020 2200 1530 917 1490 928 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 15500 1350 3280 695 1740 28500 1370 1670 235 1330 927 SED. SUSP. FALL DIAM. «6 FINER THAN .002 MM (70326) 27 47 51 49 39 27 68 69 79 53 73 SED. SUSP. FALL DIAM. «6 FINER THAN .004 MM (70327) 42 52 55 57 46 33 74 76 85 62 81 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 58 78 66 67 59 39 82 80 88 71 86 DATE NOV 1996 07... 12... 19... DEC 30... JAN 1997 22... FEB 01... MAY 27... JUL 21... 30... AUG 22... SEP 26... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 65 79 77 79 68 50 88 88 91 82 89 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 74 88 83 86 76 64 90 89 93 85 93 SED. SUSP. SIEVE DIAM. 96 FINER THAN .062 MM (70331) 86 99 94 99 89 83 99 99 99 96 99 SED. SUSP. SIEVE DIAM. 96 FINER THAN .125 MM (70332) 96 100 98 100 96 93 99 99 99 98 100 SED. SUSP. SIEVE DIAM. «6 FINER THAN .250 MM (70333) 98 100 99 100 99 98 100 100 100 99 100 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 100 100 100 100 100 100 100 100 100 100 SED. SUSP. SIEVE DIAM. 96 FINER THAN 1.00 MM (70335) 100 100 100 100 100 100 100 100 100 100 100 278 RIO ORANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JTJNCOS, PR—Continued DATE NOV 1996 06... 11... 13... 13... 19... DEC 21... JAN 1997 22... 22... FEB 08... •TON 02... JUL 19... 24... AUG 30... SEP 08... 21... ni OATf ,T AND TIME 1700 0100 0545 0815 0230 0740 0610 0730 1720 0745 0715 1145 1548 2030 1740 L, WATER YEAR OCTOBER 1995 TO SEPTEMBER CLAY PERCENT OF SUSPENDED SEDIMENT DIS- SEDI- SED. CHARGE, INST. CUBIC FEET PER SECOND (00061) 678 278 367 387 492 15 161 434 18 19 13 220 14 218 61 SEDI- MENT, SUS- PENDED (MO/L) (80154) 1970 646 3860 1080 1290 105 1820 2820 291 232 524 658 313 1030 1050 MENT, DIS- CHARGE, SUS- PENDBD (T/DAY) (80155) 3610 485 3830 1130 1710 4.3 791 3300 14 12 18 391 12 606 173 SUSP. SIEVE DXAM. * FINER THAN .062 MM (70331) 91 96 94 95 92 97 94 94 98 99 99 93 99 95 99 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR 279 LOCATION.—Lat 18°15'30", long 65°58'05", Hydrologic Unit 21010005, on left bank, at bridge on Highway 181, 0.3 mi (0.5 km) east of Gurabo, and 4.5 mi (7.6 km) upstream from Rio Grande de Loiza. DRAINAGE AREA.--60.2 mi* (155.9 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--1958 (occasional low-flow measurements only), January to September 1959 (monthly measurements only), October 1959 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 131.58 ft (40.106 m) above mean sea level. Prior to Oct. 1, 1989 datum 5.0 ft (1.5 m) higher. REMARKS.--Records fair. Gage-height and precipitation satellite telemetry at station. Low flow affected by diversions for water supply about, 400 ft (121 m) upstream from station by PRASA. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN AUG SEP 1 78 74 2 73 135 3 68 66 4 74 54 5 72 46 6 63 134 7 81 804 8 76 167 9 93 101 10 153 82 11 113 344 12 71 1390 13 60 654 14 56 148 15 53 93 16 50 82 17 45 109 18 43 147 19 40 332 20 40 158 21 36 139 22 89 379 23 48 179 24 38 154 25 33 120 26 107 67 27 104 53 28 94 60 29 165 62 30 67 77 31 47 —— TOTAL 2230 6410 MEAN 71.9 214 MAX 165 1390 MXN 33 46 AC-FT 4420 12710 CFSM 1.19 3.55 IN. 1.38 3.96 STATISTICS OF MONTHLY MEAN MEAN 212 211 MAX 1414 1045 (WY) 1971 1988 MIN 16 . 0 23 . 7 (WY) 1968 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 88 67 50 44 41 35 41 33 29 28 83 62 34 28 26 29 28 25 24 22 24 24 23 23 33 27 24 37 48 132 83 1295 41.8 132 22 2570 .69 .80 46 34 32 26 24 26 22 25 29 24 32 22 21 19 20 19 19 17 17 30 64 365 94 100 77 31 22 24 43 25 20 1369 44.2 365 17 2720 .73 .85 613 208 99 39 48 68 64 65 54 62 50 50 91 67 60 47 44 43 42 45 48 57 52 37 35 37 36 25 ___ ___ —— 2186 78.1 613 25 4340 1.30 1.35 DATA FOR WATER YEARS 1960 148 863 1988 10.7 1968 FOR 61.5 204 1992 16.4 1968 47.2 131 1989 12.6 1968 26 24 28 35 31 30 24 24 26 24 22 21 22 22 21 22 26 24 25 21 20 19 18 17 17 17 17 16 18 30 22 709 22.9 35 16 1410 .38 .44 - 1997 38.6 97.5 1985 11.2 1965 1996 CALENDAR YEAR 64679.7 177 26200 3.7 5.2 128300 2.94 39.97 210 36 11 Sep 10 May 27 May 25 19 65 224 32 22 18 16 15 14 14 14 13 13 12 11 11 11 11 11 11 10 11 11 9.6 9.6 9.1 10 11 11 11—— 660.3 22.0 224 9.1 1310 .37 .41 10 9.7 9.7 9.8 10 10 9.9 16 20 31 29 24 16 20 24 21 22 18 15 13 16 13 12 11 11 12 12 43 21 26 20 535.1 17.3 43 9.7 1060 .29 .33 23 22 38 28 24 18 17 15 14 14 15 16 15 15 13 14 12 11 12 17 17 13 25 126 37 23 22 18 15 14 —— 663 22.1 126 11 1320 .37 .41 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 1551 50.0 377 11 3080 .83 .96 27 20 24 21 21 16 14 13 21 183 72 59 230 80 43 39 52 105 46 28 22 905 170 782 302 62 44 44 33 27 73 3578 115 905 13 7100 1.92 2.21 51 55 48 24 20 18 17 25 35 15 12 17 23 25 64 31 18 19 16 13 19 32 44 43 22 401 78 32 23 79 —— 1319 44.0 401 12 2620 .73 .82 , BY WATER YEAR (WY) 41.3 108 1978 13.1 1995 FOR 1997 22505 61 1390 9 9 6290 17 44640 1 13 106 27 12 141 746 1985 12.7 1990 WATER YEAR .4 .7 Nov 12 .1 Apr 26 .9 May 1 Nov 12 .42 Nov 12 .02 .91 130 468 1970 16.8 1972 114 376 1993 20.7 1994 WATER 129 286 42. 26200 3. 5. 62100 31. 93230 2. 29. 202 47 16 163 610 1979 24.8 1967 YEARS 1960 - 2 Sep 10 7 May 27 2 May 25 Sep 10 44 Sep 10 14 04 235 1225 1960 8.76 1967 1997 1979 1967 1996 1996 1996 1996 1996 280 RIO GRANDB DE LOIZA BASIN 50057000 RIO OORABO AT OURABO—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1985 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1983 to current year. INSTRUMENTATION.— USDH-48 and USD-77 sediment sampler, since 1984. Automatic sediment sampler, since 1984. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediments samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 9,220 mg/L Nov 27, 1987; Minimum daily mean, 3 mg/L August 09, 1994. SEDIMENT LOADS: Maximum daily mean, 686,000 tons (622,340 tonnes) Nov 27, 1987; Minimum daily mean, 0.08 tons (0.07 tonne) August 09, 1994. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,090 mg/L January 22, 1997; minimum daily mean, 4 mg/L December 10, 1996. SEDIMENT LOADS: Maximum daily mean, 4,790 tons (4,350 tonnes) November 12, 1996; minimum daily 0.22 tons (0.20 tonne) April 16, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 78 73 68 74 72 63 81 76 93 153 113 71 60 56 53 50 45 43 40 40 36 89 48 38 33 107 104 94 165 67 47 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 78 73 68 74 72 63 81 76 93 153 113 71 60 56 53 50 45 43 40 40 36 89 48 38 33 107 104 94 165 67 47 42 34 12 9 10 12 12 10 15 35 102 88 80 55 35 23 20 18 15 12 11 125 289 162 79 94 88 79 144 85 47 8.8 6.6 2.1 1.9 2.0 2.1 2.6 2.0 3.8 15 32 17 13 8.3 5.1 3.1 2.4 2.1 1.6 1.3 1.1 51 38 17 7.1 29 25 23 67 16 6.1 74 135 66 54 46 134 804 167 101 82 344 1390 654 148 93 82 109 147 332 158 139 379 179 154 120 67 53 60 62 77 NOVEMBER 155 121 102 41 28 104 578 148 87 75 276 782 555 123 53 53 70 131 397 150 126 213 150 117 101 52 29 39 26 54 DECEMBER 28 47 19 6.0 3.5 54 1810 73 26 18 515 4790 1290 51 13 12 35 55 442 65 52 380 75 52 34 9.6 4.1 6.6 4.5 14 88 67 50 44 41 35 41 33 29 28 83 62 34 28 26 29 28 25 24 22 24 24 23 23 33 27 24 37 48 132 83 41 26 22 18 13 9 22 16 7 4 57 34 26 23 20 18 16 11 8 7 6 6 6 5 16 23 21 32 42 87 69 10 4.8 3.0 2.2 1.5 .87 2.7 1.5 .56 .31 16 5.9 2.4 1.7 1.4 1.4 1.2 .77 .51 .41 .40 .38 .35 .32 1.7 1.7 1.4 3.3 5.8 38 16 2230 413.1 6410 9984.3 1295 128.48 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 281 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 46 34 32 26 24 26 22 25 29 24 32 22 21 19 20 19 19 17 17 30 64 365 94 100 77 31 22 24 43 25 20 MEAN CONCEN- TRATION (MO/L) JANUARY 39 24 16 11 12 19 11 18 11 10 11 9 12 16 10 9 9 10 11 14 32 1090 84 77 62 30 19 20 36 17 18 SEDIMENT DISCHARGE (TONS/DAY) 4.9 2.2 1.3 .78 .80 1.4 .65 1.2 .86 .62 .96 .56 .74 .85 .54 .46 .45 .46 .54 1.2 7.2 2040 22 22 14 2.5 1.1 1.8 4.8 1.1 .98 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 613 208 99 39 48 68 64 65 54 62 50 50 91 67 60 47 44 43 42 45 48 57 52 37 35 37 36 25 343 180 133 33 35 58 68 74 76 65 21 17 22 31 41 54 59 30 14 10 16 48 37 31 23 23 13 9 1500 138 37 3.5 4.8 11 13 14 11 11 2.8 2.3 5.5 5.5 6.5 6.9 7.0 3.4 1.6 1.2 2.6 7.4 5.2 3.1 2.2 2.4 1.3 .64 MEAN DISCHARGE (CFS) 26 24 28 35 31 30 24 24 26 24 22 21 22 22 21 22 26 24 25 21 20 19 18 17 17 17 17 16 18 30 22 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 9 8 7 6 7 9 11 13 16 18 13 8 10 17 32 54 50 42 26 15 11 9 7 7 8 8 9 10 13 57 27 .60 .52 .53 .59 .59 .70 .68 .86 1.1 1.2 .74 .46 .61 .99 1.8 3.3 3.5 2.7 1.8 .84 .58 .44 .35 .34 .36 .39 .40 .42 .65 4.6 1.6 TOTAL 1369 2138.95 2186 1810.84 709 34.24 282 RIO GRANDB DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 19 65 224 32 22 18 16 15 14 14 14 13 13 12 11 11 11 11 11 11 10 11 11 9.6 9.6 9.1 10 11 11 11 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) APRIL 20 47 359 167 108 69 44 27 16 9 14 26 41 20 8 7 9 14 24 37 25 14 12 12 12 13 17 12 13 13 —— MAY 1.0 92 320 15 6.5 3.3 1.8 1.1 .59 .35 .51 .88 1.4 .67 .23 .22 .26 .41 .71 1.1 .68 .40 .34 .31 .32 .31 .50 .36 .37 .37 10 9.7 9.7 9.8 10 10 9.9 16 20 31 29 24 16 20 24 21 22 18 15 13 16 13 12 11 11 12 12 43 21 26 20 13 16 19 24 34 48 38 28 19 25 22 21 17 16 17 20 14 10 10 9 13 10 9 9 9 11 13 34 18 22 18 .37 .41 .51 .63 .92 1.3 1.0 1.2 1.0 2.2 1.9 1.4 .77 .89 1.2 1.2 .83 .52 .38 .32 .55 .37 .28 .26 .28 .35 .40 4.6 1.1 1.6 .95 JUNE 23 22 38 28 24 18 17 15 14 14 15 16 15 15 13 14 12 11 12 17 17 13 25 126 37 23 22 18 15 14 40 21 21 26 28 27 24 22 22 24 34 50 51 46 42 41 46 49 29 15 17 25 38 209 148 69 82 47 21 15 2.5 1.3 2.2 2.0 1.8 1.4 1.1 .92 .84 .87 1.4 2.1 2.1 1.9 1.5 1.5 1.5 1.5 .89 .65 .75 .88 5.2 73 15 4.4 4.9 2.3 .87 .56 —— TOTAL 660.3 451.99 535.1 29.69 663 137.83 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 283 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 1551 22505.4 13 12 11 11 11 13 21 14 18 20 18 15 17 23 18 18 24 21 32 33 315 377 55 59 34 25 28 106 55 95 39 13 12 13 12 11 12 17 14 12 11 10 10 13 19 11 11 27 19 27 30 234 144 53 51 45 39 30 83 50 108 97 .44 .41 .39 .37 .32 .46 .93 .50 .58 .60 .51 .41 .66 1.2 .54 .55 1.8 1.1 2.4 3.0 463 339 7.9 9.8 4.1 2.7 2.3 42 8.3 34 10 27 20 24 21 21 16 14 13 21 183 72 59 230 80 43 39 52 105 46 28 22 905 170 782 302 62 44 44 33 27 73 69 38 25 14 11 9 9 10 16 223 243 48 229 219 132 38 58 102 106 79 56 608 137 602 408 294 150 32 27 23 86 5.1 2.2 1.7 .81 .62 .41 .36 .36 1.4 141 54 39 162 47 16 4.7 8.6 37 13 5.9 3.4 3530 76 3290 456 48 18 3.9 2.6 1.7 29 51 55 48 24 20 18 17 25 35 15 12 17 23 25 64 31 18 19 16 13 19 32 44 43 22 401 78 32 23 79 129 64 125 26 19 16 14 23 110 71 31 20 19 21 57 62 52 29 15 13 17 23 37 39 20 496 184 29 19 64 20 22 19 1.6 1.0 .77 .65 4.3 11 2.8 1.0 1.1 1.2 1.6 11 5.3 2.6 1.5 .65 .46 1.0 2.1 4.8 5.2 1.2 1340 36 2.5 1.2 18 940.27 25590.98 3578 7999.76 1319 1521.53 284 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR—Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE NOV 1996 07... AUG 1997 22... 22... SEP 26... DATE NOV 1996 07... AUG 1997 22... 22... TIME 0655 1515 1705 1905 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 63 69 74 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 2120 2580 3170 375 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 73 80 81 SEDI- MENT, SUS- PENDED (MG/L) (80154) 4450 2860 2050 2560 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 87 91 92 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 25500 19900 17500 2590 SED. SUSP. SIEVE DIAM. 9g FINER THAN .125 MM (70332) 97 97 96 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 35 35 45 34 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 41 44 54 40 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 52 55 64 48 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 26... 60 69 83 95 99 99 100 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 285 DATE OCT 1996 22... JAN 1997 22... APR 03... JUN 18... AUG 22... 22... 24... SEP 26... 26... TIME 1737 1535 1600 1545 1725 1930 2045 1222 1530 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 589 340 77 12 3180 2240 3950 843 1190 SEDI- MENT, SUS- PENDED (MG/L) (80154) 443 2960 240 53 1600 887 1430 1010 1010 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 704 2720 50 1.7 13700 5360 15200 2300 3240 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 100 99 98 94 97 92 87 97 286 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO NEAR GURABO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°15'56", long 65°59'04", at bridge on Highway 941, 1.2 mi (1.9 km) west-northwest from gaging station 50057000, and 1.0 mi (1.6 km) northwest of Gurabo plaza. DRAINAGE AREA.—62.8 mi 2 (162.7 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DZS- DEMAND, FORM, STREP - ZNST. CZFZC WHOLE SOLVED CHEM- FECAL, TOCOCCZ CUBIC CON- FZELD TEMPER- TUR- OXYGEN, (PER- ZCAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BZD- DZS- CENT (HZGH UM-MF (COLS. TZME PER ANCE ARD WATER ZTY SOLVED SATDR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATZON) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1300 E65 387 7.4 30.0 1.6 8.2 106 <10 3300 420 0800 E44 490 6.6 24.5 2.7 2.8 33 <10 41000 280 0830 29 323 6.5 27.0 12 3.8 48 12 2000 160 1105 E44 287 6.6 30.0 17 2.3 30 14 2900 510 ALKA- HARD- NESS TOTAL (MG/L AS CACO3) (00900) 130 — 92 83 FLUO- RZDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.15 0.15 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) — 0.82 0.80 0.84 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 32 — 21 20 SILICA, DZS- SOLVED (MG/L AS SZO2) (00955) 30 — 31 27 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 1.9 1.6 1.6 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 — 9.2 8.0 SOLZDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 244 — 192 174 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 0.73 8.6 7.3 6.9 SODIUM, DZS- SOLVED (MG/L AS NA) (00930) 30 — 25 20 SOLZDS, DZS- SOLVED (TONS PER DAY) (70302) E42.8 — 14.8 E20.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.230 0.200 0.200 0.520 SODIUM AD- SORP- TION RATZO (00931) 1 — 1 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 8 7 23 36 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.1 — 3.6 4.5 NZTRO- GEN, NZTRATE TOTAL (MG/L AS N) (00620) 1.10 1.10 0.730 0.660 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LZNZTY WAT WH TOT FET FZELD MG/L AS CACO3 (00410) 140 160 100 98 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.060 0.120 0.062 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 — <10 — SULFZDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, N02+NO3 TOTAL (MG/L AS N) (00630) 1.10 1.10 0.850 0.720 CADMIUM WATER UNPLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 — 15 14 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.240 0.430 0.270 0.120 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 33 — 27 21 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.49 0.40 0.53 0.72 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... DATE OCT 1996 09... FEB 1997 20... MAY 16... AUG 28... K - non-ideal count E - Estimated near station 50057000 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO NEAR GURABO, PR—Continued MATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 287 DATE OCT 1996 09... FEB 1997 20... MAY 16... AUO 28... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (U6/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 370 220 <1 <1 350 190 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 0.02 <0.01 288 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR LOCATION.--Lat 18°17'41", Ion? 66°02'44", Hydrologic Unit 21010005, at right bank, off road 798, upstream side of bridge on Highway 52, 0.5 mi (0.8 km ) northeast from Escuela Segunda Unidad de Francisco Valdes, and 0.8 mi (1.3 km) north of La Barra. DRAINAGE AREA.--7.53 mi 2 (19.50 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—March 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 164 ft (50 m), from topographic map. REMARKS.--Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC APR MAY JUN JUL SEP 1 20 11 2 18 8.6 3 9.5 13 4 9.1 9.5 5 8.8 11 6 8.7 9.2 7 8.6 13 8 8.3 8.9 9 8.2 7.6 10 8.1 11 11 8.2 19 12 9.6 38 13 8.6 29 14 7.9 12 15 7.4 9.4 16 7.4 8.4 17 7.3 18 18 7.3 9.2 19 7.4 7.4 20 7.4 6.9 21 7.3 18 22 7.2 65 23 7.0 17 24 6.7 15 25 6.7 11 26 24 9.2 27 9.4 11 28 46 10 29 11 10 30 9.7 21 31 9.5 TOTAL 330.3 447.3 MEAN 10.7 14.9 MAX 46 65 MIN 6.7 6.9 AC-FT 655 887 CFSM 1.41 1.98 IN. 1.63 2.21 15 13 11 11 10 9.4 8.8 8.4 8.3 8.4 10 8.7 8.4 8.0 8.0 8.4 8.1 8.0 7.8 7.8 8.0 7.6 7.7 8.6 8.7 38 14 18 30 19 14 360.1 11.6 38 7.6 714 1.54 1.78 STATISTICS OF MONTHLY MEAN DATA MEAN 15.1 14.0 MAX 39.4 36.2 (WY) 1991 1993 MIN 4.60 7.18 (WY) 1992 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 11.7 29.9 1993 5.55 1994 13 18 12 12 12 10 10 9.8 9.3 8.5 8.7 8.7 8.8 8.5 8.3 8.6 8.6 9.0 9.0 8.9 49 42 27 41 21 14 12 12 12 11 10 452.7 14.6 49 8.3 898 1.94 2.24 30 16 11 e!2 e!3 e!2 e!3 e9.4 e!4 e9.0 e9.4 9.5 9.8 10 9.0 8.6 8.5 9.0 9.2 9.4 14 10 8.9 8.8 8.9 8.7 8.4 8.3 ___ ___ 307.8 11.0 30 8.3 611 1.46 1.52 FOR WATER YEARS 1990 11.7 24.5 1992 4.48 1994 9.96 18.8 1995 4.29 1994 8.2 8.5 11 8.9 11 8.5 8.8 9.2 8.7 7.6 7.3 7.7 7.7 7.6 7.7 7.7 7.3 8.1 7.1 6.8 6.8 6.9 7.0 7.3 7.3 7.7 7.8 10 7.5 6.9 6.4 247.0 7.97 11 6.4 490 1.06 1.22 - 1997 5.26 7.97 1997 2.48 1994 FOR 1996 CALENDAR YEAR 6450.7 17.6 1670 2.1 3.3 12790 2.34 31.87 24 7.4 3.7 Sep 10 Apr 19 Mar 27 6.3 7.0 6.9 6.2 5.8 5.5 5.2 5.1 5.0 4.9 .6 .6 .6 .4 .5 .4 .3 .3 .2 .2 .2 .1 .0 3.9 3.8 3.7 3.8 3.8 3.7 3.6 140.6 4.69 7.0 3.6 279 .62 .69 3.6 3.4 4.2 3.8 3.5 3.4 3.3 3.3 3.4 3.4 3.4 3.6 4.1 3.5 3.4 3.8 3.6 3.3 3.1 3.1 5.3 3.3 4.4 4.4 3.3 3.2 3.3 3.8 3.2 3.2 3.1 110.7 3.57 5.3 3.1 220 .47 .55 2.8 2.7 3.1 2.7 2.7 2.8 2.7 2.7 2.7 2.6 2.6 2.7 2.5 2. 2. 2. 2. 2. 10 3.2 2.8 2.7 2.8 3.4 2.7 2.9 2.4 2.3 2.3 13--- 97.8 3.26 13 2.3 194 .43 .48 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 118.5 3.82 6.4 3.1 235 .51 .59 3.5 3.4 3.7 3.7 3.4 3.2 3.2 3.2 3.2 8.3 10 3.6 29 59 9.9 5.4 5.2 4.7 4.1 3.9 3.8 e382 7.6 7.7 6.1 3.7 4.9 3.5 3.2 6.2 3.8 606.1 19.6 382 3.2 1200 2.60 2.99 4.9 5.3 3.3 3.1 3.2 3.4 2.9 2.6 2.7 2.8 2.7 6.0 7.5 10 4.9 4.6 2.9 2.7 2.6 2.9 2.9 4.7 3.5 7.9 3.4 10 3.8 3.9 3.2 3.2 127.5 4.25 10 2.6 253 .56 .63 , BY WATER YEAR (WY) 5.57 11.1 1993 3.24 1995 FOR 1997 3346 9 382 2 2 2330 17 2 6640 1 16 13 7 3 8.69 19.5 1992 2.50 1994 WATER YEAR .4 .17 Aug 22 .3 Jun 28 .5 Jun 12 Aug 22 .88 Aug 22 .3 Jun 27 .22 .53 .3 .1 7.60 20.0 1993 1.78 1994 8.67 24.9 1993 3.40 1990 WATER 11. 17. 5. 1670 1. 1. 7500 24. 1. 8600 1. 21. 18 5. 2. 15.6 36.8 1996 4.36 1990 YEARS 1990 9 7 77 Sep 1 Jun 2 Jun Sep 60 Sep 0 Jun 58 42 1 6 22.4 81.6 1996 4.25 1997 - 1997 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 21 1994 e Estimated RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 to current year. PERIOD 07 DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1990. REMARKS:— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 12,9000 mg/L September 10, 1996; Minimum daily mean, 1 mg/L September 11,1991 and 1996 several days. SEDIMENT LOADS: Maximum daily mean, 95,000 tons (86,200 tonnes) September 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) January 08, 1995. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 2,220 mg/L January 21, 1997; Minimum daily mean, 3 mg/L May 3, 1997. SEDIMENT LOADS: Maximum daily mean,e3,030 tons (e2,750 tonnes) August 22, 1997; Minimum daily mean, 0.03 ton (0.03 tonne) several days. 289 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 20 18 9.5 9.1 8.8 8.7 8.6 8.3 8.2 8.1 8.2 9.6 8.6 7.9 7.4 7.4 7.3 7.3 7.4 7.4 7.3 7.2 7.0 6.7 6.7 24 9.4 46 11 9.7 9.5 MEAN CONCEN- TRATION (MG/L) OCTOBER 61 37 21 19 19 17 19 22 14 7 7 76 62 30 19 18 20 23 17 11 9 8 12 23 26 707 116 1690 97 31 61 SEDIMENT DISCHARGE (TONS/DAY) 3.2 1.6 .57 .47 .46 .40 .44 .49 .31 .16 .16 4.3 1.5 .65 .38 .35 .39 .46 .34 .22 .18 .15 .23 .41 .47 109 3.5 584 3.0 .81 1.7 MEAN DISCHARGE (CFS) 11 8.6 13 9.5 11 9.2 13 8.9 7.6 11 19 38 29 12 9.4 8.4 18 9.2 7.4 6.9 18 65 17 15 11 9.2 11 10 10 21—— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 'NOVEMBER 11 8.6 13 9.5 11 9.2 13 8.9 7.6 11 19 38 29 12 9.4 8.4 18 9.2 7.4 6.9 18 65 17 15 11 9.2 11 10 10 21 234 47 268 51 257 52 286 52 46 181 576 1680 942 139 40 23 596 57 31 30 1260 1740 305 201 70 29 98 90 84 451 9.7 1.1 20 1.3 11 1.3 24 1.3 .93 9.8 97 425 116 4.9 1.0 .52 83 1.5 .61 .55 203 1470 15 8.8 2.1 .72 4.5 3.3 2.6 43 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 15 13 11 11 10 9.4 8.8 8.4 8.3 8.4 10 8.7 8.4 8.0 8.0 8.4 8.1 8.0 7.8 7.8 8.0 7.6 7.7 8.6 8.7 38 14 18 30 19 14 240 197 176 161 157 155 126 63 56 59 82 88 40 17 8 7 8 6 4 4 4 5 5 42 153 1090 591 656 1190 451 146 13 6.8 5.1 4.6 4.3 4.0 3.0 1.4 1.2 1.3 2.3 2.1 .92 .38 .17 .16 .18 .14 .09 .09 .10 .10 .10 1.2 4.4 549 41 61 171 30 5.7 330.3 720.30 447.3 2563.53 360.1 914.83 290 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED {TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 13 18 12 12 12 10 10 9.8 9.3 8.5 8.7 8.7 8.8 8.5 8.3 8.6 8.6 9.0 9.0 8.9 49 42 27 41 21 14 12 12 12 11 10 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 57 337 103 27 83 97 35 16 8 6 5 5 4 6 7 6 5 36 51 57 2220 1480 629 1170 146 55 51 59 33 15 12 1.9 26 3.4 .85 3.3 2.7 .95 .44 .21 .14 .13 .11 .10 .13 .16 .14 .13 .90 1.2 1.4 467 245 97 155 8.7 2.1 1.6 1.9 1.0 .42 .34 MEAN DISCHARGE (CFS) 30 16 11 e!2 e!3 e!2 e!3 e9.4 e!4 e9.0 e9.4 9.5 9.8 10 9.0 8.6 8.5 9.0 9.2 9.4 14 10 8.9 8.8 8.9 8.7 8.4 8.3 MEAN CONCEN- TRATION (MG/L) FEBRUARY 834 293 40 32 49 40 25 33 66 36 17 12 10 56 92 84 77 70 63 57 246 126 84 48 26 16 10 10 SEDIMENT DISCHARGE (TONS/DAY) 254 26 1.2 e.85 el. 6 el. 4 e.89 e.98 e2.1 el.l e.42 .31 .27 1.7 2.2 2.0 1.8 1.7 1.6 1.5 11 3.5 2.0 1.1 .63 .37 .23 .23 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 8.2 8.5 11 8.9 11 8.5 8.8 9.2 8.7 7.6 7.3 7.7 7.7 7.6 7.7 7.7 7.3 8.1 7.1 6.8 6.8 6.9 7.0 7.3 7.3 7.7 7.8 10 7.5 6.9 6.4 12 14 108 23 108 73 22 16 13 12 15 20 21 20 10 5 7 46 23 7 5 5 5 7 9 11 12 239 65 9 8 .27 .32 3.5 .57 3.7 1.7 .52 .40 .31 .24 .29 .41 .44 .41 .20 .10 .13 1.1 .44 .13 .09 .09 .10 .13 .17 .22 .26 13 1.4 .17 .15 452.7 1024.35 307.8 322.68 247.0 30.96 e Estimated 291 RIO QRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CPS) 1 6.3 2 7.0 3 6.9 4 6.2 5 5.8 6 5.5 7 5.2 8 5.1 9 5.0 10 4.9 11 12 13 14 15 16 17 18 19 20 21 22 23 .6 .6 .6 .4 .5 .4 .3 .3 .2 .2 .2 .1 .0 24 3.9 25 3.8 26 3.7 27 3.8 28 3.8 29 3.7 30 3.6 31 APRIL 9 27 33 7 7 7 9 12 11 9 9 10 11 9 7 6 6 6 7 7 10 15 14 12 14 19 24 20 15 16 .15 .78 .69 .12 .11 .11 .13 .17 .14 .11 .11 .13 .14 .11 .08 .07 .07 .07 .07 .08 .12 .17 .15 .13 .14 .19 .25 .20 .15 .15 —— 3.6 3.4 4.2 3.8 3.5 3.4 3.3 3.3 3.4 3.4 3.4 3.6 4.1 3.5 3.4 3.8 3.6 3.3 3.1 3.1 5.3 3.3 4.4 4.4 3.3 3.2 3.3 3.8 3.2 3.2 3.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 17 18 25 18 9 5 7 11 10 7 6 6 13 7 4 3 4 4 4 4 26 14 64 45 23 18 20 23 23 22 20 .17 .17 .32 .18 .08 .04 .06 .10 .09 .07 .05 .06 .17 .06 .03 .03 .04 .04 .03 .03 .59 .13 2.0 1.1 .21 .16 .18 .23 .20 .19 .17 MEAN DISCHARGE (CFS) MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 2.8 2.7 3.1 2.7 2.7 2.8 2.7 2.7 2.7 2.6 2.6 2.7 2.5 2. 2. 2. 2. 2. 10 3.2 2.8 2.7 2.8 3.4 2.7 2.9 2.4 2.3 2.3 13 19 14 11 18 32 25 16 11 9 7 11 17 16 13 11 9 9 9 341 37 28 23 19 23 14 18 17 14 12 273 56 .14 .10 .09 .13 .23 .19 .12 .08 .06 .05 .08 .12 .11 .09 .07 .06 .06 .06 .32 .21 .17 .15 .26 .10 .15 .11 .09 .08 54 140.6 5.09 110.7 6.98 97.8 113.48 292 RIO GRANDS DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JULY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 TOTAL 118.5 YEAR e 3346.4 Estimated 4.7 3.7 3.6 3.5 3.5 3.5 3.5 3.5 3.3 3.3 3.3 3.4 3.3 3.2 3.1 3.2 3.2 4.4 6.4 4.6 5.1 4.4 4.0 3.8 4.6 3.8 3.6 4.1 3.7 3.6 3.6 38 25 19 15 12 10 8 7 6 6 8 24 61 22 6 5 7 20 103 31 68 19 13 12 13 13 13 27 15 10 15 .49 .25 .19 .14 .12 .09 .08 .07 .06 .06 .07 .23 .55 .19 .05 .05 .06 .30 4.3 .39 1.2 .23 .14 .13 .16 .13 .13 .33 .15 .10 .15 10.59 10134.18 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 3.5 3.4 3.7 3.7 3.4 3.2 3.2 3.2 3.2 8.3 10 3.6 29 59 9.9 5.4 5.2 4.7 4.1 3.9 3.8 .382 7.6 7.7 6.1 3.7 4.9 3.5 3.2 6.2 3.8 25 23 19 14 8 5 4 5 5 260 436 23 1530 1150 87 16 11 12 15 17 20 1420 81 129 66 15 80 14 12 72 25 .24 .22 .19 .14 .08 .04 .04 .04 .04 17 33 .22 398 785 3.6 .23 .15 .15 .16 .18 .21 B3030 1.8 3.8 1.3 .15 2.3 .13 .10 2.3 .26 606.1 4281.07 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 4.9 5.3 3.3 3.1 3.2 3.4 2.9 2.6 2.7 2.8 2.7 6.0 7.5 10 4.9 4.6 2.9 2.7 2.6 2.9 2.9 4.7 3.5 7.9 3.4 10 3.8 3.9 3.2 3.2 73 124 101 36 18 13 10 8 9 10 10 208 159 306 78 72 28 25 32 27 20 154 28 522 21 504 22 23 20 17 1.2 2.7 .91 .30 .16 .12 .08 .06 .06 .07 .07 6.3 14 15 1.2 1.0 .22 .19 .23 .21 .16 2.8 .29 32 .20 60 .22 .25 .17 .15 127.5 140.32 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT CANAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 293 DATE DEC 1996 28... AU6 1997 22... 22... SEP 24... TIME 1630 1245 1820 1630 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 34 2140 31 13 3040 279 8672 50200 1110 93 3380 119 41 30 60 59 52 39 69 68 65 47 70 76 DATE DEC 1996 28... AUG 1997 22... 22... SEP 24... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 75 57 81 83 86 65 83 88 94 77 95 99 98 85 97 100 100 96 99 100 100 99 100 100 100 100 100 100 294 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT CANAS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 28... NOV 22... 24... DEC 26... JAN 1997 22... FED 21... JUL 21... AUG 11... 13... 22... SEP 12... TIME 0944 1400 1005 2145 1630 1530 1100 1615 1745 1500 1630 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 11 1200 17 327 29 17 8.5 15 204 1300 12 SEDI- MENT, SUS- PENDED (MG/L) (80154) 510 16600 532 6870 470 485 663 1710 14900 5650 2380 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 15 53800 24 6060 37 22 15 69 8210 19900 77 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 77 71 99 79 95 96 98 99 95 83 100 295 RIO GRANDE DE LOIZA BASIN 50059000 LAGO LOIZA AT DAMSITE HEAR TRXJJILLO ALTO, PR LOCATION.--Lat 18°19'49", long 66°01'00", Hydrologic Unit 21010005, at pumpsite at damsite, and 1.9 mi (3.1 km) south of Trujillo Alto plaza. DRANAIGE AREA.--208 mi 3 (539 km») . ELEVATION RECORDS PERIOD OF RECORD.—December 1987 to current year. Prior to October 1994, published as Lago Loiza at Damsite. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lake is formed by Loiza Dam, a concrete structure completed in 1954. Useable capacity of impoundment is 30,000 acre-ft (37.0 hmj ). Out flow from lake is controlled by five slide gates in powerplant and pump intake structure, four sluice gates, and concrete spillway with eight radial gates. Lake is used for municipal water supply and intermittent power generation. Gage-height satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation 147.42 ft (44.93 m), Sept. 18, 1989; minimum elevation, 108.52 ft (33.08 m), July 18, 1994. EXTREMES FOR CURRENT YEAR.—Maximum elevation 135.44 ft (41.82 m), Feb. 02; minimum elevation, 112.76 ft (34.37 m), July 17. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 98.4 111.5 120.4 Contents in acre-feet 5,000 8,900 13,000 Elevation, in feet 128.6 137.8 147.6 Contents in acre-feet 18,000 26,000 35,000 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN CAL WTR 134.46 A 134.60 134.96 134.34 134.62 134.88 134.56 134.90 A 135.12 134.72 134.20 134.42 134.64 134.82 134.92 134.56 134.66 134.76 134.80 134.61 134.70 134.76 134.80 134.30 134.80 134.76 134.33 134.54 134.64 135.12 134.20 YR 1996 YR 1997 134.92 134.80 135.00 134.68 134.84 134.55 134.82 134.90 134.92 134.46 134.54 134.52 A A 134.40 134.86 134.76 134.04 134.10 134.90 134.20 133.27 134.24 133.60 134.18 134.50 134.78 134.18 134.50 134.20 —— 135.00 133.27 MAX 135.12 MAX 135.18 134.68 133.80 134.00 134.16 134.28 134.40 134.56 134.64 134.70 134.74 134.48 134.74 134.82 134.86 134.88 133.96 133.96 133.92 133.88 133.84 133.84 133.82 133.76 133.72 133.78 134.28 134.30 134.52 134.88 134.80 134.63 134.88 133.72 MIN 130 MIN 112 134.76 134.98 135.02 135.04 135.00 135.00 134.96 134.92 134.88 134.80 135.14 134.46 134.42 134.34 134.26 134.20 134.06 133.96 133.88 133.96 134.96 134.62 134.88 134.28 134.92 135.12 135.18 134.96 135.12 135.16 135.18 135.18 133.88 .07 .76 FEB 134.26 134.38 134.98 134.96 134.78 134.82 135.08 134.66 135.00 134.86 135.00 134.72 135.00 135.04 134.70 134.76 134.78 134.78 134.82 134.84 135.10 134.88 135.10 134.96 134.97 135.10 134.96 134.86 135.10 134.26 MAR 134.82 134.76 134.74 134.74 134.74 134.68 134.56 134.56 134.48 134.32 134.18 134.06 133.96 133.84 133.76 133.72 133.68 133.64 133.52 133.40 133.24 133.08 132.90 132.72 132.52 132.36 132.18 132.06 132.02 131.92 131.78 134.82 131.78 APR 131.62 133.42 135.10 134.92 134.84 134.70 134.54 134.36 134.14 133.94 133.76 133.56 133.38 133.18 132.96 132.74 132.48 132.26 132.04 132.02 131.74 131.44 131.16 130.86 130.56 130.24 129.94 129.58 129.26 128.92 135.10 128.92 MAY 128.56 128.20 127.94 127.56 127.19 126.80 126.41 126.10 125.84 125.78 125.84 125.76 125.70 A A A A A A 124.70 124.86 124.58 124.32 124.02 123.66 123.30 122.96 123.14 123.12 123.34 123.34 128.56 122.96 JUN 123.20 123.02 123.38 123.74 123.64 123.44 123.07 122.75 122.38 122.00 121.58 121.20 120.78 120.52 120.18 119.84 119.36 118.87 118.80 118.60 118.40 118.16 118.02 118.86 118.78 118.64 118.48 118.23 117.99 117.83 123.74 117.83 JUL 117.51 117.15 116.75 116.31 115.90 115.63 115.67 115.44 115.22 114.93 114.63 114.18 113.86 113.57 113.14 112.76 113.02 113.04 113.20 113.94 118.82 123.42 123.84 124.24 124.35 124.22 124.15 125.82 126.27 127.02 127.14 127.14 112.76 AUG 127.11 127.05 127.47 127.48 127.31 127.09 126.82 126.56 126.33 127.23 127.69 127.66 129.10 129.93 129.92 129.87 129.98 130.78 130.86 130.68 130.55 134.60 134.37 134.17 134.62 134.23 134.72 134.61 134.66 134.72 134.14 134.72 126.33 SEP 134.31 134.42 134.48 134.41 134.32 132.90 132.79 133.18 133.39 133.25 133.07 133.30 133.51 133.63 134.15 134.22 134.12 134.10 134.05 133.94 134.01 134.58 134.73 134.72 134.79 134.45 134.57 134.70 134.74 134.53 134.79 132.79 A No gage-height record 296 RIO GRANDE DE LOIZA BASIN 50059000 LAGO LOIZA AT DAMSITE, PR WATER-QUALITY RECORDS at pumphouse at damsite, and 1.9 ml (3.1 km) south of Trujillo Alto LOCATION.—Lat 18°19'49", long 66°01'00 plaza. DRAINAGE AREA.--208 ml 2 (539 km*). PERIOD OF RECORD.—Water years 1974 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 02... PB OXYGEN, OXYGEN COLI- ALKA- SPE- WATER DIS- DEMAND, FORM, STREP- LINITY CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI HAT WH CON- FIELD TEMPER- OXYGEN, (PER- ICAL 0.45 FECAL, TOT FET DUCT- (STAND- ATURE DIS- CENT (HIGH UM-MF (COLS. FIELD TIME ANCE ARD WATER SOLVED SATDR- LEVEL) (COLS./ PER MG/L AS (US/CM) UNITS) (DEG C) (MG/L) ATION) (MG/L) 100 ML) 100 ML) CACO3 (00095) (00400) (00010) (00300) (00301) (00340) (31616) (31679) (00410) 1100 240 6.7 27.0 2.3 29 <10 50 220 100 1130 256 6.7 27.5 3.0 38 <10 K69 K31 100 1025 389 6.7 29.0 0.2 3 <10 K19 40 150 1100 196 6.7 30.5 0.5 7 15 84 83 66 RESIDUE NITRO- TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO- SULFZDE DEO. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 02... DATE OCT 1996 24... FEB 1997 20... JDN 04... SEP 02... TOTAL SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L FENDED (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L (MG/L AS S) (MG/L) AS N) AS N) AS N) AS N) AS N) AS N) AS N) AS NO3) (00745) (00530) (00620) (00615) (00630) (00610) (00605) (00625) (00600) (71887) <0.5 4 0.360 0.030 0.400 0.120 0.53 0.66 1.1 4.7 1 0.570 <0.010 0.580 0.030 0.34 0.36 0.94 4.2 <0.5 <1 0.070 0.120 0.190 0.440 0.60 1.0 1.2 5.4 3 0.230 <0.010 0.240 0.150 0.70 0.86 1.1 4.9 MANGA- METHY- BORON, COPPER, IRON, NESE, ZINC, LENE PHOS- TOTAL TOTAL TOTAL TOTAL TOTAL BLUE PHORUS RECOV- RECOV- RECOV- RECOV- RECOV- CYANIDE ACTIVE TOTAL ERABLE ERABLE ERABLE ERABLE ERABLE TOTAL PHENOLS SUB- (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL STANCE AS P) AS B) AS CO) AS FE) AS HN) AS ZN) AS CN) (UG/L) (MG/L) (00665) (01022) (01042) (01045) (01055) (01092) (00720) (32730) (38260) 0.040 30 <10 90 120 <10 <0.010 1 <0.01 0.040 0.040 60 24 110 240 10 <0.010 <1 0.06 0.140 non-ideal count 297 RIO GRANDE DE LOZZA BASIN 50059050 RIO GRANDE DE LOZZA BELOW DAMSITE, PR LOCATION.—Lat 18°20'33", long 66°00'20", Hydrologic Unit 21010005, on left bank of Highway 175, 1.1 mi (1.8 km) downstream of Lago Loiza Dam. DRAINAGE AREA.—209 mi 2 (541 km*). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1986 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 32 ft (10 m), from topographic map. REMARKS.—Records poor. Flow regulated by Lago Loiza Dam. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR APR MAY JUN JUL AUG SEP 1 45 1.6 2 e43 180 3 e!75 2.6 4 26 143 5 278 3.1 6 e21 178 7 21 805 8 178 151 9 17 e!24 10 223 258 11 157 460 12 196 2050 13 220 1190 14 5.2 293 15 e4.3 252 16 e3 . 9 5.0 17 e3.6 308 18 e200 413 19 e6.0 387 20 eS.O 5.9 21 e4.5 430 22 e!70 1460 23 e6.0 106 24 eS.O 389 25 e4.0 7.2 26 e350 e6.1 27 e20 6.0 28 e250 264 29 e300 8.9 30 e2.2 295 31 1.9 TOTAL 2941.6 10182.4 MEAN 94.9 339 MAX 350 2050 MIN 1.9 1.6 AC-FT 5830 20200 CFSM .45 1.62 IN. .52 1.81 8.5 352 7.1 7.0 6.8 6.8 6.4 6.2 6.2 6.0 351 e6.0 e5.4 e5.4 e6.3 e6.0 e5.6 e5.8 e5.7 e5.6 e5.6 e5.9 e5.6 e5.6 e5.5 e5.8 e6.4 e5.8 e7.0 e6.4 e5.8 881.2 28.4 352 5.4 1750 .14 .16 e5.6 e5.6 e5.4 e5.2 eS.O eS.O eS.O e4.9 e5.2 e4.9 eS.O e4.8 e4.9 eS.O eS.O e5.2 e5.2 e5.2 eS.O e4.9 e4.8 e4.8 e4.8 e4.8 eS.O e5.4 e5.4 e5.4 e5.2 eS.O e5.2 157.8 5.09 5.6 4.8 313 .02 .03 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.2 e5.2 e5.2 e5.4 e5.4 eS.O e5.2 eS.O e5.2 e5.2 eS.O eS.O eS.O e5.2 eS.O e5.2 eS.O e4.9 e5.2 e5.2 e5.2 e5.4 —— 145.1 5.18 5.4 4.9 288 .02 .03 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1987 MEAN 222 495 MAX 842 2732 (WY) 1991 1988 MIN 44.7 37.6 (WY) 1992 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 340 2603 1988 17.2 1994 FOR 151 733 1992 2.49 1995 69.1 242 1989 4.52 1990 e5.2 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.4 e5.2 e5.4 e5.4 e5.4 eS.O e5.4 e5.8 e5.6 e5.8 e5.4 e5.4 e5.4 e5.4 e5.6 e5.8 e5.6 e5.2 e4.9 e4.6 e4.2 e4.1 e4.1 e3.9 161.0 5.19 5.8 3.9 319 .02 .03 - 1997 44.9 299 1989 5.19 1997 1996 CALENDAR YEAR 184152 503 110000 1 1 365300 2 32 461 5 2 .7 Sep 10 .2 Jun 5 .3 Jun 1 .41 .78 .8 .4 e3.9 e3.9 e4.1 e4.0 e3.8 e3.7 e3.6 e3.6 83.5 83.4 83.4 83.3 83.3 83.2 83.2 84.4 83.2 83.4 83.4 83.7 83.5 83.5 83.9 84.6 85.3 84.1 83.9 87.6 4.7 4.0 —— 117.1 3.90 7.6 3.2 232 .02 .02 4.0 3.9 3.9 3.9 3.9 3.7 3.8 3.7 3.7 3.7 3.6 3.5 3.6 3.6 4.1 3.9 3.8 3.9 4.0 4.8 6.3 5.1 4.3 4.3 4.2 4.0 3.9 4.0 3.8 4.0 4.1 125.0 4.03 6.3 3.5 248 .02 .02 4.2 4.2 4.4 5.2 5.0 .5 .5 .3 .5 .5 .9 .6 .3 .0 3.9 3.8 3.6 e3.5 3.4 2.9 82.9 2.9 3.4 3.6 3.8 3.3 3.3 2.6 2.5 2.4 —— 114.9 3.83 5.2 2.4 228 .02 .02 2.2 2.1 2.2 2.3 2.5 2.7 2.7 3.5 2.9 2.8 2.6 2.4 2.2 1.9 1.8 2.6 5.5 4.9 5.0 11 7.7 4.4 3.3 3.2 3.5 3.0 2.6 3.1 2.5 2.9 3.5 105.5 3.40 11 1.8 209 .02 .02 2.4 2.1 2.2 2.4 2.3 2.5 2.7 2.8 3.0 3.2 3.7 3.2 821 6.1 3.6 3.4 4.6 4.1 3.0 2.9 4.8 1140 528 1750 8645 262 11 8222 e!3 89.1 297 4963.1 160 1750 2.1 9840 .77 .88 el? 113 ell ell elO 8394 881 e!5 e!4 e!4 e!4 e9.4 15 19 11 8.1 8.1 9.4 10 9.4 9.5 8.9 172 173 9.0 659 158 6.5 6.7 184—— 2180.0 72.7 659 6.5 4320 .35 .39 , BY WATER YEAR (WY) 29.3 112 1987 1.20 1995 FOR 1997 22074 60 2050 1 2 18100 18 43790 3 179 5 2 85.2 367 1992 1.03 1995 WATER YEAR .7 .5 NOV 12 .6 NOV 1 .3 Jun 29 Aug 22 .56 Aug 22 .29 .93 .2 .9 171 784 1987 1.96 1994 160 672 1993 1.62 1994 WATER 224 652 37 110000 223000 49 162400 1 14 368 7 2 198 718 1988 2.21 1994 YEARS 1987 .8 Sep .42 May .49 Aug Sep .31 Sep .07 .58 .9 .3 726 4255 1996 29.7 1990 - 1997 1988 1994 10 1996 13 1995 11 1994 10 1996 10 1996 e Estimated 298 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.— Water years 1987 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: December 1986 to current year. INSTRUMENTATION.— Automatic sediment sampler, since 1987. EXTREMES FOR PERIOD OF DAILY RECORD.» SEDIMENT CONCENTRATION: Maximum daily mean, 4,290 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 1,500,000 tons (1,360,000 tonnes) September 10, 1996; Minimum daily mean, <0.01 tons (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 328 mg/L September 3, 1997; minimum daily mean, 9 mg/L February 26-28, 1997. SEDIMENT LOADS: Maximum daily mean, 1,530 tons (1,390 tonnes) August 24, 1997; minimum daily 0.06 tons (0.05 tonne) July 12-13, 1997. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 45 e43 e!75 26 278 821 21 178 17 223 157 196 220 5.2 e4.3 e3.9 e3.6 e200 e6.0 eS.O e4.5 e!70 e6.0 eS.O e4.0 e350 e20 e250 e300 e2.2 1.9 46 45 49 40 51 37 36 46 36 45 37 39 40 26 23 22 22 23 24 24 23 43 16 10 17 48 58 45 69 35 18 5.6 eS.l eSO 2.8 92 e2.1 2.0 52 1.6 67 46 57 81 .37 e.27 e.23 e.22 e.25 e.34 e.36 e.30 e7.2 e3.8 e.15 e.20 elS e21 e!2 e52 e6.5 .09 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER DECEMBER TOTAL 2941.6 584.48 1.6 180 2.6 143 3.1 178 805 151 e!24 258 460 2050 1190 293 252 5.0 308 413 387 5.9 430 1460 106 389 7.2 e6.1 6.0 264 8.9 295 10182.4 18 28 21 32 22 30 52 19 28 34 42 124 75 42 38 25 38 49 52 26 42 86 30 43 31 28 26 43 30 42 .08 51 .15 41 .19 40 250 40 e33 70 149 1160 379 97 76 .34 74 134 116 .42 120 654 22 118 .60 .47 .42 78 .71 79 3784.38 8.5 352 7.1 7.0 6.8 6.8 6.4 6.2 6.2 6.0 351 e6.0 e5.4 e5.4 e6.3 e6.0 e5.6 e5.8 e5.7 e5.6 e5.6 e5.9 e5.6 e5.6 eS.S e5.8 e6.4 eS.8 e7.0 e6.4 e5.8 881.2 28 47 11- 27 27 26 26 26 26 25 25 40 9< 25 26 27 29 30 30 30 29 29 29 29 29 29 28 28 28 28 28 28 28 .65 r .51 .50 .49 .48 .45 .43 .42 .41 .40 .39 .40 .45 .49 .47 .46 .46 • 45 .44 .45 .45 .43 .43 .43 .46 .46 .48 .50 .45 226.29 e Estimated 299 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e5.6 e5.6 e5.4 e5.2 eS.O eS.O eS.O e4.9 e5.2 e4.9 eS.O e4.8 e4.9 eS.O eS.O e5.2 e5.2 e5.2 eS.O e4.9 e4.8 e4.8 e4.8 e4.8 eS.O e5.4 e5.4 e5.4 e5.2 eS.O e5.2 RIO QRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 27 27 27 27 27 27 26 26 26 26 26 26 26 25 25 25 25 25 25 24 24 24 24 43 24 23 22 22 21 21 20 e.42 e.41 e.40 e.38 e.37 e.36 e.36 e.35 e.36 e.35 e.34 e.34 e.33 e.34 e.34 e.34 e.35 e.35 e.34 e.33 e.32 e.31 e.31 e.55 e.31 e.32 e.33 e.32 e.30 e.28 e.28 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.2 e5.2 e5.2 e5.4 e5.4 eS.O e5.2 eS.O e5.2 e5.2 eS.O eS.O eS.O e5.2 eS.O e5.2 eS.i) e4.9 e5.2 e5.2 e5.2 e5.4 —— 19 19 18 18 17 17 16 16 15 15 15 14 14 13 13 13 12 12 12 11 11 11 10 10 10 9 9 9 —— ... —— e.27 e.26 e.26 e.25 e.25 e.25 e.23 e.22 e.22 e.22 e.21 e.20 e.19 .18 .18 .18 .17 .16 .16 e.16 e.15 e.15 e.14 e.13 e.13 e.13 e.13 e.13 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH e5.2 e5.2 e5.2 e5.2 e5.4 e5.4 e5.4 e5.4 e5.2 e5.4 e5.4 e5.4 eS.O e5.4 e5.8 e5.6 e5.8 e5.4 e5.4 e5.4 e5.4 e5.6 e5.8 e5.6 e5.2 e4.9 e4.6 e4.2 e4.1 e4.1 e3.9 10 10 11 12 13 14 15 16 17 19 20 22 23 24 24 25 25 26 27 27 28 28 29 30 31 31 32 31 31 30 30 e.14 e.15 e.16 e.17 e.19 e.20 e.22 e.23 e.25 e.27 e.29 e.31 e.32 e.33 e.37 e.38 e.39 e.39 e.39 e.40 e.41 e.42 e.45 e.46 e.44 e.43 e.41 e.37 e.35 e.34 e.32 TOTAL 157.8 10.79 145.1 5.31 161.0 9.95 e Estimated 300 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL APRIL e3.9 e3.9 e4.1 e4.0 e3.8 e3.7 e3.6 e3.6 e3.5 e3.4 e3.4 e3.3 e3.3 e3,2 e3.2 e4.4 e3.2 e3.4 e3.4 e3.7 e3.5 e3.5 e3.9 e4.6 e5.3 e4.1 e3.9 e7.6 4.7 4.0 117.1 29 29 28 28 28 27 27 26 26 25 25 24 24 24 23 23 23 23 23 23 24 24 24 24 24 24 23 26 23 22 .31 .31 .31 .31 .29 .27 .26 .25 .25 .24 .23 .22 .22 .21 .20 .27 .20 .21 .21 .23 .22 .22 .25 .30 .35 .26 .24 .57 .30 .24 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY 4.0 3.9 3.9 3.9 3.9 3.7 3.8 3.7 3.7 3.7 3.6 3.5 3.6 3.6 4.1 3.9 3.8 3.9 4.0 4.8 6.3 5.1 4.3 4.3 4.2 4.0 3.9 4.0 3.8 4.0 4.1 21 20 19 18 18 17 16 16 15 14 14 13 13 12 12 11 13 15 17 20 45 85 87 92 96 101 107 112 117 118 118 .23 .21 .20 .19 .19 .17 .17 .16 .15 .14 .13 .12 .12 .12 .13 .12 .13 .15 .18 .25 .94 1.2 1.0 1.1 1.1 1.1 1.1 1.2 1.2 1.3 1.3 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 4.2 4.2 4.4 5.2 5.0 4.5 4.5 4.3 .5 .5 .9 .6 .3 .0 3.9 3.8 3.6 e3.5 3.4 2.9 e2.9 2.9 3.4 3.6 3.8 3.3 3.3 2.6 2.5 2.4 118 118 118 118 117 112 106 101 96 91 87 83 79 80 81 82 83 84 84 77 70 64 58 53 48 44 24 12 13 13 1.4 1.3 1.4 1.7 1.6 1.4 1.3 1.2 1.2 1.1 1.2 1.0 .92 .86 .85 .83 .81 e.79 .76 .61 e.55 .50 .53 .52 .50 .39 .22 .09 .09 .09 7.95 125.0 15.80 114.9 25.71 e Estimated RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 301 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 2.2 2.1 2.2 2.3 2.5 2.7 2.7 3.5 2.9 2.8 2.6 2.4 2.2 1.9 1.8 2.6 5.5 4.9 5.0 11 7.7 4.4 3.3 3.2 3.5 3.0 2.6 3.1 2.5 2.9 3.5 JULY 14 14 15 15 16 16 17 17 18 18 12 10 11 13 15 20 25 26 25 29 27 26 24 23 22 21 21 20 19 38 74 TOTAL 105.5 —— YEAR e 22074.7 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .08 .08 .09 .09 .11 .12 .12 .16 .14 .14 .09 .06 .06 .07 .07 .14 .38 .34 .34 .91 .57 .30 .22 .20 .21 .17 .14 .16 .13 .39 .71 6.79 9628.25 2.4 2.1 2.2 2.4 2.3 2.5 2.7 2.8 3.0 3.2 3.7 3.2 621 6.1 3.6 3.4 4.6 4.1 3.0 2.9 4.8 1140 528 1750 6645 262 11 6222 613 e9.1 297 4963.1 63 59 55 52 48 45 42 39 34 30 26 23 33 27 26 24 24 24 22 21 23 62 51 85 91 230 36 47 31 29 68 —— .41 .34 .33 .33 .30 .31 .31 .30 .28 .25 .26 .20 e3.1 .46 .25 .22 .30 .26 .18 .17 .33 1120 165 1530 6253 1020 1.1 658 el.l e.72 250 4407.81 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 617 113 ell ell elO 6394 681 615 614 614 e!4 69 15 19 11 8 8 9 10 9 9 8 172 173 9 659 158 6 6 184 .4 .1 .1 .4 .4 .5 .9 .0 .5 .7 34 288 328 147 73 42 39 37 36 34 33 32 40 175 136 111 91 75 61 50 41 34 58 40 37 39 29 27 26 31 1.6 108 9.9 4.2 2.0 665 68.0 el. 5 el. 4 el. 3 el. 2 6.83 2.6 9.2 4.2 2.4 2.0 1.9 1.7 1.3 1.1 .82 87 31 .90 147 10 .47 .47 34 2180.0 542.99 302 RIO GRANDE DE LOIZA BASIN 50059050 RXO GRANDE DE LOIZA BELOW DAMSITE LOIZA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. SEDI- CUBIC MENT, SUS- DATE AUG 1997 26... SEP 23... TIME PER 1011 1780 0734 1630 SEDI- MENT, DIS- CHARGE, SUS- SED. SUSP. FALL DIAM. SED • SUSP. FALL DIAM. SED • SUSP. PALL DIAM. FINER % FINER % FINER PENDED FENDED THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 13800 66300 807 3550 13 65 16 72 19 74 DATE AUG 1997 26... SEP 23... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 31 78 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 51 86 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 83 94 SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) 94 97 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 98 98 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 99 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 99 RIO GRANDE DE LOIZA BASIN 50059050 RZO GRANDB DE LOIZA BELOW DAMSITE LOIZA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 303 DATE JUN 1997 13... SEP 03... 24... 26... TIME 0845 1014 1402 1412 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 4.5 11 2400 4930 SEDI- MENT, SUS- PENDED (MG/L) (80154) 79 305 74 98 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 0.96 9.1 480 1300 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 89 92 92 304 RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°21'35", long 66°00'15", 100 ft (30 m) downstream of Highway 181 bridge, 0.4 mi (0.6 km) northwest of Trujillo Alto plaza, and 2.2 mi (3.5 km) northeast of Lago Loiza Reservoir. DRAINAGE AREA. —213 mi> (552 km2 ). PERIOD OF RECORD.—Water years 1981 to current year. REMARKS: Flow controlled by Lago Loiza reservoir. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1200 55 1040 29 0900 4 1205 14 HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) .0 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 380 354 540 336 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.8 6.5 7.3 7.4 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 27.5 0 24.5 3 29.0 2 31.5 7 SODIUM AD- SORP- TION RATIO (00931) .60 .7 .6 .5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 6.5 8.4 7.6 7.8 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 81 99 99 106 11 <10 13 14 2800 290 K160 3900 CHLO- K110 240 70 K190 SULFATE RIDE, SULFIDE TOTAL (MG/L AS S) (00745) DIS- DIS- SOLVED SOLVED (MG/L AS S04) (00945) (MG/L AS CL) (00940) OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... DATE OCT 1996 24... FEB 1997 20... JUN 04... SEP 04... 130 -- 190 110 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- 0.14 0.13 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.42 0.31 0.64 0.60 33 — 45 28 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 -- 32 24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.2 0.81 1.2 12 — 18 11 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 210 -- 339 214 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.9 5.1 3.6 5.4 25 __ 39 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 31.0 — 3.66 8.20 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.050 0.100 0.080 0.9 __ 1 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 1 <1 12 15 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 -- 2.8 — 2.8 2.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.690 0.830 0.160 0.600 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 -- 107 150 230 150 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 •eO.010 0.031 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — 70 — <0.5 _- <0.5 — NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.700 0.840 0.170 0.630 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 -- 17 -_ 23 15 NITRO- GEN* AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.030 0.030 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — 1 -- 27 -- 41 22 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.39 0.28 0.61 0.58 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 24 — K » non-ideal count DATE OCT 1996 24... FEE 1997 20... JUN 04... SEP 04... RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, LEAD, TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L 100 300 MANGA- NESE, MERCORY TOTAL TOTAL RECOV- RECOV- ERABLE ERABLE (UG/L (UG/L SILVER, ZINC, SELE- TOTAL TOTAL NIUM, RECOV- RECOV- CYANIDE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 40 160 <0.10 0.22 <1 <1 <1 <1 10 <0.010 10 <0.010 <1 MBTHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 0.02 0.06 305 306 RIO GRANDE DE LOXZA BASIN 50061800 RIO CANOVANAS NEAR CAMPO RICO, PR LOCATION.--Lat 18°19'08", long 65°53'21", Hydrologic Unit 21010005, at upstream side of bridge, on paved secondary road, 0.4 mi (0.6 km) northeast of junction of Highways 185 and 186, 1.5 mi (2.4 km) south of Campo Rico, and 4.4 mi (7.1 km) south of Loiza. DRAINAGE AREA.--9.84 mi* (25.48 km*). PERIOD OF RECORD.--March 1967 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 225 ft (68 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 18 17 2 18 27 3 25 15 4 18 14 5 15 20 6 54 27 7 27 117 8 20 38 9 16 23 10 17 19 11 22 25 12 14 262 13 13 107 14 12 44 15 11 34 16 11 26 17 11 67 18 10 64 19 9.5 39 20 10 33 21 10 40 22 10 364 23 11 68 24 9.8 180 25 11 71 26 el20 47 27 e36 40 28 e68 70 29 35 50 30 21 87 31 15 —— TOTAL 698.3 2035 MEAN 22.5 67.8 MAX 120 364 MIN 9.5 14 AC-FT 1390 4040 CFSM 2.29 6.89 IN. 2.64 7.69 STATISTICS OF MONTHLY MEAN MEAN 40.6 44.9 MAX 273 125 (WY) 1971 1985 MIN 6.74 6.66 (WY) 1968 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 60 46 38 36 33 30 28 26 24 23 229 62 36 30 34 34 28 24 22 21 22 20 19 18 18 27 25 57 61 44 30 1205 38.9 229 18 2390 3.95 4.56 DATA 32.6 116 1971 5.82 1968 24 22 19 18 20 17 17 20 18 15 15 13 13 12 12 11 10 10 10 25 89 165 87 137 76 43 35 37 34 29 45 1098 35.4 165 10 2180 3.60 4.15 FOR WATER 25.2 62.4 1969 6.66 1977 109 40 31 31 39 32 24 23 33 27 24 26 47 28 23 21 18 18 29 25 64 56 30 28 28 25 22 20 ... —— 921 32.9 109 18 1830 3.34 3.48 YEARS 1967 19.7 48.4 1988 4.04 1977 20 20 23 28 31 22 18 29 23 18 17 16 16 15 16 16 15 15 14 13 14 13 13 13 13 13 14 16 20 17 15 546 17.6 31 13 1080 1.79 2.06 - 1997 14.1 36.2 1969 3.54 1977 FOR 1996 CALENDAR YEAR 15118. 41. 4230 5. 6. 29990 4. 57. 60 14 6. 5 3 Sep 10 4 Apr 3 0 Mar 28 20 16 6 13 17 32 17 15 14 13 11 12 11 12 11 11 11 10 10 9.4 9.3 9.1 14 9.6 9.1 8.6 8.4 8.5 8.2 8.5 8.7 8.0 7.6 —— 347.0 11.6 32 7.6 688 1.18 1.31 7.7 7.7 7.7 7.6 7.7 7.3 9.1 21 16 14 10 9.1 9.6 16 9.6 8.2 8.4 8.1 7.2 6.7 7.1 8.1 7.3 6.9 7.0 6.4 8.0 24 13 21 9.2 316.7 10.2 24 6.4 628 1.04 1.20 6.9 7.4 19 12 7.6 6.8 6.3 5.4 5.5 5.1 5.2 5.2 5.0 .9 .5 .1 .0 .0 3.9 4.2 4.2 3.8 5.5 9.3 6.1 .6 .3 .3 .0 .0 --- 177.1 5.90 19 3.8 351 .60 .67 3.9 3.9 4.0 3.9 4.4 4.4 4.2 4.3 7.5 13 11 9.7 9.0 8.3 8.8 10 11 10 9.8 21 43 28 29 17 13 12 13 20 17 13 18 385.1 12.4 43 3.9 764 1.26 1.46 15 13 12 18 17 12 9.8 9.0 13 26 18 12 13 14 11 11 23 58 21 14 12 262 42 22 28 14 14 14 12 13 13 785.8 25.3 262 9.0 1560 2.58 2.97 13 11 9.0 7.6 7.4 7.7 9.0 9.5 15 12 11 14 17 35 20 17 14 13 13 12 15 21 18 18 12 45 27 18 17 18—— 476.2 15.9 45 7.4 945 1.61 1.80 , BY WATER YEAR (WY) 15.0 53.2 1971 4.36 1994 FOR 1997 8991 24 364 3 4 4010 9 17830 2 33 44 15 7 27.6 93.2 1969 4.28 1974 WATER YEAR .2 .6 Nov 22 .8 Jun 22 .0 Jun 28 Nov 22 .71 Nov 22 .50 .99 .0 18.0 63.7 1970 2.80 1974 19.1 63.7 1979 3.72 1974 WATER 27. 58. 10. 4230 . 1. 15000 13. . 19540 2. 37. 43 12 5. 25.4 137 1979 5.69 1991 YEARS 1967 0 0 5 Sep 80 Jul 5 Jul Sep 10 Sep 80 Jul 74 25 1 38.1 196 1996 5.20 1967 - 1997 1971 1994 10 1996 24 1977 18 1977 13 1982 13 1982 24 1977 e Estimated 307 ATLANTIC OCEAN LAS PIEDRAS Csr Mop orec EXPLANATION ^0670 SURFACE-WATER STATION AND NUMBER V0725 QUALITY-OF-WATER STATION AND NUMBER DA(LY SED |MENT STATION AND NUMBER NUMBER 01 23456 KILOMETERS 01234 MILES Figure 20.--Northeastern river basins the Rfo Herrera to Ri'o Ant6n Ruiz basins. 308 RIO ESPIRITU SANTO BASIN 50063440 QUEBRADA SONADORA NEAR EL VERDE, PR LOCATION.—Lat 18°19'24", long 65°49'03", Hydrologic Unit 21010005, in Caribbean National Forest, at El Yunque, 0.6 mi (1.0 km) upstream from Rio Espiritu Santo, 0.2 mi (0.3 km) upstream from Highway 186, and about 1.2 mi (1.9 km) south of El Verde. DRAINAGE AREA.—1.01 mi* (2.62 km1 ). PERIOD OF RECORD.—March 1983 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 1,230 ft (375 m), from topographic map. REMARKS.—Records poor. REVISIONS.—The maximum discharges for some water years have been revised as shown in the following tables. They supersede figures published in the reports for 1984-1986, 1988, 1989, and 1992-1995. Water Discharge Gage-height Water Year Date (ftVs) (ft) Year Date 1984 Dec. 2, 1983 1,260 8.60 1992 May 1, 1985 May 14, 1985 1,820 9.36 1993 Sept. 15, 1986 Aug. 24, 1986 1,790 9.32 1994 Oct. 22, 1988 Dec. 7, 1987 1,870 9.42 1995 Oct. 20, 1989 Sept. 18, 1989 1,340 8.72 DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO DAY OCT NOV 1 1.5 1.6 2 1.6 e!9 3 1.5 e!9 4 1.1 e8.0 5 6.9 e7 . 8 6 9.5 e26 7 5.0 e4 . 8 8 9.6 e4.5 9 4.7 e2.4 10 8.3 e2.4 11 2.0 e2 . 0 12 1.5 e2.0 13 7.9 e3 . 0 14 1.9 e2.1 15 .89 el. 9 16 7.2 e2 . 2 17 2.6 e2.1 DEC .25 1.2 .65 .44 .49 .18 .13 5.9 3.7 .89 1.3 15 14 1.3 1.8 37 e60 18 3.7 el. 7 e!20 19 6.1 el. 9 20 1.4 el. 2 21 .89 el. 2 22 1.1 el.O 23 27 el.O 24 20 e3.9 25 3.1 el. 5 26 2.6 el. 5 27 1.3 e.93 28 .96 el. 5 29 .85 3.2 30 .71 1.1 31 1.1 TOTAL 144.50 132.43 MEAN 4.66 4.41 MAX 27 26 MIN .71 .93 AC-FT 287 263 CFSM 4.62 4.37 IN. 5.32 4.88 e25 e3.5 e3.1 e2.5 e2.1 el. 8 el. 9 el. 7 el. 9 e4.0 e2.0 el. 9 el. 8 317.43 10.2 120 .13 630 10.1 11.69 JAN el. 6 el. 6 el. 6 el. 6 e2.0 e3.7 e!5 e!4 e2.1 el. 4 e2.7 e!4 e2.5 e45 e24 e21 e5.2 e8.0 e20 e50 e!4 elO e6.8 elO eS.O e3.1 e6.0 e37 e9.0 3.2 4.2 345.3 11.1 50 1.4 685 11.0 12.72 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 5.69 9.37 MAX 16.8 19.8 (WY) 1986 1985 MIN .22 2.47 (WY) 1993 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 8.11 20.9 1988 .92 1990 FOR 6.85 11.1 1996 3.42 1985 DAILY FEB 3.7 2.2 10 8.8 5.3 25 12 3.0 2.6 1.8 1.4 1.1 1.0 1.1 .95 1.1 1.0 .95 1.4 1.2 .99 .93 .90 15 3.0 1.3 1.0 .85 .76 —— 110.33 3.80 25 .76 219 3.77 4.06 YEARS 1983 6.14 11.9 1988 1.56 1992 Discharge (ftVs) 1992 993 1993 688 1993 537 1994 685 SEPTEMBER 1996 Gage-height (ft) 8.14 7.56 7.20 7.56 MEAN VALUES MAR .68 .65 .73 .74 17 4.7 4.3 5.2 9.4 1.9 6.4 2.5 1.3 1.0 .97 1.9 1.2 .99 .82 .63 .50 .40 .34 .28 .21 .35 1.8 6.8 5.0 .67 .42 79.78 2.57 17 .21 158 2.55 2.94 - 1996 4.82 14.3 1990 1.53 1993 1995 CALENDAR YEAR 2467. 6. 120 . . 4890 6. 90. 17 2. . 03 76 Dec 18 11 Fab 14 21 Apr 27 69 86 2 44 APR .29 .19 .13 55 4.1 .91 .63 .52 .45 .40 .37 19 4.6 4.5 16 10 1.4 1.0 .70 .72 e.99 el. 4 e26 el. 5 el. 5 el. 8 el. 4 e2.1 e5.6 el. 6 —— 164.80 5.49 55 .13 327 5.44 6.07 MAY el.l e.92 e.90 e.80 e2.5 09.8 05.2 07.8 04.6 02.2 02.1 e!2 03.5 02.2 el. 7 1.3 1.1 .88 .81 .93 1.3 1.9 2.9 5.4 .94 .66 .56 .45 .41 .36 .59 77.81 2.51 12 .36 154 2.49 2.87 JUN 1.1 4.2 1.5 14 5.3 14 9.3 3.1 1.1 1.1 20 26 11 20 46 31 5.7 8.3 3.7 2.0 3.9 13 2.9 1.4 1.2 1.1 1.5 7.1 1.2 .88 —— 262.58 8.75 46 .88 521 8.67 9.67 JUL .78 .69 .95 .62 .51 .52 1.4 75 11 4.5 1.6 14 10 e44 elO 03.9 03.2 03.0 02.5 012 02.3 el. 6 1.3 1.7 15 12 1.7 3.4 2.4 1.2 2.3 245.07 7.91 75 .51 486 7.83 9.03 AUG 11 4.9 25 16 12 6.9 2.0 1.6 3.2 1.2 .94 1.2 36 52 9.4 20 5.2 2.1 2.0 1.2 .97 .80 26 13 2.2 1.3 1.2 2.7 1.1 .76 .65 264.52 8.53 52 .65 525 8.45 9.74 SEP .45 .32 .28 .36 2.4 1.2 .51 10 61 0425 029 02.7 2.2 2.9 21 020 el. 4 02.3 02.4 04.2 012 el. 6 el. 5 el. 5 el. 4 02.0 06.8 029 07.6 03.5 —— 656.52 21.9 425 .28 1300 21.7 24.18 , BY WATER YEAR (WY) 4.80 9.76 1987 1.09 1984 FOR 1996 2801 7 425 4020 11 5560 7 103 19 2 7.81 14.3 1992 2.51 1996 6.06 13.7 1987 .98 1985 WATER YEAR .07 .65 .13 .39 .35 .06 .58 .17 .0 .65 Sep 10 Dec 7 Mar 20 Sep 10 Sep 10 Dec 7 6.62 12.7 1983 2.33 1991 6.73 14.2 1988 .50 1993 WATER YEARS 1983 6.63 9.32 3.91 425 .00 Sep Aug .01 Mar 4020 11.35 .00 4800 6.56 89.15 17 2.6 .43 Sep Sep Aug 7.28 21.9 1996 2.45 1986 - 1996 1988 1994 10 1996 14 1993 31 1994 10 1996 10 1996 13 1993 a Estimated RIO ESPIRITU SANTO BASIN 50063440 QUEBRADA SONADORA NEAR EL VERDE, PR—Continued DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 309 DAY OCT NOV 1 1.7 5.6 2 2.3 12 3 4.6 3.1 4 1.8 3.3 5 1.4 17 6 1.2 3.9 7 1.8 44 8 1.5 4.0 9 1.2 11 10 3.9 2.4 11 1.6 24 12 1.4 e64 13 3.1 elS 14 2.2 e7 . 0 15 1.3 e4.5 16 1.1 e2.9 17 .99 e!6 18 .94 e6.2 19 .89 e4.0 20 .84 e2.8 21 .80 e2.9 22 .77 e34 23 .98 eS.O 24 1.1 e52 25 2.3 e7.2 26 36 e3.3 27 4.6 e2 . 5 28 22 e!7 29 13 e4.0 30 1.6 e30 31 1.5 —— TOTAL 120.41 410.6 MEAN 3.88 13.7 MAX 36 64 MIN .77 2.4 AC -FT 239 814 CFSM 3.85 13 . 6 IN. 4.43 15.12 DEC eS.O e4.5 e2.4 e2.4 e2.2 e2.0 el. 8 el. 6 el. 5 el. 7 e40 eB.O e2.7 e2.0 e2.4 elO e2.5 el. 6 1.5 1.4 1.4 1.9 1.5 3.8 1.8 e4.1 e6.2 elO e24 e7.4 e4.1 163.4 5.27 40 1.4 324 5.22 6.02 JAN e2.5 e2.8 el. 9 el. 4 e2.2 el. 9 el. 7 el. 4 el. 7 el. 3 el. 2 el.l el.O e.98 e.90 e.82 .77 .73 5.3 11 e36 e46 e36 e41 e9.0 e7.8 e3.4 e6.4 e5.2 e3.9 e4.8 242.10 7.81 46 .73 480 7.73 8.92 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 5.56 9.68 MAX 16.8 19.8 (WY) 1986 1985 MIN .22 2.47 (WY) 1993 1991 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 7.90 20.9 1988 .92 1990 FOR 6.92 11.1 1996 3.42 1985 FEB e20 eS.O e4.1 e3.9 e!2 elO e3.0 e2.8 elS e3.3 e2.7 e5.2 e20 e3.4 e2.4 e2.0 el. 8 el. 8 elO e4.0 e29 elO e3.1 e3.1 e2.8 e3.2 e2.2 el. 7 ___ ___ ___ 187.5 6.70 29 1.7 372 6.63 6.91 YEARS 1983 6.18 11.9 1988 1.56 1992 MAR 1.7 3.1 6.8 6.3 13 2.8 1.9 11 8.0 1.9 1.5 2.5 2.6 1.7 2.7 3.1 el. 3 el.l el. 2 el.l el.O e.98 e.92 e.88 e.85 .83 .80 .78 1.0 .89 .72 84.95 2.74 13 .72 168 2.71 3.13 - 1997 4.67 14.3 1990 1.53 1993 1996 CALENDAR YEAR 2901. 7. 425 . . 5750 7. 106. 20 2. . 12 93 Sap 10 13 Apr 3 39 Mar 20 85 85 3 71 APR .68 2.1 2.7 2.6 4.3 1.1 .88 .84 .79 .76 .78 .77 .77 .64 .50 .48 .46 .50 .67 .79 .51 .43 .41 .38 .36 .35 .37 .36 .33 .33 ___ 26.94 .90 4.3 .33 53 .89 .99 MAY .32 .32 .31 .31 .31 .31 19 e24 el 6 2.2 11 3.1 9.9 2.5 1.2 2.9 3.6 1.4 1.0 1.1 e2.2 el.O e.88 e.93 e.82 e.76 el.l el. 7 ell e3.0 e2.0 126.17 4.07 24 .31 250 4.03 4.65 JUN e4.3 e35 e25 el.O e.89 e.86 e.80 e.77 e.74 e.71 e.70 e.68 el.l e3.2 e.90 e.73 e.70 e.73 el. 6 e4.3 e4.7 el. 4 e!6 e6.4 e2.7 1.7 1.1 .89 .83 .80 ___ 121.23 4.04 35 .68 240 4.00 4.47 JUL .78 .69 .65 .65 .72 1.3 1.5 1.5 2.6 2.3 1.0 .90 4.0 1.8 1.3 8.3 3.6 1.5 8.4 18 e23 e5.6 e!3 el. 7 el. 7 e2.1 el. 2 el. 5 el. 4 e2.0 ell 125.69 4.05 23 .65 249 4.01 4.63 AUG e3.0 el. 2 e5.8 ell el. 7 el. 2 1.1 1.0 2.4 18 1.6 5.1 2.4 1.2 1.1 7.6 14 16 1.9 1.4 1.2 e37 e7.4 e6.8 e6.4 e4.3 e4.9 e3.3 e2.1 el. 9 el. 9 175.9 5.67 37 1.0 349 5.62 6.48 SEP el. 9 e2.5 e2.3 el. 9 el. 6 el. 3 el. 5 el. 4 e3.6 e2.3 el. 3 el. 7 e4.0 elO e3.5 e2.0 el. 4 el. 5 el. 5 el. 3 e4.5 e7.0 e5.6 4.8 11 e!6 e3.8 e2.3 e2.0 e2.1 107.6 3.59 16 1.3 213 3.55 3.96 , BY WATER YEAR (WY) 4.54 9.76 1987 .90 1997 FOR 1997 1892 5 64 614 7 3750 5 69 13 2 7.56 14.3 1992 2.51 1996 WATER YEAR .49 .18 Nov 12 . 31 May 3 .32 Apr 30 Jul 21 .39 Jul 21 .31 May 1 .13 .70 .0 .75 5.93 13.7 1987 .98 1985 6.45 12.7 1983 2.33 1991 WATER 6 9 3 425 4020 11 4730 6 87 16 2 6.66 14.2 1988 .50 1993 YEARS 1983 .52 .32 .91 .00 .01 .35 .00 .46 .77 .6 .46 Sep Aug Mar Sep Sep Aug 7.04 21.9 1996 2.45 1986 - 1997 1988 1994 10 1996 14 1993 31 1994 10 1996 10 1996 13 1993 e Estimated 310 RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO ORANDE, PR LOCATION.—Lat 18°21'37", long 65°48'49", Hydrologic Unit 21010005, at downstream side of bridge on Highway 966, 0.1 mi (0.2 km) upstream from Quebrada Jimenez, and 1.9 mi (3.1 km) southeast of Rio Orande. DRAINAGE AREA.—8.62 mi 2 (22.33 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February 1959 to April 1963 (annual low-flow and occasional measurements only), August 1966 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 40 ft (12 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR MAY JUN JUL AUG SEP 1 49 61 2 54 124 3 77 48 4 51 76 5 38 163 6 34 84 7 34 400 8 34 92 9 26 86 10 45 60 11 37 146 12 29 694 13 41 383 14 38 122 15 26 67 16 23 48 17 20 168 18 19 121 19 18 226 20 18 57 21 19 41 22 18 310 23 19 85 24 25 656 25 30 102 26 206 59 27 69 43 28 138 156 29 e!20 73 30 e32 278 31 e27 TOTAL 1414 5029 MEAN 45.6 168 MAX 206 694 MIN 18 41 AC-FT 2800 9980 CFSM 5.29 19.4 IN. 6.10 21.70 85 79 42 42 48 47 41 37 35 35 212 88 43 39 41 98 49 36 29 28 28 30 30 49 48 110 145 222 347 124 90 2377 76.7 347 28 4710 8.90 10.26 63 86 e60 e45 e70 e60 e52 e45 e52 e42 e38 e34 e32 e31 e29 e29 28 26 30 104 377 499 405 500 156 148 60 91 113 59 66 3430 111 500 26 6800 12.8 14.80 270 142 82 85 111 88 61 50 213 60 54 121 153 57 46 40 36 36 62 37 252 208 47 53 44 56 35 28 —— —— 2527 90.3 270 28 5010 10.5 10.91 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1966 MEAN 59.7 85.7 MAX 202 196 (WY) 1971 1985 MZN 12.3 29.1 (WY) 1969 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 72.3 179 1971 16.8 1994 FOR 55.1 119 1969 18.5 1977 51.2 117 1982 10.8 1983 27 36 55 65 102 49 35 87 83 39 32 35 35 30 37 41 36 35 34 31 29 28 25 21 20 21 21 21 24 23 21 1178 38.0 102 20 2340 4.41 5.08 - 1997 38.6 153 1990 9.53 1996 1996 CALENDAR YEAR 27444.4 75.0 2000 3.6 5.5 54440 8.70 118.44 161 37 10 Sep 10 Apr 2 Mar 20 20 19 56 33 56 26 23 22 21 20 19 18 18 18 15 14 14 14 16 26 16 16 20 20 19 17 18 20 20 19 —— 653 21.8 56 14 1300 2.53 2.82 18 17 17 20 21 19 141 186 93 53 77 76 66 49 19 32 63 34 25 22 41 24 22 26 21 22 26 56 72 65 32 1455 46.9 186 17 2890 5.44 6.28 51 410 102 24 15 13 12 12 11 11 12 12 13 33 14 12 11 11 12 19 19 14 75 69 51 32 20 14 12 12 —— 1128 37.6 410 11 2240 4.36 4.87 12 12 12 13 15 20 22 26 30 33 23 22 26 34 25 58 55 31 66 197 330 105 112 38 62 50 33 37 33 66 86 1684 54.3 330 12 3340 6.30 7.27 36 30 29 48 28 21 20 20 41 148 44 55 59 32 30 75 102 236 88 73 71 923 103 140 105 49 35 27 23 24 31 2746 88.6 923 20 5450 10.3 11.85 39 48 34 48 30 23 24 28 97 38 24 33 197 259 223 61 38 93 55 31 e80 e!28 e82 e61 e48 e350 elOO e48 e42 e45 2407 80.2 350 23 4770 9.31 10.39 , BY WATER YEAR (WY) 43.1 119 1981 6.27 1984 FOR 1997 26028 71 923 11 12 4700 8 51630 8 112 147 39 18 66.1 185 1979 14.9 1973 WATER YEAR .3 Aug 22 Jun 9 Jun 6 Aug 22 .33 Aug 22 .27 .33 45.8 120 1970 10.0 1975 52.2 114 1983 11.1 1975 WATER 57 98 21 2600 3 4 21200 16 41710 6 90 123 26 10 60.4 123 1988 18.5 1994 YEARS 1966 .6 .6 .6 Dec .6 Apr .4 Jun Aug . 62 Aug .68 .74 59.6 191 1989 17.7 1971 - 1997 1979 1994 7 1987 2 1996 30 1975 13 1990 13 1990 e Estimated RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO GRANDE, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1958, 1961-66, 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 311 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 31... 1200 26 116 6.2 26.5 2.0 6.7 85 <10 4300 290 FEB 1997 19... 0900 47 107 6.5 21.5 3.2 8.6 96 <10 2600 K1700 JUN 06... 0940 13 92 6.8 26.5 2.8 7.8 97 <10 330 510 SEP 10... 1020 27 68 6.5 25.0 2.6 7.7 94 <10 K1500 2200 ALKA- DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 35 — 210 44 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- 0.13 <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 7.9 — 66 9.5 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 19 -- 38 23 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.7 — 11 4.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 71 — 236 100 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 7.9 __ 38 9.6 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.98 — 8.41 7.29 SODIUM AD- SORP- TION RATIO (00931) 0.6 __ 1 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 1 <1 7 7 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 0.50 — 3.5 5.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.080 0.090 0.040 0.090 LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 39 34 31 20 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 <0.010 <0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.00 0.090 0.050 0.090 SULFATE DIS- SOLVED (MG/L AS 304) (00945) 1.8 — 11 1.9 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.010 0.020 0.020 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 9.1 -- 50 15 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.36 <0.20 <0.20 0.23 DATE OCT 1996 31... FEB 1997 19... JUN 06... SEP 10... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.40 <0.20 <0.20 0.24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.28 0.22 0.22 0.33 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.3 0.97 0.97 1.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 <0.020 <0.020 <0.020 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- 20 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non-ideal count 312 RIO ESPIRITTJ SANTO BASIN 50063800 RIO ESPIRITtJ SANTO NEAR RIO GRANDE, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1958, 1961-66, 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 31... FEE 1997 19... JUN 06... SEP 10... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 260 120 <1 <1 10 10 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.02 <0.02 RIO ESFZRITU SANTO BASIN 50064200 RIO GRANDE NEAR EL VERDE, PR LOCATION.—Lat 18°20'42", long 65°50'30", Hydrologic Unit 21010005, on left bank 250 ft (7.6 m) upstream side of bridge at Hwy 960, 0.05 mi (0.08 km) southwest of junction of Highways 956 and 960, 1.1 mi (1.8 km) west of El Verde, and 2.7 mi (4.3 km) south of Rio Grande. DRAINAGE AREA.--7.31 mi 2 (18.93 km*). PERIOD OP RECORD.--May 1967 to December 1970, January 1972 to September 1982, August 1990 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, wich are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 313 DAY OCT NOV JAN APR JUL AUG SEP 1 12 26 2 13 62 3 25 17 4 14 21 5 9.6 49 6 12 36 7 23 140 8 15 38 9 11 20 10 33 14 11 20 44 12 8.6 e292 13 10 138 14 7.7 64 15 6.8 41 16 6.2 26 17 5.5 72 18 5.0 56 19 5.0 37 20 4.5 25 21 4.3 26 22 4.1 155 23 5.4 42 24 4.7 237 25 36 62 26 140 e28 27 41 e21 28 77 e76 29 49 e35 30 13 e!40 31 8.6 TOTAL 630.0 2040 MEAN 20.3 68.0 MAX 140 292 MIN 4.1 14 AC-FT 1250 4050 CFSM 2.78 9.30 IN. 3.21 10.38 STATISTICS OF MONTHLY MEAN MEAN 55.7 67.7 MAX 392 172 (WY) 1971 1970 MIN 8.45 14.3 (WY) 1969 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e42 e38 e20 e20 19 17 15 14 13 14 185 68 23 17 20 48 24 15 13 12 14 16 13 16 19 37 55 94 134 68 37 1140 36.8 185 12 2260 5.03 5.80 23 25 17 13 20 17 15 13 15 12 11 9.9 9.2 8.8 8.2 7.4 6.8 6.9 7.7 34 170 213 163 192 , 77 65 29 53 43 33 41 1358.9 43.8 213 6.8 2700 6.00 6.92 DATA FOR WATER 47.0 140 1971 13.8 1968 FOR 43.0 151 1969 10.1 1977 96 41 35 34 58 47 25 24 71 28 23 44 95 28 20 17 15 15 49 34 137 76 26 26 24 27 18 15 ... ... —— 1148 41.0 137 15 2280 5.61 5.84 YEARS 1967 31.0 76.4 1969 5.80 1977 15 21 28 38 55 23 17 44 31 18 14 13 14 12 12 13 10 8.5 8.7 8.2 8.2 7.7 7.2 6.8 6.9 7.5 7.3 6.6 7.5 7.2 6.0 482.3 15.6 55 6.0 957 2.13 2.45 - 1997 20.7 54.4 1969 4.50 1977 1996 CALENDAR YEAR 13344. 36. 1100 4. 4. 26470 4. 67. 72 18 6. 8 5 Sep 10 1 Oct 22 7 Oct 18 99 91 2 6.0 13 35 11 21 10 8.1 7.7 7.4 7.1 7.4 7.7 7.2 7.0 6.5 6.0 5.8 5.6 6.7 15 6.3 5.1 4.7 4.7 4.7 4.7 5.0 4.9 4.2 4.0 —— 249.5 8.32 35 4.0 495 1.14 1.27 3.9 4.5 4.1 3.9 3.6 4.1 57 67 46 25 21 21 26 29 11 9.8 28 15 8.5 8.0 9.0 7.8 7.4 7.5 7.2 6.7 42 43 29 40 16 612.0 19.7 67 3.6 1210 2.70 3.11 20 106 72 27 14 13 11 8.9 8.4 7.3 7.0 6.8 6.9 12 7.4 6.6 5.6 e5.6 12 10 67.5 5.6 44 43 622 26 11 7.6 6.4 5.8 546.4 18.2 106 5.6 1080 2.49 2.78 5.2 5.0 4.6 4.5 5.4 7.1 5.8 7.2 7.7 7.8 5.3 4.9 4.6 5.4 10 11 17 14 20 102 129 51 75 26 26 31 19 23 21 32 60 747.5 24.1 129 4.5 1480 3.30 3.80 26 18 30 56 25 18 17 16 53 95 30 25 48 22 20 49 112 162 39 27 24 348 69 66 62 42 48 29 22 19 20 1637 52.8 348 16 3250 7.22 8.33 21 26 25 21 17 16 17 16 39 27 15 20 62 106 41 25 18 19 19 17 53 67 53 41 19 152 36 22 19 20 1049 35.0 152 15 2080 4.78 5.34 , BY WATER YEAR (WY) 26.8 119 1978 6.29 1995 FOR 1997 11640 31 348 3 4 3100 11 3 23090 4 59 68 19 5 50.6 203 1969 10.2 1974 WATER YEAR .6 .9 Aug 22 .6 May 5 .0 Apr 30 Nov 12 .73 Nov 12 .4 May 5 .36 .24 .7 30.8 86.5 1968 6.22 1975 36.7 109 1969 8.66 1994 WATER 40 87 17 3470 2 2 17400 15 1 29040 42.7 90.0 1968 7.39 1991 YEARS 1967 - .1 .1 .3 May 21 .2 Aug 15 .5 Aug 10 Sep 16 .50 Sep 16 .6 Mar 13 48.6 153 1975 12.4 1967 1997 1969 1994 1969 1991 1991 1975 1975 1977 5.48 74 78 17 6 .51 .6 e Estimated 314 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR LOCATION.--Lat 180 19'46", long 65°45'04", Hydrologic Unit 21010005, on left bank, at bridge on Highway 988, 1.4 mi (2.3 km) west of Sabana, 2.0 mi (3.2 km) downstream from Rio da la Mina, and 3.2 mi (5.1 km) southeast of Mameyes. DRAINAGE AREA.--6.88 mi 2 (17.82 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—August 1967 to December 1973, June 1983 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 275 ft (84 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 32 44 2 e36 e57 3 e49 39 4 e43 42 5 e69 87 6 e36 50 7 e31 362 8 e!9 64 9 22 e47 10 e78 e35 11 e26 131 12 19 e326 13 29 e286 14 25 e83 15 22 e70 16 29 e56 17 e28 elOO 18 26 e58 19 e25 109 20 e23 e47 21 e22 e54 22 e23 e62 23 e23 e50 24 e23 e280 25 e26 e62 26 91 e50 27 30 e52 28 163 e66 29 108 e60 30 21 6200 31 32 —— TOTAL 1229 3029 MEAN 39.6 101 MAX 163 362 MIN 19 35 AC -FT 2440 6010 CFSM 5.76 14.7 IN. 6.65 16.38 STATISTICS OF MONTHLY MEAN MEAN 63.5 80.3 MAX 240 191 (WY) 1971 1985 MIN 20.3 36.3 (WY) 1969 1974 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS e90 e60 e41 e39 e34 e32 e32 e29 e27 e30 42 29 23 23 25 39 25 22 21 20 21 21 20 23 23 29 42 46 67 44 41 1060 34.2 90 20 2100 4.97 5.73 30 41 33 30 40 37 32 34 29 27 26 25 24 23 23 22 e26 21 21 35 e90 e!80 e!30 e!40 e60 e66 e37 e56 e50 e40 e42 1470 47.4 180 21 2920 6.89 7.95 elOO e54 e74 e60 e70 e56 e54 e45 e80 e48 e48 e78 e86 e47 e40 34 34 33 45 36 e70 e50 35 36 36 36 32 30 ___ ... —— 1447 51.7 100 30 2870 7.51 7.82 DATA FOR WATER YEARS 1967 58.7 164 1971 16.6 1990 FOR 54.4 105 1969 25.0 1985 42.3 68.0 1988 21.7 1968 29 33 e40 e35 e50 34 31 e44 e41 32 e28 e33 e32 e28 29 29 25 28 26 e26 e30 e27 e26 e26 e28 e30 e45 e48 e60 e32 e31 1036 33.4 60 25 2050 4.86 5.60 - 1997 37.2 79.7 1990 18.1 1968 1996 CALENDAR YEAR 21383 58 2140 12 15 42410 8 115 92 31 17 .4 Sep 10 May 28 May 25 .49 .62 e29 e49 e39 e76 e80 e37 e34 e33 e30 e29 e30 e29 e43 e30 e29 e29 e31 e31 e38 e30 e28 e27 e25 e21 e21 e21 e26 e22 e21 e21 --- 989 33.0 80 21 1960 4.79 5.35 e20 e!9 e!8 e!8 e!7 e!7 e82 131 50 34 72 46 91 44 29 36 55 38 30 31 45 29 50 52 e37 e94 el!9 e44 54 42 44 1488 48.0 131 17 2950 6.98 8.05 56 225 93 45 35 30 26 23 20 18 18 17 23 34 18 16 16 e29 32 67 654 27 86 60 42 46 31 27 25 22 --- 1261 42.0 225 16 2500 6.11 6.82 21 19 19 18 20 21 19 23 28 24 19 20 59 33 24 44 34 24 42 63 213 71 86 32 47 38 25 33 24 68 47 1258 40.6 213 18 2500 5.90 6.80 28 29 39 55 35 33 33 35 40 109 36 37 37 28 29 63 63 70 36 33 30 373 59 66 58 41 41 35 30 29 41 1671 53.9 373 28 3310 7.83 9.04 53 40 34 47 30 27 26 27 62 34 26 31 95 101 135 41 32 54 32 29 43 76 64 46 162 401 60 47 47 45 1947 64.9 401 26 3860 9.43 10.53 , BY WATER YEAR (WY) 39.8 83.1 1973 14.5 1984 FOR 1997 17885 49 401 16 19 11400 10 35470 7 96 82 35 21 64.3 147 1970 18.7 1973 WATER YEAR .0 Sep 26 Jun 16 Apr 30 Sep 26 .65 Sep 26 .12 .70 54.9 112 1970 12.4 1985 49.7 93.4 1969 20.3 1994 WATER 55. 78. 33. 2780 6. 9. 20500 13. 5. 40140 8. 109. 100 33 16 52.6 81.4 1988 20.4 1994 YEARS 1967 4 0 1 Sep 9 Apr 4 Jun Sep 19 Sep 1 Apr 05 43 60.3 166 1989 26.6 1986 - 1997 1971 1994 18 1989 20 1970 12 1985 18 1989 18 1989 8 1970 e Estimated RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.-- Water years 1992 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1992 to current year. INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler, since 1993. REMARKS:-- Sediment samples were collected by a local observer on a weekly basis and during high flow events. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 484 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, e4,290 tons (e3,891 tonnes) September 10, 1996; Minimum daily mean, 0.03 tons (0.02 tonne) October 05, 1994. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 162 mg/L November 7,1996 - September 26, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 938 tons (851 tonnes) September 26, 1997; Minimum daily mean, 0.04 tons (0.04 tonne) May 4-6, 1997. 375 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 32 e36 e49 e43 e69 e36 e31 e!9 22 e78 e26 19 29 25 22 29 e28 26 e25 e23 e22 e23 e23 e23 e26 91 30 163 108 21 32 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 32 e36 e49 e43 e69 e36 e31 e!9 22 e78 e26 19 29 25 22 29 e28 26 e25 e23 e22 e23 e23 e23 e26 91 30 163 108 21 32 11 10 16 12 23 15 11 6 7 30 9 7 9 7 7 4 5 12 11 7 4 4 10 15 21 30 9 109 52 18 12 .99 e.98 e3.2 el. 7 e5.5 el. 5 e.99 e.32 .47 ell e.72 .34 1.1 .56 .46 .31 e.35 .84 .72 .42 .27 .21 .62 .94 el. 5 9.4 .82 264 41 1.0 1.1 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) NOVEMBER 44 e57 39 42 87 50 362 64 e47 e35 131 e326 e286 e83 e70 e56 elOO e58 109 e47 e54 e62 eSO e280 e62 eSO e52 e66 e60 e200 ___ 16 17 13 13 27 15 162 24 16 10 44 115 84 19 9 5 14 12 39 32 20 17 17 42 44 15 10 9 16 38 ___ 2.4 e3.3 2.5 1.7 10 2.3 285 4.5 2.1 .99 20 e!76 e!62 e4.5 e2.0 e.91 e3.2 e2.1 20 e5.9 e2.7 e2.7 e2.6 e!9 e20 e2.2 el. 4 el. 5 e2.7 e!4 ___ DECEMBER e90 e60 e41 e39 e34 e32 e32 e29 e27 e30 42 29 23 23 25 39 25 22 21 20 21 21 20 23 23 29 42 46 67 44 41 40 17 11 8 4 1 1 2 4 6 15 10 8 7 8 12 7 4 2 2 2 3 3 6 10 10 24 15 20 13 14 e!6 e3.5 el. 5 .90 .36 .12 .13 .19 .28 .41 1.9 .74 .51 .43 .57 1.4 .46 .23 .13 .12 .13 .15 .16 .36 .65 .91 3.1 2.3 4.4 1.5 1.6 TOTAL 1229 353.33 3029 780.20 1060 45.14 e Estimated 316 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) JANUARY 30 41 33 30 40 37 32 34 29 27 26 25 24 23 23 22 e26 21 21 35 e90 e!80 e!30 e!40 e60 e66 e37 e56 e50 e40 e42 15 14 7 6 13 12 11 12 17 21 16 10 6 4 3 5 9 14 11 11 55 41 48 66 30 18 17 18 19 14 12 1.2 1.6 .58 .47 1.4 1.2 .92 1.1 1.3 1.5 1.1 .68 .42 .27 .20 .30 e.50 .78 .61 1.1 e8.1 e!4 e20 e24 e7.9 e3.1 e2.3 e2.2 e2.7 el. 6 el. 2 elOO e54 e74 e60 e70 e56 e54 e45 eSO e48 e48 e78 e86 e47 e40 34 34 33 45 36 e70 eSO 35 36 36 36 32 30 —— 35 40 18 19 17 14 12 14 17 16 15 19 24 20 17 14 8 5 12 7 21 15 9 6 4 4 5 5 e7.0 e8.2 e3.1 e3.5 e3.0 e2.4 el. 7 el. 8 e2.8 e2.7 el. 9 e3.3 e5.2 e3.6 e2.0 1.3 .73 .42 1.6 .69 e3.9 e2.0 .88 .61 .42 .41 .39 .39 MEAN DISCHARGE (CFS) 29 33 040 035 050 34 31 044 041 32 028 033 032 028 29 29 25 28 26 026 030 027 026 026 028 030 045 048 060 032 031 MEAN CONCEN- TRATION (MG/L) MARCH 4 13 11 12 13 11 9 14 13 10 9 8 8 7 11 15 9 5 4 5 5 5 6 6 5 4 4 15 17 20 7 SEDIMENT DISCHARGE (TONS/DAY) .35 1.3 el.l el. 2 el. 4 1.0 .80 el. 8 el. 4 .82 0.64 0.72 0.66 0.56 .85 1.2 .62 .37 .29 0.32 .37 .40 .40 .38 .33 .31 .46 el. 8 02.5 02.5 0.61 1470 104.33 1447 65.94 1036 27.46 e Estimated RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 317 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e29 e49 e39 e76 e80 e37 e34 e33 e30 e29 e30 829 e43 e30 829 829 e31 e31 e38 e30 e28 827 e25 e21 821 e21 826 e22 821 821 APRIL 4 9 13 17 16 5 2 1 2 6 14 12 23 10 6 4 3 2 3 5 7 6 4 7 13 23 17 14 12 10 —— MAY 8.31 e.94 el. 6 e2.7 83.4 8.81 8.23 e.ll 8.18 e.45 el.l e.92 82.2 e.99 8.47 8.29 e.22 8.18 e.29 8.48 e.57 e.42 e.31 8.41 e.63 el.l e.90 8.71 e.56 e.47 820 e!9 e!8 e!8 e!7 e!7 e82 131 50 34 72 46 91 44 29 36 55 38 30 31 45 29 50 52 837 894 el!9 844 54 42 44 10 10 4 1 1 1 28 43 16 13 21 13 29 14 10 7 15 4 6 16 14 9 29 15 7 19 17 20 17 14 14 e.45 e.43 8.15 8.04 8.04 8.04 837 37 2.2 1.2 7.6 2.0 14 1.8 .75 .72 2.6 .40 .49 1.4 1.9 .71 6.7 2.3 8.96 84.0 84.9 83.4 3.4 1.7 1.7 56 225 93 45 35 30 26 23 20 18 18 17 23 34 18 16 16 829 32 67 e54 27 86 60 42 46 31 27 25 22 ___ MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) JUNE 13 88 30 12 5 2 2 2 2 2 2 2 3 10 2 2 3 9 4 19 17 9 26 18 13 15 9 6 4 2 2.1 218 8.1 1.5 .51 .20 .14 .12 .11 .10 .10 .09 .25 1.0 .12 .09 .14 a. 79 .34 6.6 e3.4 .66 12 3.1 1.5 1.9 .79 .46 .26 .14 TOTAL 989 23.95 1488 141.98 1261 264.61 e Estimated 318 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR MEAN DISCHARGE (CFS) 21 19 19 18 20 21 19 23 28 24 19 20 59 33 24 44 34 24 42 63 213 71 86 32 47 38 25 33 24 68 47 1258 17885 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 2 2 3 5 8 6 2 7 5 2 3 5 16 10 3 14 4 2 8 20 93 23 20 4 12 12 8 20 5 17 14 — .11 .11 .14 .24 .42 .32 .11 .45 .38 .10 .14 .26 4.1 .96 .28 1.7 .40 .13 1.4 4.9 214 5.7 9.0 .34 2.0 1.2 .54 2.3 .33 7.0 1.9 260.96 3613.72 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 28 29 39 55 35 33 33 35 40 109 36 37 37 28 29 63 63 70 36 33 30 373 59 66 58 41 41 35 30 29 41 4 6 12 10 2 2 2 2 4 36 7 5 10 5 2 17 17 22 7 3 2 123 19 20 18 13 12 11 10 9 20 .32 .47 1.3 1.8 .19 .18 .18 .19 .48 15 .68 .74 1.0 .37 .19 4.9 3.1 4.9 .71 .25 .19 307 3.1 5.1 3.0 1.4 1.4 1.0 .79 .68 2.8 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 53 40 34 47 30 27 26 27 62 34 26 31 95 101 135 41 32 54 32 29 43 76 64 46 162 401 60 47 47 45 17 8 3 14 11 10 9 9 19 11 9 10 36 38 42 12 5 16 11 9 12 22 20 7 59 162 9 6 9 9 4.6 .90 .28 1.9 .92 .76 .65 .63 6.5 1.0 .61 .85 36 26 19 1.3 .43 2.6 .92 .72 1.4 7.7 4.6 1.2 118 938 1.7 .74 1.1 1.4 1671 363.41 1947 1182.41 RIO MAMEYES BASIN 50065500 RIO MAMEYES NR SABANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 319 DATE OCT 1996 28... NOV 13... JUL 1997 21... AUG 22... SEP 13... 26... TIME 2300 0150 0700 1235 2350 1030 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1250 1370 1490 2760 799 5920 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1240 938 1050 683 591 2201 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 4180 3470 4240 5090 1274 35200 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 38 31 21 26 24 20 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 42 43 31 32 34 25 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 51 58 43 43 48 33 DATE OCT 1996 28... NOV 13... JUL 1997 21... AUG 22... SEP 1997 13... 26... SED. SUSP. FALL DIAM. *S FINER THAN .016 MM (70329) 71 71 59 58 65 47 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 83 83 72 71 79 62 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 97 95 88 88 90 81 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 98 98 93 93 95 87 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 98 98 98 95 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 99 99 99 98 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 99 100 99 320 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1996 10... NOV 07... 07... 07... 13... 22. .. MAY 1997 23... JUN 02... 02... JUL 21... 21... AUG 22... 22... 22. .. 22... 31... SEP 1997 13... 25... 26... TIME 1656 0240 0300 1445 0225 1558 1540 1630 1655 0640 0725 1255 1325 1545 1623 1255 2350 1516 0836 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND (00061) 234 1060 965 811 1150 62 62 1830 1570 1750 1030 1740 873 1060 861 54 799 1310 990 SEDI- MENT, SUS- PENDED (MG/L) (80154) 240 1120 600 454 591 233 61 815 546 1140 533 443 262 168 201 36 591 811 470 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 152 3200 1560 994 1830 39 10 4030 2310 5390 1480 2070 617 481 467 5.2 1270 2870 1260 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 89 94 92 92 95 93 97 78 83 76 87 92 92 87 93 94 90 92 90 321 RIO SABANA BASIN 50067000 RIO SABANA AT SABANA, PR LOCATION.--Lat 18°19'52", long 65°43'52", Hydrologic Unit 21010005, on right bank along Highway 988, 0.3 mi (0.5 km) north of junction of Highways 988 and 983 in Sabana, and 3.3 mi (5.3 km) south of Luquillo. DRAINAGE AREA.--3.96 mi' (10.26 kma ). PERIOD OF RECORD.—October 1979 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 260 ft (80 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Low-flow affected by Puerto Rico Aqueduct and Sewer Authority Water Intake 1.0 mi (1.6 km) upstream, and purification plant 0.2 mi (0.32 km), Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER DAY OCT NOV 1 20 28 2 18 30 3 16 28 4 32 29 5 37 50 6 20 41 7 37 350 8 20 42 9 18 31 10 38 16 11 23 18 12 17 90 13 19 147 14 21 30 15 20 17 16 18 12 17 16 12 18 17 20 19 18 56 20 16 20 21 15 59 22 15 87 23 18 43 24 15 180 25 14 32 26 21 22 27 17 20 28 69 34 29 79 25 30 21 84 31 19 TOTAL 744 1653 MEAN 24.0 55.1 MAX 79 350 MIN 14 12 AC-FT 1480 3280 CFSM 6.06 13.9 IN. 6.99 15.53 STATISTICS OF MONTHLY MEAN MEAN 22.4 32.6 MAX 66.4 79.7 (WY) 1986 1988 MIN 6.48 8.15 (WY) 1983 1981 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 34 31 25 22 19 19 18 17 16 16 18 16 15 14 16 43 17 13 13 12 13 13 12 12 12 12 26 31 125 40 24 714 23.0 125 12 1420 5.82 6.71 JAN 16 16 14 16 42 23 16 33 18 14 14 13 12 11 10 11 11 11 10 13 32 130 92 105 32 15 11 13 15 13 29 811 26.2 130 10 1610 6.61 7.62 SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBE) DAILY MEAN VALUES FEB 125 73 19 38 35 15 14 11 38 12 15 25 20 10 8.7 8.3 8.8 8.7 13 11 52 28 11 9.6 8.9 8.1 7.7 17—— —— —— 650.8 23.2 125 7.7 1290 5.87 6.11 DATA FOR WATER YEARS 1980 25.1 64.1 1982 3.92 1990 FOR 15.6 48.5 1996 6.12 1986 13.0 23.2 1997 2.94 1983 MAR 7.2 8.0 12 14 19 12 11 18 19 17 15 16 15 13 12 12 11 13 11 11 12 9.6 8.6 8.0 8.1 8.4 8.3 14 13 9.3 8.0 373.5 12.0 19 7.2 741 3.04 3.51 - 1997 11.3 36.0 1987 2.71 1994 1996 CALENDAR YEAR 11581.2 31.6 1100 2.2 2.8 22970 7.99 108.79 59 18 3.9 Sep 10 May 29 Mar 20 APR 6.6 21 23 12 9.4 6.3 5.5 5.2 5.1 4.8 4.6 4.9 4.4 4.5 4.1 3.7 3.9 4.4 4.5 5.3 5.5 5.5 .4 .3 .2 .1 .9 .1 .4 .6 —— 190.2 6.34 23 3.7 377 1.60 1.79 MAY .7 .4 .4 .0 .9 .1 .8 13 6.8 4.7 22 13 16 8.2 3.9 3.6 4.5 3.8 2.7 3.0 3.4 2.9 6.4 17 9.6 147 124 18 8.4 6.0 7.4 485.6 15.7 147 2.7 963 3.96 4.56 JUN 5.4 4.4 10 4.8 3.0 2.3 e2.1 e2.6 e2.1 el. 8 el. 7 e3.7 eS.l e3.7 el. 9 el. 7 el. 8 e3.6 e4.0 e9.4 e2.7 el. 8 e9.0 eS.O e2.0 3.6 2.8 3.0 2.2 2.1 —— 109.3 3.64 10 1.7 217 .92 1.03 R 1997 JUL 1.6 1.9 2.0 2.1 2.1 2.5 2.5 3.3 4.2 5.6 4.0 3.8 93 24 4.9 6.6 5.0 3.6 4.0 7.4 166 54 34 9.3 14 12 6.3 10 6.1 27 20 542.8 17.5 166 1.6 1080 4.42 5.10 AUG 6.5 6.0 8.1 5.7 4.5 3.8 3.9 3.7 4.6 12 5.1 4.1 3.1 3.0 3.4 4.1 7.9 8.4 4.3 3.2 3.5 124 11 22 17 6.2 7.8 6.6 11 9.2 29 352.7 11.4 124 3.0 700 2.87 3.31 SEP 34 14 7.9 9.6 7.0 6.4 6.6 5.9 17 9.3 5.0 9.1 23 45 63 13 8.0 11 7.4 6.7 8.8 30 16 15 166 e400 e21 e9.2 eS.O e52 1034.9 34.5 400 5.0 2050 8.71 9.72 , BY WATER YEAR (WY) 11.3 33.5 1990 2.20 1984 FOR 1997 7661 21 400 1 2 2960 14 15200 5 71 38 12 3 31.2 63.9 1982 4.65 1994 WATER YEAR .8 .0 Sep 26 .6 Jul 1 .0 Jun 29 Sep 26 .15 Sep 26 .30 .97 .6 20.4 50.6 1987 3.64 1997 16.8 36.0 1996 5.84 1986 WATER 20 31 7 1100 1 9600 19 14600 5 69 38 8 2 17.9 39.9 1995 3.09 1994 YEARS 1980 .2 .9 .85 .96 .0 .74 .86 .09 .17 .8 .7 Sep Apr Apr Jan Jan Apr 23.9 74.2 1996 7.23 1987 - 1997 1996 1994 10 1996 10 1983 6 1983 5 1992 5 1992 17 1983 e Estimated 322 RIO FAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, PR LOCATION.--Lat 18°16'21", long 65°43'18", Bydrologic Unit 21010005, on right bank, 4.1 mi (6.6 km) from Plaza de Naguabo, 0.5 mi (0.8 km) northeast from Escuela Sonadora, 1.5 mi (2.4 km) southwest of Colonia Paraiso, and 2.5 mi (4.0 km) norht from Escuela Segunda Unidad Mariana. DRAINAGE AREA.—3.69 mi 2 (9.56 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—Oct. 1, 1995 to Nov. 8, 1995 (estimated discharge). Nov. 9, 1995 to current year. GAGE.—Water-stage recorder. Datum of gage is 328 ft (100 m) above mean sea level, from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV 1 e7.2 ell 2 e!2 e25 3 e9.2 e54 4 el? e32 5 e!9 e45 6 ell ellO 7 e9.4 e28 8 e20 e23 9 e20 e!9 10 e!9 e!7 11 e!8 e!4 12 e!7 e!2 13 e!70 e30 14 e39 e!4 15 e32 ell 16 e!6 e21 17 e!7 e!4 18 ell elO 19 ell e9.2 20 e9.0 e8.5 21 68.5 8.5 22 e7.3 8.3 23 e25 8.0 24 e47 8.8 25 e60 9.1 26 e42 13 27 e!3 8.3 28 ell 8.9 29 e9.0 11 30 e7.4 10 31 e9.4 TOTAL 723.4 601.6 MEAN 23.3 20.1 MAX 170 110 MIN 7.2 8.0 AC-FT 1430 1190 CFSM 6.32 5.43 IN. 7.29 6.06 DEC 7.9 7.6 7.7 7.5 7.1 8.0 7.2 8.3 11 16 13 17 58 57 18 25 107 172 60 68 25 21 19 18 17 15 15 24 15 14 13 879.3 28.4 172 7.1 1740 7.69 8.86 STATISTICS OF MONTHLY MEAN DATA MEAN 23.3 20.1 MAX 23.3 20.1 (WY) 1996 1996 MIN 23.3 20.1 (WY) 1996 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 28.4 28.4 1996 28.4 1996 JAN 13 13 14 15 13 26 16 56 18 14 113 59 56 453 106 40 27 34 45 75 37 27 21 23 26 23 49 71 27 19 18 1547 49.9 453 13 3070 13.5 15.60 FOR WATER 49.9 49.9 1996 49.9 1996 FEB MAR 18 10 18 9.9 18 10 20 11 17 33 19 15 29 14 17 14 29 16 18 15 18 14 15 12 28 11 16 10 20 12 17 IS 15 11 14 12 21 11 14 10 13 10 13 9.8 11 9.7 45 9.7 15 9.7 13 9.8 12 9.8 12 15 11 15 13 —— 12 526 389.4 18.1 12.6 45 33 11 9.7 1040 772 4.92 3.40 5.30 3.93 YEARS 1996 - 1996 18.1 12.6 18.1 12.6 1996 1996 18.1 12.6 1996 1996 APR 9.7 9.5 9.2 13 18 11 9.5 9.2 9.2 9.0 8.9 39 19 11 12 12 9.8 16 16 10 9.6 12 25 18 12 12 12 23 16 19—— 419.6 14.0 39 8.9 832 3.79 4.23 , BY WATER 14.0 14.0 1996 14.0 1996 MAY 13 12 11 11 10 11 72 69 42 31 19 18 332 42 22 16 15 13 12 11 13 14 17 15 11 10 11 10 11 19 24 937 30.2 332 10 1860 8.19 9.45 YEAR (WY) 30.2 30.2 1996 30.2 1996 JUN 26 48 19 71 53 74 44 23 23 21 46 155 31 43 128 105 52 57 e55 e43 e43 e47 e46 e35 e30 e26 44 62 31 28 --- 1509 50.3 155 19 2990 13.6 15.21 50.3 50.3 1996 50.3 1996 JUL 26 25 32 25 25 26 25 332 65 32 26 38 35 229 66 29 24 21 e!7 e36 e25 e!9 e!6 e!5 e!6 e28 e!4 e!3 e!4 ell elO 1315 42.4 332 10 2610 11.5 13.26 42.4 42.4 1996 42.4 1996 AUG e!3 e!7 e21 e24 e!5 e!3 e!2 elO e!7 e!6 ell e!5 eSO e220 e90 elSO e76 e41 e34 e20 e!7 e!5 e28 e!20 e90 e33 e!7 e!9 e!5 e!4 e!2 1275 41.1 220 10 2530 11.1 12.85 41.1 41.1 1996 41.1 1996 SEP e29 e!3 elO e24 e64 e27 e!5 e35 e400 e!700 e260 e90 e98 e!30 e!40 e92 e40 e46 e41 54 49 32 32 29 27 25 26 29 25 35 — - 3617 121 1700 10 7170 32.7 36.46 121 121 1996 121 1996 FOR 1996 WATER YEAR 13739.3 37.5 1700 7.1 7.6 5110 10.72 7.0 27250 10.2 138.51 64 18 9.7 Sep 10 Dec 5 Dec 1 Sep 10 Sep 10 Dec 7 e Estimated RIO PAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, PR--Continued DISCHARGEE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 323 OCT NOV DEC JAN JUN JUL AUO SEP 1 23 23 2 24 22 3 19 28 4 19 23 5 26 20 6 19 19 7 24 164 8 17 32 9 17 67 10 36 39 11 16 69 12 14 172 13 13 87 14 13 72 15 15 33 16 11 27 17 11 43 18 17 31 19 19 79 20 18 33 21 15 99 22 14 35 23 17 24 24 15 191 25 14 20 26 27 15 27 19 20 28 56 42 29 50 26 30 17 82 31 16 —— TOTAL 631 1637 MEAN 20.4 54.6 MAX 56 191 MIN 11 15 AC-PT 1250 3250 CFSM 5 . 52 14 . 8 IN. 6.36 16.50 STATISTICS OF MONTHLY MEAN MEAN 21.8 37.3 MAX 23.3 54.6 (WY) 1996 1997 MIN 20.4 20.1 (WY) 1997 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 39 22 17 15 14 15 15 15 15 16 45 14 14 14 18 45 16 14 13 13 14 14 13 15 17 17 53 68 114 57 38 809 26.1 114 13 1600 7.07 8.16 DATA 27.2 28.4 1996 26.1 1997 21 17 16 24 40 19 19 49 20 15 14 18 14 14 14 13 14 14 17 42 89 216 135 153 e33 e28 e20 e28 e27 el9 e23 1185 38.2 216 13 2350 10.4 11.95 FOR WATER 44.1 49.9 1996 38.2 1997 e200 e28 e68 e29 e31 e!8 e!9 e!4 e43 e!7 e!5 e82 e58 e27 e!6 15 16 16 23 21 47 28 19 18 19 19 18 16 —— ___ —— 940 33.6 200 14 1860 9.10 9.48 YEARS 1996 25.7 33.6 1997 18.1 1996 16 18 23 21 27 16 16 24 19 15 15 15 15 13 13 13 12 11 11 10 13 9.9 9.8 9.5 9.5 9.5 9.8 19 16 11 11 451.0 14.5 27 9.5 895 3.94 4.55 - 1997 13.6 14.5 1997 12.6 1996 FOR 1996 CALENDAR YEAR 14612. 39. 1700 8. 9. 28980 10. 147. 71 19 11 0 9 Sep 10 9 Apr 11 8 Mar 21 8 31 10 35 18 16 19 11 10 10 9.6 9.4 9.0 8.6 8.7 8.5 8.2 7.7 7.7 7.4 7.6 7.7 7.0 7.0 7.0 7.3 7.3 7.3 7.7 7.6 7.6 7.6 —— 302.5 10.1 35 7.0 600 2.73 3.05 7.4 7.3 7.3 7.6 7.7 7.8 21 26 11 10 13 11 28 13 10 10 14 10 9.5 11 13 10 10 10 9.8 27 22 14 15 13 14 400.4 12.9 28 7.3 794 3.50 4.04 15 e50 e!8 12 11 9.7 9.4 10 9.0 8.7 8.7 8.5 11 10 8.1 7.5 8.0 elO 12 e20 ell 8.6 18 12 9.7 15 9.4 8.6 8.4 8.4 —— 365.7 12.2 50 7.5 725 3.30 3.69 8.4 8.2 8.0 8.0 7.9 7.6 7.9 9.1 8.9 8.1 7.8 8.6 11 9.1 8.1 9.4 9.6 9.7 12 17 99 29 29 15 15 19 13 17 13 18 16 467.4 15.1 99 7.6 927 4.09 4.71 13 13 13 17 13 12 12 12 15 45 14 13 14 16 16 31 23 24 15 14 13 61 20 25 20 18 16 15 14 13 19 579 18.7 61 12 1150 5.06 5.84 28 16 15 13 12 12 11 19 17 13 12 14 21 22 36 16 14 17 14 14 20 20 21 17 34 e430 e!9 16 15 28 —— 956 31.9 430 11 1900 8.64 9.64 , BY WATER YEAR (WY) 12.0 14.0 1996 10.1 1997 FOR 1997 8724 23 430 7 7 1580 6 7 17300 6 87 42 15 8 21.6 30.2 1996 12.9 1997 WATER YEAR .0 .9 Sep 26 .0 Apr 21 .2 Apr 20 Sep 26 .49 Sep 26 .0 Apr 20 .48 .95 .4 31.2 50.3 1996 12.2 1997 28.7 42.4 1996 15.1 1997 WATER 30 37 23 1700 7 7 5110 10 7 22260 8 113 54 16 9 29.9 41.1 1996 18.7 1997 YEARS 1996 - .7 .5 .9 Sep 10 .0 Apr 21 .2 Apr 20 Sep 10 .72 Sep 10 .0 Dec 7 .33 .15 .1 76.2 121 1996 31.9 1997 1997 1996 1997 1996 1997 1997 1996 1996 1995 e Estimated 324 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, PR—Continued HATER-QUALITY RECORDS PERIOD OF RECORD.—Hater years 1996 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1995 to current year . INSTRUMENTATION.— USDH-48 sediment sampler and automatic sediment sampler since 1995. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 477 mg/L September 26, 1997; Minimum daily mean, 1 mg/L several days, 1996-97. SEDIMENT LOADS: Maximum daily mean, 1,540 tons (1,4000 tonnes) January 14, 1996; Minimum daily mean, 0.01 tons (0.01 tonnes)several days, 1996-97. EXTREMES FOR HATER YEARS 1996-1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 366 mg/L May 13, 1996; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,540 tons (1,400 tonnes) January 14, 1996; minimum daily mean 0.02 tons (0.02 tonnes) several days. SEDIMENT CONCENTRATION: Maximum daily mean, 477 mg/L September 26, 1997; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 719 tons (652 tonnes) September 26, 1997; minimum daily mean 0.02 tons (0.02 tonnes) Jseveral days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 AY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) e7.2 e!2 e9.2 e!7 e!9 ell e9.4 e20 e20 e!9 e!8 e!7 e!70 e39 e32 e!6 e!7 ell ell e9.0 e8.5 e7.3 e25 e47 e60 e42 e!3 ell e9.0 e7.4 e9.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 2 1 2 3 3 1 2 4 4 3 3 3 25 8 5 3 3 2 2 1 1 1 3 11 14 5 2 1 1 1 1 e.04 e.04 e.05 e.12 e.14 e.06 e.06 e.15 e.19 e.18 e.16 e.14 e4.5 el. 9 e.46 e.19 e.12 e.08 e.05 e.04 e.03 e.02 e.12 el.O e2.0 .71 .12 .04 .03 .02 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 723.4 12.79 ell e25 e54 e32 e45 ellO e28 e23 e!9 e!7 e!4 e!2 e30 e!4 ell e21 e!4 elO e9.2 e8.5 8.5 8.3 8.0 8.8 9.1 13 8.3 8.9 11 10 601.6 3 4 9 8 10 20 5 4 3 3 2 2 4 2 2 3 1 1 1 1 1 1 1 1 1 2 1 1 1 1 e.07 e.19 e.98 e.88 el.O e3.7 e.83 e.26 e.18 e.14 e.10 e.08 e.19 e.ll e.07 e.12 e.07 e.03 e.03 e.02 .02 .02 .02 .02 .03 .10 .02 .03 .04 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 9.38 7.9 7.6 7.7 7.5 7.1 8.0 7.2 8.3 11 16 13 17 58 57 18 25 107 172 60 68 25 21 19 18 17 15 15 24 15 14 13 879.3 1 1 1 1 2 2 2 2 2 3 2 3 24 9 4 3 43 59 17 25 1 1 1 1 1 1 1 6 6 11 3 .03 .03 .03 .03 .03 .04 .03 .04 .06 .14 .08 .26 6.6 1.8 .20 .27 64 47 3.9 12 .08 .06 .05 .05 .05 .04 .04 .46 .25 .42 .12 138.19 e Estimated RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 325 MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 13 13 14 15 13 26 16 56 18 14 113 59 56 453 106 40 27 34 45 75 37 27 21 23 26 23 49 71 27 19 18 1 1 1 2 2 7 4 24 2 1 42 16 18 282 28 2 2 5 10 23 8 2 1 1 5 2 14 19 29 33 33 .04 .04 .05 .10 .07 .65 .66 7.4 .12 .05 28 3.5 4.7 1540 11 .25 .15 .57 1.6 6.7 .90 .15 .07 .06 .39 .14 2.2 4.1 2.1 1.8 1.6 18 18 18 20 17 19 29 17 29 18 18 15 28 16 20 17 15 14 21 14 1? 13 11 45 15 13 12 12 11 ___ ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 26 11 5 3 2 3 7 2 7 4 2 2 9 5 5 3 12 17 8 8 7 4 2 13 5 4 10 18 13 1.2 .54 .24 .20 .07 .15 .71 .10 .79 .22 .10 .09 1.9 .22 .29 .15 .48 .64 .53 .29 .24 .13 .06 4.4 .19 .14 .32 .55 .40 MEAN DISCHARGE (CFS) 10 9.9 10 11 33 15 14 14 16 15 14 12 11 10 12 15 11 12 11 10 10 9.8 9.7 9.7 9.7 9.8 9.8 15 15 13 12 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 9 5 3 2 9 4 2 3 8 2 1 3 4 3 2 1 1 2 8 18 6 2 2 2 2 4 5 5 4 3 2 .25 .14 .09 .06 .97 .15 .07 .18 .41 .10 .05 .09 .12 .07 .05 .04 .03 .05 .23 .49 .16 .06 .05 .05 .06 .10 .14 .25 .18 .12 .08 TOTAL 1547 1619.16 526 15.34 389.4 4.89 326 RIO PAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPT! 1996 DAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.7 9.5 9.2 13 18 11 9.5 9.2 9.2 9.0 8.9 39 19 11 12 12 9.8 16 16 10 9.6 12 25 18 12 12 12 23 16 19 1 2 2 2 4 2 1 1 2 2 1 9 4 2 1 1 1 3 2 1 1 1 5 3 2 1 1 5 1 1 .03 .04 .04 .11 .22 .06 .03 .03 .04 .05 .03 1.4 .25 .05 .03 .03 .03 .20 .09 .03 .03 .05 .54 .19 .06 .04 .04 .59 .06 .05 13 12 11 11 10 11 72 69 42 31 19 18 332 42 22 16 15 13 12 11 13 14 17 15 11 10 11 10 11 19 24 1 1 1 1 1 1 30 30 2 6 1 1 366 12 2 1 1 1 1 1 2 2 3 1 1 1 1 1 1 4 4 .04 .03 .03 .03 .03 .03 28 29 .30 .57 .06 .05 1500 1.7 .12 .06 .04 .03 .03 .03 .06 .07 .14 .05 .03 .03 .03 .03 .03 .51 .27 26 48 19 71 53 74 44 23 23 21 46 155 31 43 128 105 52 57 e55 e43 e43 e47 e46 e35 e30 e26 44 62 31 28 9 14 4 24 18 27 4 1 3 1 12 43 3 10 53 41 8 13 2 2 1 1 1 1 1 1 5 17 3 2 2.1 5.6 .23 16 13 16 .77 .06 .23 .07 4.3 39 .22 4.0 41 19 1.1 2.4 1.33 1.19 .14 .12 .13 .11 .09 e.08 .66 5.0 .26 .15 419.6 4.44 937 1561.43 1509 172.34 e Estimated 327 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 26 25 32 25 25 26 25 332 65 32 26 38 35 229 66 29 24 21 a!7 a36 a25 a!9 a!6 a!5 al6 a28 a!4 e!3 a!4 all alO JULY 2 2 2 2 3 4 5 219 13 2 1 9 25 141 22 3 1 2 2 1 1 1 2 3 3 2 2 1 1 1 2 TOTAL 1315 —— YEAR a 13739.3 Estimated .14 .14 .17 .14 .18 .26 .34 639 3.4 .19 .08 1.9 2.4 227 5.1 .23 .09 .10 .07 .07 .08 .06 .08 .14 .13 .12 .09 .05 .04 .04 .05 881.88 4706.69 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST •13 •17 a21 •24 •15 •13 a!2 •10 •17 •16 •11 a!5 •50 a220 •90 •180 a? 6 •41 •34 •20 a!7 •15 •28 •120 •90 a33 •17 •19 •15 •14 •12 1275 2 2 2 2 2 2 2 2 2 2 1 1 2 a •: 4 •] 2 2 2 2 2 2 2 11 2 1 1 1 1 2 3 4 .06 .08 .10 .12 .10 .08 .07 .06 .07 .07 .05 .04 .17 2.2 L.6 .80 .65 .30 .20 .14 .10 .09 .58 .36 .34 .15 .06 .05 .08 .13 .14 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 9.04 •29 •13 •10 •24 •64 •27 •15 •35 •400 •1700 •260 •90 •98 •130 •140 •92 •40 •46 •41 54 49 32 32 29 27 25 26 29 25 35 3617 4 4 4 5 11 8 5 5 8 48 40 3 3 7 8 6 5 4 2 15 12 5 3 3 2 2 1 1 1 9 • .21 • .21 • .13 • .21 •1.4 •1.0 • .27 • .35 •3.3 •167 •86 •1.3 • .64 a2.2 •2.7 •1.9 • .82 a.44 • .28 2.9 2.1 .48 .29 .20 .15 .11 .09 .08 .07 .98 277.81 328 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 23 24 19 19 26 19 24 17 17 36 16 14 13 13 15 11 11 17 19 18 15 14 17 15 14 27 19 56 50 17 16 19 20 16 8 9 10 8 9 10 10 6 2 1 2 3 2 1 12 64 14 2 1 1 1 1 6 5 30 19 2 1 1.2 1.3 .85 .42 .92 .55 .56 .42 .44 1.1 .26 .06 .05 .08 .14 .07 .04 1.7 3.4 .68 .07 .04 .05 .04 .04 .56 .25 27 5.8 .09 .06 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 23 22 28 23 20 19 164 32 67 39 69 172 87 72 33 27 43 31 79 33 99 35 24 191 20 15 20 42 26 82 9 12 13 9 6 4 108 8 27 14 24 74 48 3 2 3 14 16 21 16 67 10 7 122 7 4 5 14 8 17 .55 .74 1.1 .55 .33 .21 101 .75 7.1 2.1 5.4 45 15 .58 .18 .27 4.3 2.0 7.7 2.2 55 1.8 2.0 111 .47 .18 .25 2.7 .58 6.4 MEAN MEAN CONCEN- SEDIMENT DISCBARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 39 22 17 15 14 15 15 15 15 16 45 14 14 14 18 45 16 14 13 13 14 14 13 15 17 17 53 68 114 57 38 14 7 2 2 4 7 7 5 3 3 19 4 2 1 4 18 3 1 1 1 1 3 6 4 2 3 17 11 33 22 12 2.9 .49 .09 .08 .15 .30 .28 .19 .13 .12 2.8 .16 .06 .04 .62 2.8 .14 .04 .04 .04 .04 .10 .23 .16 .09 .17 2.9 4.7 19 4.0 1.4 TOTAL 631 48.24 1637 377.44 809 44.26 329 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 21 17 16 24 40 19 19 49 20 15 14 18 14 14 14 13 14 14 17 42 89 216 135 153 e33 e28 e20 e28 e27 e!9 e23 9 3 2 10 17 4 3 17 4 3 4 5 2 1 1 2 3 4 11 17 58 129 67 48 43 9 2 2 3 3 2 .52 .15 .10 1.4 2.4 .19 .15 4.4 .21 .11 .14 .23 .08 .04 .05 .08 .13 .16 .69 2.6 17 200 28 22 e!6 el. 4 e.16 e.16 e.21 e.16 e.13 FEBRUARY e200 e28 e68 e29 e31 e!8 e!9 e!4 e43 e!7 e!5 e82 e58 e27 e!6 15 16 16 23 21 47 28 19 18 19 19 18 16 —— —— —— 14 35 7 13 5 2 2 4 26 8 3 4 7 5 3 3 4 3 6 5 17 29 10 3 4 4 3 3 —— —— —— e5.5 ell e.91 el. 7 e.43 e.16 e.12 e.19 el. 8 e.68 e.ll e.51 el. 3 e.57 e.17 .14 .16 .15 .42 .29 3.0 2.3 .49 .17 .18 .20 .16 .12 MARCH 16 18 23 21 27 16 16 24 19 15 15 15 15 13 13 13 12 11 11 10 13 9.9 9.8 9.5 9.5 9.5 9.8 19 16 11 11 2 3 5 5 8 5 3 6 5 2 2 2 2 2 2 2 3 4 5 3 3 1 1 2 2 3 2 7 10 4 2 .10 .14 .30 .33 .77 .21 .12 .45 .28 .09 .08 .08 .08 .07 .07 .09 .10 .13 .15 .08 .11 .04 .03 .04 .06 .07 .07 .56 .48 .14 .06 TOTAL 1185 299.05 940 32.93 451.0 5.38 e Estimated 330 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CPS) 10 35 18 16 19 11 10 10 9.6 9.4 9.0 8.6 8.7 8.5 8.2 7.7 7.7 7.4 7.6 7.7 7.0 7.0 7.0 7.3 7.3 7.3 7.7 7.6 7.6 7.6 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MO/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MO/L) (TONS/DAY) APRIL 1 72 10 5 6 5 4 3 2 2 1 1 1 1 1 1 1 1 2 2 1 2 11 31 18 9 4 2 1 1 TOTAL 302.5 .04 26 .53 .23 .32 .15 .11 .08 .05 .04 .04 .03 .03 .02 .02 .02 .02 .03 .04 .03 .02 .04 .22 .61 .35 .18 .08 .04 .03 .02 29.42 7.4 7.3 7.3 7.6 7.7 7.8 21 26 11 10 13 11 28 13 10 10 14 10 9.5 11 13 10 10 10 9.8 27 22 14 15 13 14 400.4 MAY 2 3 4 5 4 3 9 9 4 2 3 6 16 23 13 3 3 3 2 3 4 3 3 3 2 14 5 5 5 3 2 .04 .06 .08 .09 .09 .07 1.6 .87 .12 .06 .15 .18 1.7 .78 .36 .09 .11 .08 .06 .08 .13 .08 .08 .08 .06 2.9 .83 .18 .19 .09 .10 JUNE 11.39 15 e50 e!8 12 11 9.7 9.4 10 9.0 8.7 8.7 8.5 11 10 8.1 7.5 8.0 elO 12 e20 ell 8.6 18 12 9.7 15 9.4 8.6 8.4 8.4 365.7 4 31 3 1 1 1 1 2 2 1 1 4 8 4 2 1 1 1 2 17 2 1 13 7 1 4 3 2 1 1 .15 e!3 e.16 .04 .03 .03 .03 .04 .04 .03 .03 .10 .23 .11 .04 .02 .02 e.03 .05 e2.2 e.05 .03 1.1 .26 .03 .16 .07 .04 .03 .03 18.18 e Estimated 331 RIO PAJARDO BASIN 50070500 RIO PAJARDO ABOVE PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CPS) (MO/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) 8.4 8.2 8.0 8.0 7.9 7.6 7.9 9.1 8.9 8.1 7.8 8.6 11 9.1 8.1 9.4 9.6 9.7 12 17 99 29 29 15 15 19 13 17 13 18 16 JULY 2 2 1 1 1 1 1 2 3 4 5 5 5 3 2 1 2 3 4 5 29 11 6 2 2 6 5 6 4 5 2 TOTAL 467.4 —— YEAR e 8724.0 Estimated AUGUST .04 .04 .03 .02 .02 .02 .03 .05 .08 .09 .10 .12 .15 .07 .03 .03 .05 .08 .12 .33 22 1.2 .76 .06 .10 .30 .19 .26 .13 .32 .13 26.95 1649.98 13 13 13 17 13 12 12 12 15 45 14 13 14 16 16 31 23 24 15 14 13 61 20 25 20 18 16 15 14 13 19 579 1 1 4 6 2 1 1 2 6 16 2 4 9 6 4 10 12 10 4 1 3 28 5 6 5 2 10 9 6 3 6 —— .05 .05 .13 .27 .08 .04 .04 .05 .34 2.6 .06 .16 .32 .25 .16 1.5 .87 .62 .14 .05 .10 8.1 .26 .58 .32 .10 .46 .34 .23 .12 .32 18.71 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) SEPTEMBER 28 16 15 13 12 12 11 19 17 13 12 14 21 22 36 16 14 17 14 14 20 20 21 17 34 e430 e!9 16 15 28 23 5 2 3 2 1 1 6 8 4 2 2 7 9 9 2 1 3 2 2 3 4 5 2 27 477 7 2 1 14 4.4 .22 .09 .09 .05 .03 .03 .74 .41 .13 .05 .09 .45 .64 1.1 .10 .05 .14 .08 .07 .19 .28 .29 .08 6.9 e719 e.40 .08 .05 1.8 956 738.03 332 RIO FAJARDO BASIN 50070500 RIO FAJARDO ABOVE FAJARDO, P.R.—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE SEP 1997 26... TIME 0745 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) SEDI- MENT, SUS- PENDED (MG/L) (80154) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) SED. SUSP. PALL DIAM. 9s FINER THAN .002 MM (70326) SED. SUSP. PALL DIAM. 9s FINER THAN .004 MM (70327) SED. SUSP. PALL DIAM. 9s FINER THAN .008 MM (70328) 908 3510 8610 22 26 34 DATE SEP 1997 26... SED. SUSP. PALL DIAM. 9s FINER THAN .016 MM (70329) SED. SUSP. PALL DIAM. 9s FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. 9s FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. 9s FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. 9s FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. 9s FINER THAN 1.00 MM (70335) 46 56 67 82 91 94 97 WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT DATE OCT 1996 28... NOV 07... DEC 29... FEE 1997 09... MAR 28... MAY 08... JUN 20... SEP 25... 26... TIME 2245 1700 1700 0700 1800 0600 0600 1720 0759 DIS- SEDI- SED. CHARGE, MENT, SUSP. INST. SEDI- DIS- SIEVE CUBIC MENT, CHARGE, DIAM. FEET SUS- SUS- 9s FINER PER FENDED FENDED THAN SECOND (MG/L) (T/DAY) .062 MM (00061) (80154) (80155) (70331) 436 161 128 e!4 22 57 43 77 1530 337 42 28 43 27 37 119 397 18 9.7 el.6 1.6 5.7 14 49 10 4670 19400 94 96 79 97 99 93 93 95 68 e Estimated RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR LOCATION.--Lat 18°17'56", long 65°41'42", Hydrologic Unit 21010005, on left bank off Highway 976, 0.1 mi (0.2 km) upstream from Highway 977 bridge, 0.3 mi (0.5 km) downstream from Quebrada Penon, 1.1 mi (1.8 km) northeast of Colonia Paralso, and 3.3 mi (5.3 km) southwest of Fajardo. 333 DRAINAGE AREA.--14.9 mi* (38.6 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—1960-61 (occasional low and peak-flow measurements only). March 1961 to current year. GAGE.—Water-stage recorder. Datum of gage is 137.60 ft (41.940 m) above mean sea level. Due to flood damage, gage datum has had changes as follows: Mar. 24, 1961 to May 5, 1969, 138.95 ft (42.352 m); May 6, 1969 to Mar. 16, 1972, 135.05 ft (41.163 m); Mar. 17, 1972 to Mar 25, 1975, 138.60 ft (42.245 m). REMARKS.—Records fair except those for estimated daily discharges, which are poor. Low flow affected by diversions for water supply about 400 m upstream from gaging station (estimated mean daily discharges is 9.0 ftVs (0.255 m'/s). Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT MOV DEC JAN FEB MAR APR MAY JDL AUG SEP 1 22 51 2 136 50 3 11 51 4 18 70 5 28 41 6 41 36 7 54 685 8 19 68 9 26 161 10 105 156 11 30 246 12 13 570 13 12 314 14 16 187 15 28 86 16 12 66 17 9.3 83 18 26 170 19 49 281 20 11 117 21 11 407 22 8.2 127 23 16 88 24 12 489 25 8.8 119 26 47 64 27 44 50 28 81 110 29 239 89 30 30 255 31 24 —— TOTAL 1187.3 5287 MEAN 38.3 176 MAX 239 685 MIN 8.2 36 AC-FT 2360 10490 CFSM 2.57 11.8 IN. 2.96 13.20 STATISTICS OF MONTHLY MEAN MEAN 91.0 105 MAX 260 295 (WY) 1971 1975 MIN 19.1 26.0 (WY) 1969 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 104 72 43 35 30 28 26 23 22 21 128 45 23 29 27 82 25 19 16 15 15 14 13 14 17 14 73 151 348 221 86 1779 57.4 348 13 3530 3.85 4.44 40 31 27 30 93 47 35 152 45 25 21 27 17 14 13 12 11 11 9.9 48 123 410 215 205 78 52 37 51 50 36 43 2008.9 64.8 410 9.9 3980 4.35 5.02 DATA FOR WATER 79.6 237 1976 14.9 1990 FOR 47.8 150 1996 15.4 1977 359 52 125 53 57 33 35 26 79 31 29 153 107 49 41 35 33 35 55 42 162 116 39 38 42 36 34 30 ___ ___ --- 1926 68.8 359 26 3820 4.62 4.81 YEARS 1961 38.8 80.4 1982 10.8 1983 26 32 46 45 61 31 27 55 41 27 24 25 26 22 23 26 23 22 20 20 31 19 18 18 18 17 17 37 70 26 21 914 29.5 70 17 1810 1.98 2.28 - 1997 35.0 109 1987 9.70 1977 1996 CALENDAR YEAR 29142. 79. 2610 4. 7. 57800 5. 72. 169 34 9. 5 6 Sep 10 6 May 29 4 May 24 34 76 6 18 224 126 54 77 35 30 27 26 24 24 24 23 22 20 19 18 18 17 20 17 17 17 17 16 15 17 18 16 16 --- 1012 33.7 224 15 2010 2.26 2.53 , BY WATER 43.4 129 1963 4.02 1984 19 20 20 19 19 18 77 89 22 17 25 26 80 30 15 14 23 15 13 12 24 12 11 12 13 90 88 36 23 22 23 927 29.9 90 11 1840 2.01 2.31 YEAR (WY) 90.0 399 1979 17.7 1973 26 207 31 22 14 11 10 12 9.8 8.4 8.2 8.0 12 15 8.8 7.2 7.5 17 19 64 19 10 61 29 14 25 13 10 8.8 8.1 --- 715.8 23.9 207 7.2 1420 1.60 1.79 59.2 166 1962 10.0 1985 FOR 1997 WATER YEAR 20317.9 55.7 771 6.5 7.2 6270 9.57 40300 3.74 50.73 126 26 11 Sep 26 Jul 7 JUl 1 Sep 26 Sep 26 8.0 7.8 7.6 7.1 6.9 6.6 6.5 9.9 9.4 8.4 7.8 8.0 15 13 8.1 9.8 12 10 12 40 e363 102 132 34 30 43 23 37 21 31 47 1076.9 34.7 363 6.5 2140 2.33 2.69 50.6 132 1969 11.4 1994 WATER 65 140 19 8800 1 1 21700 20 47610 4 59 128 32 10 23 19 17 28 18 14 13 15 17 190 27 18 18 24 22 66 78 52 21 15 13 e310 44 77 56 26 22 21 42 20 66 1392 44.9 310 13 2760 3.01 3.48 56.0 159 1979 9.70 1994 YEARS 1961 - .7 .0 Sep 18 .0 May 6 .5 Apr 18 Sep 18 .00 Sep 18 .86 May 3 .41 .93 219 49 28 21 17 15 14 29 37 18 11 14 34 38 194 30 20 21 15 14 28 30 33 29 185 771 42 18 16 102 —— 2092 69.7 771 11 4150 4.68 5.22 87.9 421 1989 18.9 1994 1997 1979 1994 1989 1984 1984 1989 1989 1984 e Estimated 334 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1960 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1982 to September 1986 and October 1995 to current year . INSTRUMENTATION.-- USDH-48 sediment sampler and automatic sediment sampler since 1995. EXTREMES FOR PERIOD OF DAILY RECORD.-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,210 mg/L October 6, 1985; Minimum daily mean, 1 mg/L several days, 1996-97. SEDIMENT LOADS: Maximum daily mean, 22,100 tons (20,000 tonnes) October 6, 1985; Minimum daily mean, 0.01 tons (0.01 tonnes) May 06,1996. EXTREMES FOR CURRENT YEAR 1997.-- SEDIMENT CONCENTRATION: Maximum daily mean, 620 mg/L September 26, 1997; minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 4,050 tons (3,670 tonnes) September 26, 1997; minimum daily mean 0.02 tons (0.02 tonnes) July 10-12, 1997. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1996 31... 0930 28 120 6.9 26.5 1.3 8.4 104 <10 53000 390 FEB 1997 13... 0930 148 81 6.4 23.0 17 8.3 95 <10 2000 3800 JUN 10... 0905 8.4 124 6.6 27.0 0.25 7.1 87 <10 30 110 SEP 11... 0905 11 119 6.5 26.5 1.2 7.9 99 <10 130 200 ALKA- DATE OCT 1996 31... FEB 1997 13... JUN 10... SEP 11... DATE OCT 1996 31... FEB 1997 13... JUN 10... SEP 11... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 33 -- 33 32 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- <0.10 0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 7.5 -- 7.4 6.9 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 27 -- 26 27 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 3.5 -- 3.5 3.5 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 95 -- 93 101 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- 11 13 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.15 -- 2.12 3.00 SODIUM AD- SORP- TION RATIO (00931) 0.8 -- 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 14 <1 2 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.0 -- 1.0 1.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.240 0.160 0.380 0.130 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 41 30 46 39 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 0.020 <0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 -- NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 0.240 0.160 0.400 0.140 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 5.0 -- 3.4 3.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 <0.010 0.450 0.030 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -- 13 14 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.26 0.05 0.21 335 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJAROO, PR—Continued WATER-QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE IRON, TOTAL RECOV- ERABLE (UO/L LEAD, TOTAL RECOV- ERABLE (UO/L MANGA- NESE, TOTAL RECOV- ERABLE (UO/L MERCURY TOTAL RECOV- ERABLE (UO/L SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- ERABLE (UO/L CYANIDE TOTAL (MG/L PHENOLS TOTAL METHY- LENE BLUE ACTIVE SUB- STANCE AS FB) AS PB) AS MN) AS BG) AS SE) AS AO) AS ZN) AS CN) (UO/L) (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) OCT 1996 31... FEB 1997 13... JDN 10... SEP 11... 270 90 <10 <0.10 11 <0.10 <1 <1 <1 <1 <0.010 <1 <0.010 <1 <0.02 <0.02 PESTICIDE ANALYSES CBLOR- DATE TIME PCS, TOTAL (UO/L) (39516) ALDRIN, TOTAL (UO/L) (39330) DANE, TECB- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UO/L) (39360) P,P'- DDE, TOTAL (UO/L) (39365) P,P'- DDT UNFILT RECOVER (UO/L) (39370) DI- AZINON, TOTAL (UO/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UO/L) (39388) JUN 1997 10... 0905 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 BNDRIN MATER UNFLTRD ETHION, DATE REG TOTAL (UQ/L) (UO/L) BEPTA- BEPTA- CHLOR MALA- CHLOR, EPOXIDE LINDANE TBION, TOTAL TOTAL TOTAL TOTAL (UO/L) (UG/L) (UO/L) (UO/L) (39390) (39398) (39410) (39420) (39340) (39530) METH- OXY- CBLOR, TOTAL (UO/L) (39480) METHYL PARA- THION, MXREX, TOTAL TOTAL (UO/L) (UO/L) (39600) (39755) JUN 1997 10... <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE PARA- PCNS THION, UNFILT TOTAL RECOVER (UO/L) (UO/L) (39540) (39250) PER- TBANE TOTAL (UO/L) (39034) TOX- APHENE, TOTAL (UG/L) (39400) TOTAL TRI- THION (UG/L) (39786) 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UO/L) (UG/L) (UO/L) (UG/L) (39730) (39740) (82183) (39760) JUN 1997 10... <0.010 <0.100 <0.100 <1.00 <0.010 <0.010 <0.010 <0.010 <0.010 336 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 RIO FAJARDO BASIN 50071000 RIO FAJARDO NEAR FAJARDO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN DISCHARGE (CFS) 22 136 11 18 28 41 54 19 26 105 30 13 12 16 28 12 9.3 26 49 11 11 8.2 16 12 8.8 47 44 81 239 30 24 MEAN CONCEN- TRATION (MG/L) OCTOBER 8 84 7 13 10 27 22 7 10 50 21 16 12 9 34 33 14 18 39 15 14 17 11 6 3 15 18 57 161 6 8 SEDIMENT DISCHARGE (TONS /DAY) .52 103 .21 .68 1.1 5.3 5.2 .37 .88 24 2.2 .54 .39 .41 2.9 1.0 .34 12 9.0 .44 .40 .37 .44 .19 .07 4.0 3.3 83 212 .56 .58 51 50 51 70 41 36 685 68 161 156 246 570 314 187 86 66 83 170 281 117 407 127 88 489 119 64 50 110 89 255 16 25 30 28 14 13 511 25 72 84 159 425 126 80 28 23 42 104 111 67 258 67 17 350 12 3 6 64 25 134 3.4 3.5 10 8.5 2.6 1.6 1410 5.1 46 64 184 770 186 72 8.8 4.4 28 70 150 34 696 36 4.3 625 5.5 .57 .85 28 7.2 128 i TO SEFTEHE MEAN DISCHARGE (CPS) DI 104 72 43 35 30 28 26 23 22 21 128 45 23 29 27 82 25 19 16 15 15 14 13 14 17 14 73 151 348 221 86 USK i»9Y MEAN CONCEN- TRATION (MG/L) 5CEMBER 35 54 27 10 4 5 7 9 10 9 54 18 5 10 8 37 7 5 4 4 4 4 5 5 5 5 23 113 202 211 106 SEDIMENT DISCHARGE (TONS/DAY) 17 11 3.2 .96 .32 .35 .51 .56 .58 .53 28 2.5 .34 .81 .77 10 .51 .24 .19 .17 .16 .16 .17 .19 .23 .20 6.4 130 274 134 25 TOTAL 1187.3 475.39 5287 4593.32 1779 649.05 RIO PAJARDO BASIN 50071000 RIO PAJARDO NR PAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 337 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE THAT ION DISCHARGE DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) (CPS) (MO/L) (TONS /DAY) JANUARY 40 31 27 30 93 47 35 152 45 25 21 27 17 14 13 12 11 11 9.9 48 123 410 215 205 78 52 37 51 50 36 43 91 82 77 75 45 81 18 33 16 7 6 6 3 3 3 4 4 3 3 28 71 261 143 119 41 5 3 11 15 4 8 9.8 6.8 5.5 6.6 14 11 1.9 20 2.1 .45 .34 .55 .14 .12 .12 .13 .11 .09 .08 5.5 51 929 127 93 10 .75 .34 1.7 2.1 .34 1.6 FEBRUARY 359 52 125 53 57 33 35 26 79 31 29 153 107 49 41 35 33 35 55 42 162 116 39 38 42 36 34 30 —— ___ —— 259 18 67 20 9 2 7 12 34 9 3 87 29 4 6 4 2 2 56 13 144 68 38 37 38 37 34 11 ___ ___ —— 963 2.5 88 9.3 2.0 .22 .74 .83 19 .77 .21 122 12 .47 .66 .39 .20 .19 12 1.5 109 46 3.9 3.8 4.3 3.6 3.0 .93 —— MARCH 26 32 46 45 61 31 27 55 41 27 24 25 26 22 23 26 23 22 20 20 31 19 18 18 18 17 17 37 70 26 21 3 9 19 16 32 17 22 21 19 15 12 10 9 7 6 5 4 5 6 6 10 8 9 9 8 4 7 16 34 14 11 .19 .95 2.5 2.1 8.7 1.4 1.7 3.7 2.2 1.1 .81 .70 .62 .43 .37 .36 .26 .29 .31 .33 .90 .40 .44 .44 .39 .18 .31 3.2 11 .97 .63 TOTAL 2008.9 1302.16 1926 1410.51 914 47.88 338 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 18 224 126 54 77 35 30 27 26 24 24 24 23 22 20 19 18 18 17 20 17 17 17 17 16 15 17 18 16 16 MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 9 156 77 19 28 4 4 9 9 7 6 6 10 17 18 16 9 5 5 7 8 7 7 7 6 4 3 2 2 3 .47 403 64 3.3 6.8 .35 .34 .64 .60 .47 .38 .35 .59 .99 .99 .85 .44 .23 .26 .40 .35 .32 .33 .32 .25 .17 .14 .11 .10 .13 MEAN DISCHARGE (CFS) 19 20 20 19 19 18 77 89 22 17 25 26 80 30 15 14 23 15 13 12 24 12 11 12 13 90 88 36 23 22 23 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 5 10 8 4 4 5 44 42 9 4 9 14 48 10 5 4 8 8 3 2 8 3 2 4 4 53 52 11 6 4 5 .27 .53 .40 .23 .23 .24 40 23 .55 .21 .97 1.0 33 .95 .21 .15 .61 .34 .12 .06 .56 .09 .06 .14 .13 63 47 1.6 .50 .27 .40 MEAN DISCHARGE (CFS) 26 207 31 22 14 11 10 12 9.8 8.4 8.2 8.0 12 15 8.8 7.2 7.5 17 19 64 19 10 61 29 14 25 13 10 8.8 8.1 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 5 118 9 8 3 2 3 3 3 4 3 2 3 4 3 4 4 5 9 38 7 2 38 8 2 5 1 2 2 1 362 .40 ! .86 .50 .10 .07 .07 .10 .09 .09 .07 .05 .15 .21 .07 .09 .08 .29 .45 33 33 .43 .07 I .90 .08 .43 .05 .05 .04 .03 TOTAL 1012 487.67 927 216.82 715.8 433.82 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 339 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN DISCHARGE (CFS) 8.0 7.8 7.6 7.1 6.9 6.6 6.5 9.9 9.4 8.4 7.8 8.0 15 13 8.1 9.8 12 10 12 40 e363 102 132 34 30 43 23 37 21 31 47 TOTAL 1076.9 YEAR e 20317.9 Estimated MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 2 6 4 2 2 2 2 2 1 1 1 1 4 5 6 12 7 3 3 17 245 40 85 25 14 10 6 12 9 14 26 —— .05 .13 .09 .04 .04 .04 .04 .05 .04 .02 .02 .02 .27 .18 .13 .32 .24 .10 .11 3.3 ellOO 17 63 2.4 1.1 1.3 .37 1.5 .53 1.9 5.2 1199.53 15989.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 23 19 17 28 18 14 13 15 17 190 27 18 18 24 22 66 78 52 21 15 13 1310 44 77 56 26 22 21 42 20 66 4 3 2 6 3 4 7 4 3 119 7 2 1 7 5 31 32 19 6 5 6 43 27 60 71 45 89 96 75 94 57 .23 .13 .09 .57 .15 .14 .23 .18 .14 108 .53 .12 .06 .47 .30 24 17 4.4 .37 .22 .20 e63 3.9 35 13 3.5 5.4 6.2 11 5.2 13 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 219 49 28 21 17 15 14 29 37 18 11 14 34 38 194 30 20 21 15 14 28 30 33 29 185 771 42 18 16 102 139 133 109 111 110 35 7 13 47 35 26 8 12 17 151 93 93 96 95 31 6 8 11 11 133 620 9 4 3 56 232 19 8.3 6.3 5.1 1.4 .26 5.3 5.6 1.8 .79 .31 1.1 2.5 164 7.6 4.9 5.4 3.8 1.1 .40 .94 1.3 .94 272 4050 1.4 .17 .14 53 1392 316.73 2092 4856.85 340 RIO FAJARDO BASIN 50071000 RIO FAJARDO NR FAJARDO, P.R.—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE SEP 1997 01... 26... DATE SEP 1997 01... 26... TIME 1800 0820 SED. SUSP. FALL DIAM. 9s FINER THAN .016 MM (70329) 83 45 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1010 1480 SED. SUSP. FALL DIAM. 9s FINER THAN .031 MM (70330) 89 63 SEDI- MENT, SUS- PENDED (MG/L) (80154) 969 5580 SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) 95 76 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2640 2230 SED. SUSP. SIEVE DIAM. 9s FINER THAN .125 MM (70332) 99 91 SED. SUSP. FALL DIAM. 9s FINER THAN .002 MM (70326) 54 21 SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) 99 97 SED. SUSP. FALL DIAM. 9s FINER THAN .004 MM (70327) 62 23 SED. SUSP. SIEVE DIAM. 9s FINER THAN .500 MM (70334) 100 99 SED. SUSP. FALL DIAM. 9s FINER THAN .008 MM (70328) 71 32 SED. SUSP. SIEVE DIAM. 9s FINER THAN 1.00 MM (70335) 100 99 RIO FAJARDO BASIN 50071000 —RIO FAJARDO NR FAJARDO, P.R.—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT 341 DATE NOV 1996 13... 21... 21... 21... DEC 29... JAN 1997 08... FEB 01... 19... JUL 21... AUG 22... SEP 01... 26... TIME 1140 1000 1150 1540 1400 1355 1130 1610 0652 1440 1610 0822 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 212 893 505 234 878 465 2830 93 614 1400 115 1760 SEDI- MENT, SUS- PENDED (MG/L) (80154) 46 387 241 262 78 72 2460 434 1500 83 445 5240 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 26 933 328 165 185 90 18800 109 2490 314 141 24800 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 88 97 97 97 93 98 96 94 90 95 98 90 342 LOCATION.—Lat 18°19'35", east of Fajardo plaza. RIO FAJARDO BASIN 50072500 RIO FAJARDO BELOW FAJARDO, PR WATER-QUALITY RECORDS long 65°38'47", 1.2 mi (1.9 km) southwest of Playa de Fajardo, and 0.5 mi (0.8 km) DRAINAGE AREA.—23.4 mi* (60.6 km*). PERIOD OF RECORD.—Water years 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. DATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) NOV 1996 13... 1125 E250 120 6.2 25.0 79 7.3 86 21 3800 3600 FEB 1997 13... 1115 E175 103 6.3 23.5 17 8.2 98 <10 2500 4100 JUN 10... 1105 8.8 143 6.6 30.0 0.47 7.4 98 <10 220 K140 SEP 11... 1035 13 132 6.3 30.0 0.70 6.8 90 23 440 280 ALKA- DATE NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... DATE NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... DATE NOV 1996 13... FEB 1997 13... JUN 10... 11... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 24 — 37 36 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.63 1.0 <0.20 0.23 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 5.6 — 8.2 7.7 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 17 -- 23 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.97 1.2 <0.20 0.26 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 2.5 — 4.1 4.0 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 64 — 101 113 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.3 5.4 0.56 1.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 8.3 -- 13 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 43 — 2.40 3.96 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.090 0.040 <0.020 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.7 — 0.9 1.0 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 44 12 <1 2 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 — 1.1 1.3 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.320 0.180 <0.010 0.030 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 21 31 56 44 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.340 0.190 <0.020 0.030 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 5.3 — 3.9 4.8 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.070 0.030 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — 15 16 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.60 0.97 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 — E • estimated K • non-ideal count RIO FAJARDO BASIN 50072500 RIO FAJARDO BELOW FAJARDO, PR—Continued HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 343 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS HN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SELE- NIUM, TOTAL (UO/L AS SE) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) CYANIDE TOTAL (MO/L AS CN) PHENOLS TOTAL (UO/L) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) NOV 1996 13... FEB 1997 13... JUN 10... SEP 11... 2300 170 <1 <1 70 18 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 344 RIO BLANCO BASIN 50074950 QUEBRADA OUABA NEAR NAGUABO, PR LOCATION.—Lat 18°17'02", long 65°47'20", Hydrologie Unit 21010005, on right bank, off Highway 191 at El Yungue Caribbean National Forest, 4.8 mi (7.7 km) southeast of Campamento Eliza Colberg, 1.3 mi (2.1 km) southeast of Mt. Britton, 2.0 mi (3.2 km) northwest of Pico del Este and 7.3 mi (11.7 km) southeast of Rio Orande Plaza. DRAINAGE AREA.—0.05 mi 3 (0.13 km3 ). PERIOD OF RECORD.—June 1992 to current year. GAGE.—Water-stage recorder. Elevation of gage is 2,100 ft (640 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 .29 .43 2 .24 .44 3 .35 .29 4 .22 .25 5 .21 .25 6 e.25 .27 7 e.30 1.7 8 .21 .34 9 .26 .29 10 .60 .27 11 .26 .47 12 .22 2.7 13 .25 .84 14 e.22 .56 15 e.26 .44 16 .30 .39 17 .29 .50 18 .29 .38 19 .30 .46 20 .24 .38 21 .24 .32 22 .22 .40 23 .28 .34 24 .23 2.0 25 .63 .57 26 .82 .45 27 .32 .42 28 .81 .52 29 .43 .39 30 .26 1.2 31 .22 TOTAL 10.02 18.26 MEAN .32 .61 MAX .82 2.7 MIN .21 .25 AC-FT 20 36 CFSM 2.69 5.07 IN. 3.11 5.66 DEC .61 .56 .56 .58 .52 .50 .45 .47 .43 .42 1.1 .57 .46 .42 .44 .56 .44 .43 .40 .43 .41 .38 .37 .45 .47 .56 .68 .86 1.3 .63 .63 17.09 .55 1.3 .37 34 4.59 5.30 JAN .49 .55 .47 .44 .49 .43 .39 .44 .38 .37 .38 .38 .37 .34 .36 .36 .36 .34 .41 .69 2.1 2.5 1.8 1.9 .83 .74 .49 .59 .48 .52 .51 20.90 .67 2.5 .34 41 5.62 6.48 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN .33 .49 MAX .41 .76 (WY) 1994 1993 MIN .25 .32 (WY) 1993 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .40 .61 1993 .22 1994 FOR .47 .67 1997 .28 1994 DAILY FEB .86 .41 .52 .57 .56 .40 .41 .35 .60 .33 .34 .58 .74 .36 .33 .34 .33 .37 .46 .56 1.0 .39 .32 .32 .37 .48 .36 .32 —— —— 12.98 .46 1.0 .32 26 3.86 4.02 YEARS 1992 .44 .60 1994 .32 1993 MEAN VALUES MAR .31 .34 .39 .34 .41 .30 .30 .51 .43 .36 .34 .36 .34 .31 .34 .29 .25 .27 .24 .25 .21 .21 .18 .19 .18 .19 .18 .24 .34 .17 .17 8.94 .29 .51 .17 18 2.40 2.77 - 1997 .28 .30 1995 .23 1994 1996 CALENDAR YEAR 193. f 23 . . 384 4. 59. . . . 42 53 Sep 10 10 Apr 10 13 May 24 40 96 74 33 17 APR .16 .25 .22 .58 .54 .29 .27 .26 .27 .25 .26 .21 .25 .22 .21 .20 .21 .18 .20 .19 .16 .15 .14 .12 .12 .12 .17 .12 .11 .11 —— 6.54 .22 .58 .11 13 1.82 2.03 MAY .09 .09 .09 .10 .08 .09 .77 1.1 .55 .47 .59 .45 .68 .43 .33 .38 .76 .33 .23 .26 .31 .32 .28 .27 .22 .34 .48 .32 .50 .30 .29 11.50 .37 1.1 .08 23 3.09 3.57 JUN .37 5.3 .51 .33 .23 .21 .22 .22 .20 .18 .15 .14 .34 .19 .15 .13 .18 .32 .26 .25 .18 .16 .43 .27 .22 .31 .18 .15 .15 .14 —— 12.07 .40 5.3 .13 24 3.35 3.74 JUL .14 .15 .14 .13 .13 .13 .13 .15 .22 .14 .13 .13 .20 .26 .23 .27 .22 .18 .30 .51 1.3 .25 .52 .22 .24 .30 .20 .22 .16 .50 .25 8.05 .26 1.3 .13 16 2.16 2.50 AUG .18 .14 .28 .40 .18 .16 .20 .21 .71 .92 .32 .34 .31 .25 .28 .73 .55 .71 .28 .24 .25 2.6 .44 .52 .41 .36 .33 .29 .28 .30 .35 13.52 .44 2.6 .14 27 3.63 4.19 SEP .39 .37 .29 .23 .21 .22 .22 .30 .31 .23 .22 .26 .77 .41 .51 .28 .23 .28 .22 .26 .48 .47 .39 .32 .76 1.4 .50 .43 .44 .44 —— 11.84 .39 1.4 .21 23 3.29 3.67 , BY WATER YEAR (WY) .28 .33 1994 .21 1995 FOR 1997 151 5 92 10 301 3 47 .39 .61 1993 .32 1996 WATER YEAR .71 .42 .3 Jun 2 .08 May 5 .09 Apr 30 Jun 2 .58 Jun 2 . 05 May 1 .46 .03 .63 .33 .16 .38 .50 1996 .32 1993 .53 1.18 1992 .22 1994 WATER 23 102 10 290 3 45 .37 .56 1992 .19 1993 YEARS 1992 .40 .49 .32 Sep .08 May .09 Apr Sep .74 Sep .05 May .34 .37 .70 .28 .16 .58 1.42 1996 .34 1993 - 1997 1996 1994 10 1996 5 1997 30 1997 10 1996 10 1996 1 1997 e Estimated RIO BLANCO BASIN 50075000 RIO ICACOS NEAR NAGUABO, PR 345 LOCATION.—Lat 18°16'38", long 65°47'09", Hydrologic Unit 21010005, in Caribbean National Forest, at Highway 191, at El Yunque, 1.6 mi (2.6 km) upstream from confluence with Rio Cubuy, 2.8 mi (4.5 km) north of Florida, and 5.3 mi (8.5 km) northwest of Naguabo Plaza. DRAINAGE AREA.--1.26 mi a (3.26 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—July 1945 to March 1953 (operated by Puerto Rico Water Resources Authority), annual maximum, water years 1953-62, annual low-flow measurements 1962-66, October 1979 to current year. GAGE.—Water-stage recorder, crest-stage gage and sharp-crested weir. Elevation of gage is 2,020 ft (616 m), from topographic map. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY NOV DEC MAR JUN AUG SEP 1 15 23 2 16 25 3 23 19 4 16 14 5 13 16 6 12 18 7 15 97 8 11 20 9 15 16 10 30 16 11 13 43 12 11 124 13 12 56 14 11 41 15 14 31 16 10 30 17 10 38 18 10 32 19 10 36 20 10 32 21 10 28 22 8.7 33 23 12 29 24 9.2 113 25 27 36 26 44 29 27 15 30 28 39 39 29 25 34 30 11 83 31 10 —— TOTAL 487.9 1181 MEAN 15.7 39.4 MAX 44 124 MIN 8.7 14 AC-FT 968 2340 CFSM 12.5 31.2 IN. 14.40 34.87 49 26 17 17 15 14 14 13 12 13 56 21 13 13 14 21 12 11 10 10 10 9.7 8.0 12 16 22 29 40 61 32 31 641.7 20.7 61 8.0 1270 16.4 18.95 19 25 19 19 22 18 16 19 17 15 16 15 14 14 13 13 13 13 19 28 72 92 74 74 33 36 22 31 27 25 28 861 27.8 92 13 1710 22.0 25.42 55 29 40 39 40 31 30 25 47 26 26 43 47 26 24 23 22 23 32 33 64 31 24 24 25 30 21 17 —— —— 897 32.0 64 17 1780 25.4 26.48 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1945 MEAN 15.3 19.1 MAX 32.1 46.9 (WY) 1986 1951 MIN 4.78 8.03 (WY) 1993 1948 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 15.6 31.3 1988 4.99 1990 FOR 14.0 28.4 1996 6.65 1994 14.4 44.0 1950 4.86 1983 13 15 20 17 26 12 11 25 16 11 9.6 11 10 9.3 12 11 8.8 9.0 8.2 8.2 9.0 8.0 8.1 8.0 8.8 9.4 9.8 14 19 10 9.7 376.9 12.2 26 8.0 748 9.65 11.13 - 1997 10.5 26.2 1949 3.90 1951 1996 CALENDAR YEAR 8296.6 22.7 737 3.2 4.4 16460 18.0 244.95 37 15 6.5 Sep 10 Apr 10 Apr 5 9.0 14 12 24 25 10 9.0 9.0 8.2 8.0 8.2 8.0 11 8.0 7.9 8.0 8.6 8.4 11 8.4 7.9 7.2 6.7 5.7 5.7 5.7 7.2 5.9 5.7 5.7 —— 279.1 9.30 25 5.7 554 7.38 8.24 , BY WATER 12.1 34.4 1950 4.77 1984 FOR 1997 6888 18 172 2 3 1110 6 2 13660 15 203 37 13 5 5.5 5.1 4.8 4.7 4.5 4.5 46 37 11 7.6 17 9.3 21 10 7.2 9.3 20 10 8.6 10 11 8.7 8.0 8.8 8.0 15 19 8.2 22 9.1 11 381.9 12.3 46 4.5 757 9.78 11.28 YEAR (WY) 16.5 26.6 1948 6.84 1994 15 172 19 9.6 7.6 7.3 6.4 7.7 6.5 6.4 6.4 6.1 17 9.9 6.0 5.7 7.3 13 11 20 11 6.9 23 9.6 6.8 16 5.3 4.2 3.6 3.5 —— 449.8 15.0 172 3.5 892 11.9 13.28 12.7 23.7 1996 5.19 1985 WATER YEAR .3 .9 .7 .2 .42 .5 .0 .37 .6 Jun 2 Jul 11 Jul 6 Jun 2 Jun 2 Jul 6 3.5 3.4 3.2 3.2 3.6 3.1 2.9 3.9 3.8 2.9 2.7 2.9 6.1 5.3 6.2 7.6 5.7 3.8 12 23 69 12 23 3.7 5.6 7.5 3.3 4.7 3.2 23 8.6 272.4 8.79 69 2.7 540 6.97 8.04 13.8 39.0 1952 7.21 1994 WATER 14 21 8 737 1 2 2860 8 2 10650 11 158 29 8 4 4.3 4.1 14 20 6.0 4.9 6.2 6.0 17 50 21 26 26 21 24 46 38 44 22 19 18 114 14 19 11 8.7 6.9 6.0 5.7 5.4 9.2 637.4 20.6 114 4.1 1260 16.3 18.82 14.7 24.5 1945 5.91 1993 YEARS 1945 .7 .1 .00 Sep .5 Mar .0 Apr Apr .96 Apr .5 Jul .7 .48 .4 .6 13 9.1 7.7 6.9 5.3 5.2 5.0 11 13 5.8 5.1 7.5 32 22 24 8.2 6.4 9.4 5.7 6.5 18 21 18 8.4 29 75 10 10 13 11—— 422.2 14.1 75 5.0 837 11.2 12.46 18.0 51.7 1996 7.03 1986 - 1997 1952 1994 10 1996 22 1946 7 1946 21 1983 21 1983 6 1997 346 THIS PAGE WAS LEFT BLANK INTENTIONALLY 0123456 KILOMETERS H-——-L-——i 01234 MILES I.X Mop or 0.600 0.630 0.420 0.390 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 ~ LINITY WAT HH TOT FET FIELD MG/L AS CACO3 (00410) 93 120 110 43 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.020 0.020 0.018 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.600 0.650 0.440 0.410 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS 804) (00945) 9.3 — 11 4.7 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.230 0.060 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 29 — 42 13 NITRO- GEMy ORGANIC TOTAL (MG/L AS N) (00605) 0.33 0.29 0.30 2.2 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K - non- ideal count 350 RIO HOMACAO BASIN 50082000 RIO HUMACAO AT HIGHWAY 3 AT HUMACAO, PR—Continued HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 18... FEB 1997 24... MAY 22... AUO 28... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) [01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 830 400 120 <0.10 70 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.01 0.02 RIO GUAYANES BASIN 50083500 RIO GUAYANES AT YABUCOA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°03'33", long 65°54'03", at bridge on Highway 182, 1.4 mi (2.2 km) west-northwest of Yabucoa plaza. DRAINAGE AREA.—17.2 mi* (44.6 km*). PERIOD OF RECORD.—Water years 1958-62, 1968-70, 1980 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 351 DATE OCT 1996 10... FEB 1997 21... HAY 19... AUO 22... OCT 10 FEB 21 MAY 19 AUG 22 OCT 10 FEB 21 MAY 19 AUG 22 OCT DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (HG/L) ATION) (HO/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0930 62 175 6.6 25.0 34 7.2 85 <10 2700 3400 1030 65 212 6.6 22.0 54 8.6 96 17 49000 31000 1115 20 210 6.6 26.5 47 7.0 86 12 2500 4100 1045 E350 74 6.6 25.5 52 7.2 88 20 32000 61000 ALKA- DATE 1996 ... 1997 ... ... ... DATE 1996 ... 1997 ... ... DATE 1996 10... FEB 21 MAY 19 AUG 1997 ... ... 22... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 51 -- 66 44 FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) 0.10 — 0.12 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.22 0.65 0.47 2.2 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 13 — 17 11 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 35 -- 38 33 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.75 1.1 0.74 2.5 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.5 __ 5.5 3.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (HG/L) (70301) 123 -- 151 107 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 3.3 4.9 3.3 11 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 __ 17 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 21 -_ 8.02 E101 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.050 0.100 0.080 0.270 SODIUM AD- SORP- TION RATIO (00931) 0.9 — 0.9 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 48 27 92 88 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.7 __ 1.8 1.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.520 0.450 0.260 0.220 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 57 66 84 20 NITRO- GEN, NITRITE TOTAL (HG/L AS N) (00615) <0.010 0.010 <0.010 0.059 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- 50 — SULFIDE TOTAL (HG/L AS S) (00745) 1.8 __ <0.5 -- NITRO- GEN, NO2+NO3 TOTAL (HG/L AS N) (00630) 0.530 0.460 0.270 0.280 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 4.4 __ 5.2 3.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.330 0.040 0.030 0.070 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -_ 16 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.61 0.44 2.1 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 <10 — K « non-ideal count E « estimated 352 RIO GUAYANES BASIN 50083500 RIO GUAYANES AT YABUCOA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 10... FEE 1997 21... HAY 19... AU6 22... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) SELE- NIUM, TOTAL (UG/L AS SE) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) CYANIDE TOTAL (MG/L AS CN) PHENOLS TOTAL (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 2600 800 <1 <1 160 120 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 PESTICIDE ANALYSES DATE MAY 1997 19... PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFILT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DDT UNPILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) 1115 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) MAY 1997 19... HEPTA- HEPTA- CHLOR MALA- CHLOR, EPOXIDE LINDANE THION, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) METH- OXY- CHLOR, TOTAL (UG/L) METHYL PARA- THION, MIREX, TOTAL TOTAL (UG/L) (UG/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) (39600) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 19... PARA- THION, TOTAL (UG/L) (39540) <0.010 PCNS UNFILT RECOVER (UG/L) (39250) <0.100 PER- THANE TOTAL (UG/L) (39034) <0.100 TOX- APHENE, TOTAL (UG/L) (39400) <1.00 TOTAL TRI- THION (UG/L) (39786) <0.010 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (39730) (39740) (82183) (39760) <0.010 <0.010 <0.010 <0.010 RIO GUAYANES BASIN 50086500 RIO GUAYANES ABOVE MOUTH AT PLAYA DE GUAYANES, PR WATER-QUALITY RECORDS LOCATION.—Lat 18»03'45", long 65°49'42", at old railroad croiiing, 0.2 mi (0.3 km) from mouth, 0.4 mi (0.6 km) weit of Playa de Guayanei, and 3.5 mi (5.6 km) northeait of Yabucoa plaza. DRAINAGE AREA.— 34.0 mi» (88.1km2 ). PERIOD OF RECORD.—Water yeari 1974 to current year. 353 OCT 10 FEB 24 MAY 22 AUG 28 DATE 1996 1997 . . . ... ... DATE OCT 1996 10... FEB 1997 24... MAY 22... AUG 28... WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DBG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1100 110 0915 1000 0835 300 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 53 -- 59 58 - - CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 14 -- 15 15 184 450 209 232 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.5 -- 4.9 5.1 6.8 6.7 6.8 6.7 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 15 -- 18 19 26.5 54 25.0 17 26.0 18 28.0 59 SODIUM AD- SORP- TION RATIO (00931) 0.9 — 1 1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 -- 2.2 3.2 7.2 5.0 6.4 4.2 ALKA- LINITY WAT WH TOT PET FIELD MG/L AS CACO3 (00410) 62 110 82 79 88 59 78 54 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — <10 2200 17 5200 <10 K900 4100 4400 600 16 22000 53000 CHLO- SULFATE RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS SO4) AS CL) (00945) (00940) 6.4 18 — 5.3 18 3.8 19 DATE OCT 1996 10... FEB 1997 24... MAY 22... AUG 28... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — 0.12 0.15 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 36 — 38 32 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 131 — 151 144 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 39 — — 117 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 92 22 25 58 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.610 <0.230 0.270 0.230 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 0.015 NITRO- GEN* NO2+N03 TOTAL (MG/L AS N) (00630) 0.620 0.240 0.270 0.250 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.050 0.040 0.050 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.41 0.27 0.72 DATE OCT 1996 10... FEB 1997 24... NAY 22... AUG 28... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.23 0.46 0.31 0.77 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.85 0.71 0.58 1.0 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 3.8 3.1 2.6 4.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.080 0.070 0.040 0.200 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 -- BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- <10 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 -- CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 -- COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) ^10 — ^10 — non-ideal count 354 OCT 1996 10... FEE 1997 24... HAY 22... AUG 28... RIO GUAYANES BASIN 50086500 RIO GUAYANES ABOVE MOUTH AT PLAYA DE GUAYANES, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 IRON, TOTAL RECOV- ERABLE (UG/L 3500 2900 MANGA- METHY- LEAD, TOTAL RECOV- ERABLE (UG/L TOTAL RECOV- ERABLE (UG/L MERCURY SILVER, ZINC, TOTAL SELE- TOTAL TOTAL RECOV- NIUM, RBCOV- RECOV- CYANIDE ERABLE TOTAL ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 180 120 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 RIO MAUNABO BASIN 50090500 RIO MAUNABO AT LIZAS, PR LOCATION.—Lat 18°01'38", long 65°56'24", Hydrologic Unit 21010005, on right bank, off Highway 759 at Lizas, about 1.0 mi (1.6 km) downstream from Quebrada Coroco, and about 3.0 mi (4.8 km) northwest of Maunabo. DRAINAGE AREA.--5.38 mi* (13.93 km*). PERIOD OF RECORD.—February 1971 to January 1985, February 1991 to current year. GAGE.—water-stage recorder and crest-stage gage. Elevation of gage is 230 ft (70 m), from topographic map. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES 355 OCT NOV DEC JAN FEB HAY JUL AUG SEP 1 36 23 2 e35 22 3 e34 e!8 4 31 24 5 31 18 6 e29 el? 7 47 23 8 29 e!7 9 28 e39 10 e33 22 11 e28 56 12 25 156 13 23 48 14 24 43 15 26 28 16 22 22 17 e21 18 18 e31 17 19 e30 28 20 22 30 21 20 18 22 19 15 23 18 16 24 18 e!5 25 17 e!4 26 34 e!3 27 25 13 28 45 12 29 22 e!2 30 19 13 31 18 TOTAL 840 810 MEAN 27.1 27.0 MAX 47 156 MIN 17 12 AC-PT 1670 1610 CFSM 5.04 5.02 IN. 5.81 5.60 11 10 e9.4 e8.2 8.1 8.4 e9.5 e8.3 8.3 e9.4 e9.2 8.3 8.2 8.3 8.6 8.5 8.2 8.0 7.8 8.1 8.1 7.7 7.7 11 12 9.7 9.7 9.3 14 e!2 9.2 284.2 9.17 14 7.7 564 1.70 1.97 STATISTICS OF MONTHLY MEAN DATA MEAN 26.7 31.1 MAX 52.6 88.9 (WY) 1979 1978 MIN 10.4 7.46 (WY) 1994 1982 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 17.7 35.2 1978 8.74 1994 FOR 8.9 8.6 9.0 9.0 8.8 8.6 e8.8 e9.2 e9.6 9.5 17 11 e9.9 8.9 8.3 8.4 e8.5 8.0 7.7 8.0 8.4 30 e!2 9.5 8.3 12 8.0 e21 12 11 10 327.9 10.6 30 7.7 650 1.97 2.27 FOR WATER 13.0 27.1 1992 7.79 1981 54 27 21 13 e56 36 15 11 14 10 11 10 33 21 13 12 10 9.5 12 11 38 21 13 14 11 19 12 9.0 —— —— 536.5 19.2 56 9.0 1060 3.56 3.71 YEARS 1971 12.5 24.5 1982 6.10 1979 9.4 e9.7 ell e!4 13 e9.7 e8.0 e9.8 7.9 7.1 6.9 9.1 9.2 7.4 e8.4 18 10 21 11 7.9 7.0 6.2 5.8 5.8 6.2 6.2 6.1 6.5 6.8 6.7 8.7 280.5 9.05 21 5.8 556 1.68 1.94 - 1997 9.80 18.9 1976 4.32 1979 1996 CALENDAR YEAR 10006. 27. 1280 5. 6. 19850 5. 69. 47 17 8. 9 3 Sep 10 7 May 30 5 May 24 08 19 1 8.0 40 25 11 8.7 7.6 7.4 7.2 7.1 7.0 6.8 6.8 7.3 6.8 6.4 6.1 6.0 6.1 5.6 5.5 5.5 5.4 5.3 5.1 5.0 5.4 5.2 5.3 5.2 5.8 —— 245.6 8.19 40 5.0 487 1.52 1.70 5.8 5.2 4.8 5.0 5.0 5.2 8.0 6.6 9.0 7.9 6.2 7.0 7.2 6.3 6.1 6.4 6.8 6.8 5.4 5.4 5.6 5.0 5.0 5.5 6.7 6.9 7.0 8.0 27 13 11 226.8 7.32 27 4.8 450 1.36 1.57 11 elO 15 9.0 8.3 8.3 e7.7 e6.5 e6.0 e5.8 e6.2 e6.0 e8.0 e!2 e7.0 e6.3 e5.8 e5.5 e6.1 e5.9 eS.l 4.7 4.9 4.4 3.8 4.2 3.8 3.6 3.5 4.6 —— 199.0 6.63 15 3.5 395 1.23 1.38 4.1 3.7 3.5 3.3 3.9 4.1 3.7 3.8 .0 .2 .1 .5 .6 .3 .4 4.8 5.2 11 21 31 88 18 e30 e!8 15 22 13 74 e!7 e!2 8.7 450.9 14.5 88 3.3 894 2.70 3.12 7.6 e7.1 e8.2 11 8.1 7.7 7.0 6.6 14 14 elO e8.9 20 8.4 8.5 9.3 16 93 14 9.7 8.7 63 26 16 15 11 28 28 15 13 21 533.8 17.2 93 6.6 1060 3.20 3.69 13 12 9.8 10 8.9 8.6 8.2 8.1 7.9 7.9 7.7 7.6 7.6 8.3 79 12 9.5 8.5 7.7 7.5 35 22 19 21 12 113 15 13 15 17—— 531.8 17.7 113 7.5 1050 3.29 3.68 , BY WATER YEAR (WY) 7.21 10.8 1976 3.92 1979 12.7 25.1 1979 5.13 1974 17.9 47.1 1979 4.40 1974 FOR 1997 WATER YEAR 5267.0 14.4 156 3.3 3.7 1080 7.97 10450 2.68 36.42 28 9.3 5.2 Nov 12 Jul 4 Jul 2 Sep 26 Sep 26 17.6 40.2 1993 3.70 1974 WATER 18 36 10 2480 2 2 9950 17 13200 3 46 33 11 5 22.7 131 1979 6.18 1974 YEARS 1971 .2 .7 .8 Aug .2 Jul .8 Jul Sep .46 Sep .39 .02 .2 28.6 94.6 1996 7.99 1980 - 1997 1979 1994 31 1979 16 1974 11 1974 20 1994 20 1994 e Estimated 356 RIO MAUNABO BASIN 50091000 RIO MAUNABO AT MAUNABO, PR HATER-QUALITY RECORDS LOCATION.--Lat 18°00'24-, long 65°54'19-, at bridge on Highway 3, 0.4 mi (0.6 km) southwest of Maunabo plaza, and 1.3 mi (2.1 km) upstream from mouth. DRAINAGE AREA.--12.4 mi 2 (32.1 km 2 ). PERIOD OF RECORD.--Hater years 1958-66, 1975 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 18 FEB 21 MAY 19 AUG 22 DATE 1996 1997 . . . ... DATE OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- HATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD HATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0900 24 0900 0850 7 0900 75 HARD- NESS TOTAL (MG/L AS CAC03) (00900) 86 -- 89 73 - .7 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 22 -- 22 18 270 210 273 172 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.6 -- 8.1 6.8 6.9 6.7 6.8 6.6 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 20 __ 21 19 25.0 5. 22.5 240 25.5 2. 26.0 2. SODIUM AD- SORP- TION RATIO (00931) 0.9 -- 1 1 5 2 8 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.5 — 1.3 1.5 7.3 6.8 7.5 7.9 ALKA- LINITY HAT HH TOT PET FIELD MG/L AS CACO3 (00410) 92 85 100 66 87 77 91 97 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- <0.5 — <10 2000 800 55 210000 220000 <10 K1800 870 <10 46000 69000 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 9.0 -- 13 10 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 20 -- 26 20 DATE FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... 0.10 -- 0.14 0.10 37 39 36 172 191 154 11.1 3.99 31.2 NITRO- NITRO- NITRO- NITRO- NITRO- GEN, GEN, GEN, GEN, GEN, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (MG/L (MG/L AS N) AS N) AS N) AS N) AS N) (00620) (00615) (00630) (00610) (00605) 46 810 6 19 0.470 0.360 0.150 0.220 <0.010 0.020 <0.010 0.028 0.480 0.380 0.160 0.250 0.020 0.060 0.020 0.040 0.41 2.7 <0.20 1.0 DATE OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.43 2.7 0.20 1.1 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.91 3.1 0.36 1.3 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.0 14 1.6 5.8 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.610 <0.020 0.130 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- <1 -- BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- <10 — CADMIUM HATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 -- <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- <10 — non-ideal count RIO MAUNABO BASIN 50091000 RIO MAUNABO AT MAUNABO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 357 DATE IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) HETHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) OCT 1996 18... FEB 1997 21... MAY 19... AUG 22... 2000 730 150 <0.10 60 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 358 RIO CHICO BASIN 50091800 RIO CHICO AT PROVIDENCIA, PR WATER-QUALITY RECORDS LOCATION.—Lat 17°59'16", long 66°00'18", at flat low bridge 200 ft (61 m) south of Highway above mouth, and 1.5 mi (2.4 km) southeast of patillas plaza. DRAINAGE AREA.—4.9 mi 2 (12.8 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. HATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 3, 0.5 mi (0.8 km) DATE OCT 1996 29... FEE 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DIS- PH OXYGEN, OXYGEN COLI- CHAR6E, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 0850 4.0 374 7.3 27.0 3.4 6.7 82 18 K7200 2000 0850 2.4 434 7.0 24.5 3.0 6.0 71 37 K930 700 0920 2.7 513 6.9 28.0 74 0.9 12 320 K600000 780000 0905 3.8 365 7.0 27.5 3.6 5.7 72 24 K730 570 ALKA- HARD- NESS TOTAL (MG/L AS CACO3) (00900) 97 — 83 100 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — 0.12 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.2 13 36 1.6 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 24 — 20 25 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 — 25 30 NITRO- GEN, TOTAL (MG/L AS N) (00600) 4.6 13 36 4.8 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.0 — 7.9 10 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 214 — 262 207 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 21 59 160 21 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 36 — 38 36 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 2.29 — 1.94 2.12 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 1.10 1.40 5.90 1.00 SODIUM AD- SORP- TION RATIO (00931) 2 — 2 2 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 48 9 180 18 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.4 — 5.9 2.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 3.40 0.220 0.00 3.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 100 170 180 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.090 0.160 0.020 0.170 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 70 — 80 __ SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 3.50 0.380 0.020 3.10 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 __ SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 17 — 15 19 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.150 13.0 20.0 0.730 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — 3 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 34 — 42 28 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.0 0.0 16 0.92 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — 69 — K = non-ideal count RIO CHICO BASIN 50091800 RIO CHICO AT PROVIDENCIA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 359 DATE OCT 1996 29... FEB 1997 12... MAY 13... AUO 25... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SELE- NIUM, TOTAL (UO/L AS SB) SILVER, TOTAL RECOV- ERABLE (UO/L AS AC) ZINC, TOTAL RBCOV- ERABL1 (UO/L AS ZN; 1600 3900 TOTAL PHENOLS (MO/L TOTAL AS CN) (UO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 90 <0.10 170 <0.10 <1 <1 10 <0.010 250 <0.010 BLUE ACTIVE SUB- STANCE (MO/L) (38260) 0.04 4.8 360 RZO GRANDE DE PATZLLAS BASIN 50092000 RZO GRANDE DE PATZLLAS NEAR PATILIAS, PR LOCATION.--Lat 18°02'04", long 66°01'58", Hydrologic Unit 21010004, on left bank, at foot bridge, off Highway 184, 1.2 mi (1.9 km) upstream from Lago Patillas Dam and 2.2 mi (3.5 km) northwest of Patillas. DRAINAGE AREA.--18.3 mi 2 (47.4 km2 ). WATER-DISCHARGE RECORDS PERZOD OF RECORD.—February 1959 to October 1965 (annual low-flow and occasional measurements only), January 1966 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 235 ft (72 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 e62 59 2 e60 53 3 e62 41 4 e58 68 5 e54 42 6 e54 46 7 e52 42 8 e56 42 9 e66 42 10 e!20 37 11 e75 160 12 e60 333 13 e50 210 14 e48 84 15 e50 62 16 e43 52 17 e39 47 18 42 44 19 83 45 20 69 46 21 45 55 22 38 51 23 35 50 24 33 42 25 32 37 26 35 35 27 36 34 28 36 35 29 35 33 30 33 37 31 48 —— TOTAL 1609 1964 MEAN 51.9 65.5 MAX 120 333 MZN 32 33 AC-FT 3190 3900 CFSM 2.84 3.58 ZN. 3.27 3.99 STATZSTZCS OF MONTHLY MEAN MEAN 95.9 89.0 MAX 593 393 (WY) 1971 1978 MZN 14.4 16.1 (WY) 1968 1968 SUMMARY STATZSTZCS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAZLY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 34 33 30 31 28 26 27 26 26 25 49 30 26 25 25 24 23 23 22 22 22 21 21 22 24 22 21 20 37 68 24 857 27.6 68 20 1700 1.51 1.74 JAN 22 21 20 19 18 18 18 18 18 18 72 27 21 19 19 18 18 17 17 20 28 118 28 25 24 26 21 22 21 21 22 794 25.6 118 17 1570 1.40 1.61 DAILY FEE 104 55 40 28 30 43 28 27 31 29 29 28 86 54 39 34 30 28 29 26 42 38 41 33 29 76 35 29 —— 1121 40.0 104 26 2220 2.19 2.28 DATA FOR WATER YEARS 1966 50.2 152 1971 8.63 1968 FOR 34.3 125 1992 14.0 1973 28.7 94.6 1982 7.09 1973 MEAN VALUES MAR 27 26 27 27 24 23 23 25 23 22 20 21 24 22 28 31 24 25 22 20 20 19 17 16 15 15 15 15 18 16 18 668 21.5 31 15 1320 1.18 1.36 - 1997 24.5 45.5 1996 6.74 1968 1996 CALENDAR YEAR 22945 62.7 1770 18 19 45510 3.43 46.64 113 36 22 Sep 10 Apr 20 May 2 APR 17 145 60 20 17 16 15 15 15 14 14 14 16 14 14 13 13 13 13 13 14 13 13 13 14 14 14 14 14 14 —— 608 20.3 145 13 1210 1.11 1.24 MAY 14 14 14 13 13 13 15 17 19 25 18 19 26 25 29 36 44 34 28 24 22 20 26 26 27 25 40 33 43 66 25 793 25.6 66 13 1570 1.40 1.61 JUN 26 40 253 33 24 21 20 24 21 15 15 15 16 21 14 12 11 11 14 26 18 16 15 15 14 14 13 13 13 11 —— 774 25.8 253 11 1540 1.41 1.57 JUL 10 10 11 13 19 18 17 18 19 15 12 12 20 19 19 30 43 24 50 95 231 53 47 33 26 26 29 178 48 39 46 1230 39.7 231 10 2440 2.17 2.50 AUG e35 e30 e32 e29 e26 e25 e21 e23 e25 e56 e64 e40 e35 e26 e24 e31 e33 el63 e57 e35 e28 e580 102 134 75 38 46 39 42 33 36 1963 63.3 580 21 3890 3.46 3.99 SKf 28 28 25 22 20 18 18 17 17 16 15 16 16 23 73 24 19 19 18 16 94 198 111 60 41 78 57 36 34 49 —— 1206 40.2 198 15 2390 2.20 2.45 , BY WATER YEAR (WY) 21.7 43.4 1976 9.98 1968 FOR 1997 13587 37 580 10 12 2410 9 9 26950 2 27 61 26 14 50.5 172 1969 10.3 1974 WATER YEAR .2 Aug 22 Jul 1 Jun 27 Aug 22 .06 Aug 22 .8 Jul 1 .03 .62 64.3 200 1979 13.1 1974 64.4 164 1979 14.1 1974 69.5 231 1979 17.2 1994 WATER YEARS 1966 - 56.2 117 19.8 4780 4.8 5.0 30900 unknown 4.6 40730 3.07 41.74 96 28 12 Sep 16 May 9 Apr 10 Jan 5 Jan 5 May 13 87.7 314 1979 12.1 1967 1997 1979 1994 1975 1968 1968 1992 1992 1968 e Estimated RIO GRANDE DE PATILLAS BASIN 50092000 RIO GRANDE DE PATILLAS NEAR PATILLAS, PR—Continued WATER-QUALITY RECORDS 361 PERIOD OF RECORD.—Water years 1960 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DATE OCT 1996 29... FEB 1997 12... MAY 13... AUG 25... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1025 37 177 7.4 24.5 8.6 7.7 90 <10 2100 620 1110 26 154 6.7 23.5 0.70 7.7 89 <10 K660 3100 1135 27 174 6.9 26.5 41 6.8 85 <10 K8200 5900 1110 64 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 53 — 55 48 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 <0.20 <0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 13 — 13 11 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 25 — 21 24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.32 <0.20 0.22 0.33 115 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.1 — 5.3 4.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 115 — 118 120 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 1.4 0.45 0.97 1.5 6.8 26.5 46 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 14 — 13 14 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 11.4 — 8.60 21.0 PHOS- PHORUS TOTAL (MG/L AS P) (00665) <0.020 <0.020 <0.020 <0.020 SODIUM AD- SORP- TION RATIO (00931) 0.8 — 0.8 0.9 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 20 2 39 26 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 0.90 — 0.79 0.60 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.150 0.030 0.030 0.180 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 __ 7.5 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 56 56 67 34 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — 30 — 94 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.150 0.030 0.040 0.180 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 K1700 620 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 11 — 12 11 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 <0.010 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 — 12 12 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — <10 — K • non-ideal count 362 DATE RIO GRANDE DE PATILLAS BASIN 50092000 RIO GRANDE DE PATILLAS NEAR PATILLAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MANGA- IRON, LEAD, NESE, MERCURY TOTAL TOTAL TOTAL TOTAL RECOV- RECOV- RECOV- RECOV- ERABLE ERABLE ERABLE ERABLE (UG/L (UG/L (UG/L (UG/L AS FE) AS PB) AS MN) AS HG) (01045) (01051) (01055) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SOB- STANCE (MG/L) (38260) OCT 1996 29... FEB 1997 12... HAY 13... AUG 25... 910 1500 100 <0.10 110 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 <0.01 <0.01 RIO PATILLAS BASIN 50093045 LAGO PATILLAS AT DAMSITE NEAR PATILLAS, PR 363 LOCATION.—Lat 18°01'15" / long 66°01'19", Hydrologic Unit 21010004, on right bank, in a concrete tower at Damsite, 1.05 mi (1.69 km) northeast from Patillas plaza, 0.45 mi (0.72 km) northeast from Escuela Segunda Unidad de Real and 2.30 mi (3.70 km) from Escuela Segunda Unidad de Jesus Maria Rodriguez. DRAINAGE AREA.—25.2 mi 1 (65.3 km1 ). ELEVATION RECORDS PERIOD OF RECORD.--March 1995 to current year. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Patillas was completed in 1914. The dam is a semihydraulic earthfill structure about 147 ft (45 m) height, a top width of 15 ft (4.6 m), maximum pool elevation of 230 ft (70.1 m), a base width of 625 ft (190 m), a crest lenght of 1,067 ft (325 m) and has maximum pool storage of 17,073 ac-ft (21.05 hm} ) . The Patillas Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and its primary purpose is for irrigation of lands served by the Patillas irrigation canal. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 225.92 ft (68.86 m) Sept. 10, 1996; minimum elevation, 211.19 ft (64.37 m), May 29, 1995, July 19, 1997. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximun elevation, 222.22 ft (67.73 m), Nov. 12; minimum elevation, 211.19 ft (64.37 m), July 19. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet 143 190 Contents, in acre-feet 0 5,492 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN Elevation, in feet 200 225 230 Contents, in acre-feet 7,752 15,005 16,773 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES NOV DEC JAN 221.41 A 221.90 221.77 221.76 221.90 221.84 221.73 220.92 220.98 220.79 220.54 220.27 221.03 221.29 221.45 221.53 221.77 221.98 221.99 221.87 221.70 221.60 221.51 221.48 221.56 221.62 221.85 221.91 221.92 222.02 222.02 220.27 1996 1997 221.97 221.79 221.56 221.63 221.56 221.49 221.44 221.42 221.51 221.47 222.05 221.98 220.88 220.69 220.45 220.17 219.92 219.66 219.45 219.25 219.26 219.47 219.75 219.97 220.11 220.21 220.31 220.44 220.55 220.72 --- 222.05 219.25 MAX 223.60 MAX 222.05 220.83 220.91 220.95 220.92 220.86 220.81 220.80 220.78 220.76 220.72 220.81 220.78 220.71 220.67 220.64 220.61 220.45 220.42 220.37 220.33 220.31 220.29 220.23 220.23 220.23 A 220.15 220.05 220.15 220.38 220.37 220.95 220.05 MIN 216 MIN 211 220.34 220.32 220.28 220.26 220.23 220.19 220.13 220.06 219.97 219.79 220.11 220.11 220.03 219.97 219.93 219.86 219.75 219.69 219.59 219.56 219.55 220.15 220.20 220.22 220.26 220.30 220.23 220.28 220.23 220.20 220.20 220.34 219.55 .02 .26 FEB 220.80 221.06 221.24 221.31 221.61 221.81 221.87 221.85 221.90 221.86 221.81 221.77 221.85 221.08 220.84 220.86 220.86 220.88 220.96 220.98 221.29 221.42 221.57 221.61 221.61 221.95 221.87 221.74 221.95 220.80 MAR 221.61 221.50 221.44 221.39 221.35 221.29 221.26 221.25 221.21 221.10 221.01 220.94 220.83 220.83 220.89 220.98 220.65 220.87 220.83 220.72 220.62 220.49 220.42 220.31 220.15 220.10 219.98 219.94 219.84 219.75 219.69 221.61 219.69 APR 219.62 220.43 220.64 220.65 220.61 220.53 220.45 220.40 220.31 220.23 220.12 220.04 219.98 219.85 219.73 219.61 219.50 219.38 219.24 219.10 218.99 218.86 218.72 218.54 218.43 218.27 218.14 218.05 217.88 217.71 220.65 217.71 MAY 217.58 217.47 217.30 217.15 216.99 216.88 216.74 216.67 216.56 216.49 216.39 216.29 216.24 216.12 216.03 215.97 215.93 215.86 215.70 215.59 215.43 215.26 215.08 214.98 214.88 214.69 214.85 214.86 214.97 215.24 215.26 217.58 214.69 JUN 215.25 215.31 215.82 215.99 215.94 215.85 A A A A A A A A A A 214.54 214.35 214.28 214.34 214.31 214.22 214.07 213.92 213.83 213.67 213.59 213.47 213.35 213.21 215.99 213.21 JUL 213.11 212.98 212.79 212.66 212.56 212.50 212.34 212.24 212.14 212.00 211.83 211.66 211.52 211.36 211.30 211.30 211.30 211.26 211.32 211.79 212.84 213.04 213.25 213.37 213.42 213.52 213.54 214.47 214.60 214.69 214.80 214.80 211.26 AUG 214.80 214.77 214.73 214.73 214.69 214.59 214.51 214.44 214.43 214.60 214.73 214.77 214.81 214.77 214.73 214.78 214.98 215.94 216.01 215.99 215.93 219.77 220.34 220.91 221.22 221.34 221.62 221.75 221.83 221.78 221.79 221.83 214.43 SEP 221.69 221.62 221.49 221.41 221.56 A A A A A A A A A A A A A A A A A A A A A A A A A 221.69 221.41 A No gage-height record 364 THIS PAGE WAS LEFT BLANK INTENTIONALLY AI8GNIT0 EXPLANATION A 1080 SURFACE-WATER STATION AND NUMBER V 1085 QUAUTY-OF-WATER STATION AND NUMBER A 1109 DAILY SEDIMENT STATION AND NUMBER 87 WELL AND WELL NUMBER 1113 LAKE-ELEVATION STATION AND NUMBER CAYE V boundary Islarx: CARIBBEAN SEA 4- 0123456 KILOMETERS 01234 MILES -Wop oreo Figure 22.-South coast river basins the Rio Salinas to Rio Jacaguas basins. 366 RIO SALINAS BASIN 50100200 RIO LAPA NEAR RABO DEL BUEY, PR LOCATION.—Lat 18°03'36", long 66°14'28", Hydrologic Unit 21010004, on left bank, at bridge on Highway 1, Km 9.7, 1.5 mi (2.4 km) north of Rabo del Busy, and 4.4 mi (7.1 km) northeast of salinas Plaza. DRAINAGE AREA.--9.92 mi 1 (25.69 tan'). PERIOD OF RECORD.—1953-63 (annual low-flow measurements only), September 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 394 ft (120 m), from topographic map. REMARKS.—Records poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT DEC JAN FEE APR JUN JUL AUG SEP 1 5.1 1.2 2 4.1 1.1 3 3.8 .89 4 3.8 .80 5 3.8 .59 6 6.3 .66 7 4.8 .51 8 4.7 .32 9 5.1 .37 10 5.7 .49 11 6.1 6.5 12 6.1 e6.7 13 6.2 e5.4 14 7.0 e3.6 15 7.6 e2.8 16 7.8 e2.1 17 7.9 e2.4 18 8.1 e2.2 19 8.9 e2.1 20 9.4 e2.5 21 9.2 66.0 22 8.7 e4.0 23 7.6 63.6 24 5.5 e3.2 25 3.6 e2.7 26 3.3 e2.0 27 4.3 el. 8 28 2.8 e2.0 29 2.0 e2.2 30 1.2 e2.4 31 .95 —— TOTAL 171.45 73.13 MEAN 5.53 2.44 MAX 9.4 6.7 MIN .95 .32 AC-FT 340 145 CFSM .55 .24 IN. .64 .27 STATISTICS OF MONTHLY MEAN MEAN 13.5 5.31 MAX 76.1 28.4 (WY) 1991 1991 MIN 1.46 1.07 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 62.8 62.5 e2.5 e2.5 e2.5 e2.5 e2.7 e2.3 el. 9 el. 8 e5.4 e3.0 e2.4 e2.2 62.1 el. 7 el. 5 el. 3 el. 2 el.l el.l el. 3 el. 2 el. 2 el. 2 el.l el. 2 el.l el.l e2.4 e2.0 60.8 1.96 5.4 1.1 121 .20 .23 el. 3 el.l el.l e.96 e.86 e.94 e.96 e.78 e.82 e.86 el. 3 el. 8 el.l e.96 e.86 e.86 e.86 e.78 e.82 e.78 e.78 e3.6 el. 8 e.86 e.70 e.60 e.47 e.40 e.40 e.40 e.40 30.21 .97 3.6 .40 60 .10 .11 DATA FOR WATER 2.06 6.09 1991 .75 1995 FOR 8.86 68.8 1992 .47 1994 el.O el. 3 e.80 e.58 e.50 e.68 a. 56 e.50 e.50 e.54 e.56 e.50 e2.0 el. 8 el. 2 a. 76 a. 62 e.58 e.56 e.56 a. 88 el. 4 el.l e.80 el. 3 e5.4 e4.8 el.O —— —— 32.78 1.17 5.4 .50 65 .12 .12 YEARS 1988 2.75 12.4 1991 .49 1990 e.82 e.70 a. 52 e.70 e.70 a. 66 e.54 e.52 a. 60 a. 60 e.37 a. 30 a. 28 a. 35 e.30 a. 45 a. 66 e.50 el.O el.l el.l el. 2 el.O el. 2 a. 84 e.68 e.84 a. 74 el.O a. 90 e.74 21.91 .71 1.2 .28 43 .07 .08 - 1997 .94 2.08 1992 .44 1990 1996 CALENDAR YEAR 3176. 8. 1900 . . 6300 . 11. 7. 1. . 39 68 03 05 87 82 6 1 12 Sap 10 May 25 May 29 a. 45 a. 46 el. 2 e.80 e.52 a. 45 e.33 6.31 .33 .33 .33 .33 .34 .41 .43 .44 .57 .56 .56 .55 .87 .52 .33 .32 .28 .26 .26 .23 .22 .23 —— 13.22 .44 1.2 .22 26 .04 .05 .23 .23 .23 .23 .23 .20 .18 .37 .24 .32 .20 .36 .23 .20 .16 .21 .14 .13 .11 .08 .07 .09 .09 .09 .09 .09 .09 .09 .09 .08 .09 5.24 .17 .37 .07 10 .02 .02 .08 .09 .09 .08 .09 .09 .09 .09 .08 .08 .08 .08 .08 .07 .07 .07 .06 .06 .06 .06 .05 .05 .05 .04 .04 .04 .04 .03 .03 .03 —— 1.95 .065 .09 .03 3.9 .01 .01 .03 .03 .03 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .03 .03 .04 .03 .03 .05 .05 .05 .05 .06 .06 .06 .06 .07 .07 .07 .08 1.20 .039 .08 .02 2.4 .00 .00 .08 .07 .08 .08 .07 .07 .07 .07 .07 .08 .13 .15 .20 .17 .13 .14 .19 .18 .14 .12 .17 1.2 .62 .34 .31 .21 .24 .26 .21 .18 .17 6.20 .20 1.2 .07 12 .02 .02 .17 .16 .13 .09 .08 .07 .05 .03 .03 .02 .01 .02 .02 .01 .01 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .60 .03 .01 .01 .01 —— 1.56 .052 .60 .00 3.1 .01 .01 , BY WATER YEAR (WY) 1.03 3.07 1992 .28 1990 4.68 36.6 1992 .086 1994 2.32 10.4 1993 .036 1994 FOR 1997 WATER YEAR 419.65 1.15 9.4 .00 .00 unknown unknown 832 .11 1.56 3.6 .46 .03 Oct 20 Sep 16 Sep 16 Nov 11 Nov 11 1.92 7.80 1993 .009 1994 WATER 5 11 1900 18100 18 3850 7 5 1 2.36 6.06 1990 .001 1994 YEARS 1988 - .31 .2 .57 Sep 10 .00 Jun 24 .00 Jul 21 Sep 10 .65 Sep 10 .53 .22 .4 .0 .10 17.9 81.2 1996 .052 1997 1997 1991 1994 1996 1994 1994 1996 1996 e Estimated RIO SALINAS BASIN 50100450 RIO MAJADA AT LA PLENA, PR 367 LOCATION.—Lat 18«02'40", long 66°12'27", Hydrologic Unit 21010004, on right bank, upstream side of bridge on Hwy 712, about 0.3 mi (0.5 km) southwest of La Plena. DRAINAGE AREA.—16.7 mi* (43.3 km*). PERIOD OF RECORD.—January 1973 to April 1979 (montly measurements only), September 1988 to current year. GAGE.—Water-stage recorder. Elevation of gage is 410 ft (125 m), from topographic map. REMARKS.-Records fair except those for estimated daily discharges, which are poor. Some regulation at low flow upstream from station by local residents for agricultural purposes. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB APR MAY JUN JUL AUG SEP 1 16 5.4 2 13 6.0 3 12 5.1 4 11 .9 5 9.8 .3 6 11 .4 7 8.4 .9 8 7.4 .3 9 6.4 .2 10 7.9 3.0 11 10 14 12 7.1 22 13 6.0 8.2 14 6.3 3.5 15 6.0 2.8 16 6.2 2.1 17 6.1 2.4 18 8.0 2.2 19 9.9 2.1 20 6.4 2.7 21 5.9 7.0 22 5.5 5.1 23 4.6 3.3 24 4.4 2.9 25 4.0 2.4 26 5.0 1.6 27 8.0 1.4 28 6.8 1.6 29 6.4 1.7 30 6.5 1.9 31 6.0 TOTAL 238.0 137.4 MEAN 7.68 4.58 MAX 16 22 MIN 4.0 1.4 AC-FT 472 273 CFSM .46 .27 IN. .53 .31 STATISTICS OF MONTHLY MEAN MEAN 12 . 5 6 . 53 MAX 76.4 25.2 (WY) 1991 1991 MIN 1.43 1.53 (WY) 1992 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 2.2 2.0 2.0 2.0 2.0 2.0 2.1 1.8 1.5 1.4 4.3 2.4 1.6 1.3 1.2 1.0 .86 .78 .71 .67 .67 .74 .73 .71 .71 .66 .70 .69 .68 1.4 1.2 42.71 1.38 4.3 .66 85 .08 .10 .76 .64 .63 .58 .52 .56 .51 .47 .49 .52 .77 1.1 .63 .58 .52 .52 .52 .47 .49 .47 .47 2.2 1.1 .51 .42 .36 .28 .24 .24 .24 .24 18.05 .58 2.2 .24 36 .03 .04 .59 .76 .48 .35 .30 .41 .33 .30 .30 .32 .33 .30 1.2 1.1 .55 .46 .36 .35 .34 .34 .55 .84 .69 .48 .80 3.3 2.9 1.9 —— —— 20.93 .75 3.3 .30 42 .04 .05 DATA FOR WATER YEARS 1973 3.24 9.67 1991 .62 1995 FOR 9.74 68.8 1992 .37 1995 3.07 12.1 1991 .63 1990 1.5 1.3 .96 1.3 1.3 1.2 1.0 .96 1.1 1.1 .70 .54 .52 .63 .55 .82 1.2 .90 1.8 2.0 2.1 2.2 1.9 2.3 1.6 1.3 1.6 1.4 1.9 1.7 1.4 40.78 1.32 2.3 .52 81 .08 .09 - 1997 1.92 3.92 1991 .59 1990 1996 CALENDAR YEAR 4464.33 12.2 2270 .51 .69 8850 .73 9.94 10 2.4 .86 Sep 10 May 22 May 6 .86 .88 2.2 1.5 1.0 .85 .62 .57 .54 .66 .52 .52 .61 .57 .64 1.2 .85 .66 .37 .29 .29 .32 .29 .29 .29 .35 .32 .31 .32 .38 —— 19.07 .64 2.2 .29 38 .04 .04 .47 .58 .52 .49 .87 .53 .66 1.4 .99 1.0 1.1 1.2 1.1 1.2 1.3 1.2 1.7 1.1 ,.62 .38 .30 .39 .31 .38 .58 .54 .33 .33 .30 .28 .35 22.50 3. .73 1.7 .28 45 7 .04 .05 33 .04 21 .03 23 .02 30 .02 47 .02 30 .01 27 .01 17 .01 17 .02 09 .01 10 .03 06 .01 06 .01 05 .01 06 .02 06 .02 04 .02 02 .01 04 .00 04 .00 05 .00 04 .00 02 .00 05 .00 06 .00 06 .00 05 .00 05 .01 04 .01 05 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 .03 .02 .02 .02 .03 .03 .02 .02 .02 .17 .08 .05 .04 .03 .04 .04 .03 .03 .02 .02 .02 .01 .01 .01 .01 .01 .01 .00 .00 .01 .01 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .09 .00 .00 .00 .00 .02 54 0.36 0.88 0.23 12 .012 .028 .008 47 .04 .17 .09 02 .00 .01 .00 .0 .7 1.7 .5 01 .00 .00 .00 01 .00 .00 .00 , BY WATER YEAR (WY) 1.43 3.69 1992 .30 1995 3.78 3. 25.5 12 18 3.21 2.17 19.9 .1 12.9 7.74 109 1992 1992 1993 1992 1996 .21 .042 .012 .010 .008 1994 1994 1997 1994 1997 FOR 1997 WATER YEAR 544.45 1.49 22 .00 .00 47 3.51 1080 .089 1.21 4.9 .52 .01 NOV 12 Jul 19 Jul 19 NOV 11 Nov 11 WATER YEARS 1973 - 1997 5.90 12.1 1992 .81 1994 2270 Sep 10 1996 .00 Oct 3 1994 .00 Oct 8 1994 17700 Sep 10 1996 19.69 Sep 10 1996 4270 .35 4.80 7.8 1.6 .15 e Estimated 368 RIO COAMO BASIN 50106100 RIO COAMO AT COAMO, PR LOCATION.—Lat 18°05'00", long 66°21'16", Hydrologic Unit 21010004, on Highway 14 bridge, 0.8 mi (1.3 km) northeast from Parque Atletico, 1.2 mi (1.9 km) southeast from (W.C.P.R.) Antena de Radio. DRAINAGE AREA.—3.5 mi* (112.7 km*). PERIOD OF RECORD.—January 1987 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 335 ft (110 m), from topographic map. REMARKS.—Records poor. Low flow is affected by domestic discharges about 200 ft (65.6 m), upstream from gaging station. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT JAN FEB MAR APR MAY JUN JUL AUG SEP 1 21 19 2 19 20 3 28 21 4 27 23 5 22 22 6 47 21 7 34 21 8 27 18 9 27 25 10 29 37 11 30 30 12 25 25 13 26 21 14 24 18 15 22 16 16 24 18 17 36 66 18 35 49 19 47 45 20 34 61 21 38 112 22 31 51 23 28 58 24 25 51 25 23 34 26 24 25 27 27 18 28 29 17 29 28 15 30 37 14 31 22 TOTAL 896 971 MEAN 28.9 32.4 MAX 47 112 MIN 19 14 AC -FT 1780 1930 CFSM .66 .74 IN. .77 .83 STATISTICS OF MONTHLY MEAN MEAN 55.5 27.2 MAX 274 62.9 (WY) 1991 1988 MIN 10.3 4.91 (WY) 1989 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 14 12 14 16 17 16 15 15 14 14 15 15 12 13 15 14 13 11 11 11 11 11 11 10 10 10 10 11 13 35 13 422 13.6 35 10 837 .31 .36 13 20 16 16 12 12 10 10 9.9 9.3 8.7 9.3 7.7 6.8 7.7 7.7 7.2 6.8 6.5 7.9 7.7 15 14 11 10 9.6 8.6 8.1 7.7 7.0 7.3 310.5 10.0 20 6.5 616 .23 .27 DATA FOR WATER 17.7 83.8 1988 3.72 1989 FOR 18.4 79.0 1992 2.71 1995 7.8 10 8.4 7.6 7.3 7.3 7.2 7.1 7.2 7.2 6.9 6.7 6.9 6.6 5.8 5.9 6.3 5.8 5.9 6.1 5.8 6.1 6.3 5.8 5.4 6.0 6.0 5.3 —— 186.7 6.67 10 5.3 370 .15 .16 YEARS 1987 9.26 17.0 1988 3.17 1989 5.4 5.8 5.4 5.5 5.0 4.9 5.1 5.1 5.2 5.0 .6 .6 .7 .5 .8 .6 .8 .7 5.1 4.4 4.2 3.9 3.9 4.7 3.8 3.6 5.3 13 e8.8 6.5 5.6 162.5 5.24 13 3.6 322 .12 .14 - 1997 5.86 9.79 1988 3.09 1987 1996 CALENDAR YEAR 7560. 20. 1440 1. 1. 15000 . 6. 35 8. 4. 1 7 Sep 10 3 Jul 6 6 Jun 30 47 47 5 1 5.3 18 15 6.5 5.5 5.2 5.1 5.1 .6 .6 .5 .1 .1 3.7 3.5 3.6 3.4 3.7 3.7 4.0 4.0 3.7 3.8 3.6 3.7 3.8 3.5 3.4 3.1 3.0 —— 148.8 4.96 18 3.0 295 .11 .13 3.1 3.0 3.3 3.2 3.5 3.1 2.9 2.7 3.0 3.1 3.0 3.2 2.8 2.8 2.9 3.1 3.9 4.4 4.0 3.5 3.2 3.8 3.5 3.3 3.2 3.9 4.6 4.1 3.9 3.5 3.3 104.8 3.38 4.6 2.7 208 .08 .09 3.7 3.5 3.4 2.7 2.5 2.5 2.9 3.4 3.4 3.8 4.5 4.0 3.2 2.8 2.5 2.8 2.1 2.2 2.6 2.5 2.9 2.7 2.6 2.9 2.3 2.2 2.3 2.9 2.5 2.7 —— 87.0 2.90 4.5 2.1 173 .07 .07 2.5 2.1 2.2 2.1 2.2 2.2 1.9 2.1 2.6 2.5 1.9 1.9 1.9 1.9 2.0 2.1 2.0 2.4 2.8 5.1 4.2 3.3 3.1 2.8 3.0 2.5 2.8 2.9 2.8 2.5 1.9 78.2 2.52 5.1 1.9 155 .06 .07 2.0 2.1 2.8 2.7 1.7 2.0 1.8 1.9 5.1 3.8 2.4 2.2 79 4.3 2.2 2.0 2.0 1.8 1.7 1.7 1.6 1.8 1.8 2.2 2.1 1.7 1.6 1.8 1.7 1.7 1.6 144.8 4.67 79 1.6 287 .11 .12 1.8 1.7 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.4 1.4 1.5 1.7 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.5 1.6 1.5 1.7 1.6 2.1 19 7.5 —— 69.3 2.31 19 1.4 137 .05 .06 , BY WATER YEAR (WY) 10.5 27.6 1987 2.49 1995 FOR 1997 3581 9 112 1 1 977 7 7100 3 25 4 1 15.8 69.6 1992 1.66 1989 WATER YEAR .6 .81 Nov 21 .4 Sep 12 .4 Sep 16 Nov 21 .18 Nov 21 .23 .06 .7 .8 14.2 76.1 1987 1.99 1989 7.27 15.5 1988 .78 1989 WATER 17. 36. 4. 1580 . . 51600 25. 12850 . 5. 33 6. 2. 8.75 23.3 1990 1.28 1994 YEARS 1987 - 7 8 52 jan 5 67 Aug 2 70 Jul 27 Jan 8 67 Jan 8 41 54 8 1 28.8 92.8 1996 1.61 1994 1997 1991 1994 1992 1989 1989 1992 1992 e Estimated RIO COAHO BASIN 369 50106500 RIO COAHO NEAR COAHO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°03'52", long 66°22'10", Hydrologic Unit 21010004, on Highway 153 bridge, 0.4 mi (0.6 km) above Rio de la Mina, and 1.8 mi (2.9 km) south of Coamo plaza. DRAINAGE AREA.--46.0 mi' (119.1 km'). PERIOD OF RECORD.—Water years 1978 to current year. WATER-QUALITY RECORDS, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OCT 24 FEB 26 MAY 21 SEP 03 DATE 1996 ... 1997 ... ... ... DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1035 19 0915 8 0905 4 1145 2 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 240 — 200 230 .4 .4 .2 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 63 -- 70 59 564 620 612 607 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 19 _- 6.8 20 8.2 7.3 7.2 7.5 28.0 25.0 27.0 33.0 0.70 0.30 1.5 1.5 SODIUM POTAS- SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 31 — 14 35 AD- SORP- TION RATIO (00931) 0.9 — 0.4 1 SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.9 — 1.4 2.7 8.5 8.8 8.4 8.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 200 250 230 250 106 104 104 113 <10 <10 <10 <10 K730 K91 3100 K170 K140 K110 370 K1800 CHLO- SULFATE RIDE, SULFIDE TOTAL (MG/L AS S) (00745) <0.5 __ <0.5 — DIS- DIS- SOLVED SOLVED (MG/L AS SO4) (00945) 36 — 7.9 33 (MG/L AS CL) (00940) 37 — 25 39 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — <0.10 0.18 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 — 6.2 36 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 340 -- 269 374 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 17.4 -- 3.19 2.26 RESIDUE TOTAL AT 105 DEG. C, SUS- FENDED (MG/L) (00530) 3 <1 2 4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 2.30 2.00 0.830 0.960 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.020 0.020 NITRO- NITRO- NITRO- GEN, GEN/ GEN/ N02+N03 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 2.30 0.020 0.43 2.00 0.020 0.24 0.030 0.030 <0.20 0.980 0.040 0.20 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.45 0.26 <0.20 0.24 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.8 2.3 1.0 1.2 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 12 10 4.6 5.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.150 0.100 0.080 0.160 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- <100 — BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 70 — 20 — CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 __ <1 — CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- <1 — COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 -- <10 — K - non-ideal count 370 RIO COMIO BASIN 50106500 RIO COAMO NEAR COAMO, PR—Continued WATER-QUALITY RECORDS, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE OCT 1996 24... FEB 1997 26... MAY 21... SEP 03... IRON, TOTAL RECOV- ERABLE (UG/L AS PE) 170 110 MANOA- LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) TOTAL RECOV- ERABLE (UG/L AS MN) MERCURY TOTAL RECOV- ERABLE (UO/L AS BO) SILVER, ZINC, SELE- NIUM, TOTAL (UO/L AS SE) TOTAL RECOV- ERABLE (UO/L AS AG) TOTAL RECOV- ERABLE (UO/L AS ZN) CYANIDE TOTAL PHENOLS (MO/L TOTAL AS CN) (UO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) <1 20 <0.10 30 <0.10 <1 <1 <1 <1 <0.010 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) <0.01 <0.01 RIO DESCALABRADO BASIN 50108000 RIO DESCALABRADO NEAR LOS LLANOS, PR 371 LOCATION.--Lat 18°03'08", long 66°25'34", Hydrologic Unit 21010004, at bridge on Highway 14, 1.5 mi (2.4 km) west of Los Llanos, and 5.3 mi (8.5 km) east of JUana Diaz. DRAINAGE AREA.—12.9 mi* (33.4 tan') - PERIOD OP RECORD.—1959-65 (annual low-flow measurements only), 1965 (annual maximum discharge), January 1966 to June 1969, July to December 1969 (maximum discharge only), February 1984 to current year. GAGE.—Water-stage recorder. Elevation of gage is 220 ft (67 m), from topographic map. REMARKS.--Records poor. Some regulation at low flow by local resident upstream from station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAY OCT NOV 1 ell e7 . 0 2 elO e6.2 3 e9.2 e5.8 4 9.2 e5.4 5 8.8 e5 . 0 6 8.1 e4.7 7 7.6 4.5 8 7.2 4.2 9 6.3 30 10 6.1 16 11 5.9 8.9 12 4.7 8.8 13 4.3 6.8 14 3.9 5.2 15 3.7 5.4 16 3.3 19 17 3.1 e97 18 3.1 e!8 19 36 13 20 23 22 21 53 e71 22 73 e!9 23 22 e!06 24 12 e46 25 9.4 13 26 7.9 10 27 7.6 9.4 28 10 8.4 29 9.5 8.0 30 14 7.7 31 elO —— TOTAL 402.9 591.4 MEAN 13.0 19.7 MAX 73 106 MIN 3.1 4.2 AC-FT 799 1170 CFSM 1.01 1.53 IN. 1.16 1.71 STATISTICS OF MONTHLY MEAN MEAN 26.6 14.8 MAX 117 41.0 (WY) 1986 1985 MIN 2.02 1.04 (WY) 1968 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 8.4 8.1 7.6 7.5 7.3 6.6 6.3 6.6 6.7 6.3 6.3 5.8 5.7 6.3 11 11 5.5 4.9 4.1 3.9 4.2 4.0 3.7 3.5 3.4 3.1 3.0 4.8 5.5 5.5 5.1 181.7 5.86 11 3.0 360 .45 .52 JAN 4.5 8.6 13 7.4 3.7 3.5 3.2 4.4 5.8 3.2 4.9 3.8 3.4 3.6 3.4 3.3 3.5 3.5 3.3 3.1 3.1 4.5 3.1 2.9 2.6 2.8 2.4 2.6 2.5 2.3 2.7 124.6 4.02 13 2.3 247 .31 .36 DAILY FEB 2.4 2.3 2.2 2.2 2.1 1.9 2.1 1.9 1.8 1.8 1.9 1.8 1.6 1.5 1.7 1.7 1.6 1.6 1.5 1.6 1.4 1.4 1.4 1.5 1.3 1.1 1.2 1.2 —— —— —— 47.7 1.70 2.4 1.1 95 .13 .14 DATA FOR WATER YEARS 1966 5.02 24.5 1988 .19 1968 FOR 4.84 36.4 1992 .057 1968 3.64 23.9 1995 .020 1968 MEAN VALUES MAR 1.1 1.0 .95 .95 .88 .83 .87 .85 .83 .73 .69 .73 .73 .77 .77 1.2 1.3 .86 .56 .55 .57 .52 .54 .57 .62 .55 .46 .35 .42 .60 .62 22.97 .74 1.3 .35 46 .06 .07 - 1997 1.97 8.93 1996 .012 1968 1996 CALENDAR YEAR 15617.79 42.7 10000 .34 .38 30980 3.31 45.04 27 4.0 .65 Sep 10 Jan 24 Jan 22 APR .68 .55 .47 .56 .56 .56 .53 .58 .49 .56 .57 .53 .54 .51 .49 .51 .47 .48 .51 .52 .52 .46 .47 .51 .47 .49 .45 .44 .45 .40 —— 15.33 .51 .68 .40 30 .04 .04 MAY .36 .32 .32 .31 .31 .32 .30 .30 .31 .26 .28 .28 .28 .29 .29 .24 .25 .24 .25 .25 .21 .17 .17 .19 .19 .18 .17 .18 .16 .17 .16 7.71 .25 .36 .16 15 .02 .02 JUN .18 .15 .16 .15 .15 .15 .16 .15 .13 .14 .14 .15 .12 .13 .13 .13 .13 .14 .12 .14 .15 .18 .25 .38 .77 .15 .43 .39 .30 .14 —— 5.99 .20 .77 .12 12 .02 .02 JUL .13 .14 .16 .18 .32 .16 .30 .17 .14 .31 .34 .25 .38 .18 .57 .20 1.2 .28 .15 .15 .15 .15 .21 .24 .24 .39 .68 .30 .85 .50 .52 9.94 .32 1.2 .13 20 .02 .03 AUG 1.2 2.7 1.5 1.8 2.3 2.6 3.8 1.5 2.3 .33 e.30 e.18 e6.4 e.35 e.18 e.16 e.16 e.15 e.14 e.14 e.13 e.15 e.15 e.18 e.17 e.14 e.13 e.15 e.14 e.14 e.13 29.80 .96 6.4 .13 59 .07 .09 SEP e.15 e.14 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.12 e.25 .40 .57 .43 1.3 .47 .14 .13 .11 .23 .85 .25 .17 .19 .57 .45 3.8 98 20—— 129.68 4.32 98 .11 257 .34 .37 , BY WATER YEAR (WY) 4.22 18.8 1985 .000 1968 FOR 1997 1569 4 106 1530 7 3110 4 8 14.8 62.2 1985 .032 1968 WATER YEAR .72 .30 NOV 23 .11 Sep 20 . 12 Sep 3 Sep 29 .77 Jul 22 .33 .53 .8 .77 .15 4.98 25.2 1987 .000 1967 2.69 10.5 1991 .000 1967 WATER 10 41 1 10000 30000 24 7830 11 14 1 3.98 13.1 1996 .19 1990 YEARS 1966 .8 .7 .69 .00 .00 .37 .84 .38 .3 .05 Sep Jun Jun Oct Oct 34.8 395 1996 .063 1967 - 1997 1996 1994 10 1996 22 1966 22 1966 7 1985 7 1985 e Estimated 372 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR LOCATION.--Lat 18°07'37", long 66°27'24", Hydrologic Unit 21010004, on right bank, off a dirt road about 0.3 mi (0.5 tan) from road 553, 2.4 mi (3.9 tan) southeast from Villalba plaza, and 0.2 mi (0.3 tan) downstream from confluence with Quebrada Limon. DRAINAGE AREA.—7.64 mi 1 (19.79 tan'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--April 1989 to current year. GAGE.—Water stage recorder. Elevation of gage is 525 ft (160 m ), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor, satellite telemetry at station. Gage-height and precipitation DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL MEAN MAX MIN AC-FT CFSM IN. el6 el4 e21 e22 19 24 26 21 18 18 17 n!6 15 16 15 13 13 14 28 17 53 40 39 28 23 21 21 20 21 30 21 680 21.9 53 13 1350 1.54 1.78 STATISTICS OF MEAN MAX (WY) MIN (WY) 42.2 109 1991 4.61 1992 18 18 17 17 17 16 16 16 33 24 41 29 21 17 16 24 54 57 44 47 69 46 79 73 39 29 25 21 20 19 —— 962 32.1 79 16 1910 2.26 2.52 19 17 17 17 16 15 14 13 13 13 17 13 12 11 11 9.9 9.0 8.6 8.5 8.0 7.6 7.3 7.0 6.8 6.8 6.6 6.8 6.8 9.3 7.8 7.0 341.8 11.0 19 6.6 678 .78 .90 MONTHLY MEAN DATA 17.1 40.1 1991 2.19 1992 6.98 12.4 1993 1.42 1992 7.0 10 8.9 11 7.0 6.3 6.6 6.5 6.3 6.4 6.8 7.1 7.3 20 12 6.8 6.2 7.1 7.1 7.1 7.2 11 12 9.1 8.6 7.2 6.3 5.7 5.5 5.2 5.2 246.5 7.95 20 5.2 489 .56 .65 FOR WATER 9.97 43.1 1992 1.79 1995 5.6 5.3 4.7 4.5 4.5 .3 .4 .4 .2 .1 4.0 3.8 3.8 3.7 3.5 3.6 3.3 3.3 3.4 3.3 3.0 3.3 3.1 3.0 3.0 3.1 3.1 3.0 ___ 106.3 3.80 5.6 3.0 211 .27 .28 YEARS 1989 5.45 12.6 1996 2.38 1990 3.0 3.0 2.9 3.0 3.0 2.9 2.9 2.9 2.8 2.9 2.7 2.6 2.6 2.6 2.6 2.6 2.5 2.4 2.6 2.5 2.4 2.4 2.5 2.5 2.4 2.4 2.6 2.8 4.2 3.2 2.5 84.9 2.74 4.2 2.4 168 .19 .22 - 1997, 3.49 5.01 1996 1.67 1990 2.4 2.6 2.6 2.3 2.2 2.0 1.9 2.0 2.1 2.0 1.8 1.8 1.8 1.9 1.9 1.7 1.7 1.7 1.6 1.7 1.6 1.8 1.9 1.7 1.5 1.3 1.4 1.3 1.4 1.3 —— 54.9 1.83 2.6 1.3 109 .13 .14 BY WATER 7.94 26.3 1993 1.46 1990 1.2 1.2 1.2 1.2 1.2 1.1 1.1 1.1 1.2 1.5 1.4 1.1 1.1 1.1 1.1 .98 1.1 1.1 1.0 .91 1.1 1.4 1.0 1.0 1.2 2.3 4.5 3.4 1.8 1.7 1.6 43.89 1.42 4.5 .91 87 .10 .11 YEAR (WY) 19.5 76.1 1995 1.42 1997 1.7 1.6 1.6 1.5 1.4 1.5 1.6 1.2 1.3 1.2 1.3 1.3 1.3 1.3 1.2 .96 1.5 1.4 1.2 1.2 1.1 1.1 1.0 1.1 1.0 .98 .97 1.1 1.9 1.7 —— 39.21 1.31 1.9 .96 78 .09 .10 10.2 35.4 1992 1.23 1990 1.7 1.2 1.1 1.1 .95 .82 .76 .92 .98 1.1 1.2 1.4 1.3 1.3 1.4 1.4 1.9 2.0 2.1 3.5 1.5 .74 .63 .60 .57 .57 .64 .73 .81 .95 1.2 37.07 1.20 3.5 .57 74 .08 .10 6.69 14.4 1992 .71 1990 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 125.3 4.04 36 1.3 249 .28 .33 6.91 11.9 1989 2.74 1990 1.9 28 15 3.7 4.9 2.0 1.7 1.4 1.2 1.2 1.1 1.1 1.4 1.5 1.4 1.4 1.3 1.3 1.2 1.0 1.1 1.4 1.3 1.2 1.2 1.9 1.5 2.1 79 29 --- 193.4 6.45 79 1.0 384 .45 .51 32.6 94.6 1996 3.21 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS FOR 1996 CALENDAR YEAR 6940.7 19.0 2050 Sep 10 2.2 Aug 9 2.7 Aug 4 13770 1.34 18.18 29 7.4 3.3 FOR 1997 WATER YEAR WATER YEARS 1989 - 1997 2915 7 79 821 6 5780 7 21 2 1 .27 .99 .57 .64 .19 .42 .56 .64 .6 .1 Nov Jul Jul Sep Sep Jul 23 25 22 29 29 14 14.2 20.3 4.02 2050 .45 .61 15000 18.65 .42 10290 1.00 13.59 31 4.1 1.3 1996 1994 Sep 10 1996 Aug 7 1990 Jul 9 1990 Sep 10 1996 Sep 10 1996 Jul 14 1997 e Estimated RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1988 to current year. PERIOD OP DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: April 1988 to current year. INSTRUMENTATION.-- USDH-48 and automatic sediment sampler since 1988. REMARKS.— Sediment samples were collected by a local observer on a weekly basis. During high flow events sediment samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 10,200 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several years. SEDIMENT LOADS: Maximum daily mean, 75,700 tons (68,600 tonnes) September 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonne) several years. EXTREMES FOR CURRENT YEAR 1997.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,810 mg/L September 29, 1997; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 1,550 tons (1,406 tonnes) September 29, 1997; Minimum daily mean, 0.01 ton (0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 e!6 e!4 e21 e22 19 24 26 21 18 18 17 16 15 16 15 13 13 14 28 17 53 40 39 28 23 21 21 20 21 30 21 16 17 21 27 34 113 136 23 5 6 11 12 11 10 11 13 25 59 281 102 720 538 193 50 22 20 24 27 25 212 100 el. 2 el. 3 el. 5 el. 6 1.7 9.1 10 1.3 .22 .28 .52 .51 .44 .43 .44 .49 .88 2.4 43 4.9 252 134 22 3.8 1.4 1.2 1.4 1.5 1.4 36 5.9 18 18 17 17 17 16 16 16 33 24 41 29 21 17 16 24 54 57 44 47 69 46 79 73 39 29 25 21 20 19 27 19 20 21 23 26 22 18 345 183 518 251 136 120 106 206 941 855 1030 689 1060 581 1330 686 9 6 16 12 6 9 1.3 .89 .91 .95 1.1 1.1 .96 .77 69 12 107 21 7.6 5.6 4.5 19 323 153 125 87 461 79 520 175 1.1 .43 1.1 .72 .33 .46 TOTAL 680 542.81 962 2180.82 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) DECEMBER 19 17 17 17 16 15 14 13 13 13 17 13 12 11 11 9.9 9.0 8.6 8.5 8.0 7.6 7.3 7.0 6.8 6.8 6.6 6.8 6.8 9.3 7.8 7.0 341.8 18 33 40 44 53 64 58 48 40 33 81 77 55 42 33 26 26 28 19 12 8 6 15 19 19 11 5 8 18 36 40 —— .88 1.5 1.8 2.0 2.3 2.6 2.3 1.7 1.4 1.1 4.2 2.8 1.8 1.3 .95 .69 .63 .64 .44 .26 .17 .11 .30 .34 .35 .19 .09 .15 .45 .77 .76 34.97 e Estimated 374 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) JANUARY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 7.0 10 8.9 11 7.0 6.3 6.6 6.5 6.3 6.4 6.8 7.1 7.3 20 12 6.8 6.2 7.1 7.1 7.1 7.2 11 12 9.1 8.6 7.2 6.3 5.7 5.5 5.2 5.2 39 54 49 80 79 75 55 38 35 37 37 36 36 141 56 10 14 22 21 19 20 21 11 5 4 4 4 8 16 24 30 .72 1.8 1.2 2.3 1.5 1.3 .95 .65 .60 .63 .67 .69 .70 11 2.7 .22 .26 .42 .39 .37 .39 .62 .37 .12 .09 .08 .07 .12 .24 .33 .42 FEBRUARY 5.6 5.3 .7 .5 .5 .3 .4 .4 .2 .1 4.0 3.8 3.8 3.7 3.5 3.6 3.3 3.3 3.4 3.3 3.0 3.3 3.1 3.0 3.0 3.1 3.1 3.0 —— 28 24 21 16 12 10 11 14 17 22 28 34 38 41 44 47 51 53 39 26 18 21 29 38 23 17 15 7 —— —— .42 .35 .26 .19 .15 .11 .13 .16 .20 .24 .30 .35 .39 .41 .45 .46 .45 .47 .35 .25 .16 .19 .24 .31 .19 .14 .12 .05 ___ —— MARCH 3.0 3.0 2.9 3.0 3.0 2.9 2.9 2.9 2.8 2.9 2.7 2.6 2.6 2.6 2.6 2.6 2.5 2.4 2.6 2.5 2.4 2.4 2.5 2.5 2.4 2.4 2.6 2.8 4.2 3.2 2.5 3 1 1 1 1 2 4 8 10 12 13 7 3 1 2 7 17 14 8 5 5 7 8 5 2 1 2 4 13 17 11 .02 .01 .01 .01 .01 .01 .03 .06 .08 .09 .09 .05 .02 .01 .02 .05 .11 .09 .05 .03 .03 .04 .05 .03 .02 .01 .01 .03 .19 .15 .08 TOTAL 246.5 31.92 106.3 7.49 84.9 1.49 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE IiAOO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) (NG/L) (TONS/DAY) APRIL MAY JUNE 1 2.4 8 .05 1.2 8 .03 1.7 4 .02 2 2.6 11 .08 1.2 9 .03 1.6 3 .01 3 2.6 20 .14 1.2 12 .04 1.6 3 .01 4 2.3 35 .22 1.2 15 .05 1.5 3 .01 5 2.2 34 .20 1.2 13 .04 1.4 4 .01 6 2.0 27 .14 1.1 10 .03 1.5 4 .01 7 1.9 22 .12 1.1 8 .03 1.6 4 .01 8 2.0 27 .15 1.1 8 .02 1.2 3 .01 9 2.1 37 .20 1.2 8 .03 1.3 3 .01 10 2.0 48 .27 1.5 8 .03 1.2 3 .01 11 1.8 50 .24 1.4 8 .03 1.3 4 .01 12 1.8 47 .23 1.1 8 .03 1.3 4 .01 13 1.8 45 .22 1.1 8 .03 1.3 5 .02 14 1.9 47 .24 1.1 8 .03 1.3 7 .02 15 1.9 51 .26 1.1 8 .02 1.2 8 .03 16 1.7 55 .25 .98 8 .02 .96 5 .01 17 1.7 49 .22 1.1 8 .02 1.5 2 .01 18 1.7 41 .19 1.1 8 .02 1.4 1 <.01 19 1.6 34 .15 1.0 8 .02 1.2 1 <.01 20 1.7 32 .14 .91 8 .02 1.2 1 <.01 21 1.6 31 .13 1.1 8 .02 1.1 2 <.01 22 1.8 29 .14 1.4 8 .03 1.1 2 .01 23 1.9 23 .12 1.0 8 .02 1.0 3 .01 24 1.7 17 .08 1.0 8 .02 1.1 3 .01 25 1.5 13 .05 1.2 8 .03 1.0 3 .01 26 1.3 18 .06 2.3 12 .17 .98 3 .01 27 1.4 30 .11 4.5 33 1.9 .97 2 <.01 28 1.3 47 .17 3.4 19 .25 1.1 2 .01 29 1.4 32 .12 1.8 6 .03 1.9 2 .01 30 1.3 16 .05 1.7 4 .02 1.7 2 .01 31 —— —— —— 1.6 4 .02 —— —— --- TOTAL 54.9 —— 4.74 43.89 —— 3.08 39.21 —— 0.30 376 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAOO TOA VACA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 TOTAL YEAR 1.7 1.2 1.1 1.1 .95 .82 .76 .92 .98 1.1 1.2 1.4 1.3 1.3 1.4 1.4 1.9 2.0 2.1 3.5 1.5 .74 .63 .60 .57 .57 .64 .73 .81 .95 1.2 37.07 2915.27 JULY 2 2 3 3 3 3 5 10 20 30 40 52 29 12 5 5 6 7 8 23 5 4 5 7 7 7 7 7 7 7 7 —— .01 .01 .01 .01 .01 .01 .01 .03 .05 .09 .13 .19 .10 .04 .02 .02 .03 .04 .04 .65 .02 .01 .01 .01 .01 .01 .01 .01 .01 .02 .02 1.64 4798.04 MEAN DISCHARGE (CFS) 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 125.3 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 1.3 1.3 1.3 1.3 1.5 1.5 1.5 1.8 36 9.9 2.6 2.2 17 7.5 2.7 1.8 1.7 1.6 1.5 1.4 1.5 1.6 1.6 1.9 2.7 1.8 2.1 7.0 3.8 2.1 1.8 6 6 6 6 6 17 50 39 557 58 14 11 142 21 12 12 13 9 6 4 4 5 5 5 6 6 10 94 16 7 6 .02 .02 .02 .02 .03 .07 .20 .26 200 2.7 .10 .06 22 .40 .08 .06 .06 .04 .03 .02 .02 .02 .02 .03 .04 .03 .06 14 .20 .04 .03 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 1.9 28 15 3.7 4.9 2.0 1.7 1.4 1.2 1.2 1.1 1.1 1.4 1.5 1.4 1.4 1.3 1.3 1.2 1.0 1.1 1.4 1.3 1.2 1.2 1.9 1.5 2.1 79 29 5 534 103 26 59 101 90 81 72 65 56 49 42 41 40 40 43 48 53 54 55 54 47 40 33 28 23 19 1810 235 .03 163 6.3 .26 2.1 .56 .41 .31 .24 .20 .16 .15 .16 .16 .15 .15 .16 .16 .17 .15 .16 .21 .17 .13 .11 .14 .09 .11 1550 22 240.68 193.4 1748.10 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 377 DATE NOV 1996 21... 21... 21... SEP 1997 29... 29... DATE NOV 1996 21... 21... 21... SEP 1997 29... 29... TIME 1445 1455 1520 1510 1545 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 27 52 63 22 69 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 392 392 247 418 821 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 34 61 76 31 82 SEDI- MENT, SUS- PENDED (M6/L) (80154) 16400 5860 3290 36600 6328 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 46 77 90 50 93 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 17300 6200 2190 41300 14000 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 74 92 97 68 98 SED. SUSP. PALL DIAM. % FINER THAN .002 MM (70326) 12 23 28 7 30 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 95 98 99 92 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 15 30 37 10 41 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 100 100 98 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 21 40 49 15 51 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 99 100 378 RIO JACAGUAS BASIN 50110900 RIO TOA VACA ABOVE LAGO TOA VACA, PR—Continued WATER QUALITY DATA, MATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT OCT 1996 21... NOV 21... JAN 1997 06... MAR 29... AUO 09... SEP 29... TIME 1521 1450 1420 1630 1700 1600 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 594 392 6.5 3.2 224 427 SEDI- MENT, SUS- PENDED (MO/L) (80154) 112 7820 77 8 4120 6170 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 180 8300 1.4 0.10 2490 7110 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 99 72 98 53 99 94 RIO JACAGUAS BASIN 50111300 LAGO GUAYABAL AT DAMSITE NEAR JUANA DIAZ, PR 379 LOCATION.—Lat 18°05'17", long 66°30'09", Hydrologic Unit 21010004, at Damsite, 2.30 mi (3.70 km) northeast from Juana Diaz plaza, 0.70 mi (1.13 km) northeast from Escuela Salvador Bous-- .-'•y ->> 1440 Rio Cul*t)r-,no» basin^ •*" ~"">«^_~'" —^ w#/'0 ! MAYA V—^v--^ V '-W* — -»» CMMM kMi» ^/ ?C «.'» Cn ••!»>*• »fc NV^^^————^>———^f~^' / ^. ^*"v ^N^.X^ /—-^-/ : MARtCAO^ S / fa& Drainoo* boundory-y / / J ^**r it /<^-<~'- (^../^-^ \ EXPLANATION \ 1440 SURFACE-WATER STATION AND NUMBER 1388 QUAUTY-OF-WATER STATION AND NUMBER 1415 LAKE-ELEVATION STATION AND NUMBER LARES «i"o rename'fee»i* 1415 ^ :.~r-\ yv i'o faaco Map area- 0123456 KILOMETERS I S " 'T^ i1 ""H 01234 MILES Figure 25.--Rio Yaguez and Rio Grande de Anasco basins. d1 ft ^ ' ° RIO YAGUEZ BASIN 50138800 RIO YAGUEZ NEAR MAYAGUEZ, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°12'31", long 67°07'07", at steel-truss bridge on unnumbered paved road about 800 ft (244 m) south of Highway 106, 1.8 mi (2.9 km) west of Highways 106 and 352 junction, and 1.4 mi (2.3 km) east-northeast from Mayaguez plaza. DRAINAGE AREA.—6.7 mi 2 (17.3 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 TIME DIS- CHARGE, INST. CUBIC FEET PER SECOND SPE- CIFIC CON- DUCT- ANCE (US/CM) PH WATER WHOLE FIELD (STAND- ARD UMITS) TEMPER- ATURE WATER (DEG C) TUR- BID- ITY (NTU) OXYGEN, DIS- SOLVED (MG/L) OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) STREP- TOCOCCI FECAL, (COLS. PER 100 ML) NOV 1996 12... MAR 1997 05... MAY 29... AU6 19... 1430 1435 1145 1445 (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 37 4.6 1.6 7.6 210 310 304 270 6.6 7.1 7.0 7.0 25.0 23.5 25.5 27.0 180 0.70 0.60 5.7 8.0 8.9 7.6 7.8 96 105 93 98 230000 1800 270 580 250000 3400 880 600 NOV 1996 12... MAR 1997 05... MAY 29... AU6 19... HARD- NESS TOTAL (MG/L AS CACO3) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS SO4) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 80 21 130 34 110 27 6.7 12 9.0 7.1 12 9.6 0.3 0.5 0.4 3.6 2.7 2.9 85 190 150 130 <0.5 <0.5 5.1 8.3 7.2 7.3 11.0 9.8 NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... FLUO- RIDE, DIS- SOLVED (M6/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MO/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.10 21 0.10 29 <0.10 28 123 193 172 0.83 3.52 324 6 9 1 1.30 0.020 0.620 <0.010 0.640 0.010 0.920 <0.010 NITRO- NITRO- NITRO- GEN, GEN, GEN, NO2+NO3 AMMONIA ORGANIC TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L AS N) AS N) AS N) (00630) (00610) (00605) 1.30 0.080 1.9 0.630 0.020 0.21 0.650 0.040 <0.20 0.920 0.020 <0.20 DATE NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 2.0 0.23 <0.20 <0.20 3.3 15 0.86 3.8 0.78 3.4 1.0 4.5 0.410 0.080 0.060 0.030 <1 <1 <100 100 30 50 <1 <1 10 <1 10 non-ideal count RIO YAGUEZ BASIN 50138800 RIO YAGUEZ NEAR MAYAGUEZ, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 419 DATE NOV 1996 12... MAR 1997 05... MAY 29... AUG 19... IRON, TOTAL RECOV- ERABLE (UG/L LEAD, TOTAL RECOV- ERABLE (UG/L MANGA- NESE, TOTAL RECOV- ERABLE (UG/L MERCURY TOTAL RECOV- ERABLE (UG/L SELE- NIUM, TOTAL (UG/L SILVER, TOTAL RECOV- ERABLE (UG/L ZINC, TOTAL RECOV- ERABLE (UG/L CYANIDE TOTAL (MG/L PHENOLS TOTAL METHY- LENE BLUE ACTIVE SUB- STANCE AS FE) AS PB) AS MN) AS HG) AS SE) AS AG) AS ZN) AS CN) (UG/L) 7100 300 (MG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) <1 490 23 <0.10 <0.10 <1 <1 <1 <1 50 •cO.010 <0.010 <1 <1 <0.01 <0.01 420 RIO GRANDE DC ANASCO BASIN 50141500 LAGO GUAYO AT DAMSITE NEAR CASTANER, PR LOCATION.—Lat 18°12'46", long 66°50'06", Hydrologic Unit 21010003, at Guayo Dam on Rio Guayo, 1.1 mi (1.8 km) southwest of Lago Yahuecas, 2.6 mi (4.2 km) southwest of Lago Prieto, 2.1 mi (3.4 km) north of Castaner, and 6.0 mi (9.6 km) west of Adjuntas. DRAINAGE AREA.—9.60 mi 2 (24.86 km2 ). ELEVATION RECORDS PERIOD OP RECORD.--April 1980 to January 1985, June 1989 to current year. Lago Guayo near Castaner. GAGE.—Water-stage recorder. Datum of gage is mean sea level. Prior to October 1994, published as REMARKS.--Lago Guayo was completed in 1956. The dam is on Rio Guayo and is the largest in the southwestern Puerto Rico project. The maximum storage is 17,400 ac-ft (21.5 hm3 ) for power and irrigation. The dam is a concrete gravity structure with a total length of 555 ft (169 m), a maximum structural height of 190 ft (58 m), and a maximum width at the base of 145 ft (44 m). The ungated overflow spillway with a crest elevation of 60.00 ft (18.29 m) and a crest length of 220 ft (67 m) was designed to pass a maximum flood of 30,200 ftVs (855 mVs) at a reservoir elevation of 70.00 ft (21.34 m) . Timber flashboards that were added to increase storage capacity were subsequently removed and their use discontinued. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation, 1462.43 ft (445.75 m), May 27, 1980; minimum elevation recorded, 1415.43 ft (431.42 m), June 2, 1990, but may have been less during period of no gage-height record June 2-5, 1990. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 1460.84 ft (445.26 m), Nov. 21; minimum elevation recorded 1425.63 ft (434.53 m), Jun. 5. Capacity Table (based on data from Puerto Rico Water Resources Authority) Elevation, in feet 1415 1449 Contents, in acre-feet 3,960 10,660 Elevation, in feet Contents, in acre-feet 1460 1465 13,550 15,000 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY OBSERVATION AT 2400 VALUES OCT DEC APR MAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MAX MIN 1444.75 A 1445.69 1446.04 1446.51 A 1447.36 1447.79 1448.20 1448.58 1448.94 1449.31 1450.30 1450.73 1450.88 1451.12 1452.02 1452.44 1453.37 1453.93 1453.26 1453.81 1452.46 1452.20 1452.43 1451.08 1450.52 1450.98 1451.76 1451.52 1451.51 1453.93 1444.75 1451.72 1451.83 1452.56 1452.75 1453.23 1453.46 1453.44 1453.86 1454.38 1455.67 1456.27 1457.70 1457.09 1457.00 1457.47 1457.69 1458.97 1459.49 1459.46 1460.18 1460.57 1460.35 1459.66 1459.41 1459.08 1458.95 1458.45 1459.02 1459.02 1459.29 —— 1460.57 1451.72 1459.50 1458.56 1457.96 1457.73 1457.14 1457.20 A 1456.73 1456.94 1455.95 1455.80 A A A A 1457.32 1457.58 1457.43 A 1457.87 1457.75 1457.42 1457.10 1457.01 1457.28 1456.49 1455.69 1455.86 1455.90 1455.58 1455.41 1459.50 1455.41 1455.41 1455.44 1455.04 1455.31 1455.25 1455.39 1455.04 1455.27 A 1454.93 1453.96 A 1452.39 1451.69 1451.08 1450.59 1450.83 1450.95 1451.25 1451.60 1452.42 A 1454.13 1454.46 1454.73 1454.99 1455.23 1455.44 1455.56 1455.78 1456.00 1456.00 1450.59 1456.23 1456.53 1456.76 1455.92 1455.53 1455.06 1455.08 1455.32 1455.53 1455.50 1455.62 1455.57 1455.48 1455.09 1455.22 1454.22 1454.13 1454.07 1453.19 1452.51 1451.35 1451.53 1451.30 1450.76 1450.27 1449.75 1448.66 1448.23 —— —— 1456.76 1448.23 1448.42 1448.60 1447.68 1446.89 1446.58 1445.80 1445.08 1445.28 1445.45 1445.08 1444.53 1444.00 1443.40 1441.94 1441.47 1440.95 1440.25 1440.20 1441.31 1440.85 1440.50 1440.02 1437.89 1437.90 1437.97 1438.25 1438.70 1439.49 1440.69 1441.35 1442.02 1448.60 1437.89 1440.66 1440.20 1439.95 1440.25 1440.50 1440.76 1441.02 1441.28 1441.22 1440.71 1440.65 1440.57 1440.80 1441.03 1440.66 A A 1439.79 1439.09 1438.72 1438.46 1438.18 A 1437.94 1437.57 1437.76 1437.97 1438.15 1438.33 —— 1441.28 1437.57 1438.28 1441.05 1441.87 1442.24 1442.01 A 1441.42 1440.54 1440.30 1438.37 1438.05 1436.37 1436.21 1435.17 1433.33 1433.42 1433.63 1432.60 1431.49 1431.61 A 1430.15 1430.82 1431.27 1431.62 1431.94 1431.40 1430.71 1431.04 1431.32 1431.59 1442.24 1430.15 1431.74 A A A 1425.75 A A A A A A A A A A A 1426.06 A 1426.65 1426.95 1427.18 1427.93 1428.56 1429.18 1429.51 1429.76 1429.99 1430.34 1430.87 1431.69 —— 1431.74 1425.75 1431.93 1432.18 1432.35 1432.53 1432.68 1432.84 1432.99 1433.32 1433.67 1433.85 1434.02 1434.26 1434.45 1434.61 1434.78 1434.89 1435.04 1435.58 1436.02 1436.45 1436.92 1437.22 1437.46 1437.66 1437.88 1438.08 1438.24 1438.40 1438.52 1438.29 1438.61 1438.61 1431.93 1437.83 1437.97 1439.00 1439.61 1439.31 1438.77 1438.94 1438.92 1439.07 1439.46 1439.70 1439.90 1440.57 1441.07 1441.52 1441.79 1442.00 1441.43 1441.51 1441.67 1440.47 1439.86 1440.28 1440.70 1440.91 1440.50 1439.78 1439.77 1440.00 1441.33 1441.84 1442.00 1437.83 1443.68 1444.93 1444.47 1442.91 1442.20 1441.10 1441.36 1439.85 1438.08 1436.67 1435.51 1435.44 1435.90 1436.46 1436.88 1437.13 1437.35 1437.54 1437.73 1437.91 1438.13 1438.36 1438.58 1438.90 1439.17 1439.35 1439.68 1439.92 1440.01 1440.67 —— 1444.93 1435.44 CAL YR 1996 WTR YR 1997 MAX 1460.75 MAX 1460.57 MIN 1439.10 MIN 1425.75 A No gage-height record RIO GRANDE DE ANASCO BASIN 50143000 RIO GRANDE DE ANASCO NEAR LARES, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°15'26", long 66°55'00", at bridge on Highway 124, 0.7 mi (1.1 km) downstream from confluence of Rio Blanco and Rio Prieto, and 3.7 mi (6.0 km) southwest of Lares plaza. DRAINAGE AREA.—26.3 mi* (68.1 km*) this does not include 36.2 mi* (93.8 km*) which contributes only dur- ing high floods, and 3.5 mi 1 (9.1 km*) which contributes only part of its storm runoff. PERIOD OF RECORD.—Water years 1959-68, 1970 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 13... FEB 1997 11... JDN 09... AUO 27... TIME 0905 0945 1340 1050 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 277 60 18 26 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 336 292 291 299 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 5.5 7.4 8.7 8.3 TEMPER- ATURE WATER (DEC C) (00010) 22.5 21.0 33.5 28.0 TUR- BID- ITY (NTU) (00076) 210 0.50 1.1 5.3 OXYGEN, DIS- SOLVED (MG/L) (00300) 8.1 9.5 10.1 8.1 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 93 106 135 106 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 16 <10 <10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 21000 K80 K10 K100 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 49000 300 K60 220 HARD- MESS CALCIUM TOTAL DIS- (MG/L SOLVED AS (MG/L MAGNE- SIUM, SODIUM, DIS- DIS- SOLVED SOLVED (MG/L (MG/L SODIUM AD- SORP- TION RATIO ALKA- POTAS- LINITY SIUM, WAT WH DIS- SOLVED CACO3) AS CA) AS MG) AS NA) (MG/L AS K) TOT FET SULFIDE FIELD TOTAL MG/L AS (MG/L CACO3 CHLO- SULFATE RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS S) AS SO4) AS CL) (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) NOV 1996 13... FEB 1997 11... JUN 09... AUG 27... 63 -- 120 120 17 — 32 32 4.9 — 9.3 10 6.6 — 13 12 0.4 __ 0.5 0.5 2.9 — 1.7 1.9 55 110 110 110 <0.5 — <0.5 — 9.7 — 25 20 6.2 — 11 8.9 DATE NOV 1996 13... FEB 1997 11... JUN 09... AUG 27... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.12 0.11 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 21 -- 33 32 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 101 -- 192 184 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 75.7 -- 9.10 12.7 RESIDUE TOTAL AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 216 3 <1 8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.70 1.20 0.300 0.710 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 <0.010 0.012 NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.70 1.20 0.310 0.730 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.010 0.030 0.030 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.91 0.23 <0.20 0.27 DATE NOV 1996 13... FEB 1997 11... JUN 09... AUG 27... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.94 2.6 12 0.240 0.25 1.4 6.4 0.030 <0.20 0.50 2.2 <0.020 0.30 1.0 4.5 0.050 K • non-ideal count <100 <100 20 30 10 422 RIO GRANDE DB ANASCO BASIN 50143000 RIO GRANDE DB ANASCO NEAR LARES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 13... FEB 1997 11... JUN 09... AUG 27... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) ;01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SB) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 6100 110 <1 300 17 <0.10 <0.10 <1 <1 <1 <1 20 <0.010 20 <0.010 0.02 0.04 RIO GRANDE DE ANASCO BASIN 50144000 RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN, PR 423 LOCATION.—Lat 18°17'05", long 67°03'05", Hydrologic Unit 21010003, on left bank, at downstream side of bridge on Highway 108, 0.4 mi (0.6 km) downstream from Quebrada La Zumbadora, 4.4 mi (7.1 km) northwest of Las Marias, 5.4 mi (8.7 km) southwest of San Sebastian. DRAINAGE AREA.--94.3 mi 2 (244.2 km2 ), does not include 36.2 mi 3 (93.8 km2 ) which contributes only during high floods, and 3.5 mi 2 (9.1 km2 ) which contributes only part of its storm runoff. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—Harch 1963 to current year. GAGE.—Water-stage recorder. Datum of gage is 103.72 ft (31.614 m) above mean sea level (Puerto Rico Department of Public Works bench mark). Previous to Oct. 30, 1975, at site 600 ft (180 m) upstream at same datum. REMARKS.—Records fair except those for estimated daily dischages, which are poor. Transbasin diversion (except during floods) to Rio Yauco basin for hydroelectric power and irrigation above Lago Guayo, Yahuecas, and Prieto, combined useable storage 17,300 acre-fit (21.3 hm3 ). Limited storm runoff is contributed to basin by 3.5 mi' (9.1 km2 ) above Rio Toro Diversion dam. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER DAY OCT NOV 1 626 518 2 407 429 3 564 491 4 497 423 5 389 339 6 433 331 7 359 334 8 353 347 9 347 366 10 301 701 11 351 735 12 817 1130 13 1700 905 14 2250 466 15 773 335 16 475 675 17 674 917 18 571 e!440 19 383 e392 20 421 e363 21 792 e523 22 626 e514 23 391 e371 24 334 e381 25 309 e375 26 291 e360 27 310 e347 28 552 e335 29 577 e324 30 903 e313 31 1100 TOTAL 18876 15480 MEAN 609 516 MAX 2250 1440 MIN 291 313 AC-FT 37440 30700 CFSM 6.46 5.47 IN. 7.45 6.11 DEC 6314 e294 e287 e279 e273 e266 e271 e262 6253 e253 e278 e248 e231 e224 e220 e211 e206 e202 e!93 186 184 184 179 177 177 185 170 167 167 166 164 6871 222 314 164 13630 2.35 2.71 STATISTICS OF MONTHLY MEAN DATA MEAN 665 435 MAX 1467 746 (WY) 1993 1982 MIN 344 197 (WY) 1983 1994 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 225 482 1966 103 1992 JAN 164 165 300 375 301 296 332 239 229 240 205 196 445 596 248 207 190 183 178 249 343 1020 393 293 250 225 212 201 194 188 205 8862 286 1020 164 17580 3.03 3.50 SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY FEB 193 215 217 189 214 204 410 211 209 184 203 188 172 167 164 161 158 156 154 154 156 155 149 145 144 140 140 138 —— 5090 182 410 138 10100 1.93 2.01 FOR WATER YEARS 1963 143 286 1997 83.6 1965 116 345 1996 62.3 1992 MEAN VALUES MAR 136 133 131 133 131 130 129 130 126 123 121 119 122 119 117 117 118 122 134 169 114 106 100 96 93 90 89 124 194 240 141 3947 127 240 89 7830 1.35 1.56 - 1997 105 271 1972 54.4 1965 FOR 1996 CALENDAR YEAR 159141 435 15700 87 88 315700 4.61 62.78 828 225 108 Sep 10 Mar 27 Mar 24 APR 117 97 92 88 86 83 81 81 81 79 76 74 78 73 72 72 71 69 68 67 67 73 114 76 69 67 67 66 68 67 —— 2339 78.0 117 66 4640 .83 .92 MAY 68 70 187 94 74 89 72 85 117 112 126 85 63 58 60 61 60 59 58 57 72 102 169 335 310 385 250 126 94 107 138 3743 121 385 57 7420 1.28 1.48 JUN 171 94 80 73 68 66 89 76 65 63 60 60 59 60 57 57 56 71 134 163 134 140 118 147 164 139 168 234 283 345 —— 3494 116 345 56 6930 1.24 1.38 JUL 299 135 102 91 97 81 79 153 194 102 86 89 154 379 261 167 125 106 156 159 121 109 103 96 92 127 116 97 120 97, 98* 4191 135 379 79 8310 1.43 1.65 AUG 97 88 88 221 115 96 90 141 280 361 418 278 1100 1300 640 493 256 209 199 329 218 169 442 415 229 175 188 630 615 , 496 405 10781 348 1300 88 21380 3.69 4.25 SEP 1030 1230 329 250 237 238 193 180 175 164 175 154 155 224 177 148 157 140 132 240 166 165 181 649 456 205 168 159 788 485 9150 305 1230 132 18150 3.23 3.61 , BY WATER YEAR (WY) 144 313 1971 49.3 1968 FOR 1997 92824 254 2250 56 58 9710 9 52 184100 2 36 496 175 72 371 1084 1986 63.7 1967 WATER YEAR Oct 14 Jun 17 Jun 11 Oct 14 .21 Oct 14 Jun 17 .70 .62 288 815 1979 71.2 1977 267 657 1979 111 1990 WATER 310 460 189 19400 32 35 140000 33 31 224900 3 44 654 185 74 359 936 1979 152 1967 YEARS 1963 Sep Apr Apr Sep .90 Sep Apr .29 .73 611 1422 1984 206 1983 - 1997 1979 1967 16 1975 18 1965 14 1965 16 1975 16 1975 19 1965 e Estimated 424 RIO GRANDE DE ANASCO BASIN 50144000 RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—water years 1963 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 13... FEB 1997 27... MAY 21... AUG 20... DIS- CHARGE, INST. CUBIC FEET TIME PER SPE- CIFZC CON- DUCT- ANCE PH WATER WHOLE FIELD TEMPER- (STAND- ATTIRE ARD WATER OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- TUR- OXYGEN, (PER- ICAL BID- DIS- CENT (HIGH ITY SOLVED SATUR- LEVEL) STREP - COLI- FORM, FECAL, TOCOCCI 0.45 FECAL, UM-MF (COLS./ SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) (COLS. PER 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1345 E580 1100 140 1145 76 1150 167 377 258 247 245 6.8 7.4 8.5 7.8 24.0 180 23.5 0.70 28.0 1.2 28.0 4.7 7.8 9.6 10.6 7.8 91 109 136 99 15 <10 <10 <10 K17000 28000 330 K10 K10 K45 240 K130 DATE NOV 1996 13... FEB 1997 27... MAY 21... AUG 20... HARD- NESS TOTAL (MG/L AS CAC03) (00900) CALCIUM DIS- SOLVED (MG/L AS CA) (00915) MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) SODIUM, DIS- SOLVED (MG/L AS NA) (00930) SODIUM AD- SORP- TION RATIO (00931) POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) SULFIDE TOTAL (MG/L AS S) (00745) SULFATE DIS- SOLVED (MG/L AS S04) (00945) CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 69 18 120 30 100 26 5.9 10 8.7 6.0 11 9.8 0.3 0.4 0.4 2.3 2.0 2.0 75 110 110 77 <0.5 7.3 <0.5 11 10 7.2 9.6 7.5 DATE NOV 1996 13... FEB 1997 27... MAY 21... AUG 20... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.10 23 0.11 0.10 32 28 115 E180 172 151 35.3 68.1 212 8 17 1.60 0.450 0.130 0.940 0.020 <0.010 <0.010 <0.010 1.60 0.020 0.460 0.010 0.140 0.080 0.950 0.050 0.72 <0.20 0.72 0.21 DATE NOV 1996 13... FEB 1997 27... MAY 21... AUG 20... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) NITRO- GEN, TOTAL (MG/L AS N) (00600) NITRO- GEN, TOTAL (MG/L AS N03) (71887) PHOS- PHORUS TOTAL (MG/L AS P) (00665) ARSENIC TOTAL (UG/L AS AS) (01002) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CD) (01042) 0.75 <0.20 0.79 0.26 E - estimated K - non-ideal count 2.4 11 0.57 2.5 0.93 4.1 1.2 5.3 0.230 <0.020 <0.020 0.030 <100 <100 20 10 RIO ORANDE DE ANASCO BASIN 50144000 RIO ORANDE DE ANASCO NEAR SAN SEBASTIAN, PR—CONTINUED WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 425 DATE NOV 1996 13... FEB 1997 27... MAY 21... AUQ 20... IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UO/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UO/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UO/L AS HO) (71900) SELE- NIUM, TOTAL (UO/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UO/L AS AO) (01077) ZINC, TOTAL RECOV- ERABLE (UO/L AS ZN) (01092) CYANIDE TOTAL (MO/L AS CN) (00720) PHENOLS TOTAL (UO/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MO/L) (38260) 8400 5100 370 <0.10 160 <0.10 20 <0.010 <0.010 <0.01 <0.01 426 RIO GRANDE DE ANASCO BASIN 50146000 RIO GRANDE DE ANASCO NEAR ANASCO, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°16'00", long 67°08'05", at bridge on Highway 430, 0.2 mi (0.3 km) south of Highway 109 at El Espino and 1.4 mi (2.3 km) east-southeast from Afiasco plaza. DRAINAGE AREA.—139 mi' (360 km1 ) this does not include 39.7 mi* (102.8 km'), flow is diverted to south coast. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 13... MAR 1997 05... MAY 21... AUG 20... DATE NOV 1996 13... MAR 1997 05... MAY 21... AUG 20... DATE NOV 1996 13... MAR 1997 05... MAY 21... AUG 20... DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. IE PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 10 -- 280 6.5 24.0 290 8.1 94 11 K7800 42000 15 177 260 7.8 25.0 0.80 8.9 104 <10 K80 K27 15 79 253 7.7 26.5 6.6 6.4 79 <10 K180 200 15 234 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 70 — 110 63 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — <0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.1 <0.20 <0.20 <0.20 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 18 — 28 17 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 23 — 31 18 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.7 0.36 <0.20 1.0 245 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.1 — 9.1 4.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 111 — 164 99 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 12 1.6 0.75 4.6 7.6 29.0 8 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 6.5 — 9.8 6.4 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) -- — 34.7 62.5 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.320 0.060 <0.020 0.040 SODIUM AD- SORP- TION RATIO (00931) 0.3 — 0.4 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 368 <1 5 28 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 __ .0 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 — 1.5 2.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.50 0.240 0.060 0.850 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — 7.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 69 110 110 100 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — 93 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 — NITRO- GEN, NO2+N03 TOTAL (MG/L AS N) (00630) 1.60 0.250 0.070 0.860 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — <10 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 7.6 — 10 8.5 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.020 0.030 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 12 — <1 — 450 380 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 5.8 — 8.0 6.2 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.1 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 — <10 — K » non-ideal count RIO ORANDE DE ANASCO BASIN 50146000 RIO ORANDE DE ANASCO NEAR ANASCO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 427 DATE NOV 1996 13... MAR 1997 05... MAY 21... AUO 20... IRON, TOTAL RECOV- ERABLE (UO/L LEAD, TOTAL RECOV- ERABLE (UO/L MANGA- NESE, TOTAL RECOV- ERABLE (OO/L MERCURY TOTAL RECOV- ERABLE (UO/L SELE- NIUM, TOTAL (UO/L SILVER, TOTAL RECOV- ERABLE (UO/L ZINC, TOTAL RECOV- ERABLE (UO/L CYANIDE TOTAL (MO/L PHENOLS TOTAL METHY- LENE BLUE ACTIVE SUB- STANCE AS FE) AS PB) AS MN) AS HO) AS SE) AS AO) AS ZN) AS CN) (UO/L) 11000 3800 DATE MAY 1997 21... (MO/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) (38260) <1 610 290 <0.10 <0.10 <1 <1 <1 <1 30 <0.010 <0.010 <1 <1 <0.01 <0.01 PESTICIDE ANALYSES TIME PCB, TOTAL (UO/L) (39516) ALDRIN, TOTAL (UO/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UO/L) (39350) P,P'- DDD UNFILT RECOVER (UO/L) (39360) P,P'- DDE, TOTAL (UO/L) (39365) P,P'- DDT UNFILT RECOVER (UO/L) (39370) DI- AZINON, TOTAL (UO/L) (39570) DI- ELDRIN TOTAL (UO/L) (39380) ENDO- SULFAN, I TOTAL (UO/L) (39388) 0835 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENDRIN MATER HEPTA- UNFLTRD ETHION, CHLOR, DATE REC TOTAL TOTAL (UO/L) (UO/L) (UO/L) MAY 1997 21... HEPTA- METH- CHLOR MALA- OXY- EPOXIDE LINDANE THION, CHLOR, TOTAL TOTAL TOTAL TOTAL (UO/L) (UO/L) (UO/L) (UO/L) (39390) (39398) (39410) (39420) (39340) (39530) (39480) METHYL PARA- THION, TOTAL (UO/L) (39600) MIREX, TOTAL (UO/L) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 21... PARA- THION, TOTAL (UO/L) (39540) PCNS UNFILT RECOVER (UO/L) (39250) PER- THANE TOTAL (UO/L) (39034) TOX- APHENE, TOTAL (UO/L) (39400) TOTAL TRI- THION (UO/L) (39786) 2,4-D, TOTAL (UO/L) (39730) 2,4,5-T TOTAL (UO/L) (39740) 2, 4-DP TOTAL (UO/L) (82183) SILVEX, TOTAL (UO/L) (39760) <0.010 <0.100 <0.100 <1.00 <0.010 <0.010 <0.010 <0.010 <0.010 425 THIS PAGE WAS LEFT BLANK INTENTIONALLY AGUADIU.A Drainage boundary «nc«r»ain LARES EXPLANATION ^1478 SURFACE-WATER STATION AND NUMBER ^1476 QUAUTY-OF-WATER STATION AND NUMBER A200 WELL AND WELL NUMBER v- Map area ' AStMeUi.*^ ^ 0123456 KILOMETERS 01234 MiLES Figure 26.--Rio Culebrinas basin. NJ 430 RIO CULEBRINAS BASIN 50147600 RIO COLBBRINAS NEAR SAN SEBASTIAN, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°20'51", long 67°02'40", at bridge on Highway 423, 1.3 mi (2.1 tan) south of Quebrada El Salto Bridge on Highway 111, and 2.1 mi (3.4 km) west of Central La Plata. DRAINAGE AREA.—58.2 mi* (150.7 km*). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DIS- PH OXYGEN, OXYGEN COLI- CHARGE, SPE- WATER DIS- DEMAND, FORM, STREP - INST. CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI CUBIC CON- FIELD TEMPER- TOR- OXYGEN, (PER- ICAL 0.45 FECAL, FEET DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. IATE TIME PER ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER SECOND (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) .996 1125 94 394 6.9 24.5 15 8.5 100 <10 K8500 2200 .997 1000 39 296 7.0 24.0 1.2 7.6 88 <10 500 K120 0850 42 307 7.7 25.0 5.1 7.3 88 <10 K680 350 1030 257 302 7.9 25.0 21 8.0 96 <10 6000 K16000 ALKA- DATE NOV 1996 13... MAR 1997 06... MAY 22... AUG 21... DATE NOV 1996 13... MAR 1997 06... MAY 22... AUG 21... DATE NOV 1996 13... MAR 1997 06... MAY 22... AUG 21... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 93 — 130 130 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.11 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.33 0.25 0.31 0.83 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 29 _. 42 44 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 37 — 31 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.7 1.4 1.3 1.9 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 4.9 — 5.6 4.3 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 166 — 191 176 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 7.6 6.3 5.8 8.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 10 — 15 8.2 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 42.4 — 21.4 122 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.120 0.090 0.090 SODIUM AD- SORP- TION RATIO (00931) 0.5 — 0.6 0.3 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 25 3 10 33 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.8 — 2.8 3.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.40 1.20 0.980 1.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 110 120 110 130 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.020 0.030 0.022 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — <10 — SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 ~~ NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.40 1.20 1.00 1.00 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 7.3 — 15 13 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.030 0.050 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — CHLO- RIDE, DIS- SOLVED (MG/L AS CD (00940) 9.5 — 14 7.9 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.30 0.21 0.27 0.78 COPPER, TOTAL RECOV- ERABLE (UG/L AS CTJ) (01042) <10 — <10 — K » non-ideal count DATE NOV 1996 13... MAR 1997 06... MAY 22... AUG 21... RIO CULEBRINAS BASIN 50147600 RIO CULEBRINAS NEAR SAN SEBASTIAN, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 SILVER, ZINC, TOTAL TOTAL RECOV- RECOV- CYANIDE ERABLE ERABLE TOTAL PHENOLS (UG/L (UG/L (MG/L TOTAL AS FE) AS PB) AS MN) AS HG) AS SB) AS AG) AS ZN) AS CN) (UG/L) (01045) (01051) (01055) (71900) (01147) (01077) (01092) (00720) (32730) 431 IRON, TOTAL RECOV- ERABLE (UG/L LEAD, TOTAL RECOV- ERABLE (UG/L MANGA- NESE, TOTAL RECOV- ERABLE (UG/L MERCURY TOTAL RECOV- ERABLE (UG/L SELE- NIUM, TOTAL (UG/L 610 30 <0.10 210 <1 20 <0.10 <1 <1 <0.010 2 <0.010 METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) <0.01 <0.01 432 RIO CULEBRINAS BASIN 50147800 RIO CULEBRINAS AT HIGHWAY 404 NEAR MOCA, PR LOCATION.--Lat 18021'42", long 67°05'33", Hydrologic Unit 21010003, on right bank, at bridge on Highway 404, 0.3 mi (0.5 km) downstream from Quebrada Yagruma, and 2.8 mi (4.5 km) southeast of Moca. DRAINAGE AREA.--71.2 mi* (184.4 km*). PERIOD OF RECORD.—July 1967 to current year. GAGE.—Water-stage recorder. Elevation of gage is 45 ft (14 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor, satellite telemetry at station. Gage-height and precipitation DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO S DAY OCT NOV 1 201 177 2 171 141 3 319 134 4 225 128 5 294 123 6 214 120 7 297 117 8 192 115 9 176 113 10 168 269 11 171 164 12 193 117 13 1770 120 14 1290 108 15 1210 521 16 365 461 17 1330 362 18 537 537 19 256 271 20 222 178 21 1600 262 22 265 478 23 212 250 24 192 175 25 176 158 26 168 148 27 210 141 28 301 137 29 191 134 30 464 139 31 247 TOTAL 13627 6298 MEAN 440 210 MAX 1770 537 MIN 168 108 AC-FT 27030 12490 CFSM 6.17 2.95 IN. 7.12 3.29 STATISTICS OF MONTHLY MEAN MEAN 625 325 MAX 1086 799 (WY) 1973 1982 MIN 231 108 (WY) 1968 1979 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS DEC 135 126 123 125 122 119 131 139 117 115 154 129 113 103 100 99 103 99 98 96 97 100 95 93 92 90 88 86 86 85 84 3342 108 154 84 6630 1.51 1.75 DATA 144 424 1982 72.1 1992 JAN 81 81 151 143 90 83 79 116 129 75 72 82 113 212 84 72 67 65 69 197 792 11000 458 338 281 244 221 208 197 188 449 16437 530 11000 65 32600 7.45 8.59 FOR WATER 92.2 530 1997 51.2 1979 DAILY FEB 276 178 162 149 139 131 159 123 181 133 114 99 85 80 78 75 73 72 71 69 68 69 66 64 64 62 61 60 —— 2961 106 276 60 5870 1.49 1.55 YEARS 1967 80.9 371 1996 37.0 1992 EFTfiMNEIK 1997 MEAN VALUES MAR 58 55 55 53 52 51 50 49 47 49 50 49 49 49 50 51 52 55 57 61 56 54 52 52 51 50 49 52 80 81 51 1670 53.9 81 47 3310 .76 .87 - 1997 70.6 319 1981 30.4 1979 FOR 1996 CALENDAR YEAR 106396 291 3750 42 49 211000 4. 55. 551 151 63 Aug 19 May 5 Apr 29 08 59 APR 49 53 48 46 45 42 41 41 41 40 41 41 41 41 40 39 39 38 38 37 37 39 42 38 38 39 39 38 39 38 —— 1228 40.9 53 37 2440 .57 .64 MAY 38 37 37 36 38 37 38 39 122 90 458 204 91 89 96 74 71 71 66 68 80 76 89 1310 834 342 333 270 285 238 221 5878 190 1310 36 11660 2.66 3.07 JUN 204 157 126 99 86 78 75 76 65 61 73 72 63 64 e60 e57 53 51 51 58 52 49 47 48 48 46 50 56 70 97 —— 2192 73.1 204 46 4350 1.03 1.15 JUL 84 80 53 48 58 45 41 41 44 39 38 53 173 457 539 359 127 73 63 65 64 56 59 54 49 186 142 163 495 122 739 4609 149 739 38 9140 2.09 2.41 AUG 276 132 105 217 148 102 92 113 276 222 141 135 568 293 196 327 210 134 208 982 708 260 244 358 228 164 795 3540 709 320 502 12705 410 3540 92 25200 5.76 6.64 SEP 450 583 284 273 209 180 166 157 157 139 142 134 125 131 126 126 141 133 119 114 113 117 114 285 413 168 162 150 116 114 5641 188 583 113 11190 2.64 2.95 , BY WATER YEAR (WY) 131 621 1986 26.4 1970 FOR 1997 76588 210 11000 36 37 31300 29 36 151900 2 40 348 113 42 464 2054 1986 96.7 1973 WATER YEAR Jan 22 May 4 Apr 30 Jan 22 .27 Jan 22 Apr 20 .95 .02 381 769 1984 73.1 1997 293 847 1979 66.7 1994 WATER 289 457 179 13300 19 20 69000 36 16 209300 4 55 596 134 43 334 831 1979 119 1970 YEARS 1967 Oct Apr Apr sep . 60 Sep Apr .06 .13 503 1350 1978 145 1986 - 1997 1986 1977 21 1972 16 1979 13 1979 16 1975 16 1975 17 1979 e Estimated 433 RIO CULEBRINAS BASIN 50149100 RIO CULEBRINAS NEAR AGUADA, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°24'03", long 67°09'40", at bridge on Highway 2, and 2.3 mi (3.7 km) northeast of Aguada plaza. DRAINAGE AREA.—97.0 mi 2 (251.2 km*). PERIOD OF RECORD.—Water years 1958, 1970 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 15... MAR 1997 05... MAY 22... AUG 20... DATE NOV 1996 15... MAR 1997 05... MAY 22... AUG 20... DATE NOV 1996 15... MAR 1997 05... MAY 22... AUG 20... DATE NOV 1996 15... MAR 1997 05... MAY 22... AUG 20... TIME 0900 1345 0645 1630 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 120 — 140 100 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — 0.10 <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.24 0.72 0.29 1.0 PH OXYGEN, OXYGEN COLI- SPE- WATER DIS- DEMAND, FORM, STREP - CIFIC WHOLE SOLVED CHBM- FECAL, TOCOCCI CON- FIELD TEMPER- TUR- OXYGEN, (PER- ICAL 0.45 FECAL, DUCT- (STAND- ATURE BID- DIS- CENT (HIGH UM-MF (COLS. ANCE ARD WATER ITY SOLVED SATUR- LEVEL) (COLS./ PER (US/CM) UNITS) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 294 6.9 26.0 15 6.9 83 <10 K2000 K1000 328 7.6 26.0 2.2 6.5 77 14 2300 >100000 346 7.6 26.0 22 6.0 73 <10 K1100 K1100 314 7.7 28.0 5. 6.3 80 <10 20000 9300 ALKA- CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 39 — 47 33 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 32 — 32 13 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.3 1.1 0.78 8.1 MAGNE- SIUM, SODIUM, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS MG) AS NA) (00925) (00930) 5.8 12 — 5.8 14 5.4 6.7 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 182 — 208 151 NITRO- PHOS- GEN, PHORUS TOTAL TOTAL (MG/L (MG/L AS NO3) AS P) (71887) (00665) 5.6 0.050 4.7 0.120 3.5 0.040 8.1 0.140 SODIUM AD- SORP- TION RATIO (00931) 0.5 -- 0.5 0.3 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 30 8 33 13 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — <1 — POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.3 — 2.6 3.6 NITRO- GEN, LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 120 140 130 140 NITRO- GEN, SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — <0.5 -- NITRO- GEN, SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 7.2 — 14 16 NITRO- GEN, CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 __ 15 7.8 NITRO- GEN, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC TOTAL (MG/L AS N) (00620) 1.00 0.320 0.480 0.780 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — <100 — TOTAL (MG/L AS N) (00615) 0.020 0.010 0.010 0.022 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 -- <10 — TOTAL (MG/L AS N) (00630) 1.00 0.330 0.490 0.800 CADMIUM WATER UNFLTRD TOTAL (UG/L AS CD) (01027) <1 — <1 — TOTAL (MG/L AS N) (00610) 0.040 0.040 0.060 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — <1 — TOTAL (MG/L AS N) (00605) <0.20 0.69 0.23 0.97 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -_ <10 — K - non-ideal count 434 RIO CULEBRINAS BASIN 50149100 RIO CULEBRINXS NEAR AGUADA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DATE NOV 1996 15... MAR 1997 05... MAY 22... AUG 20... IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) SELE- NIUM, TOTAL (UG/L AS SE) (01147) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 830 270 <1 <1 70 30 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <1 <0.01 <0.01 PESTICIDE ANALYSES DATE MAY 1997 22... TIME 0645 PCS, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P'- DDD UNFTLT RECOVER (UG/L) (39360) P,P'- DDE, TOTAL (UG/L) (39365) P,P'- DOT UNFILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) VI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 ENORIN WATER UNFLTRD ETHION, DATE REC TOTAL (UG/L) (UG/L) MAY 1997 22... HEPTA- HEPTA- CHLOR CHLOR, EPOXIDE LINDANE TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MIREX, TOTAL (UG/L) (39755) (39390) (39398) (39410) (39420) (39340) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE MAY 1997 22... PER- TOX- TOTAL THANE APHENE, TRI- 2,4-D, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL THION TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39540) (39250) (39034) (39400) (39786) (39730) (39740) (82183) (39760) PARA- PCNS THION, UNFILT TOTAL RECOVER <0.010 <0.100 <0.100 <1.00 <0.010 0.040 <0.010 <0.010 <0.010 C* 436 DISCHARGE AT PARTIAL-RECORD STATIONS As the number of streams on which streamflow information is likely to ba desired far exceeds the number of stream-gaging stations feasible to operate at one time, the Geological Survey collects limited streamflow data at sites other than stream-gaging stations. When limited streamflow data are collected on a systematic basis over a period of years for use in hydrologic analyses, the site at which the data are collected is called a partial-record station. Data collected at these partial-record stations are useable in low-flow or floodflow analyses, depending on the type of data collected. In addition, discharge measurements are made at other sites not included in the partial- record program. These measurements are generally made in times of drought or flood to give better areal coverage to those events. Those measurements and others collected for some special reason are called measurements at miscellane- ous sites. Low-flow partial-record stations Measurements of streamflow in the areas covered by this report made at low-flow partial-record stations are given in the following table. These measurements were made during periods of base flow when streamflow is pri- marily from ground-water storage. These measurements, when correlated with the simultaneous discharge of nearby stream when continuous records are available, will give a picture of the low-flow potentiality of stream. Discharge measurements made at low-flow partial-records stations during water year 1997 PUBLICATION RECORD STATION STATION NUMBER NAME 50010520 Rio Guajataca above sewage plant at Lares, PR LOCATION AND BASIN Rio Guajataca basin Lat 18°18'13", long 66°52'34", Hydrologic Unit 21010001, at barrio Pueblo, 0.5 mi (0.8 km) downstream from Highway 111, 1.5 mi (2.4 km) northwest from Cerro Palma, and 0.5 mi (0.8 km) north of Lares plaza. DRAINAGE AREA mi' 144 146 I I I I I I I I I I I I I I I I I \ Q Z H 150 152 154 156 158 \ 0 \ \ \ e Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June JulyAug 1996 1997 WATER YEAR 470 GROUND-WATER LEVELS RIO GRANDE DE ARECIBO BASIN 182626066345100. Local number, TI-1. LOCATION.—Let 18026'26", long 66°34'51", Hydrologic Unit 21010002, 1.45 ml south of Hwy 682, 1.15 ml northwest of the intersection of Hwy 140 with Hwy 2 (Cruce Davila), 0.48 mi north of Hwy 2, and approximately 100 feet south of Hwy 22. Owner: P.R. Aqueduct and Sewer Authority, Name: Tiburones 1. AQUIFER.—Aymamon Limestone. NELL CHARACTERISTICS.—Drilled water-table well, diameter 12 in (0.30 m). Depth 320 ft (97.5 m). INSTRUMENTATION.—Prior to December 19, 1996, pressure transducer with data logger—60-minute interval. DATUM.—Elevation of land-surface datum is about 295 ft (89.9 m) above mean sea level, from topographic map. Measuring point: Top of 4 in (0.10 m) PVC cap, above shelter floor, 3.40 ft (1.04 m) above land-surface datum. REMARKS.—Observation well. Prior to December 19, 1996, recording observation well. PERIOD OF RECORD.—May 14, 1996 to current year.. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 290.88 ft (88.66 m) below land-surface datum, Sept. 13, 14, 1996; lowest water level measured, 292.79 ft (89.24 m) below land-surface datum, Jan. 17, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION Date Dec. 19 Jan. 17 Water level 292.10 292.79 Date May 20 Aug. 15 water level 292.27 292.15 Date Sept. 23 Water level 292.19 Date Sept. 26 Water level 292.07 290.8 291.0 291.2 {291.4 '291.6 291.8 292.0 292.2 292.4 292.6 \ i i r O O 0 - - - - e Oct Nov Dec Jan Fab Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept 1996 1997 WATER YEAR WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM W W (O (O (O (O (O (O (O (O (O J W (O (O (O (O w w w w w W (0 (0 (0 (0 (O (O (0 (O (O 00 00 00 *O **J 10 (0 (0 (0 (0 w w w w w w w w w w wwwww wwwww wwwww w w w w w w 00 00 00 00 00 IO w w w w w w w w w w wwwww wwwww wwwww (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O (O IO (O (O (O (O (O(O(O(O(O IO IO IO (O (O (O (O (O (O (O (O IO (O (O (O (O (O(O(O(O(O 00000 RHHRH (O (O (O Kl (O O O O O O (0(0(0(0(0 (0(0(0(0(0 (0(0(0(0(0 472 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182757066325600. Local number, 206. LOCATION.—Lat 18°27'57", long 66°32'56", Hydrologic Unit 21010002, 0.84 mi northwest of Barceloneta plaza, 0.64 mi west of Central Plazuela, and 1.96 mi southeast of Escuela Agustin Balseiro. Owner: P.R. Department of Agriculture, Name: Plazuela No. 2. AQUIFER.—Aymamon Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 16 in (0.41 m), cased 16 in (0.41 m) 0-85 ft (0-25.9 m), open hole 85-101 ft (25.9-30.8 m). Depth 101 ft (30.8 m). INSTRUMENTATION.--Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 7.0 ft (2.1 m) above mean sea level, from topographic map. Measuring point: Hole on side of casing, 1.30 ft (0.40 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 3.75 ft (1.14 m) below land-surface datum, Sept. 11, 1988; lowest water level recorded, 6.03 ft (1.84 m) below land-surface datum, Sept. 15, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT 4.81 NOV DEC JAN APR MAY JUN JUL 4.92 5.26 5.22 5.26 5.38 5.42 5.41 5.51 5.48 WTR YR 1997 MEAN 5.29 HIGHEST 4.68 OCT. 1, 1996 LOWEST 5.65 JUNE 23, 1997 AUG 5.41 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 4.72 4 4.74 ! 4.76 ! 4.78 ! 4.76 ! 4.74 ! 4.75 ! 4.74 < 4.73 < 4.74 4 4.74 4 4.73 £ 4.74 4 4.76 4 4.79 4 4.82 t 4.88 4 4.89 < 4.84 4.82 4.82 4.85 4.86 .88 .87 .88 .90 .91 .94 ! .92 ! .96 1.98 5.06 5.00 5.08 i.OO 5.07 5.01 5.07 5.03 5.08 5.03 5.14 5.01 5.16 1.97 5.16 1.95 5.13 1.94 5.14 1.97 5.18 i.OO 5.26 1.94 5.31 1.94 5.35 1.93 5.33 1.92 5.30 1.92 5.28 1.87 5.27 .85 5.28 .83 5.30 .79 5.31 .81 5.32 .72 5.32 .74 5.35 .74 5.39 .86 5.42 .93 5.40 .97 5.41 5.03 5.37 5.03 5.38 —— 5.37 5.35 5.33 5.31 5.20 5.24 5.29 5.29 5.31 5.31 5.32 5.31 5.33 5.35 5.38 5.34 5.32 5.32 5.34 5.37 5.41 5.40 5.13 5.02 .96 .92 .93 .95 .98 5.04 5.08 5.08 5.08 5.09 5.11 5.12 5.13 5.16 5.17 5.17 5.19 5.20 5.20 5.22 5.27 5.31 5.31 5.33 5.34 5.36 5.37 5.40 5.40 5.37 5.36 5.34 5.31 5.30 5.30 5.33 —— —— —— 5.34 5.35 5.33 5.30 5.32 5.34 5.35 5.33 5.34 5.34 5.36 5.36 5.35 5.38 5.39 5.38 5.36 5.36 5.37 5.39 5.39 5.39 5.38 5.37 5.40 5.45 5.47 5.44 5.43 5.46 5.48 5.48 5.44 5.43 5.41 5.42 5.41 5.41 5.42 5.42 5.42 5.43 5.48 5.51 5.48 5.48 5.45 5.42 5.38 5.36 5.36 5.35 5.36 5.37 5.36 5.36 5.42 5.45 5.47 5.49 5.46 —— 5.44 5.41 5.39 5.38 5.38 5.38 5.35 5.37 5.40 5.42 5.42 5.41 5.43 5.45 5.45 5.48 5.46 5.46 5.48 5.47 5.45 5.41 5.40 5.39 5.37 5.37 5.37 5.38 5.40 5.42 5.43 5.42 5.43 5.42 5.41 5.38 5.39 5.41 5.45 5.48 5.52 5.54 5.55 5.52 5.46 5.47 5.45 5.47 5.51 5.55 5.57 5.57 5.57 5.59 5.61 5.61 5.62 5.60 5.60 5.58 5.59 ___ 5.59 5.58 5.57 5.58 5.59 5.59 5.59 5.56 5.55 5.55 5.57 5.57 5.54 5.52 5.50 5.50 5.51 5.46 5.39 5.34 5.32 5.34 5.34 5.37 5.38 5.39 5.39 5.42 5.44 5.47 5.47 5.43 5.42 5.40 5.38 5.38 5.37 5.37 5.36 5.37 5.40 5.44 5.49 5.51 5.49 5.49 5.49 5.45 5.42 5.39 5.37 5.35 5.38 5.41 5.43 5.45 5.48 5.44 5.40 5.37 5.36 5.34 5.32 5.31 5.33 5.31 5.32 5.31 5.29 5.28 5.30 5.35 5.40 5.43 5.42 5.40 5.38 5.36 5.34 5.33 5.37 5.39 5.41 5.43 5.42 5.44 5.43 5.39 5.41 5.39 5.38 5.34 -_- 5.37 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 473 182710066303700. Local number, 207. LOCATION.—Lat 18°27'10", long 66°30'37", Hydrologic Unit 21010002, 1.92 mi east of Barceloneta plaza, 1.35 mi north of Central Monserrate, and 2.68 mi northeast of Escuela Jose Cordero. Owner: P.R. Aqueduct and Sewer Authority, Name: Cantito La Luisa. AQUIFER.--Aymamon Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 20 in (0.51 m), cased 20 in (0.51 m) 0-30 ft (0-9.14 m), cased 10 in (0.25 m) 0-126 ft (0-38.4 m), perforated 80-126 ft (24.4-38.4 m) . Depth 126 ft (38.4 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 59.0 ft (18.0 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 2.80 ft (0.85 m) above land-surface datum. Prior to Nov. 20, 1992, hole on side of casing, 2.00 ft (0.61 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 36.38 ft (11.09 m) below land-surface datum, May 15, 1986; lowest water level recorded, 89.83 ft (27.38 m) below land-surface datum, Oct. 5, 1985. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV JAN FEB JUN JUL AUG MEAN 38.56 38.53 38.60 38.34 38.48 38.72 38.84 39.03 39.19 39.18 WTR YR 1997 MEAN 38.81 HIGHEST 38.03 JAN. 26, 27, 28, 1997 LOWEST 39.29 JULY 7, 8, 1997 39.18 SEP 1 2 3 4 5 38.43 38.45 38.48 38.51 38.49 38.56 38.57 38.58 38.60 38.62 38.41 38.42 38.42 38.41 38.42 38.65 38.66 38.65 38.25 38.23 38.14 38.18 38.21 38.25 38.29 38.65 38.66 38.66 38.65 38.66 38.87 38.87 38.81 38.76 38.76 38.93 38.93 38.93 38.94 38.94 39.07 39.08 39.07 39.06 39.08 39.25 39.26 39.26 39.26 39.26 39.14 39.14 39.14 39.14 39.14 39.20 39.16 39.10 39.12 39.10 6 7 8 9 10 38.50 38.51 38.52 38.53 38.55 38.64 38.65 38.65 38.66 38.67 38.46 38.53 38.59 38.61 38.63 38.28 38.31 38.34 38.37 38.38 38.32 38.35 38.37 38.39 38.40 38.66 38.66 38.66 38.66 38.65 38.75 38.76 38.78 38.79 38.81 38.94 38.95 38.96 38.98 38.99 39.10 39.14 39.16 39.16 39.17 39.28 39.29 39.29 39.26 39.25 39.14 39.14 39.15 39.16 39.17 39.10 39.10 39.09 39.08 39.05 11 12 13 14 15 38.57 38.58 38.59 38.60 38.62 38.70 38.73 38.65 38.62 38.61 38.64 38.64 38.65 38.66 38.65 38.39 38.41 38.42 38.44 38.46 38.40 38.42 38.45 38.48 38.50 38.66 38.67 38.68 38.68 38.67 38.83 38.85 38.87 38.88 38.88 39.00 39.00 39.02 39.04 39.06 39.20 39.20 39.20 39.19 39.16 39.25 39.25 39.24 39.20 39.18 39.17 39.18 39.16 39.15 39.15 39.01 39.02 39.02 39.04 39.04 16 17 18 19 20 38.60 38.61 38.62 38.60 38.59 38.58 38.56 38.51 38.44 38.43 38.64 38.63 38.62 38.61 38.63 38.46 38.47 38.50 38.55 38.60 38.50 38.60 38.64 38.66 38.64 38.68 38.70 38.71 38.71 38.72 38.89 38.90 38.88 38.86 38.86 39.07 39.08 39.08 39.12 39.12 39.17 39.18 39.19 39.21 39.23 39.14 39.14 39.14 39.10 39.08 39.18 39.19 39.21 39.22 39.22 39.03 39.03 39.03 39.06 39.09 21 22 23 24 25 38.58 38.58 38.59 38.59 38.59 38.42 38.43 38.39 38.41 38.37 38.64 38.65 38.66 38.67 38.68 38.62 38.40 38.23 38.09 38.06 38.65 38.64 38.63 38.62 38.64 38.74 38.75 38.76 38.77 38.77 38.85 38.83 38.82 38.81 38.83 39.13 39.11 39.10 39.12 39.08 39.27 39.27 39.26 39.27 39.27 39.07 39.07 39.09 39.09 39.08 39.23 39.23 39.25 39.23 39.23 39.10 39.11 39.11 39.12 39.10 26 27 28 29 30 31 38.60 38.61 38.62 38.62 38.44 38.50 38.37 38.39 38.39 38.41 38.42 —— 38.71 38.71 38.71 38.68 38.66 38.65 38.04 38.03 38.04 38.08 38.11 38.12 38.65 38.66 38.65 —— —— —— 38.81 38.81 38.79 38.81 38.86 38.87 38.87 38.88 38.89 38.91 38.93 —— 39.06 39.05 39.06 39.06 39.06 39.06 39.27 39.26 39.26 39.26 39.25 —— 39.08 39.09 39.12 39.12 39.14 39.14 39.20 39.18 39.18 39.18 39.18 39.19 39.10 39.13 39.12 39.11 39.10 —— 39.09 36 38 ^40 42 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 474 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182308066260400. Local number, 210. LOCATION.—Lat 18°23'08", long 66°26'04", Hydrologic Unit 21010002, 4.88 mi southeast of Manati plaza, 5.24 mi southwest of Vega Baja plaza, and 2.25 mi west of Escuela Evaristo Camacho. Owner: Gelo Martinez, Name: Gelo Martinez well. AQUIFER.--Lares Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 8 in (0.20 m), cased 8 in (0.20 m). INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 574 ft (174.9 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 3.30 ft (1,01 m) above land-surface datum. Prior to January 14, 1993, hole on side of casing, 2.00 ft (0.61 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 40.56 ft (12.36 m) below land-surface datum. May 22, 1986; lowest water level recorded, 85.50 ft (26.06 m) below land-surface datum, Oct. 14, 15, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV DEC JAN FEB MAY JUN MEAN 74.72 75.08 72.08 71.47 68.85 70.84 71.38 71.77 72.14 WTR YR 1997 MEAN 73.27 HIGHEST 68.10 FEB. 7, 1997 LOWEST 80.12 SEPT. 30, 1997 74.28 76.92 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 72.37 72.61 72.86 73.12 73.35 73.57 73.75 73.92 74.07 74.23 74.36 74.50 74.62 74.73 74.83 74.95 75.03 75.14 75.23 75.34 75.46 75.56 75.66 75.74 75.82 75.88 75.92 75.94 75.93 75.91 75.85 75.73 75.62 75.55 75.52 75.52 75.54 75.56 75.58 75.61 75.64 75.67 75.71 75.73 75.73 75.71 75.64 75.56 75.49 75.46 75.44 75.44 75.45 75.44 75.38 75.21 74.54 73.11 72.18 71.88 71.80 —— 71.75 71.73 71.72 71.73 71.80 71.85 71.93 72.01 72.09 72.18 72.24 72.29 72.29 72.28 72.28 72.27 72.25 72.20 72.13 72.06 72.04 72.04 72.07 72.10 72.15 72.20 72.18 72.21 72.20 72.17 72.14 72.12 72.11 72.11 72.08 72.03 71.92 71.84 71.80 71.78 71.77 71.79 71.81 71.85 71.89 71.92 71.97 72.02 72.09 72.14 72.19 72.23 72.18 72.02 71.54 71.05 70.53 70.01 69.56 69.23 69.02 68.88 68.74 68.58 68.43 68.29 68.20 68.13 68.10 68.12 68.16 68.22 68.31 68.41 68.52 68.63 68.72 68.81 68.90 68.98 69.06 69.16 69.30 69.41 69.55 69.64 69.71 69.82 69.92 70.02 —— —— 70.10 70.16 70.23 70.29 70.33 70.40 70.45 70.53 70.58 70.63 70.68 70.72 70.78 70.80 70.86 70.91 70.95 70.97 71.00 71.03 71.06 71.09 71.12 71.16 71.20 71.23 71.28 71.31 71.34 71.38 71.40 71.38 71.36 71.35 71.34 71.34 71.34 71.33 71.33 71.34 71.35 71.37 71.39 71.40 71.40 71.40 71.41 71.39 71.38 71.37 71.37 71.37 71.36 71.37 71.38 71.38 71.38 71.39 71.43 71.46 71.49 —— 71.50 71.52 71.55 71.56 71.58 71.61 71.63 71.66 71.68 71.69 71.70 71.72 71.73 71.75 71.76 71.77 71.80 71.81 71.82 71.84 71.84 71.85 71.87 71.87 71.90 71.91 71.94 71.96 71.99 72.00 72.02 72.03 72.04 72.05 72.07 72.09 72.10 72.10 72.10 72.10 72.11 72.12 72.13 72.13 72.13 72.12 72.11 72.10 72.10 72.10 72.10 72.12 72.14 72.15 72.18 72.21 72.24 72.27 72.29 72.30 72.33 —— 72.35 72.38 72.41 72.44 72.65 72.89 73.05 73.19 73.30 73.49 73.74 73.95 74.15 74.34 74.49 74.61 74.70 74.78 74.86 74.90 75.00 75.10 75.22 75.30 75.40 75.49 75.60 75.65 75.71 75.78 75.82 75.87 75.90 75.96 76.03 76.09 76.15 76.21 76.29 76.38 76.48 76.55 76.65 76.72 76.77 76.84 76.93 76.99 77.06 77.14 77.25 77.33 77.39 77.45 77.51 77.57 77.66 77.73 77.78 77.83 77.92 78.04 78.13 78.24 78.33 78.43 78.52 78.64 78.75 78.86 79.01 79.14 79.25 79.36 79.46 79.53 79.61 79.68 79.75 79.80 79.84 79.88 79.93 79.96 79.99 80.02 80.04 80.06 80.08 80.09 80.11 80.12 —— 79.42 60 70 f 80 90 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 475 182548066265700. Local number CS-7 LOCATION.Lat 18°25'48", long 66°26'57", Hydrologic Unit 21010002, 0.92 mi east of the intersection of Hwy 686 with Hwy 670, 0.79 mi south of Hwy 2, 0.27 mi east of the intersection of Hwy 672 with Hwy 670, and 0.01 mi south of Hwy 670. Owner: P.R. Aqueduct and Sewer Authority, Name: Cotto Sur No. 7. AQUIFER.--Tertiary Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 20 in (0.51 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 270.0 ft (82.3 m) above mean sea level, from topographic map. Measuring point: Top of 20 in (0.51 m) casing, 2.30 ft (0.70 m) above land-surface datum. REMARKS.—Observation well. Automated Digital Recorded (ADR) installed on July 11, 1994, changed to an Electronic Data Logger (EDL) on May 15, 1997. PERIOD OF RECORD.--July 11, 1994 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 254.41 ft (77.54 m) below land-surface datum, Sept. 15, 1996; lowest water level recorded, 260.63 ft (79.44 m) below land-surface datum, Aug. 14, 15, 1996. HATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC FEB MAR APR MAY JTJN JUL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 257.61 257.67 257.72 257.78 257.78 257.81 257.90 257.95 257.98 258.00 258.05 258.09 258.13 258.15 258.17 258.22 258.25 258.26 258.26 258.29 258.31 258.32 258.35 --- ___ —— —— ___ MEAN 258.05 —— —— —— —— —— —— 258.39 258.67 WTR YR 1997 MEAN 258.86 HIGHEST 257.59 OCT. 1, 1996 LOWEST 259.61 SEPT. 23, 1997 SEP — --- ___ --- ___ —— 258.33 258.29 258.31 258.33 258.38 258.36 258.37 258.36 258.41 258.40 258.41 258.42 258.43 258.42 258.43 258.46 258.45 258.46 258.46 258.47 258.48 258.51 258.48 258.53 258.54 258.56 258.59 258.62 258.63 258.68 258.65 258.65 258.70 258.69 258.70 258.74 258.75 258.76 258.78 258.79 258.78 258.80 258.81 258.83 258.83 258.86 258.86 —— 258.85 258.88 258.91 258.93 258.95 258.98 258.97 258.98 258.98 258.97 259.00 259.01 259.01 259.02 259.04 259.01 259.03 259.05 259.04 259.03 259.02 259.03 259.03 259.06 259.04 259.03 259.04 259.06 259.09 259.10 259.08 259.09 259.13 259.14 259.14 259.14 259.18 259.19 259.17 259.20 259.19 259.20 259.21 259.25 259.28 259.30 259.30 259.30 259.32 259.32 259.32 259.26 259.27 259.26 259.28 259.29 259.29 259.32 259.32 259.31 259.29 259.29 259.31 259.29 259.32 259.34 259.30 259.33 259.33 259.33 259.31 259.33 259.33 259.33 259.36 259.38 259.41 259.39 259.39 259.42 259.42 259.43 259.45 259.45 259.53 259.51 259.50 259.44 259.40 259.34 259.33 259.31 259.01 259.24 259.38 256 ,258 '260 262 I I I I I I I I I I I I I I I I I I I I I I Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept 1996 1997 WATER YEAR 476 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182506066280200. Local number, HI-2. LOCATION.—Lat 18°25'06", long 66°28'02", Hydrologic Unit 21010002, 0.72 mi southwest of the intersection of Hwy 686 with Hwy 670, 0.73 mi southeast of intersection of Hwy 149 with Hwy 670, and 0.78 mi northeast of Escuela Sabana Seca. Owner: U.S. Geological Survey, WRD, Name: USGS Hill 2. AQUIFER.--Aymamon Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), screened 360-410 ft (109.7-125.0 m). Depth 410 ft (125.0 m). INSTROHENTATION.--Pressure transducer with Data Logger. DATUM.—Elevation of land-surface datum is about 312 ft (95.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.76 ft (1.15 m) above land-surface datum. REMARKS.—Recording observation well. Electronic Data Logger installed on May 28, 1996. PERIOD OF RECORD.—May 28, 1996 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 267.96 ft (81.67 m) below land-surface datum, Jan. 24, 1997; lowest water level recorded, 293.09 ft (89.33 m) below land-surface datum, Sept. 5, 6, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC APR HAY JUN JUL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 286.59 286.52 286.44 286.53 286.50 286.45 286.42 286.49 286.50 286.52 286.48 286.55 286.51 286.50 286.57 286.55 286.49 286.42 286.40 286.51 286.55 286.58 286.66 286.64 286.71 286.76 286.67 286.63 286.61 286.43 286.05 286.22 286.32 286.41 286.56 286.69 286.75 286.76 286.74 286.75 286.87 287.08 287.22 287.13 286.22 286.10 286.40 286.46 286.50 286.58 286.65 286.76 286.79 286.69 286.62 286.34 284.79 285.25 285.51 285.59 285.62 285.54 285.43 285.33 285.35 285.44 285.49 285.50 285.57 285.68 285.81 285.81 285.70 285.38 285.27 285.19 285.08 284.99 285.06 285.07 285.07 285.06 285.04 284.98 284.85 284.80 284.81 284.71 284.47 284.18 283.96 283.42 283.55 283.71 283.73 283.60 282.94 282.97 283.06 283.07 283.07 283.03 282.97 282.97 282.92 282.85 282.75 282.72 282.71 282.64 282.65 282.65 282.49 277.86 276.94 ___ ___ —— ___ —— ___ —— —— ___ —— 277.48 277.37 277.36 277.29 277.22 277.28 277.19 277.31 277.39 277.35 277.33 277.34 277.29 277.37 277.27 277.24 277.24 277.23 277.10 276.87 276.73 276.81 276.85 276.88 —— 276.93 276.87 276.91 276.93 276.94 276.95 276.97 277.01 277.02 277.10 277.05 277.16 277.21 277.27 277.25 277.25 277.29 277.33 277.36 277.34 277.42 277.53 277.64 277.74 277.80 277.81 277.76 277.78 277.86 277.85 277.88 277.87 —— 277.98 —— 278.09 —— 278.20 —— 278.27 —— 278.28 278.20 —— 278.19 —— 278.20 —— 278.31 —— 278.47 —— 278.53 —— 278.59 —— 278.62 —— 278.69 —— 278.69 278.67 —— 278.71 —— 278.87 —— 278.99 —— 279.04 —— 279.12 —— 279.17 —— 279.26 —— 279.41 —— 279.53 —— 279.58 —— 279.68 —— —— 281.97 282.10 —— 282.20 282.21 282.22 282.22 282.17 282.35 282.46 282.55 282.61 282.75 282.85 283.05 283.07 283.16 283.23 283.27 283.33 283.43 283.59 283.67 283.65 283.72 283.84 283.86 283.86 283.89 283.95 284.12 284.20 284.32 284.43 —— 284.46 284.51 284.65 284.75 284.90 284.97 285.02 285.02 284.91 285.03 285.18 285.23 285.20 285.37 285.50 285.55 285.64 285.64 285.71 285.78 285.91 285.97 286.00 286.08 286.08 286.06 286.14 286.24 286.34 286.32 286.33 286.39 286.44 286.47 286.49 286.55 286.65 286.66 286.69 286.77 286.85 286.85 ___ —— 287.02 287.07 287.17 287.20 287.18 287.18 287.22 287.29 287.36 287.36 287.36 287.41 287.46 287.52 287.56 287.59 287.62 287.68 287.76 287.83 287.83 287.79 287.84 287.86 287.80 287.84 287.90 287.99 288.13 288.17 288.18 288.24 288.31 288.33 288.30 288.32 288.36 288.34 288.43 288.47 288.50 288.54 288.57 288.64 288.67 288.68 288.65 288.71 MEAN 286.52 286.41 285.10 282.52 277.20 277.33 278.69 282.09 283.27 285.50 287.07 WTR YR 1997 MEAN 283.58 HIGHEST 267.96 JAN. 24, 1997 LOWEST 288.72 SEPT. 28, 29, 30, 1997 288.23 270 ,280 "290 300 I I I I I I I I I [ I T I I I I II II I I I I I I I I I I I__ I_ I I I I I I I I I I I I Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept 1996 1997 WATER YEAR GROUND-WATER LEVELS RZO CZBUCO BASZN 477 182647066201700. Local number, 70. LOCATION.--Lat 18°26'47", long 66°20'17", Hydrologic Unit 21010002, 1.52 mi north of Vega Alta plaza, 4.78 mi southwest of Dorado plaza, and 2.01 mi northwest of Escuela Industrial para Mujeres. Owner: P.R. Aqueduct and Sewer Authority, Name: Sabana Hoyos. AQUIFER.—Limestone of Tertiary Age. WELL CHARACTERISTICS.--Drilled unused artesian well, diameter 8 in (0.20 m), cased 0-90 ft (0-27.43 m), perforated. Depth 90 ft (27.43 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 49 ft (14.9 m) above mean sea level, from topographic map. Measuring point: Top of casing wooden cover, 1.30 ft (0.40 in) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—February 1960 to current year. EXTREMES FOR PERZOD OF RECORD.—Highest water level recorded, 21.33 ft (6.50 m) below land-surface datum, Oct. 26, 1976; lowest water level recorded, 31.12 ft (9.48 m) below land-surface datum, May 12, 13, 1995. WATER LEVEL, ZN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1965 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN APR JUN AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 27.68 27.73 27.78 27.84 27.89 27.94 27.98 28.03 28.07 28.10 28.13 28.17 28.20 28.24 28.28 28.32 28.36 28.38 28.41 28.45 28.48 28.53 28.57 28.60 28.63 28.66 28.68 28.69 28.64 28.56 28.52 28.49 28.49 28.48 28.49 28.50 28.51 28.53 28.54 28.52 28.51 28.52 28.53 28.51 28.47 28.43 28.40 28.38 28.37 28.35 28.34 28.34 28.33 28.26 28.10 27.93 27.84 27.78 27.74 27.71 27.70 -__ 27.70 27.69 27.69 27.70 27.71 27.73 27.75 27.78 27.81 27.84 27.86 27.88 27.90 27.93 27.95 27.97 27.98 28.00 28.02 28.05 28.08 28.09 28.11 28.07 28.04 28.04 28.00 27.97 27.95 27.91 27.88 27.85 27.81 27.78 27.66 27.64 27.63 27.63 27.64 27.65 27.67 27.70 27.71 27.73 27.75 27.76 27.80 27.83 27.85 27.89 27.92 27.95 27.88 27.76 27.61 27.48 27.40 27.34 27.30 27.28 27.28 27.28 27.29 27.29 27.30 27.32 27.34 27.36 27.38 27.40 27.42 27.44 27.46 27.49 27.51 27.53 27.56 27.57 27.59 —— 27.65 27.67 27.68 27.71 27.72 27.73 27.73 27.74 27.74 27.76 —— —— 27.77 27.78 27.79 27.80 27.81 27.82 27.83 27.85 27.87 27.88 27.91 27.93 27.95 27.97 27.99 28.01 28.03 28.05 28.07 28.08 28.09 28.12 28.14 28.17 28.20 28.23 28.25 28.28 28.30 28.32 28.35 28.38 28.41 28.43 28.46 28.48 28.50 28.52 28.54 28.56 28.58 28.61 28.63 28.65 28.67 28.69 28.72 28.74 28.76 28.78 28.80 28.83 28.86 28.88 28.90 28.92 28.95 28.98 29.00 29.02 29.04 —— 29.06 29.08 29.09 29.10 29.11 29.13 29.16 29.18 29.20 29.22 29.22 29.23 29.25 29.27 29.29 29.31 29.33 29.34 29.36 29.38 29.41 29.42 29.43 29.45 29.44 29.44 29.44 29.44 29.44 29.46 29.47 29.48 29.49 29.50 29.51 29.52 29.53 29.54 29.56 29.58 29.60 29.61 29.63 29.64 29.65 29.66 29.67 29.70 29.72 29.74 29.75 29.76 29.77 29.78 29.79 29.80 29.81 29.82 29.83 29.84 29.85 —— 29.86 29.87 29.89 29.91 29.93 29.94 29.95 29.96 29.96 29.98 29.99 30.00 30.01 30.01 30.02 30.04 30.05 30.05 30.05 30.05 30.05 30.06 30.06 30.07 30.08 30.08 30.09 30.09 30.10 30.12 30.13 30.13 30.13 30.13 30.13 30.14 30.14 30.15 30.16 30.17 30.18 30.18 30.19 30.19 30.19 30.20 30.20 30.18 30.15 30.14 30.14 30.13 30.13 30.12 30.12 30.10 30.08 30.07 30.06 30.05 30.04 30.04 30.03 30.03 30.02 30.01 30.01 30.01 30.01 30.00 29.99 29.99 29.99 30.00 30.00 29.99 29.98 29.98 29.98 29.98 29.98 29.98 29.99 29.98 29.98 29.97 29.97 29.97 29.96 29.96 29.96 29.96 —— MEAN 28.28 28.30 27.91 27.66 27.53 28.02 28.71 29.30 29.67 30.01 30.13 29.99 WTR YR 1997 MEAN 28.80 HIGHEST 27.28 JAN. 29, 30, 31, FEB 1, 2, 1997 LOWEST 30.21 AUG. 15, 16, 1997 26 28 «30 32 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1 I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 478 GROUND-HATER LEVELS RIO CIBUCO BASIN 182615066235300. Local number, 211. LOCATION.—Lat 18°26'15", long 66°23'53", Hydrologic Unit 21010002, 4.46 mi southeast of Manati plaza, 5.48 mi southwest of Vega Baja plaza, and 1.22 mi east of Hwy 155 km 58.3. Owner: P.R. Aqueduct and Sewer Authority, Name: Rosario No. 2. AQUIFER.--Aguada Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 14 in (0.36 m) 0-200 ft (0-61.0 m), diameter 12 in (0.30 m) 200-250 ft (61.0-76.2 m), cased 12 in (0.30 m) 0-250 ft (0-76.2 m), perforated 210-250 ft (64.0-76.2 m), diameter 10 in (0.25 m) 250-270 ft (76.2-82.3 m), open hole; concrete sealed 0-200 ft (0-61.0 m). Depth 270 ft (82.3 m). INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.--Elevation of land-surface datum is about 215 ft (65.5 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 3.10 ft (0.94 m) above land-surface datum. Prior to April 11, 1994, hole on side of casing, 1.15 ft (0.35 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 191.29 ft (58.30 m) below land-surface datum. May 16, 1986; lowest water level recorded, 194.1 ft (59.16 m) below land-surface datum, Mar. 31, Apr. 1 to 7, 1995. HATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, HATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT DEC FEB 1 2 3 4 5 192.75 192.79 192.81 192.82 192.82 192.83 192.82 192.82 192.82 192.82 192.51 192.54 192.57 192.57 192.59 192.67 192.67 192.67 192.65 192.58 192.21 192.24 192.27 192.29 192.32 6 7 8 9 10 192.82 192.82 192.83 192.83 192.83 192.82 192.84 192.84 192.84 192.84 192.62 192.67 192.69 192.70 192.75 192.56 192.57 192.57 192.56 192.55 192.38 192.41 192.41 192.42 192.47 APR 192.86 192.90 192.90 192.89 192.89 192.89 192.89 192.89 192.89 192.89 MAY 193.03 193.03 193.03 193.03 193.03 193.03 193.03 193.04 193.07 193.09 JUN 193.19 193.19 193.25 193.26 193.25 193.25 193.27 193.27 11 12 13 14 15 192.90 192.90 192.90 192.90 192.96 192.85 192.88 192.88 192.88 192.88 192.74 192.75 192.76 192.75 192.76 192.57 192.57 192.57 192.59 192.61 192.47 192.48 192.48 192.53 192.53 —— 192.65 192.66 192.66 192.67 192.90 192.91 192.92 192.93 192.94 193.10 193.12 193.14 193.15 193.16 16 17 18 19 20 192.96 192.98 192.99 192.99 193.00 192.86 192.85 192.85 192.83 192.83 192.74 192.69 192.67 192.68 192.72 192.61 192.61 192.62 192.62 192.64 192.58 192.59 192.60 192.60 192.61 192.67 192.67 192.67 192.67 192.72 192.95 192.95 192.94 192.94 192.94 193.16 193.16 193.16 193.16 193.17 21 22 23 24 25 193.00 193.00 193.00 193.01 193.01 192.82 192.82 192.74 192.59 192.48 192.72 192.72 192.72 192.71 192.71 192.70 192.66 192.54 192.55 192.53 192.72 192.94 193.19 192.72 192.93 193.20 192.73 192.94 193.16 192.73 192.93 193.16 192.76 192.93 193.16 26 27 28 29 30 31 193.01 193.01 193.01 193.01 192.94 192.91 192.42 192.42 192.41 192.44 192.46 —— 192.71 192.71 192.71 192.69 192.68 192.67 192.53 192.54 192.54 192.17 192.18 192.20 192.85 192.85 192.85 192.85 192.85 192.85 192.94 192.96 192.97 193.03 193.03 193.17 193.17 193.17 193.17 193.18 193.18 MEAN 192.92 192.75 192.68 192.55 192.44 192.74 192.93 193.12 193.24 WTR YR 1997 MEAN 192.88 HIGHEST 192.17 JAN. 29, 30, 1997 LOWEST 193.40 AUG. 15-29, 1997 AUG SEP 193.37 193.34 193.35 193.35 193.35 193.35 193.35 193.33 193.31 193.31 193.32 193.34 193.37 193.37 193.37 193.37 193.37 193.37 193.37 193.38 193.38 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.40 193.39 193.38 193.37 193.39 193.34 192 ,193 '194 195 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO CIBUCO BASIN 479 182515066194000. Local number, 212. LOCATION.--Lat 18°25'15", long 66° 19-40", Hydro logic Unit 21010002, 5.15 mi southwest of Dorado plaza, 0.49 mi north of Vega Alta plaza, and 1.04 mi northwest of Escuela Industrial para Mujeres. Owner: U.S. Geological Survey, WRD, Name: Ponderosa TW-1. AQUIFER.—Aguada Limestone-Cibao Formation. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-136 ft (0-41.1 m), perforated 121-131 ft (36.9-39.9 m); bentonite packed 0.5-121 ft (0.15-36.9 m). Depth 136 ft (39.9 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 98.0 ft (29.9 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 2.55 ft (0.78 m) above land-surface datum. Prior to November 3, 1989, hole on top of shelter floor casing, 3.00 ft (0.91 m) above land-surface datum. REMARKS.—Recording observation well. Water levels affected by nearby pumping well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 63.05 ft (19.22 m) below land-surface datum, July 15, 1987; lowest water level recorded, 75.33 ft (22.96 m) below land-surface datum, Feb. 27, Mar. 4, 5, 6, 1995 WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC MAR APR JUN JUL AUG MEAN 68.97 69.35 69.02 68.41 67.12 66.94 68.81 70.05 70.83 WTR YR 1997 MEAN 69.82 HIGHEST 65.18 FEB 17, 1997 LOWEST 73.78 AUG. 10-13, 1997 72.90 73.41 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 69.81 69.88 69.83 69.15 67.77 68.72 69.08 69.18 69.25 69.29 69.29 69.36 67.82 68.94 69.21 67.82 67.73 67.70 67.69 67.69 67.77 69.24 69.45 69.52 69.60 69.71 69.76 69.79 69.53 69.32 69.23 69.25 69.44 69.48 69.51 69.51 69.51 69.51 69.51 68.18 67.81 69.04 69.18 69.22 68.94 69.49 69.62 69.64 69.66 69.66 69.67 69.67 69.68 69.68 69.68 69.59 69.43 69.33 69.28 69.22 69.21 ___ 69.18 69.15 69.05 69.05 69.05 69.00 68.98 68.99 68.99 69.01 69.04 69.05 69.04 69.06 69.08 67.66 68.80 69.00 69.04 69.07 69.13 69.17 69.19 69.19 69.19 69.20 69.18 69.09 69.06 69.02 69.01 68.35 68.77 68.79 68.80 68.80 68.80 68.80 68.79 68.79 68.79 68.77 68.79 68.82 68.82 68.85 66.61 66.44 68.02 68.60 68.74 68.85 68.85 68.67 68.43 68.25 68.12 68.01 67.97 67.91 67.87 67.79 67.77 67.76 67.53 67.68 67.71 67.43 67.64 67.69 67.70 66.06 67.36 65.96 65.40 67.17 65.78 65.27 67.12 67.49 67.59 67.64 67.74 67.75 67.83 67.86 65.76 67.32 67.65 65.60 —— 65.52 65.40 67.08 67.54 65.48 67.26 67.62 67.70 67.86 67.90 67.98 68.08 68.20 68.25 66.52 66.09 67.47 66.26 67.88 66.33 66.10 66.02 66.01 66.07 --- ___ —— —— —— ___ —— —— 66.26 68.07 68.66 67.35 66.92 66.83 68.54 68.98 69.21 69.37 67.40 68.95 69.38 69.57 69.75 69.83 68.66 67.96 69.58 69.98 70.11 70.23 70.04 68.75 68.29 68.19 69.60 70.24 —— 68.45 70.05 68.37 68.32 70.06 70.51 70.68 70.52 70.90 68.81 68.64 70.45 70.64 70.65 69.31 68.91 68.84 68.82 68.80 70.63 71.12 71.32 71.44 71.55 69.39 71.10 71.52 69.81 69.38 71.13 71.58 71.72 70.11 71.43 71.82 70.40 71.64 69.76 69.63 69.59 69.59 69.56 69.56 69.56 69.56 69.57 69.56 69.57 69.59 69.58 71.06 71.90 72.06 72.22 71.94 71.87 72.23 72.34 72.48 72.53 72.61 —— 72.68 72.70 72.78 72.82 72.87 70.99 70.75 72.44 72.79 72.89 72.95 72.97 71.21 72.73 72.99 73.10 73.15 73.17 73.18 73.20 73.23 73.28 73.33 73.34 73.38 73.38 73.45 73.45 73.52 73.55 73.56 73.57 73.57 73.59 73.60 73.62 73.66 73.68 73.74 73.76 73.77 73.78 73.78 71.91 73.27 73.60 73.68 73.72 73.70 73.64 73.63 73.63 71.87 72.74 73.34 73.00 73.01 73.29 73.34 73.37 73.41 73.43 73.44 73.15 73.36 73.44 73.45 73.46 73.46 71.54 71.08 70.86 70.77 70.68 70.61 70.48 70.38 70.37 70.36 70.31 70.26 70.22 70.19 70.17 70.13 70.08 70.02 70.02 70.00 69.96 69.93 69.93 —— 71.07 65 ,70 '75 80 ONDJFMAMJJAS 1993 ONDJFMAMJJAS 1994 ONDJFMAMJJAS 1995 WATER YEAR ONDJFMAMJJAS 1996 ONDJFMAMJJAS 1997 480 GROUND-WATER LEVELS RIO CIBUCO BASIN 182330066185700. Local number, 213. LOCATION. --La t 18°23'30", long 66°18'57", Hydrologic Unit 21010002, 1.82 mi southeast of Vega Alta plaza, 4.23 mi west of Toa Alta plaza, and 1.27 mi northwest off the intersection of Hwy 820 with Hwy 823. Owner: P.R. Aqueduct and Sewer Authority, Name: Pampano No. 2. AQUIFER.—Rio Indio Limestone-Lares Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 20 in (0.51 m), cased 20 in (0.51 m) 0-130 ft (0-39.6 m), diameter 14 in (0.36 m), cased 12 in (0.30 m) 0-220 ft (0-67.1 m); open hole 220-330 ft (67.6- 100.6 m). Depth 330 ft (100.6 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 394 ft (120 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 9.32 ft (2.84 m) above land-surface datum. Prior April 27, 1993, hole on side of casing, 2.95 ft (0.90 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 34.40 ft (10.50 m) below land-surface datum, Dec. 6, 1985; lowest water level recorded, 65.68 ft (20.02 m) below land-surface datum, Aug. 20, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT DEC 46.74 46.47 46.20 45.96 45.86 45.68 45.51 45.40 45.41 45.44 45.33 45.29 45.13 45.09 45.03 JAN FEB MAR APR JUN JUL AUG 52.58 52.60 52.61 52.59 52.61 52.58 52.62 52.74 52.81 52.82 52.77 52.81 49.92 49.43 48.94 48.91 48.64 48.37 48.09 47.82 47.55 47.28 47.01 MEAN 52.68 48.36 45.64 —— —— 40.55 42.68 45.64 48.08 50.41 WTR YR 1997 MEAN 47.98 HIGHEST 40.03 MAR. 11, 1997 LOWEST 54.71 SEPT. 26-30, 1997 52.27 SEP 41.28 41.45 41.53 41.72 41.81 44.15 44.32 44.47 44.53 44.62 47.04 47.12 47.17 47.20 47.27 49.32 49.39 49.46 49.59 49.70 51.49 51.55 51.60 51.64 51.70 53.22 53.32 53.37 53.40 53.56 40.18 40.19 40.20 40.19 40.16 41.87 41.91 41.93 42.05 42.13 44.71 44.84 44.92 45.06 47.38 47.41 47.56 47.65 47.13 49.78 49.82 49.86 49.95 50.05 51.80 51.82 51.86 51.90 51.79 53.63 53.64 53.76 53.87 54.01 40.13 40.16 40.23 40.26 40.21 42.30 42.33 42.44 42.52 42.63 45.15 45.24 45.30 45.35 45.49 47.03 47.55 47.70 47.91 47.99 50.13 50.17 50.18 50.30 50.38 51.94 52.01 52.03 52.12 52.19 54.13 54.19 54.23 54.36 54.44 40.27 40.31 40.35 40.37 40.50 42.65 42.69 42.79 42.90 43.03 45.61 45.72 45.84 45.93 46.05 48.14 48.22 48.38 48.49 48.54 50.42 50.55 50.59 50.67 50.73 52.25 52.36 52.38 52.40 52.43 54.50 54.43 54.46 54.48 54.49 40.55 40.58 40.71 40.83 40.96 43.13 43.17 43.27 43.47 43.66 46.10 46.24 46.34 46.44 46.45 48.59 48.72 48.79 48.82 48.91 50.79 50.82 50.90 50.97 50.97 52.52 52.62 52.66 52.71 52.77 54.56 54.58 54.60 54.61 54.61 41.05 41.04 41.10 41.16 41.24 41.25 43.75 43.88 43.95 44.06 44.10 46.48 46.60 46.70 46.79 46.90 47.00 48.98 49.02 49.10 49.20 49.26 —— 50.98 51.09 51.18 51.24 51.34 51.40 52.82 52.90 52.97 53.02 53.07 53.17 54.68 54.69 54.70 54.68 54.70 —— 54.20 20 40 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO CIBUCO BASIN 481 182614066261500. Local number, PA-2. LOCATION.—Lat 18°26'14", long 66°26'15", Hydrologic Unit 21010002, 1.80 mi east of the intersection of Hwy 686 with Hwy 670, 0.30 mi south of Hwy 2, 0.70 mi northeast of Escuela Ramirez de Arellano, and 0.32 mi north of Hwy 670. Owner: U.S. Geological Survey, WRD, Name: Palo Alto 2. AQUIFER.—Aymamon Limestone. NELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), screened 265-310 ft (80.8-94.5 m). Depth 310 ft (94.5 m). INSTRUMENTATION.-Pressure transducer with Electronic Data Logger (EDL). DATUM.—Elevation of land-surface datum is 245.5 ft (74.8 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.79 ft (1.16 m) above land-surface datum. REMARKS.—Recording observation well. Electronic Data Logger (EDL) installed on May 28, 1996. PERIOD OF RECORD.—May 28, 1996 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 221.78 ft (67.60 m) below land-surface datum, Sept. 12, 1996; lowest water level recorded, 240.04 ft (73.16 m) below land-surface datum, Aug. 12-15, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 IAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT 237.41 237.57 237.71 237.85 237.33 237.65 237.86 238.03 238.13 238.24 238.33 238.40 238.48 238.40 238.54 238.61 238.66 238.72 238.76 238.81 238.83 238.86 238.58 238.80 238.90 238.92 237.97 238.36 238.60 235.58 236.44 NOV 237.05 237.51 237.89 238.17 238.40 238.56 238.69 238.78 238.85 238.93 239.00 239.05 236.64 237.25 237.38 237.83 238.13 238.32 238.47 238.58 238.67 238.74 233.15 232.92 230.56 231.16 231.97 232.79 233.55 234.26 —— DEC 234.60 235.16 235.64 235.70 235.34 236.11 237.01 238.04 239.07 238.80 236.66 237.16 237.67 238.13 238.52 237.17 237.72 238.18 238.45 238.65 238.89 238.96 239.17 239.34 239.41 239.53 237.28 237.55 237.47 237.77 238.03 JAN 238.27 238.47 238.66 236.18 236.26 236.59 236.95 237.29 237.61 237.91 238.18 238.44 238.66 238.84 239.00 239.14 239.27 239.39 239.50 239.43 237.53 230.85 228.87 227.81 —— ___ —— —— —— —— —— FEB ___ —— —— —— 232.98 233.42 233.81 234.16 234.46 234.74 234.99 235.20 235.41 235.58 235.75 235.90 236.05 236.15 236.24 236.31 235.70 235.88 236.06 236.14 236.26 236.39 236.50 —— —— —— MAR 236.59 236.66 236.72 236.78 236.80 236.78 236.86 236.92 236.97 237.01 237.04 237.09 237.12 237.16 237.20 237.22 237.25 237.28 237.30 237.33 237.36 237.39 237.42 237.45 237.48 237.51 237.54 237.56 237.58 237.60 237.62 APR 237.64 237.68 237.70 237.72 237.72 237.73 237.74 237.75 237.76 237.79 237.82 237.84 237.86 237.87 237.89 237.91 237.92 237.93 237.95 237.97 237.98 237.99 238.00 238.02 238.04 238.05 238.07 238.09 238.11 238.13 —— MAY 238.15 238.17 238.19 238.20 238.21 238.23 238.24 238.26 238.28 238.29 238.30 238.31 238.33 238.35 238.37 238.39 238.40 238.42 238.43 238.47 238.49 238.49 238.51 238.52 238.52 238.53 238.53 238.54 238.55 238.57 238.59 JUN 238.59 238.60 238.61 238.61 238.63 238.64 238.64 238.65 238.67 238.67 238.69 238.70 238.72 238.73 238.74 238.75 238.76 238.78 238.80 238.81 238.83 238.84 238.85 238.86 238.88 238.89 238.90 238.90 238.91 238.92 ___ JUL 238.92 238.93 238.94 238.94 238.95 238.96 238.97 238.98 238.98 239.00 239.00 239.01 239.00 239.01 239.02 239.03 239.04 239.05 239.05 239.04 239.04 239.04 239.04 239.04 239.05 239.04 239.05 239.06 239.07 239.08 239.09 AUO 239.10 —— —— —— —— —— —— —— —— ___ —— —— 239.22 239.23 239.24 239.24 239.25 239.26 239.26 239.27 239.28 239.28 239.28 239.28 239.29 239.30 239.29 239.29 239.29 239.29 SEP 239.29 239.29 239.30 239.30 239.30 239.31 239.31 239.30 239.29 239.30 239.31 239.32 239.33 239.35 239.35 239.34 239.34 239.35 239.36 239.37 239.39 239.41 239.40 239.39 239.40 239.40 239.40 239.41 239.41 239.43 —— MEAN 238.17 236.71 237.65 237.05 235.39 237.18 237.89 238.38 238.75 239.01 WTR YR 1997 MEAN 237.92 HIGHEST 227.70 JAN. 24, 1997 LOWEST 239.59 DEC. 9, 10, 1996 239.26 239.35 220 ,230 250 I I I I I I I I I I I I I I I I I I Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept 1996 1997 WATER YEAR 482 GROUND-WATER LEVELS RIO CIBUCO BASIN 182712066251700. Local number TO-3. LOCATION.—Lat 18°27'12", long 66°25'17", Hydro logic Unit 21010002, 0.60 mi north of the intersection of Hwy 687 with Hwy 2, 0.55 mi southeast of the eastern shoreline of Laguna Tortuguero, 0.32 mi east of Laguna Rica, and 0.12 mi west of Hwy 687. Owner: U.S. Geological Survey WRD, Name: USGS Tortuguero TW-3. AQUIFER.--Aymamdn Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), screened 68-218 ft (20.7-66.4 m). Depth 218 ft (66.4 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 30 ft (9.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.40 ft (1.04 m) above land-surface datum. REMARKS.—Recording observation well. Automated Digital Recorder (ADR) installed on May 31, 1996. PERIOD OF RECORD.--May 31, 1996 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 23.48 ft (7.16 m) below land-surface datum, Sept. 12, 13, 1996; lowest water level recorded, 25.26 ft (7.70 m) below land-surface datum, June 21, 22, 23, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV JAN MAR APR MAY JUN JUL 1 2 3 4 5 24.25 24.26 24.29 24.32 24.28 24.27 24.31 24.32 24.33 24.36 24.06 24.09 24.09 24.10 24.13 24.09 24.11 24.11 24.02 23.98 23.83 23.84 23.87 23.90 23.92 24.19 24.20 24.20 24.20 24.19 24.48 24.47 24.46 24.39 24.39 24.62 24.62 24.61 24.60 24.60 24.77 24.77 24.77 24.77 24.76 6 7 8 9 10 24.29 24.31 24.31 24.32 24.35 24.37 24.38 24.38 24.38 24.38 24.18 24.21 24.23 24.24 24.24 23.98 23.99 24.02 24.04 24.06 23.95 23.98 23.99 24.00 24.01 24.19 24.20 24.20 24.21 24.21 24.39 24.39 24.41 24.44 24.47 24.61 24.60 24.63 24.66 24.67 24.76 24.77 —— —— ___ 11 12 13 14 15 24.35 24.35 24.35 24.37 24.47 24.47 24.49 24.38 24.33 24.31 24.21 24.19 24.20 24.23 24.23 24.07 24.08 24.10 24.11 24.11 24.02 24.03 24.05 24.07 24.09 24.22 24.22 24.22 24.23 24.25 24.48 24.50 24.51 24.52 24.53 24.68 24.69 24.71 24.72 24.73 16 17 18 19 20 24.47 24.49 24.50 24.48 24.47 24.28 24.27 24.27 24.26 24.26 24.12 24.09 24.09 24.09 24.13 24.12 24.12 24.15 24.19 24.21 24.11 24.12 24.14 24.16 24.18 24.25 24.25 24.26 24.26 24.27 24.52 24.52 24.51 24.50 24.51 24.74 24.74 24.74 24.76 24.76 21 22 23 24 25 24.46 24.47 24.48 24.48 24.49 24.25 24.26 24.13 24.06 23.94 24.17 24.19 24.19 24.21 24.19 24.23 24.04 23.87 23.78 23.69 24.20 24.16 24.16 24.17 24.16 24.28 24.28 24.29 24.29 24.30 24.50 24.50 24.50 24.51 24.51 24.77 24.77 24.75 24.75 24.75 26 27 28 29 30 31 24.50 24.49 24.49 24.49 24.27 24.25 23.93 23.97 24.01 24.04 24.05 —— 24.20 24.16 24*13 24.10 24.09 24.09 23.68 23.69 23.72 23.76 23.79 23.81 24.15 24.15 24.16 —— —— —— 24.33 24.37 24.37 24.36 24.38 24.42 24.52 24.54 24.56 24.61 24.63 —— 24.74 24.74 24.74 24.75 24.76 24.77 MEAN 24.39 24.25 24.16 23.99 24.06 24.26 24.49 24.70 24.77 WTR YR 1997 MEAN 24.40 HIGHEST 23.68 JAN. 25, 26, 27, 1997 LOWEST 24.95 AUG. 16, 1997 AUG 24.90 24.90 24.90 24.90 24.90 24.91 24.92 24.94 24.93 24.93 24.93 24.93 24.91 24.91 24.90 24.89 24.89 24.90 24.90 24.89 24.90 24.90 24.87 24.85 24.84 24.83 24.90 SEP 24.83 24.82 24.83 24.83 24.82 24.82 24.80 24.77 24.76 24.77 24.79 24.81 24.82 24.81 24.79 24.79 24.79 24.80 24.81 24.82 24.83 24.83 24.82 24.81 24.81 24.79 24.79 24.79 24.79 24.80 24.80 23 24 "25 26 Till I I I I I I I I I I I I I I I I I Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec Jan Feb Mar Apr May June July Aug Sept 1996 1997 WATER YEAR GROUND-WATER LEVELS 483 RIO DE LA PLATA BASIN 182530066135400. Local number, 216. LOCATION.--Lat 18°25'30", long 66°13'54", Hydrologic Unit 21010005, 2.61 mi northeast of Toa Alta plaza, 2.73 mi southwest of Sabana Seca U.S. Naval Radio Station, and 1.76 mi southeast of Bwy 2 km 17.7. Owner: P.R. Aqueduct and Sewer Authority, Name: Pozo Navy-Campanillas. AQUIFER.—Aguada Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 16 in (0.41 m) 0-106 ft (0-32.3 m), cased 16 in (0.41 m) 0-20 ft (0-6.10 m), cased 12 in (0.30 m) 0-106 ft (0-32.3 m), perforated 20-106 ft (6.10-32.3 m), diameter 10 in (10.25 m) 106-140 ft (32.3-42.7 m), cased 10 in (0.25 m) 106-140 ft (32.3-42.7 m), perforated 106-140 ft (32.3-42.7 m). Depth 140 ft (42.7 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 13.0 ft (3.96 m) above mean sea level, from topographic map. Measuring point: Hole on side of casing, 1.80 ft (0.55 m) above land-surface datum. REMARKS.—Recording observation well, water levels affected by nearby pumping well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 9.38 ft (2.86 m) below land-surface datum, June 23, 1987; lowest water level recorded, 18.40 ft (5.61 m) below land-surface datum, Sept. 24, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV DEC APR MAY JUN JUL AUO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 13.87 13.94 14.01 14.11 14.30 14.33 14.22 14.38 14.40 14.41 14.50 14.55 14.45 12.36 14.32 14.49 14.49 14.54 14.67 14.71 14.63 14.65 14.84 14.71 14.78 14.96 14.89 14.71 14.67 13.16 13.04 13.05 13.10 13.14 13.10 13.11 13.71 14.42 14.39 13.66 13.16 13.15 13.11 12.93 12.79 12.79 12.85 12.90 12.77 12.77 12.74 12.74 12.80 14.28 12.27 13.81 13.88 13.98 14.04 14.08 13.97 —— 14.10 13.94 13.99 14.00 14.05 14.12 14.28 14.37 14.16 13.78 13.66 13.66 13.72 13.88 13.84 13.65 13.69 13.70 13.72 13.74 13.79 13.85 13.85 13.84 13.84 13.83 14.40 14.34 14.47 14.42 14.43 14.33 14.37 14.37 14.41 14.42 14.60 14.54 14.51 14.54 14.56 14.69 14.71 14.94 14.79 14.82 14.86 13.14 14.77 14.91 14.96 15.16 14.47 14.13 14.20 14.15 14.15 14.17 13.98 14.04 14.03 14.17 14.12 14.42 13.67 14.15 14.01 14.12 14.19 14.24 14.20 14.09 14.37 14.25 14.18 14.25 14.48 14.77 14.51 14.37 14.50 14.65 14.57 13.48 14.55 14.52 14.48 14.56 14.65 14.49 —— —— ___ 14.61 14.53 14.54 14.58 14.62 14.72 14.70 14.77 14.76 14.75 14.78 14.75 14.80 14.86 14.90 14.97 14.99 14.92 14.95 14.96 15.03 15.12 15.13 15.14 15.20 15.22 15.33 15.25 15.35 15.38 15.42 15.43 15.45 15.48 15.42 15.56 15.50 15.46 15.50 15.63 15.72 15.74 15.75 15.83 15.81 15.91 15.89 16.06 16.00 16.06 15.95 16.21 16.08 15.98 16.10 15.85 16.21 16.11 14.66 15.30 16.21 —— 16.05 16.05 16.31 16.24 16.23 16.28 16.36 16.36 16.37 14.19 16.21 16.21 16.20 16.37 16.37 16.43 16.59 16.93 16.70 16.71 16.73 16.77 16.86 16.90 16.75 15.77 16.41 16.46 16.55 16.68 16.79 16.81 16.58 14.79 16.58 16.58 16.79 16.90 16.94 16.92 16.97 17.27 16.90 16.90 16.93 16.93 16.91 17.00 17.14 16.89 16.64 16.86 16.92 16.87 16.66 16.69 16.65 16.71 16.79 16.76 16.76 —— 16.77 16.82 16.83 16.94 16.79 16.75 16.83 16.70 16.77 16.83 16.78 16.78 16.85 16.80 17.14 17.09 17.16 17.42 17.56 17.62 17.46 17.51 17.12 17.58 17.09 17.02 16.86 16.91 16.89 15.82 15.41 15.20 16.53 16.54 16.47 16.28 16.41 16.40 16.47 16.75 16.89 16.81 16.32 15.89 15.83 15.55 15.71 15.57 15.27 15.28 15.33 15.33 15.27 15.23 15.13 14.95 14.92 15.13 15.15 15.13 15.27 15.19 15.02 15.00 14.90 15.00 15.09 15.18 15.11 15.07 14.49 15.05 15.03 15.14 15.16 15.10 14.96 14.89 15.00 15.03 15.11 15.20 15.16 15.07 14.95 14.93 14.98 14.99 15.02 15.04 15.01 15.12 —— MEAN 14.33 13.32 13.97 14.45 14.32 14.94 15.76 16.38 16.77 WTR YR 1997 MEAN 15.17 HIGHEST 11.92 NOV. 24, 1996 LOWEST 17.62 JULY 20, 1997 16.93 15.75 15.03 10 15 20 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 484 GROUND-WATER LEVELS RIO DE LA PLATA BASIN 182655066142400. Local number, 217. LOCATION.— Lat 18°26'55", long 66°14'24", Hydrologic Unit 21010005, 4.00 mi northeast of Toa Alta plaza, 3.40 mi northwest of Hwy 2 km 17.7, and 3.49 mi northwest of Sabana Seca U.S. Naval Radio Station. Owner: U.S. Geological Survey, WRD, Name: Monserrate TW-2. AQUIFER. -Alluvial Deposits. WELL CHARACTERISTICS. — Drilled unused water-table well, diameter 4 in (0.10 m) , cased 4 in (0.10 m) 0-80 ft (0-24.4 m), perforated 10-80 ft (3.05-24.4 m) . Depth 80 ft (24.4 m) . INSTRUMENTATION. — Digital water level recorder- -60 -minute punch. DATUM. — Elevation of land-surface datum is about 3.30 ft (1.00 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 3.50 ft (1.07 m) above land-surface datum. REMARKS. — Recording observation well. Instrument flooded during Hurricane Hortense. PERIOD OF RECORD. --November 1985 to current year. EXTREMES FOR PERIOD OF RECORD. — Highest water level recorded, 0.02 ft (0.006 m) below land-surface datum, May 16, 1986; lowest water level recorded, 3.72 ft (1.13 m) below land-surface datum. May 13, 1*95. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV DEC JAN MAR MAY JUN JUL MEAN 1.63 1.18 WTR YR 1997 MEAN 2.37 2.05 1.93 2.02 2.22 2.39 2.80 3.08 HIGHEST 0.94 NOV. 24, 25, 1996 LOWEST 3.35 JULY 15, 1997 3.21 2.84 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 —— —— —— ___ ___ —— ___ —— —— —— 1.62 1.65 1.66 1.64 1.65 1.64 1.68 1.72 1.72 1.72 1.69 1.71 1.74 1.62 1.33 1.32 1.36 1.37 1.37 1.35 1.35 1.35 1.42 1.40 1.31 1.23 1.21 1.30 1.19 1.16 1.11 1.07 1.10 1.09 1.02 1.04 1.04 1.07 1.10 1.08 .95 1.07 1.10 1.10 1.12 1.10 ___ —— —— —— ___ —— ___ ___ —— —— ___ —— —— ___ —— —— —— 2.07 2.06 2.10 2.17 2.09 2.07 2.03 2.08 2.00 1.95 1.92 1.90 1.92 1.85 1.87 1.91 1.96 1.99 2.00 1.99 1.95 1.98 1.98 2.01 2.01 2.07 2.09 1.99 2.03 2.22 2.25 2.29 1.84 1.73 1.69 1.67 1.69 1.74 1.74 1.84 1.86 1.92 1.93 1.87 1.77 1.92 1.92 1.94 1.95 1.96 1.96 1.96 1.95 1.98 1.89 2.00 2.07 2.09 2.10 2.11 2.12 2.13 2.19 2.13 2.13 2.13 2.10 2.09 2.10 2.13 —— 2.13 2.16 2.17 2.13 2.17 2.17 2.19 2.15 2.13 2.15 2.16 2.17 2.19 2.23 2.24 2.24 2.26 2.27 2.13 2.18 2.19 2.19 2.19 2.19 2.28 2.31 2.36 2.34 2.33 2.39 2.40 2.42 2.41 2.41 2.41 2.41 2.41 2.41 2.42 2.41 2.46 2.50 2.52 2.52 2.52 2.52 2.53 2.54 2.54 2.54 2.54 2.54 2.54 1.95 2.12 2.07 2.20 2.16 2.20 2.18 2.32 ___ 2.40 2.43 2.47 2.49 2.56 2.66 2.69 2.89 2.82 2.71 2.75 2.91 2.88 2.89 2.90 2.92 2.92 2.95 2.99 3.07 3.05 3.03 3.02 3.00 2.89 2.76 2.72 2.69 2.72 2.78 2.83 2.89 2.84 2.72 2.74 2.80 2.83 2.87 3.01 3.05 3.17 3.10 3.05 3.05 3.12 3.15 3.20 3.29 3.21 3.21 3.20 3.26 3.21 3.28 3.11 3.13 3.14 3.17 3.17 3.15 3.15 —— 3.20 3.21 3.24 3.24 3.23 3.24 3.23 3.21 3.17 3.19 3.23 3.23 3.23 3.24 3.35 3.27 3.23 3.24 3.25 3.25 3.13 3.18 3.17 3.20 3.22 3.14 3.11 3.14 3.15 3.19 3.05 2.91 2.99 3.04 2.98 2.99 3.09 3.04 3.04 3.07 3.10 3.11 3.11 2.95 2.92 2.91 2.92 2.88 2.80 2.85 2.83 2.80 2.79 2.65 2.66 2.52 2.50 2.51 2.51 2.54 2.60 2.51 2.44 2.44 2.44 2.44 2.44 2.44 2.44 2.44 2.45 2.45 2.46 2.52 2.54 2.52 2.52 2.51 2.52 2.52 2.54 2.56 2.58 2.59 2.56 2.56 2.55 2.54 2.55 2.59 2.57 2.57 —— 2.51 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO DE LA PLATA BASIN 485 182804066173500. Local number, DA-1. LOCATION. —Lat 18°28'04", long 66°17'35", Bydrologic Unit 21010005, 2.04 mi west of Dorado plaza, 1.15 mi north of Hwy 696, and 0.03 mi south of Hwy 693. Owner: Dorado Airport, Name: Dorado Airport Well. AQUIFER.--Aymam6n Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m). Depth 98 ft (29.9 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 62.15 ft (18.9 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.88 ft (1.18 m) above land-surface datum. REMARKS.—Recording observation well, water levels affected by nearby pumping well. PERIOD OF RECORD.—February 2, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 56.67 ft (17.27 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 59.21 ft (18.05 m) below land-surface datum Apr. 16, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC APR JUN JUL AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 57.51 57.57 57.67 57.75 57.73 57.74 57.73 57.75 57.73 57.72 57.68 57.69 57.70 57.73 57.80 57.86 57.90 57.91 57.90 57.89 57.87 57.91 57.93 57.97 57.85 57.88 57.95 57.91 57.83 57.74 57.81 57.82 57.86 57.86 57.87 57.90 57.90 57.85 57.78 57.72 57.71 57.78 57.83 57.78 57.74 57.72 57.73 57.73 57.67 57.69 57.68 57.67 57.66 57.60 57.65 57.56 57.63 57.70 57.74 57.73 57.66 —— 57.62 57.61 57.58 57.58 57.59 57.66 57.66 57.67 57.65 57.63 57.57 57.60 57.71 57.78 57.86 57.82 57.81 57.84 57.89 57.93 57.90 57.87 57.87 57.88 57.85 57.85 57.82 57.85 57.81 57.80 57.77 57.81 57.82 57.79 57.76 57.77 57.79 —— —— —— —— ___ —— —— —— —— ___ —— —— —— —— ___ —— —— —— —— ___ —— —— 57.71 57.71 57.72 57.66 57.72 57.72 57.73 57.71 57.72 57.71 57.67 57.70 57.69 57.69 57.72 57.75 57.83 57.84 57.85 57.84 57.85 57.84 57.85 57.84 57.82 57.82 57.81 57.78 57.80 57.81 57.84 —— —— —— 57.84 57.85 57.84 57.83 57.85 57.83 57.85 57.79 57.81 57.82 57.83 57.85 57.86 57.90 57.92 57.91 57.92 57.95 57.93 57.93 57.96 57.98 57.98 58.00 58.05 58.09 58.11 58.08 58.10 58.15 58.17 58.19 58.18 58.15 58.15 58.20 58.20 58.19 58.16 58.14 58.18 58.24 58.29 58.30 58.28 58.32 58.28 58.26 58.24 58.23 58.22 58.27 58.38 58.38 58.31 58.30 58.42 58.40 58.45 58.43 58.46 —— 58.46 58.43 58.53 58.46 58.51 58.49 58.42 58.46 58.45 58.38 58.38 58.41 58.46 58.47 58.51 58.54 58.47 58.50 58.56 58.59 58.58 58.50 58.50 58.48 58.31 58.29 58.26 58.25 58.31 58.38 58.50 58.47 58.48 58.49 58.46 58.45 58.46 58.54 58.60 58.62 58.65 58.62 58.62 58.66 58.72 58.74 58.75 58.76 58.77 58.76 58.76 58.73 58.73 58.74 58.66 58.68 58.72 58.75 58.76 58.80 58.80 —— 58.82 58.81 58.80 58.78 58.79 58.77 58.75 58.66 58.62 58.68 58.74 58.76 58.73 58.78 58.81 58.79 58.78 58.73 58.65 58.60 58.53 58.51 58.48 58.60 58.57 58.58 58.64 58.72 58.75 58.77 58.77 58.68 58.63 58.59 58.50 58.53 58.49 58.51 58.55 58.58 58.69 58.76 58.75 58.74 58.74 58.73 58.77 58.67 58.60 58.52 58.46 58.45 58.51 58.55 58.63 58.62 58.66 58.65 58.56 58.54 58.52 58.41 58.40 58.38 58.34 58.29 58.33 58.29 58.23 58.25 58.30 58.38 58.45 58.53 58.54 58.49 58.45 58.35 58.26 58.25 58.34 58.36 58.42 58.47 58.45 58.50 58.49 58.50 58.52 58.49 58.43 58.38 —— MEAN 57.79 57.74 57.75 57.76 57.77 57.93 58.27 58.45 58.66 WTR YR 1997 MEAN 58.18 HIGHEST 57.47 OCT. 1, 1996 LOWEST 58.84 JULY 5, 1997 58.70 58.60 58.40 56 58 60 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1995 1996 1997 WATER YEAR 486 GROUND-WATER LEVELS RIO DE LA PLATA BASIN 182620066163403. Local number, H6-4. LOCATION.—Lat 18^6-20", long 66°16'34", Hydrologic Unit 2101005, 1.85 mi south of Dorado plaza, 0.70 mi southwest of Laboratorio Dorado, 0.65 mi northwest of the intersection of Hwy 695 with Hwy 693, and 0.09 mi north of Hwy 695. Owner: U.S. Geological Survey, WRD, Name: Higuillar NO. 4. AQUIFER.—Aguada Limes tone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-100 ft (0-30.5 m), screened 80-90 ft (24.4-27.4 m). Depth 100 ft (30.5 m) INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 49.2 ft (15.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.60 ft (1.10 m) above landOsurface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—January 23, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 31.84 ft (9.70 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 36.15 ft (11.02 m) below land-surface datum. May 1, 11, 13, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT 33.38 NOV DEC JAN FEB MAR MAY JUN JUL AUG 33.28 33.15 32.91 32.77 33.28 34.08 34.57 34.88 35.24 35.35 WTR YR 1997 MEAN 34.02 HIGHEST 32.42 JAN. 25, 1997 LOWEST 35.46 AUG> 15-19, 1997 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32.77 32.82 32.93 32.97 33.01 33.04 33.11 33.18 33.22 33.23 33.25 33.31 33.31 33.36 33.42 33.45 33.48 33.52 33.55 33.55 33.60 33.69 33.69 33.72 33.73 33.74 33.70 33.76 33.72 33.50 33.46 33.47 33.53 33.56 33.57 33.58 33.63 33.64 33.53 33.49 33.47 33.49 33.48 33.27 33.23 33.22 33.25 33.32 33.34 33.30 33.32 33.33 33.31 33.12 33.01 32.82 32.85 32.86 32.83 32.85 32.83 —— 32.77 32.81 32.80 32.85 32.88 32.89 32.96 33.03 33.07 33.13 33.14 33.09 33.13 33.19 33.22 33.19 33.20 33.25 33.29 33.33 33.35 33.38 33.39 33.42 33.38 33.39 33.24 33.25 33.23 33.13 33.13 33.09 33.10 33.03 32.98 32.98 32.99 32.99 33.01 33.01 33.04 33.06 33.06 33.10 33.11 33.13 33.14 33.13 33.21 33.23 33.24 33.25 32.75 32.64 32.51 32.43 32.44 32.49 32.49 32.52 32.52 32.52 32.53 32.53 32.54 32.57 32.59 32.61 32.62 32.62 32.66 32.68 32.69 32.70 32.70 32.73 32.74 32.77 32.81 32.85 32.89 32.92 32.97 32.97 32.97 32.98 32.98 32.98 32.98 32.99 —— —— —— 33.00 33.01 33.02 33.02 33.03 33.03 33.10 33.10 33.11 33.17 33.17 33.20 33.20 33.20 33.20 33.23 33.29 33.33 33.33 33.34 33.38 33.38 33.38 33.42 33.53 33.54 33.54 33.55 33.67 33.67 33.68 33.74 33.76 33.83 33.83 33.84 33.84 33.88 33.89 33.88 33.90 33.91 33.95 34.02 34.03 34.05 34.06 34.06 34.08 34.12 34.13 34.24 34.24 34.26 34.27 34.33 34.45 34.45 34.47 34.47 34.48 —— 34.48 34.48 34.50 34.50 34.50 34.51 34.52 34.53 34.54 34.37 34.38 34.40 34.55 34.57 34.57 34.57 34.63 34.63 34.63 34.63 34.63 34.64 34.65 34.65 34.65 34.64 34.64 34.64 34.65 34.65 34.65 34.65 34.66 34.66 34.66 34.72 34.72 34.73 34.73 34.73 34.74 34.74 34.80 34.85 34.86 34.86 34.95 34.95 35.03 35.03 35.03 35.03 35.03 35.04 35.04 35.04 35.04 35.04 35.05 35.05 35.06 —— 35.06 35.07 35.09 35.09 35.10 35.10 35.11 35.18 35.18 35.18 35.19 35.22 35.24 35.24 35.26 35.28 35.28 35.30 35.31 35.31 35.31 35.31 35.31 35.31 35.31 35.31 35.31 35.32 35.33 35.37 35.37 35.37 35.37 35.37 35.37 35.37 35.38 35.39 35.40 35.41 35.42 35.42 35.43 35.44 35.44 35.45 35.46 35.46 35.45 35.30 35.31 35.31 35.31 35.31 35.32 35.23 35.23 35.23 35.24 35.25 35.26 35.25 35.26 35.26 35.27 35.27 35.28 35.28 35.29 35.29 35.30 35.30 35.31 35.31 35.32 35.32 35.33 35.33 35.34 35.35 35.35 35.33 35.31 35.29 35.23 35.21 35.19 35.18 35.16 35.14 35.13 35.11 —— 35.27 30 32 34 36 38 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJA 1995 1996 ONDJFMAMJJAS 1997 WATER YEAR GROUND-WATER LEVELS RIO DE LA PLATA BASIN 487 182657066162700. Local number, SA-1. LOCATION.--Lat 18°26'57", long 66°16'27", Hydrologic Unit 21010005, 1.16 mi south of Dorado plaza, 0.45 mi west of Laboratories Dorado, 1.79 mi southeast of Dorado airport main gate, and 0.19 mi west of the P.R. Aqueduct and Sewer Authority San Antonio public supply well (San Antonio No. 3). Owner: U.S. Geological Survey, WRD, Name: San Antonio No. 1. AQUIFER.—Aguada Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-290 ft (0-88.4 m), screened 270-280 ft (82.3-85.3 m). Depth 290 ft (88.4 m) . INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 19.6 ft (6.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m), casing, 3.20 ft (0.98 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—October 19, 1994 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 13.97 ft (4.26 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 19.56 ft (5.96 m) below land-surface datum. May 3, 4, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC MAR APR MAY JUN JUL AUG MEAN 16.29 16.14 16.01 15.84 15.72 16.22 16.89 17.37 17.64 WTR YR 1997 MEAN 16.81 HIGHEST 15.42 JAN. 25, 1997 LOWEST 18.03 AUG. 10, 1997 17.90 17.90 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 15.82 15.85 15.92 16.00 16.03 16.05 16.08 16.12 16.16 16.16 16.17 16.20 16.21 16.25 16.29 16.35 16.39 16.43 16.45 16.46 16.47 16.49 16.50 16.54 16.57 16.57 16.59 16.60 16.58 16.37 16.33 16.34 16.36 16.43 16.38 16.40 16.44 16.43 16.43 16.30 16.28 16.29 16.31 16.18 16.10 16.09 16.10 16.15 16.17 16.16 16.16 16.18 16.19 16.00 15.90 15.72 15.73 15.75 15.74 15.76 15.74 —— 15.65 15.67 15.65 15.70 15.74 15.76 15.82 15.89 15.92 15.97 15.97 15.94 15.99 16.06 16.09 16.06 16.07 16.10 16.13 16.19 16.21 16.23 16.26 16.28 16.25 16.25 16.17 16.16 16.13 16.04 16.00 15.99 15.99 15.90 15.87 15.88 15.90 15.90 15.91 15.91 15.92 15.94 15.96 15.99 16.00 16.02 16.03 16.02 16.07 16.12 16.14 16.15 15.77 15.64 15.52 15.44 15.44 15.48 15.50 15.53 15.53 15.52 15.53 15.53 15.53 15.56 15.56 15.55 15.56 15.58 15.60 15.62 15.64 15.65 15.65 15.67 15.70 15.74 15.75 15.78 15.79 15.87 15.91 15.90 15.91 15.93 15.90 15.91 15.92 15.93 —— —— —— 15.94 15.97 15.98 15.99 16.01 16.02 16.05 16.04 16.06 16.04 16.10 16.12 16.14 16.17 16.19 16.22 16.25 16.27 16.26 16.27 16.30 16.33 16.34 16.36 16.41 16.47 16.46 16.46 16.50 16.54 16.58 16.60 16.61 16.58 16.57 16.63 16.64 16.67 16.70 16.69 16.69 16.73 16.82 16.87 16.88 16.94 16.95 16.96 16.96 16.98 16.99 17.01 17.06 17.09 17.09 17.09 17.16 17.16 17.21 17.20 17.24 —— 17.23 17.22 17.28 17.23 17.28 17.30 17.29 17.31 17.32 17.23 17.29 17.33 17.36 17.37 17.40 17.41 17.41 17.42 17.45 17.46 17.47 17.47 17.48 17.51 17.41 17.38 17.38 17.37 17.41 17.45 17.48 17.48 17.46 17.44 17.45 17.46 17.48 17.52 17.57 17.59 17.61 17.59 17.62 17.65 17.65 17.65 17.69 17.70 17.71 17.72 17.68 17.72 17.73 17.72 17.70 17.71 17.72 17.74 17.77 17.78 17.78 —— 17.79 17.79 17.81 17.83 17.84 17.82 17.82 17.82 17.82 17.82 17.86 17.91 17.89 17.90 17.95 17.94 17.93 17.94 17.93 17.93 17.88 17.90 17.92 17.95 17.96 17.95 17.98 17.99 18.01 18.02 17.99 17.95 17.95 17.96 17.94 17.95 17.93 17.96 17.98 18.01 18.03 18.00 18.02 17.99 17.99 18.00 18.01 17.94 17.86 17.84 17.86 17.88 17.86 17.83 17.84 17.76 17.77 17.78 17.79 17.78 17.80 17.74 17.69 17.69 17.70 17.69 17.72 17.73 17.67 17.67 17.67 17.68 17.72 17.78 17.77 17.70 17.68 17.68 17.68 17.69 17.75 17.78 17.77 17.79 17.78 17.75 17.72 17.72 17.75 17.75 17.75 17.70 —— 17.72 I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 488 GROUND-HATER LEVELS RIO DE LA PLATA BASIN 182657066162701. Local number, SA-3. LOCATION.—Lat 18°26'57", long 66°16'27", Hydrologic Unit 21010005, 20 ft north of San Antonio US6S # 1. Owner: U.S. Geological Survey, WRD, Name: San Antonio No. 3. AQUIFER.—Aymaxnon Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-80 ft (0-24.4 m), screened 65-75 ft (19.8-22.9 m). Depth 80 ft (24.4 m) . INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 19.6 ft (6.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m), casing, 3.38 ft (1.03 m) above land-surface datum. REMARKS.—Recording observation well. Electronic Data Logger (EDL) installed on February 6, 1997. PERIOD OF RECORD.—October 19, 1994 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 13.95 ft (4.25 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 19.03 ft (5.80 m) below land-surface datum. May 13, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV JAN APR JUN JUL AUG MEAN 16.49 16.35 16.28 16.11 15.82 16.28 16.82 17.32 17.65 WTR YR 1997 MEAN 16.92 HIGHEST 15.60 FEB. 6, 1997 LOWEST 18.15 JULY 30, 1997 18.02 18.01 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 15.99 16.03 16.08 16.15 16.19 16.21 16.24 16.29 16.32 16.35 16.36 16.41 16.43 16.46 16.50 16.57 16.62 16.65 16.67 16.69 16.69 16.74 16.76 16.78 16.77 16.78 16.78 16.79 16.76 16.57 16.54 16.55 16.61 16.64 16.59 16.63 16.67 16.64 16.63 16.50 16.49 16.50 16.50 16.36 16.29 16.27 16.30 16.35 16.37 16.36 16.37 16.38 16.38 16.19 16.08 15.90 15.93 16.01 16.01 16.03 16.00 —— 15.91 15.92 15.90 15.95 15.98 16.01 16.07 16.16 16.20 16.24 16.23 16.21 16.27 16.34 16.37 16.35 16.34 16.38 16.42 16.45 16.46 16.49 16.52 16.54 16.52 16.52 16.42 16.42 16.39 16.31 16.29 16.27 16.26 16.17 16.14 16.16 16.17 16.17 16.19 16.17 16.20 16.23 16.24 16.27 16.30 16.31 16.33 16.31 16.36 16.41 16.43 16.42 16.01 15.87 15.76 15.70 15.72 15.75 15.77 15.80 15.81 15.80 15.79 15.78 15.77 15.79 15.77 15.62 15.62 15.66 15.65 15.67 15.67 15.67 15.69 15.73 15.74 15.80 15.82 15.85 15.87 15.90 16.00 16.00 16.01 16.02 16.02 16.02 16.02 16.04 —— —— —— 16.05 16.08 16.08 16.08 16.08 16.08 16.09 16.15 16.16 16.17 16.17 16.24 16.25 16.26 16.26 16.30 16.30 16.31 16.31 16.31 16.32 16.34 16.44 16.44 16.51 16.52 16.48 16.48 16.48 16.50 16.56 16.57 16.57 16.57 16.57 16.58 16.61 16.61 16.61 16.61 16.61 16.61 16.71 16.75 16.77 16.84 16.91 16.92 16.91 16.91 16.91 16.91 16.97 16.98 16.99 16.99 17.03 17.09 17.16 17.17 17.17 —— 17.17 17.15 17.19 17.22 17.22 17.27 17.27 17.27 17.28 17.12 17.25 17.28 17.29 17.32 17.36 17.36 17.37 17.37 17.39 17.43 17.46 17.43 17.45 17.45 17.37 17.37 17.33 17.34 17.35 17.37 17.44 17.45 17.46 17.44 17.45 17.45 17.44 17.49 17.50 17.51 17.53 17.54 17.55 17.64 17.64 17.66 17.68 17.69 17.69 17.70 17.71 17.75 17.75 17.75 17.76 17.85 17.87 17.88 17.93 17.89 17.91 —— 17.92 17.92 17.94 17.95 17.98 17.97 17.98 17.98 17.97 17.98 17.98 17.99 18.00 18.01 18.04 18.05 18.04 18.07 18.06 18.06 18.06 18.06 18.04 18.07 18.06 18.04 18.03 18.12 18.14 18.14 18.10 18.10 18.04 18.08 18.09 18.08 18.07 18.06 18.07 18.08 18.10 18.08 18.13 18.05 18.05 18.08 18.10 18.06 18.02 18.00 18.01 17.98 17.98 17.94 17.94 17.93 17.88 17.85 17.85 17.89 17.91 17.86 17.85 17.83 17.82 17.82 17.85 17.84 17.79 17.79 17.78 17.77 17.79 17.81 17.85 17.83 17.83 17.82 17.82 17.82 17.85 17.87 17.87 17.87 17.86 17.85 17.81 17.81 17.84 17.85 17.84 17.84 —— 17.83 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS WATER YEAR GROUND-WATER LEVELS RIO DE LA PLATA BASIN 489 182548066164401. Local number MA-2 LOCATION. —Lat 18°25'48", long 66°16'44", Hydrologic Unit 2101005, 1.47 mi north of Hwy 2, 0.60 mi south of Hwy 695, 0.04 mi south of the intersection of Hwy 694 with 659, and 0.02 mi east of Hwy 659. Owner: U.S. Geological Survey WRD, Name: Maguayo USGS No. 2 AQUIFER.—Aguada Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-110 ft (0-33.5 m), screened 95-105 ft (29.0-32.0 m). Depth 110 ft (33.5 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 39.4 ft (12.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.80 ft (1.16 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—June 22, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 24.89 ft (7.59 m) below land-surface datum, Sept. 18, 19, 1996; lowest water level recorded, 29.05 ft (8.85 m) below land-surface datum, July 20, 21, 22, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM INSTANTANEOUS DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT 25.85 25.91 25.97 26.04 26.09 26.13 26.17 26.25 26.29 26.33 26.37 26.42 26.43 26.49 26.54 26.56 26.62 26.66 26.70 26.74 26.76 26.86 26.86 26.89 26.93 26.94 26.95 26.95 26.97 26.85 26.80 NOV 26.80 26.80 26.81 26.81 26.81 26.81 26.84 26.84 26.81 26.81 26.81 26.82 26.67 26.62 26.61 26.59 26.59 26.59 26.59 26.59 26.59 26.59 26.48 26.34 26.16 26.12 26.09 25.98 25.96 25.97 —— DEC 25.97 25.97 25.97 25.97 25.97 25.97 26.00 26.05 26.09 26.13 26.17 26.17 26.17 26.21 26.25 26.26 26.28 26.32 26.36 26.39 26.41 26.45 26.48 26.50 26.50 26.50 26.45 26.43 26.41 26.35 26.30 JAN 26.26 26.26 26.20 26.17 26.15 26.12 26.11 26.10 26.10 26.10 26.10 26.10 26.10 26.15 26.16 26.18 26.17 26.20 26.24 26.28 26.31 26.10 25.98 25.84 25.77 25.70 25.68 25.67 25.66 25.65 25.65 FEB 25.65 25.65 25.66 25.66 25.67 25.68 25.76 25.77 25.78 25.79 25.80 25.84 25.86 25.90 25.91 25.95 25.98 26.02 26.05 26.08 26.11 26.11 26.12 26.14 26.14 26.13 26.13 26.14 —— —— —— , WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OBSERVATION AT 1200 MAR 26.16 26.19 26.21 26.20 26.23 26.23 26.25 26.27 26.28 26.32 26.33 26.36 26.39 26.41 26.44 26.45 26.49 26.52 26.54 26.54 26.61 26.64 26.64 26.66 26.73 26.76 26.79 26.82 26.86 26.88 26.92 APR 26.94 26.98 26.97 26.99 27.00 27.03 27.05 27.07 27.09 27.10 27.12 27.15 27.17 27.18 27.20 27.21 27.23 27.25 27.26 27.29 27.33 27.35 27.36 27.41 27.48 27.52 27.55 27.55 27.61 27.63 —— MAY 27.61 27.65 27.67 27.68 27.72 27.75 27.78 27.80 27.81 27.73 27.76 27.78 27.81 27.84 27.86 27.87 27.89 27.90 27.91 27.95 27.97 27.98 28.00 28.03 28.06 28.06 28.06 28.07 28.08 28.09 28.09 JUN 28.10 28.11 28.11 28.13 28.15 28.19 28.21 28.22 28.25 28.27 28.28 28.30 28.32 28.32 28.34 28.34 28.35 28.34 28.35 28.35 28.35 28.36 28.37 28.39 28.40 28.40 28.42 28.46 28.46 28.48 —— JUL 28.48 28.50 28.52 28.54 28.55 28.56 28.57 28.58 28.61 28.61 28.63 28.65 28.64 28.65 28.66 28.68 28.68 28.72 28.72 28.72 28.74 28.74 28.74 28.74 28.75 28.75 28.75 28.77 28.78 28.79 28.79 AUG 28.78 28.77 28.76 28.76 28.76 28.71 28.77 28.79 28.78 28.78 28.78 28.78 28.77 28.77 28.77 28.76 28.71 28.65 28.65 28.65 28.66 28.65 28.59 28.58 28.52 28.51 28.51 28.51 28.51 28.53 28.53 SEP 28.52 28.50 28.50 28.50 28.50 28.50 28.50 28.50 28.50 28.49 28.49 28.49 28.49 28.47 28.46 28.44 28.44 28.45 28.45 28.45 28.46 28.46 28.46 28.46 28.45 28.44 28.44 28.44 28.44 28.45 —— 26.53 26.56 26.24 26.04 25.91 26.49 27.24 27.88 28.30 28.66 28.68 28.47 WTR YR 1997 MEAN 27.26 HIGHEST 25.65 JAN. 30, 31 Feb. 1, 2 3, 1997 LOWEST 28.79 JULY 29, 30,31, AUG 8, 9, 1997 I I I I I I ONDJFHAHJJASONDJFHAHJJASONDJFMAMJJAS WATER YEAR 490 GROUND-WATER LEVELS RIO DE LA PLATA BASIN 182526066165001. Local number, SR-2. LOCATION.—Lat 18°25'26", long 66°16'50", Hydrologic Unit 21010005, 1.03 mi north of Hwy 2, 0.93 mi west of the intersection of Hwy 659 with Hwy 693, and 0.03 mi north of Hwy 659. Owner: U.S. Geological Survey, WRD, Name: Santa Rosa USGS No. 2. AQUIFER.—Aguada Limestone. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-140 ft (0-42.7 m), screened 120-130 ft (36.6-39.6 m). Depth 140 ft (42.7 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 91.8 ft (28.0 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.31 ft (1.01 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--February 2, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 60.42 ft (18.42 m) below land-surface datum, Sept. 20, 1995; lowest water level recorded, 64.93 ft (19.79 m) below land-surface datum. May 2-5, 10-15, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT 61.73 NOV FEB MAR JUN 61.76 61.44 61.29 61.10 61.72 62.54 63.12 63.49 63.95 WTR YR 1997 MEAN 62.50 HIGHEST 60.86 FEB. 1, 3, 1997 LOWEST 64.13 JULY 29, 30, 1997 63.97 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 61.01 61.05 61.10 61.19 61.22 61.23 61.36 61.44 61.48 61.55 61.59 61.64 61.67 61.72 61.77 61.81 61.87 61.93 61.98 62.02 62.05 62.09 62.09 62.09 62.14 62.16 62.17 62.17 62.19 62.00 62.00 62.00 62.00 62.00 62.00 61.98 62.01 62.03 61.96 61.96 61.96 61.96 61.96 61.85 61.85 61.83 61.80 61.80 61.80 61.80 61.81 61.81 61.81 61.72 61.46 61.42 61.33 61.29 61.23 61.21 61.21 —— 61.19 61.18 61.19 61.19 61.19 61.19 61.19 61.22 61.26 61.29 61.33 61.33 61.34 61.37 61.42 61.44 61.46 61.50 61.53 61.57 61.60 61.64 61.67 61.71 61.71 61.70 61.66 61.66 61.63 61.59 61.54 61.50 61.48 61.45 61.39 61.37 61.35 61.34 61.33 61.33 61.33 61.33 61.33 61.37 61.40 61.42 61.46 61.48 61.48 61.53 61.57 61.59 61.37 61.12 61.12 61.04 60.96 60.93 60.91 60.90 60.88 60.87 60.86 60.87 60.86 60.88 60.89 60.91 60.95 60.95 60.95 60.95 60.95 61.03 61.03 61.07 61.11 61.12 61.17 61.20 61.24 61.26 61.28 61.28 61.31 61.33 61.33 61.33 61.33 61.36 —— —— —— 61.37 61.39 61.40 61.42 61.44 61.45 61.49 61.50 61.50 61.52 61.55 61.60 61.62 61.64 61.67 61.69 61.72 61.74 61.78 61.79 61.83 61.89 61.91 61.92 61.97 62.02 62.03 62.06 62.10 62.13 62.18 62.21 62.25 62.28 62.28 62.28 62.28 62.32 62.34 62.35 62.35 62.37 62.42 62.47 62.49 62.54 62.55 62.58 62.59 62.63 62.66 62.68 62.71 62.73 62.73 62.79 62.80 62.84 62.84 62.88 62.90 —— 62.90 62.90 62.93 62.93 62.94 62.97 63.03 63.03 63.07 63.07 63.07 63.07 63.07 63.08 63.11 63.12 63.15 63.16 63.17 63.20 63.21 63.23 63.24 63.25 63.25 63.25 63.25 63.25 63.25 63.25 63.26 63.29 63.29 63.29 63.29 63.33 63.36 63.36 63.38 63.40 63.41 63.42 63.45 63.47 63.50 63.51 63.54 63.55 63.55 63.57 63.57 63.57 63.58 63.59 63.64 63.64 63.64 63.65 63.66 63.66 63.68 —— 63.71 63.72 63.74 63.76 63.79 63.80 63.81 63.82 63.84 63.86 63.87 63.87 63.89 63.89 63.92 63.93 63.97 64.01 64.04 64.06 64.08 64.08 64.08 64.10 64.10 64.10 64.10 64.11 64.12 64.13 64.12 64.11 64.10 64.09 64.08 64.07 64.06 64.05 64.04 64.03 64.02 64.01 64.00 63.99 63.98 63.97 63.96 63.95 63.94 63.93 63.92 63.92 63.92 63.91 63.91 63.90 63.90 63.89 63.89 63.88 63.88 63.87 63.87 63.86 63.86 63.85 63.85 63.84 63.84 63.83 63.83 63.82 63.82 63.81 63.81 63.80 63.80 63.79 63.78 63.77 63.75 63.74 63.73 63.72 63.71 63.70 63.68 63.67 63.66 63.65 63.64 63.63 —— 63.77 60 62 64 66 I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJA 1995 ONDJFMAMJJASONDJFMAMJJAS 1996 1997 WATER YEAR GROUND-WATER LEVELS 491 RIO DE LA PLATA BASIN 182654066150600. Local number, TB-1. LOCATION.--Lat 18°26'54", long 66°15'06", Hydrologic Unit 21010005, 0.92 mi southeast of the Dorado bridge, 0.66 mi east of Hwy 693, 0.09 mi north of the intersection of Hwy 165 with Hwy 867, and 0.01 mi east of Hwy 165. Owner: U.S. Geological Survey, WRD, Name: Toa Baja TW-1. AQUIFER.—Tertiary Limestone. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-165 ft (0-50.3 m), screened 25-165 ft (7.62-50.3 m). Depth 167 ft (50.9 m). INSTRUMENTATION.--Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 7.0 ft (2.1 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor on top of 4 in (0.10 m) casing, 3.60 ft (1.10 m) above land-surface datum. REMARKS.—Recording observation well. Water levels affected by nearby pumping well. PERIOD OF RECORD.— November 16, 1992 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 3.04 ft (0.93 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 10.68 ft (3.25 m) below land-surface datum May 3, 4, 1995. DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN 8.99 8.84 8.95 9.02 8.87 9.17 9.67 9.94 10.20 10.30 10.13 9.91 WTR YR 1997 MEAN 9.50 WATER LEVEL, IN FEET BELOW LAND- SURFACE DATUM, INSTANTANEOUS OCT 8.62 8.69 8.78 8.87 8.88 8.83 8.86 8.87 8.86 8.86 8.85 8.91 8.91 8.91 8.96 9.03 9.10 9.13 9.17 9.25 9.21 9.23 9.24 9.23 9.10 9.08 9.15 9.13 9.05 8.94 9.01 NOV 9.02 9.10 9.17 9.11 9.13 9.15 9.11 9.03 8.89 8.87 8.90 8.94 8.81 8.71 8.75 8.79 8.88 8.82 8.79 8.82 8.82 8.82 8.69 8.66 8.41 8.41 8.41 8.71 8.78 8.67 —— DEC 8.68 8.71 8.67 8.70 8.75 8.81 8.82 8.89 8.86 8.92 8.85 8.85 9.05 9.09 9.09 9.01 8.96 8.87 8.99 9.01 9.00 9.00 9.04 9.06 9.06 9.09 9.16 9.09 9.05 9.03 9.16 JAN 9.11 9.07 9.07 9.05 9.04 9.04 8.99 8.93 8.92 8.92 9.06 9.06 9.08 9.11 9.11 9.11 9.13 9.13 9.13 9.13 9.09 9.05 9.02 8.99 8.99 8.98 8.98 8.98 8.73 8.76 8.76 FEB 8.73 8.75 8.75 8.78 8.75 8.77 8.78 8.77 8.78 8.80 8.82 8.82 8.79 8.91 8.91 8.93 8.92 8.94 8.92 8.98 8.99 8.96 8.97 8.95 8.92 8.97 8.99 9.01 —— —— —— WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OBSERVATION AT 1200 MAR 9.00 9.00 9.00 9.00 9.03 8.99 9.05 8.93 8.98 9.00 9.09 9.04 9.09 9.16 9.18 9.14 9.20 9.22 9.11 9.20 9.24 9.29 9.22 9.27 9.30 9.39 9.37 9.31 9.40 9.43 9.49 APR 9.51 9.48 9.41 9.37 9.50 9.45 9.52 9.52 9.53 9.56 9.62 9.62 9.66 9.66 9.77 9.72 9.72 9.71 9.71 9.63 9.72 9.85 9.85 9.75 9.71 9.90 9.77 9.93 9.88 9.99 —— MAY 9.98 9.93 10.06 9.86 10.07 10.08 9.87 9.93 9.91 9.77 9.84 9.90 9.93 9.92 9.97 9.97 9.95 9.98 10.05 10.06 10.02 9.98 10.02 10.01 9.85 9.83 9.79 9.78 9.84 9.91 10.03 JUN 10.00 9.98 9.93 9.91 9.96 9.95 10.07 10.12 10.13 10.19 10.16 10.19 10.26 10.30 10.30 10.34 10.36 10.31 10.27 10.23 10.27 10.31 10.29 10.19 10.22 10.26 10.31 10.36 10.40 10.38 —— JUL 10.40 10.37 10.38 10.34 10.32 10.29 10.29 10.21 10.24 10.25 10.32 10.37 10.33 10.38 10.43 10.35 10.32 10.34 10.31 10.26 10.13 10.18 10.15 10.26 10.24 10.28 10.30 10.33 10.34 10.39 10.30 AUG 10.20 10.22 10.19 10.06 10.16 10.14 10.16 10.20 10.25 10.30 10.32 10.31 10.25 10.27 10.27 10.29 10.16 10.03 10.03 10.00 10.03 10.01 10.02 10.06 10.00 10.03 10.02 10.13 10.05 10.06 9.83 SEP 9.84 9.84 9.84 9.84 9.87 9.87 9.76 9.82 9.82 9.85 9.93 10.02 9.98 9.92 9.87 9.85 9.80 9.81 9.90 9.96 9.97 10.03 9.99 10.01 9.98 9.99 10.01 10.02 9.96 9.89 —— 8.95 9.02 8.87 9.17 9.67 9.94 10.20 HIGHEST 8.40 NOV. 27, 1996 LOWEST 10.47 JULY 2, 1997 12 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 492 GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 182441066082600. Local number, 219. LOCATION.—Lat 18°24'41", long 66°08'26", Hydrologic Unit 21010005, 0.47 mi west of Fort Buchanan Military Res. main gate, 1.74 mi northeast of Bayamon plaza, and 1.88 mi southwest of P.R. National Cementery. Owner: U.S. Department of Defense, Name: Ft. Buchanan No.Vl, Buchanan Park well. AQUIFER.--Cibao Formation. WELL CHARACTERISTICS.--Drilled water-table well, diameter 10 in (0.25 m), cased 10 in (0.25 m) 0-270 ft (0-82.3 m), perforated 46-685 ft (14.0-20.7 m), 88-120 ft (26.8-36.6 m), 160-191 ft (48.8-58.2 m), 240-270 ft (73.2-82.3 m). Depth 270 ft (82.3 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 66.0 ft (20.1 m) above mean sea level, from topographic map. Measuring point: Hole on side of casing, 0.75 ft (0.23 m) above land-surface datum. Prior June 30, 1986, top of shelter floor, 3.59 ft (1.09 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.—December 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 34.97 ft (10.66 m) below land-surface datum, Nov. 12, 13, 14, 1989; lowest water level recorded, 55.67 ft (17.0 m) below land-surface datum. May 13, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 OCT 48.78 48.83 48.76 48.85 48.84 48.83 48.85 48.91 48.96 48.99 48.99 49.03 49.06 49.10 49.19 49.24 49.24 49.24 49.26 49.35 49.29 49.39 49.38 49.36 49.37 NOV 48.88 48.87 48.87 48.89 48.89 48.89 48.86 48.77 48.70 48.70 48.75 48.78 48.69 48.48 48.35 48.29 48.18 48.04 47.94 47.90 47.86 47.82 47.59 47.48 47.29 DEC 46.99 46.91 46.86 46.91 46.98 47.00 46.99 47.04 47.10 47.17 47.19 47.22 47.23 47.24 47.28 47.29 47.31 47.39 47.44 47.43 47.45 47.47 47.48 47.45 47.46 MAY JUN JUL AU6 46.27 46.21 46.20 46.20 46.21 46.28 46.26 46.29 46.36 46.38 47.08 47.17 47.26 47.34 47.40 48.54 48.62 48.70 48.73 48.74 49.37 49.28 49.17 49.14 49.14 49.45 49.47 49.52 49.55 49.66 49.10 49.02 48.91 48.84 48.85 48.09 48.04 47.84 47.70 47.70 46.18 46.23 46.24 46.23 46.24 46.38 46.65 46.81 46.82 46.80 47.45 47.48 47.50 47.57 47.64 48.76 48.82 48.88 48.93 48.96 49.10 49.09 49.11 49.16 49.19 49.60 49.67 49.72 49.71 49.77 48.90 48.92 48.98 49.13 49.08 47.78 47.63 47.71 —— —— 46.27 46.30 46.34 46.34 46.35 46.84 46.90 46.81 46.85 46.88 47.75 47.78 47.80 47.87 47.91 49.01 49.05 49.08 49.13 49.15 49.09 49.11 49.10 49.11 49.11 49.84 49.79 49.76 49.83 49.93 48.98 48.90 48.86 48.85 48.82 46.42 46.42 46.48 46.43 46.40 46.81 46.85 46.89 46.74 46.63 47.92 47.95 47.98 48.16 48.25 49.18 49.30 49.28 49.28 49.31 49.11 49.15 49.33 49.33 49.35 49.84 49.91 49.86 49.89 49.92 48.89 48.87 48.75 48.69 48.67 —— —— 48.07 48.08 46.39 46.40 46.39 46.32 46.21 46.62 46.63 46.66 46.72 46.78 48.25 48.23 48.24 48.28 48.36 49.33 49.32 49.34 49.39 49.33 49.36 49.38 49.47 49.43 49.44 49.84 49.86 49.76 49.66 49.56 48.61 48.55 48.41 48.30 48.17 48.10 48.13 48.19 48.22 48.19 26 27 28 29 30 31 49.37 49.32 49.22 49.11 48.99 48.91 47.16 47.08 47.09 47.08 47.05 —— 47.47 47.42 47.34 47.25 47.15 —— —— 46.12 46.12 46.32 46.61 46.49 46.21 46.23 46.26 —— —— —— 46.82 46.84 46.86 46.95 47.02 47.04 48.41 48.44 48.49 48.50 48.52 —— 49.21 49.14 49.12 49.13 49.47 49.59 49.39 49.33 49.41 49.36 49.38 —— 49.46 49.34 49.35 49.28 49.27 49.19 48.12 48.12 48.16 48.18 48.29 48.25 48.36 48.52 48.47 48.35 48.11 —— MEAN 49.10 48.17 47.23 46.33 46.30 46.72 WTR YR 1997 MEAN 48.19 HIGHEST 46.11 JAN. 27, 28, 1997 47.90 49.09 49.25 49.65 LOWEST 50.04 JULY 10, 1997 48.68 48.06 60 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 493 RIO HONDO TO RIO PUERTO NUEVO BASINS 182511066045401. Local number, PN-2. LOCATION.--Lat 18 025'11, long 66°04'54", Hydrologic Unit 21010005, 1.58 mi northeast of Fort Buchannan Military Res. main gate, 2.95 mi southeast of Catafio plaza, and 2.45 mi southeast of U.S. Naval Reservation in Miramar. Owner: U.S. Geological Survey, WRD, Name: La Esperanza No. 2. AQUIFER. - -Alluvium. WELL CHARACTERISTICS.--Drilled observation well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-40 ft (0-12.2 m), perforated 30-40 ft ((9.15-12.2 m). Depth 40 ft (12.2 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.--Elevation of land-surface datum is about 13 ft (3.96 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 3.17 ft (0.97 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—July 1989 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 8.01 ft (2.44 m) below land-surface datum, Dec. 30, 31, 1992; lowest water level recorded, 11.90 ft (3.63 m) below land-surface datum, July 15, 16, 1991. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN 9.51 DEC JAN FEB MAR APR MAY JUN JUL 8.87 WTR YR 1997 MEAN 9.81 9.14 8.92 8.85 9.54 10.73 11.30 11.36 HIGHEST 8.19 NOV. 25, 1996 LOWEST 11.60 JUNE 18, 19, 1997 10.62 AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 9.03 9.11 9.15 9.17 9.20 9.25 9.35 9.40 9.47 9.52 9.55 9.58 9.65 9.75 9.53 ___ —— —— ___ 9.79 9.84 9.89 9.92 9.92 9.89 9.61 9.42 9.34 9.36 9.30 9.31 9.37 9.28 9.18 9.17 9.15 9.11 9.11 9.17 9.28 9.18 8.98 8.90 8.86 8.86 8.76 8.62 8.61 8.57 8.62 8.43 8.33 8.26 8.29 8.39 8.43 8.51 8.56 —— 8.56 8.57 8.55 8.64 8.68 8.77 8.82 8.92 9.06 9.18 9.18 9.01 8.97 8.97 9.04 9.12 9.16 9.24 9.32 9.40 9.42 9.47 9.53 9.58 9.58 9.57 9.57 9.57 9.51 9.30 9.13 9.01 8.97 8.74 8.61 8.56 8.57 8.66 8.76 8.82 8.93 8.99 9.06 9.16 9.24 9.24 9.22 9.26 9.29 9.37 9.41 9.50 9.31 8.95 8.73 8.50 8.45 8.49 8.57 8.61 8.68 8.77 8.80 8.62 8.53 8.54 8.54 8.51 8.55 8.59 8.63 8.70 8.78 8.87 8.92 8.96 8.97 9.05 9.10 9.16 9.15 9.12 9.16 9.08 9.04 8.98 8.91 8.84 8.86 8.94 —— —— 8.97 9.06 9.12 9.11 9.11 9.11 9.14 9.15 9.16 9.23 9.28 9.37 9.40 9.42 9.42 9.46 9.52 9.59 9.61 9.67 9.71 9.76 9.83 9.93 10.00 10.06 10.05 10.10 10.13 10.12 10.18 10.23 10.26 10.31 10.33 10.34 10.38 10.45 10.47 10.50 10.56 10.60 10.63 10.67 10.75 10.77 10.78 10.83 10.85 10.84 10.86 10.90 10.97 10.99 11.02 11.06 11.07 11.09 11.11 11.13 11.15 —— 11.20 11.24 11.21 11.25 11.29 11.32 11.29 11.33 11.33 11.31 11.34 11.40 11.45 11.47 11.44 11.44 11.37 11.35 11.40 11.41 11.41 11.38 11.38 11.39 11.28 11.19 11.07 11.06 11.06 11.05 11.07 11.09 11.16 11.19 11.23 11.26 11.29 11.30 11.34 11.40 11.44 11.48 11.47 11.47 11.48 11.49 11.53 11.56 11.60 11.60 11.55 11.53 11.54 11.59 11.30 11.18 11.12 11.11 11.11 11.14 11.20 —— 11.26 11.30 11.35 11.38 11.44 11.49 11.36 11.27 11.26 11.26 11.28 11.28 11.32 10.49 10.40 10.44 10.44 10.49 10.52 10.23 10.07 9.95 9.95 10.00 10.07 10.17 10.23 10.01 9.71 9.48 9.36 9.19 9.06 9.02 9.10 9.14 9.06 —— —— --- ___ ___ --- ___ —— 8.95 8.99 9.08 9.17 9.09 9.08 9.10 9.18 9.26 9.36 9.47 9.52 9.61 9.65 9.76 9.20 8.95 8.85 8.85 8.91 9.02 9.15 9.26 9.41 9.51 9.55 9.51 9.52 9.54 9.51 9.49 9.54 9.59 9.64 9.71 9.64 9.46 9.30 9.26 9.26 9.25 9.32 9.36 —— 9.18 9.37 "10 12 !Z ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJA 1993 1994 1995 1996 1997 WATER YEAR 494 GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 182435066052700. Local number, PN-5. LOCATION.—Lat 18°24'35", long 66°05'27", Hydrologic Unit 21010005, 2.94 mi southeast of Cataflo plaza, 0.44 mi north of Escuela Superior Oabriela Mistral, and 1.19 mi northeast of WAPA TV radio anthena. Owner: U.S. Geological Survey, WRD, Name: Salud Mental No. 1. AQUIFER. - -Alluvium. WELL CHARACTERISTICS.—Drilled water-table well, diameter 4.0 in (0.10 m), cased 4.0 in (0.10 m), 0-83 ft (0-25.3 m), perforated 73-83 ft (22.2-25.3 m). Depth 83 ft (25.3 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.—Elevation of land-surface datum is about 85 ft (25.9 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 2.85 ft (0.87 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—April 1989 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 25.37 ft (7.73 m) below land-surface datum, Feb. 5, 1993; lowest water level recorded, 32.82 ft (10.0 m) below land-surface datum, Sept. 25-28, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 25.94 25.93 25.93 25.93 25.93 25.93 25.93 25.93 25.93 25.93 25.94 25.94 25.94 25.95 25.95 26.00 26.02 26.06 26.10 26.11 26.14 26.18 26.19 26.19 26.24 26.25 26.26 26.26 26.26 26.26 26.28 26.33 26.33 26.36 26.36 26.38 26.38 26.41 26.43 26.43 26.52 26.60 26.62 26.64 26.64 26.64 26.64 26.64 26.64 26.64 26.64 26.64 26.67 —— —— —— ___ —— —— —— —— —— MEAN 26.06 26.53 WTR YR 1997 MEAN 27.86 DEC JAN FEB APR MAY JUN JUL AUG — —— —— —— — ___ 26.05 26.01 26.00 26.00 26.00 26.00 26.00 26.01 26.02 26.02 26.03 26.05 26.06 26.06 26.07 26.08 26.14 26.14 26.14 26.11 26.09 26.08 —— —— 26.08 26.08 26.07 26.07 26.07 26.07 26.07 26.08 26.10 26.11 26.13 26.14 26.15 26.17 26.18 26.19 26.20 26.22 26.23 26.26 26.29 26.37 26.42 26.49 26.52 26.55 26.57 26.60 26.63 26.65 26.67 26.69 26.71 26.74 26.78 26.81 26.83 26.85 26.87 26.89 26.93 26.98 27.01 27.03 27.06 27.09 27.13 27.16 27.19 27.27 27.33 27.37 27.39 27.41 27.46 27.50 27.57 27.59 27.63 27.66 27.70 —— 27.74 27.78 27.83 27.86 27.89 27.92 27.96 28.00 28.02 28.05 28.08 28.10 28.13 28.16 28.22 28.26 28.26 28.29 28.32 28.36 28.38 28.40 28.43 28.45 28.47 28.49 28.55 28.58 28.63 28.65 28.67 28.72 28.73 28.75 28.78 28.81 28.84 28.87 28.90 28.95 28.97 29.01 29.03 29.05 29.06 29.08 29.10 29.12 29.18 29.21 29.25 29.31 29.34 29.36 29.35 29.37 29.39 29.41 29.43 29.46 29.49 —— 29.51 29.54 29.57 29.63 29.69 29.77 29.80 29.80 29.85 29.90 29.95 29.97 29.99 30.01 30.03 30.05 30.06 30.07 30.08 30.08 30.01 30.01 30.04 30.05 30.05 30.02 30.01 29.99 29.96 29.95 29.90 29.82 29.81 29.79 29.76 29.75 29.75 29.74 29.73 29.73 29.72 29.71 29.70 29.70 29.69 29.64 29.64 29.64 29.60 29.57 29.56 29.54 29.52 29.48 29.43 29.36 29.34 29.33 29.29 29.26 29.22 29.21 29.20 29.21 29.07 29.06 29.07 29.03 28.95 28.94 28.91 28.90 28.90 28.89 28.89 28.88 28.88 28.88 28.83 28.78 28.71 28.66 28.65 28.69 28.71 28.73 28.77 28.82 28.84 28.86 28.87 28.85 —— 26.05 26.27 27.15 28.22 29.11 HIGHEST 25.92 OCT. 3, 1996 LOWEST 30.09 AUG. 20, 1997 29.91 29.58 28.88 20 25 *30 35 f ^ I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 495 182445066043401. Local number, PN-6. LOCATION. — Lat 18°24'45", long 66°04>34", Hydrologic Unit 21010005, 0.28 mi northeast of Escuela Dr. Pedreira, 3.52 mi southeast of Catano plaza, and 0.53 mi south of Hiram Bithorn Stadium main gate. Owner: U.S. Geological Survey, WRD, Name: Alsacia No. 2. AQUIFER. —Alluvium. WELL CHARACTERISTICS.— Drilled observation well, diameter 4 in (0.10 m) , cased 4 in (0.10 m) , 0-27 ft (0-8.23 m) , perforated 21-27 ft (6.40-8.23 m) . Depth 27 ft (8.23 m) . INSTRUMENTATION. — Digital water level recorder — 15-minute punch. DATUM. — Elevation of land-surface datum is about 10 ft (3.05 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 3.03 ft (0.91 m) above land-surface datum. REMARKS. — Recording observation well. PERIOD OF RECORD. — July 1989 to November 27, 1991, Temporary discontinued, September 9, 1993 to current year. EXTREMES FOR PERIOD OF RECORD. --Highest water level recorded, 3.11 ft (0.95 m) below land-surface datum, Sept. 18, 1989; lowest water level recorded, 13.65 ft (4.16 m) below land-surface datum, Oct. 6, 7, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT 7.69 NOV DEC JAN MAY JUN JUL 6.93 WTR YR 1997 MEAN 8.37 6.26 6.74 6.63 7.52 8.52 9.76 10.05 HIGHEST 5.85 NOV. 25, 1996 LOWEST 10.38 JULY 18, 19, 1997 10.03 AUG 9.21 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 —— —— —— —— —— ___ —— —— —— —— ___ —— —— —— —— 7.38 7.42 7.48 7.58 7.75 7.81 7.79 7.84 7.90 8.05 8.04 7.89 7.78 7.51 7.40 7.42 7.42 7.52 7.62 7.65 7.66 7.59 7.60 7.54 7.53 7.60 7.63 7.52 7.25 7.17 7.15 7.10 7.02 6.89 6.74 6.67 6.61 6.60 6.16 5.96 5.85 5.93 5.94 5.93 5.93 6.00 —— 6.07 6.06 6.16 6.23 6.14 6.24 6.31 6.37 6.49 6.56 __- —— —— —— —— _-_ —— —— —— —— ___ —— —— —— —— ___ —— —— —— —— —— —— —— —— —— ___ —— —— 6.49 6.66 6.75 6.70 6.77 6.82 6.81 6.93 7.01 7.06 7.11 7.15 7.14 6.84 6.62 6.50 6.36 6.35 6.46 6.52 6.57 6.65 6.67 6.48 6.26 6.26 6.27 6.24 6.30 6.35 6.35 6.34 6.36 6.46 6.52 6.52 6.59 6.64 6.82 6.82 6.91 6.87 6.92 6.92 6.86 6.86 6.94 6.84 6.89 6.99 7.10 —— —— 7.17 7.13 7.09 7.02 7.07 7.12 7.17 7.23 7.25 7.33 7.41 7.44 7.34 7.42 7.50 7.52 7.56 7.56 7.49 7.61 7.68 7.73 7.83 7.91 7.92 7.95 7.96 7.97 7.93 7.81 7.90 7.96 8.02 8.03 8.06 8.09 8.16 8.23 8.15 8.17 8.20 8.32 8.30 8.31 8.34 8.35 8.37 8.39 8.41 8.50 8.54 8.66 8.73 8.82 8.98 9.06 9.16 9.20 9.26 9.31 9.38 —— 9.44 9.52 9.55 9.56 9.58 9.63 9.65 9.65 9.70 9.69 9.77 9.81 9.85 9.88 9.88 9.89 9.81 9.85 9.92 9.97 9.90 9.83 9.86 9.88 9.78 9.78 9.73 9.77 9.81 9.84 9.91 9.88 9.88 9.88 9.95 10.00 10.05 10.08 10.07 10.10 10.13 10.15 10.05 10.08 10.11 10.13 10.16 10.16 10.17 10.15 10.13 10.17 10.21 10.21 9.96 9.92 9.93 9.95 9.96 9.99 10.02 —— 10.02 10.05 10.12 10.17 10.20 10.17 10.09 10.06 10.07 10.07 10.14 10.20 10.25 10.27 10.27 10.27 10.23 10.28 10.31 10.24 9.87 9.78 9.76 9.76 9.76 9.72 9.76 9.80 9.75 9.84 9.79 9.57 9.55 9.57 9.63 9.70 9.78 9.88 9.96 9.58 9.34 ___ —— —— —— —— ___ —— 8.80 8.71 8.74 8.78 8.77 8.68 8.76 8.71 8.82 8.97 9.05 9.14 9.19 9.28 9.26 9.34 8.34 8.20 8.20 8.28 8.33 8.44 8.56 8.66 8.82 8.91 8.95 9.00 9.01 9.01 9.01 9.06 9.20 9.29 9.30 9.31 9.29 9.22 9.19 9.14 9.06 9.06 9.18 9.17 —— 8.93 *f 10 15 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 496 GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 182443066041502. Local number, PN-8c. LOCATION. —Lat 18°24'43", long 66°04'15", Hydrologic Unit 21010005, 2.29 mi east of Fort Buchannan Military Res. main gate, 3.83 mi southeast of Catafio plaza, and 0.16 mi southwest of Hospital del Maestro. Owner: U.S. Geological Surrey, WRD, Name: Parque Luis Munoz Marin 1C. AQUIFER. —Alluvium. WELL CHARACTERISTICS.—Drilled observation well, diameter 4 in (0.10 m), cased 4 in (0.10), 0-33 ft (0-10.1 m), perforated 33-40 ft (10.1-12.2 m). Depth 40 ft (12.2 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.—Elevation of land-surface datum is about 13 ft (3.96 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 3.66 ft (1.12 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--February 1989 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 8.80 ft (2.68 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 16.18 ft (4.93 m) below land-surface datum, Oct. 5, 6, 7, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG MEAN 13.24 13.07 13.22 13.23 13.10 13.67 14.34 14.98 15.28 WTR YR 1997 MEAN 13.94 HIGHEST 12.04 OCT. 1, 1996 LOWEST 15.61 JULY 15, 16, 1997 15.28 13.87 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 12.12 12.24 12.38 12.48 12.63 12.71 12.78 12.91 13.03 13.11 13.13 13.25 13.31 13.29 13.33 13.40 13.47 13.52 13.58 13.63 13.68 13.69 13.72 13.75 13.79 13.78 13.68 13.61 13.38 13.51 13.58 13.58 13.62 13.66 13.65 13.66 13.58 13.63 13.65 13.64 13.68 13.70 13.71 13.00 13.20 13.30 13.34 13.32 13.01 12.90 12.93 13.00 13.05 12.34 12.27 12.06 12.05 12.08 12.09 12.20 12.21 —— 12.26 12.30 12.43 12.53 12.64 12.73 12.82 12.94 13.03 13.12 13.06 13.15 13.24 13.30 13.36 13.37 13.43 13.52 13.59 13.62 13.64 13.66 13.71 13.68 13.70 13.77 13.52 13.66 13.43 13.32 13.36 13.39 13.37 13.22 13.12 13.09 13.09 13.10 13.17 13.22 13.29 13.37 13.38 13.44 13.51 13.55 13.62 13.67 13.71 13.74 13.77 13.76 13.28 13.03 12.88 12.73 12.70 12.70 12.70 12.75 12.84 12.91 12.94 12.61 12.61 12.70 12.72 12.77 12.84 12.91 12.93 12.96 13.08 13.14 13.15 13.23 13.28 13.33 13.39 13.40 13.40 13.41 13.41 13.36 13.34 13.28 13.18 13.18 13.17 13.19 —— —— —— 13.25 13.27 13.31 13.32 13.36 13.41 13.44 13.44 13.45 13.52 13.56 13.61 13.63 13.67 13.69 13.71 13.74 13.75 13.73 13.78 13.79 13.81 13.88 13.91 13.95 13.96 13.98 14.00 13.99 13.94 13.99 14.02 14.06 14.06 14.10 14.11 14.11 14.13 14.13 14.16 14.18 14.20 14.22 14.23 14.26 14.28 14.29 14.31 14.35 14.38 14.45 14.47 14.50 14.53 14.56 14.59 14.63 14.64 14.69 14.73 14.77 —— 14.80 14.82 14.86 14.85 14.88 14.90 14.91 14.93 14.95 14.96 15.01 15.03 15.04 15.05 15.04 15.05 15.05 15.08 15.09 15.11 14.88 14.78 14.94 15.02 14.98 14.94 15.01 15.05 15.09 15.11 15.11 15.15 15.12 15.17 15.19 15.22 15.24 15.25 15.27 15.28 15.28 15.29 15.22 15.26 15.28 15.30 15.32 15.34 15.36 15.37 15.37 15.40 15.44 15.46 15.23 15.19 15.25 15.27 15.30 15.35 15.37 —— 15.37 15.41 15.45 15.53 —— ___ —— 15.48 15.48 15.50 15.52 15.54 15.55 15.58 15.59 15.54 15.52 15.55 15.50 15.43 14.86 14.96 14.99 15.04 15.00 14.90 14.93 14.95 14.92 14.97 14.81 14.51 14.51 14.52 14.59 14.65 14.75 14.81 14.89 14.41 14.21 13.90 13.79 13.26 12.92 13.05 13.30 13.38 13.10 13.10 13.20 13.34 13.36 13.29 13.49 13.53 13.70 13.86 14.00 14.09 14.21 14.34 14.32 14.46 13.06 12.94 13.00 13.12 13.28 13.41 13.57 13.71 13.87 13.99 14.03 13.96 14.08 14.24 14.31 14.40 14.48 14.52 14.56 14.62 14.61 14.48 14.53 14.59 14.56 14.58 14.62 14.41 —— 14.08 10 "15 20 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 497 RIO HONDO TO RIO PUERTO NUEVO BASINS 182417066042700. Local number, PN-10. LOCATION.—Lat 18°24 1 17", long 66°04'27", Hydrologic Unit 21010005, 3.96 mi southeast of Catano plaza, 1.00 mi southwest of Escuela J.J. Osuna, and 2.26 mi east of WAPA TV radio anthena. Owner: U.S. Geological Survey, WRD, Name: Las Americas No. 1. AQUIFER.—Alluvium. WELL CHARACTERISTICS.--Drilled observation well, cased 4.0 in (0.10 m), 0-80 ft (0-24.39 m), 4.0 in (0.10 m), perforated pipe 80-90 ft (24.39-27.43 m). Depth 90 ft (27.43 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.--Elevation of land-surface datum is about 16 ft (4.89 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 3.10 ft (0.95 m) above land-surface datum. REMARKS.—Recording observation well. Well affected by pumping during June 1994. [+, above land-surface datum]. PERIOD OF RECORD.—October 1989 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, +2.30 ft (+0.70 m) above land-surface datum, Jan. 9-12, 1993; lowest water level recorded, 6.92 ft (2.11 m) below land-surface datum, Oct. 6-9, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT .47 NOV DEC MAR APR MAY JUL .37 WTR YR 1997 MEAN 1.94 .21 .63 1.02 1.15 1.33 3.30 4.14 4.32 HIGHEST +0.19 NOV. 30, DEC. 1-4, 1996 LOWEST 4.58 JULY 18, 19, 1997 AUG 3.41 SEP 1 .21 2 .26 3 .23 4 .18 5 .23 6 .23 7 .24 8 .26 9 .28 10 .34 11 .35 12 .36 13 .78 14 .73 15 .63 16 .56 17 .54 18 .53 19 .54 20 .56 21 .58 22 .59 23 .61 24 .61 25 .64 26 .66 27 .63 28 .60 29 .54 30 .54 31 .57 .58 .65 .66 .60 .57 .54 .54 .55 .57 .68 .72 .76 .52 .53 .64 .58 .50 .35 .34 .15 .22 .22 .09 .01 .02 .04 + .01 + .11 + .14 + .15 —— + .19 + .19 + .19 + .16 + .10 + .09 + .10 + .10 + .09 + .07 + .04 + .03 .00 .01 .02 .03 .41 .73 .67 .63 .55 .54 .54 .54 .54 .56 .56 .60 .42 .27 .30 .31 .29 .23 .24 .26 .29 .32 .35 .39 .40 .42 .44 .47 .50 .50 .50 .48 .46 .47 .46 .57 .74 1.04 1.03 1.20 1.23 1.25 1.23 1.15 1.11 1.08 .97 1.54 .95 2.57 3.71 .26 3.76 3.28 .93 1.46 .94 2.56 3.76 .26 3.75 3.28 .97 1.45 .93 2.56 3.79 .27 3.74 2.93 1.02 1.38 .93 2.62 3.85 .27 3.71 2.93 1.00 1.35 .87 2.68 3.89 .29 3.71 2.90 1.02 1.31 .86 2.74 —— .31 3.71 2.90 1.05 1.31 .86 2.79 —— .38 3.70 2.90 1.07 1.30 .86 3.07 —— .38 3.70 2.90 1.06 1.28 .85 3.30 3.91 .38 3.70 2.90 1.03 1.28 .82 3.31 3.91 .38 3.60 3.10 1.03 1.28 .82 3.31 3.95 .39 3.51 3.28 1.02 1.28 .82 3.32 3.95 .45 3.48 3.29 .98 1.23 .82 3.35 .00 .48 3.38 3.29 .98 1.21 .82 3.39 .06 .49 3.37 3.22 .91 1.14 .84 3.46 .08 .51 3.36 3.21 .89 1.08 .84 3.52 .08 .51 3.35 3.21 .87 1.04 .82 3.53 .08 .55 3.35 3.17 .83 1.00 .83 3.53 .08 .57 3.23 3.17 .80 .96 .98 3.53 .33 .57 3.22 3.17 .76 .95 1.32 3.54 .47 .57 3.22 3.17 .74 .96 1.57 3.54 .49 .46 3.21 3.16 .67 .95 1.77 3.54 .51 .37 3.21 3.14 .95 .96 1.94 3.56 .52 .30 3.20 3.12 1.22 .97 2.08 3.58 .43 .24 3.19 3.08 1.21 .99 2.23 3.58 .38 .20 3.19 3.05 1.49 1.01 2.36 3.59 .34 .13 3.18 3.05 1.52 1.00 2.45 3.59 .32 .07 3.17 3.05 1.57 1.02 2.51 3.59 .31 .02 3.19 3.05 —— 1.01 2.56 3.61 .30 3.99 3.21 3.05 .96 2.58 3.65 .27 3.99 3.26 2.99 .96 —— 3.68 —— 3.95 3.28 3.10 +5 ? 5 10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR + above land-surface datum 498 GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 182349066032600. Local number, PN-13. LOCATION.--Lat 18°23'49", long 66°03'26", Hydrologic Unit 21010005, 5.15 mi southeast of Catano plaza, 1.28 mi south of Escuela J.J. Osuna, and 0.69 mi southwest of University of Puerto Rico main gate. Owner: U.S. Geological Survey, WRD, Name: Jardzn Botanico No. 1. AQUIFER. —Alluvium. WELL CHARACTERISTICS.--Drilled water-table well, diameter 4 in (0.10 m) cased 4.0 in (0.10 m), 0-45 ft (0-13.72 m), perforated 35-45 ft (10.67-13.72 m). Depth 45 ft (13.72 m). INSTRUMENTATION.--Digital water level recorder--15-minute punch. DATUM.—Elevation of land-surface datum is about 32 ft (9.75 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 2.84 ft (0.86 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--March 1989 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 6.96 ft (2.12 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 17.87 ft (5.45 m) below land-surface datum, Oct. 7, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN FEB APR MAY JUN JUL MEAN 16.10 15.83 15.60 15.63 15.75 16.11 16.58 16.82 17.04 WTR YR 1997 MEAN 16.38 HIGHEST 13.28 NOV. 13, 1996 LOWEST 17.36 AUG. 5, 1997 17.06 16.97 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 15.80 15.86 15.90 15.94 15.97 16.00 16.01 16.02 16.05 16.07 16.03 16.08 16.10 16.01 16.10 16.16 16.20 16.22 16.25 16.29 16.31 16.31 16.33 16.33 16.36 16.30 16.11 15.77 15.97 16.15 16.18 16.19 16.22 16.25 16.16 16.14 16.15 16.25 16.25 16.25 16.25 16.24 16.24 15.11 15.91 16.04 16.02 15.92 15.68 15.75 15.79 15.87 15.87 15.26 15.21 15.26 15.33 15.45 15.30 15.42 15.10 —— 15.33 15.30 15.44 15.49 15.52 15.59 15.62 15.64 15.67 15.72 15.49 15.68 15.71 15.72 15.72 15.65 15.73 15.76 15.84 15.86 15.85 15.79 15.86 15.31 15.80 15.90 15.34 15.75 15.18 14.82 15.48 15.61 15.42 15.51 15.56 15.60 15.64 15.67 15.70 15.72 15.76 15.76 15.72 15.84 15.87 15.88 15.91 15.94 15.98 15.95 15.97 15.77 14.55 14.80 15.05 15.35 15.55 15.66 15.68 15.66 15.71 15.72 15.72 15.51 15.64 15.69 15.65 15.71 15.72 15.72 15.68 15.66 15.75 15.76 15.53 15.76 15.79 15.87 15.88 15.88 15.88 15.89 15.90 15.75 15.87 15.74 —— 15.69 15.83 15.89 —— —— —— 15.90 15.91 15.91 15.85 15.66 15.91 15.97 15.93 15.95 16.03 16.07 16.09 16.09 16.10 16.12 16.13 16.17 16.17 16.11 16.18 16.21 16.24 16.28 16.30 16.32 16.33 16.33 16.35 16.30 16.19 16.30 16.33 16.38 16.39 16.39 16.44 16.46 16.47 16.47 16.48 16.49 16.55 16.55 16.55 16.58 16.58 16.61 16.61 16.61 16.61 16.65 16.67 16.67 16.69 16.70 16.72 16.72 16.73 16.73 16.75 16.76 —— 16.78 16.81 16.81 16.73 16.80 16.82 16.81 16.84 16.85 16.85 16.87 16.88 16.89 16.87 16.90 16.90 16.85 16.88 16.90 16.92 16.59 16.45 16.75 16.82 16.72 16.73 16.82 16.82 16.88 16.90 16.92 16.93 16.90 16.95 16.98 17.00 17.01 17.02 17.04 17.06 17.07 17.08 16.99 17.03 17.05 17.07 17.07 17.09 17.10 17.04 17.06 17.10 17.12 17.13 16.96 16.91 17.04 17.06 17.09 17.10 17.10 —— 17.04 17.11 17.14 17.15 17.03 17.04 17.12 17.14 17.14 17.16 17.18 17.11 17.17 17.21 17.22 16.89 17.13 17.22 17.08 16.99 16.58 16.94 17.00 17.03 16.92 16.99 17.03 17.04 17.03 17.07 16.89 16.99 17.07 17.08 17.10 17.18 17.26 17.24 17.18 17.01 17.07 17.03 17.05 16.99 16.76 16.83 16.98 16.96 16.78 16.94 16.96 16.96 16.78 16.57 16.80 16.66 16.87 16.93 16.97 17.02 17.04 17.07 17.01 17.08 16.88 16.83 16.90 16.93 16.93 16.93 16.97 17.00 17.03 17.13 16.88 16.79 16.91 17.03 17.01 17.05 17.07 17.09 17.09 17.11 17.08 16.93 16.98 16.93 16.98 17.02 17.05 16.79 ___ 16.98 18 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO HONDO TO RIO PUERTO NUEVO BASINS 499 182406066034700. Local number, PN-19. LOCATION.--Lat 18°24'06", long 66°03'47", Hydrologic Unit 21010005, 4.65 mi southeast of Catafio plaza, 0.89 mi south of Escuela J.J. Osuna, and 0.78 mi southwest of University of Puerto Rico main gate. Owner: U.S. Geological Survey, WRD, Name: Jardin Botanico No. 3. AQUIFER.--Alluvium. WELL CHARACTERISTICS.--Drilled water-table well, diameter 4 in (0.10 m) cased 4.0 in (0.10 m), 0-48 ft (0-14.6 m), perforated 38-48 ft (11.6-14.6 m). Depth 48 ft.(14.6 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.--Elevation of land-surface datum is about 32 ft (9.75 m) above mean sea level, from topographic map. Measuring point: Hole on well shaft, 2.91 ft (0.88 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.--June 1991 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 3.06 ft (0.93 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 13.43 ft (4.09 m) below land-surface datum, Nov. 8, 9, 1994. HATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV DEC JAN FEB MAR APR MAY JUN JUL MEAN 5.72 5.34 WTR YR 1997 MEAN 7.75 4.68 4.64 4.53 HIGHEST 3.91 DEC. 1, 1996 5.57 7.94 10.68 11.87 12.44 LOWEST 12.78 JULY 18, 19, 20, 1997 10.46 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 .33 .46 .55 .51 .55 .68 .84 .98 5.11 5.25 5.34 5.46 5.56 5.70 5.80 5.91 5.97 6.00 6.12 6.28 6.40 6.45 6.51 6.65 6.73 6.81 6.82 6.81 6.40 6.21 6.21 6.29 : 6.32 : 6.40 : 6.50 6.53 6.47 6.40 6.39 6.23 6.13 6.17 6.25 5.94 5.61 5.55 5.52 5.46 .91 .64 .64 ! .64 .66 .33 .06 3.94 3.97 4.01 4.05 4.03 4.03 _ __ 1.91 1.94 1.98 .04 .07 .13 .21 .23 .36 .44 .47 .47 .47 .48 .54 .59 .63 .80 .97 5.02 5.14 5.23 5.33 5.37 5.37 5.47 5.47 5.43 5.19 1.76 1.63 .60 .59 .36 .34 .34 .33 .35 .36 .37 .41 .45 .51 .55 .59 .61 .71 .81 .92 5.00 5.06 5.23 5.19 .80 .59 .53 .57 .65 .71 .75 .77 .77 .77 .40 .39 .40 .41 .42 .43 .46 .47 .45 .46 ! .49 ! .53 ! .55 ! .57 ! .58 ! .62 ! .62 ! .62 .62 .63 .59 .58 .59 .52 .51 .58 .63 ___ ___ ___ .69 6.80 .74 6.86 .75 6.94 .76 7.02 .76 7.10 .76 7.15 .76 7.22 .87 7.26 .88 7.31 .93 7.38 5.01 7.52 5.18 7.56 5.27 7.59 5.38 7.70 5.42 7.75 5.48 7.78 5.58 7.83 5.68 7.85 5.71 7.97 5.81 8.11 5.92 8.29 6.00 8.46 6.11 8.59 5.26 8.73 6.36 8.89 6.45 9.05 6.49 9.18 6.56 9.33 6.66 9.45 6.68 9.53 6.73 9.61 9.73 9.84 9.92 10.00 10.06 10.15 10.22 10.32 10.40 10.47 10.55 10.65 10.74 10.79 10.86 10.87 10.91 10.98 11.04 11.07 11.06 11.10 11.14 11.17 11.20 11.20 11.22 11.28 11.31 11.35 11.40 11.44 11.47 11.50 11.54 11.60 11.64 11.68 11.73 11.78 11.82 11.79 11.82 11.89 11.91 11.95 11.98 12.02 12.05 12.08 12.12 12.17 12.21 11.97 11.96 12.04 12.09 12.13 12.17 12.22 —— 12.25 12.28 12.32 12.37 12.42 12.45 12.45 12.47 12.47 12.51 12.55 12.58 12.63 12.68 12.71 12.73 12.74 12.77 12.78 12.78 12.48 12.34 12.34 12.38 12.38 12.15 12.11 12.13 12.13 12.13 12.13 11.65 11.55 11.58 11.66 11.73 11.80 11.88 11.94 11.61 11.54 11.47 11.44 11.18 8.74 8.96 9.43 9.76 8.56 8.47 8.75 9.09 9.43 9.50 9.65 9.81 10.01 10.20 10.43 10.61 10.78 10.91 11.07 11.19 6.03 6.21 6.82 7.39 7.86 8.25 8.66 8.96 9.26 9.55 9.66 9.71 9.77 9.89 9.90 9.94 10.04 10.14 10.20 10.26 10.13 8.97 8.09 8.34 8.62 8.14 8.13 7.23 ___ 8.95 l i i l l l l l I l l l l l l l l l l l I l l l l l l l l l l l I l l l l i l l i l l i I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJA 1993 1994 1995 1996 1997 WATER YEAR 500 GROUND-WATER LEVELS RIO GRANDE DE LOIZA BASIN 181550065593200. Local number, 50. LOCATION. —Lat 18015'50", long 65°59'32", Hydrologic Unit 21010005, 1.36 mi northwest of Gurabo plaza, 0.70 mi north of Estacion Experimental Agricola, and 2.42 mi southwest of Escuela Jos% M. Gallardo. Owner: Gurabo Agricultural Experimental Station, Name: Gurabo. AQUIFER.—Unconsolidated deposits of Quaternary Age. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 13 in (0.34 m), cased 4 in (0.10 m), 0-145 ft (0-44.2 m). Depth 145 ft (44.2 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 148 ft (45.1 m) above mean sea level, from topographic map. Measuring point: Top of 12 in (0.30 m) casing, 0.80 ft (0.24 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--December 1960 to March 1985, September 1991 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level measured, 12.6 ft (3.86 m) below land-surface datum, Sept. 9, 1975; lowest water level measured, 44.4 ft (13.5 m) below land-surface datum, June 18, 1975. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT 29.47 NOV DEC JAN MAR APR MAY JUN J0L AUQ 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 29.51 —— 29.61 29.58 —— 29.63 —— 29.59 29.51 29.51 29.47 —— 29.52 29.67 29.69 29.47 —— 29.34 —— 29.34 29.17 29.23 29.25 29.26 29.28 29.38 29.40 —— 29.51 —— 29.49 —— 29.42 29.45 29.41 29.40 29.55 29.46 29.54 29.44 29.49 29.51 —— 29.53 29.71 29.72 29.72 29.70 29.67 29.64 29.59 29.54 29.52 29.44 29.46 29.47 29.48 29.52 29.51 29.69 29.77 29.85 29.89 29.94 29.99 30.05 30.07 30.06 30.00 29.90 29.46 28.91 28.62 28.42 28.30 28.25 28.13 28.04 27.98 27.97 27.95 27.94 27.93 23.94 27.11 27.57 27.82 27.92 27.99 28.11 28.10 28.27 28.35 28.43 28.39 28.19 28.02 27.90 27.79 27.63 27.30 27.51 27.51 27.51 27.48 27.45 27.51 27.51 27.46 27.46 27.46 27.50 27.54 27.54 27.52 27.50 27.47 27.40 27.28 27.49 27.59 27.66 27.72 27.45 27.62 27.70 27.74 27.54 27.61 27.59 27.61 27.59 27.61 —— —— 27.65 27.66 27.72 27.75 27.78 27.80 27.84 27.89 27.92 27.93 27.96 28.01 28.14 28.19 28.08 29.14 29.87 30.27 30.53 30.69 30.84 30.96 31.13 31.27 31.39 31.49 31.55 31.67 31.77 31.24 30.64 30.30 30.21 29.60 29.19 28.87 28.66 28.57 28.52 28.52 28.53 28.56 28.59 28.64 28.73 28.85 28.91 29.06 29.15 29.32 29.44 29.55 29.68 29.76 29.87 30.00 30.10 30.23 30.45 31.54 32.14 —— 32.54 32.87 33.13 33.33 33.02 32.63 32.36 32.18 32.20 32.79 33.48 33.74 33.98 34.14 34.31 34.42 34.54 34.66 33.58 34.51 34.77 34.91 34.99 35.08 35.13 35.16 35.26 35.33 35.43 35.50 35.56 35.64 35.72 35.79 35.83 35.91 35.96 35.37 35.99 36.08 36.09 36.11 36.14 36.17 36.22 36.27 36.31 36.36 36.37 36.39 36.40 36.42 36.43 36.48 35.35 35.92 ___ —— —— —— —— —— —— —— —— ___ —— —— —— —— 37.16 37.19 37.23 37.27 37.32 37.36 37.38 37.39 37.40 37.42 37.40 37.33 37.31 37.29 37.24 37.24 37.29 37.30 37.28 37.25 37.24 37.22 37.19 37.17 37.05 36.96 36.95 36.94 36.95 36.96 36.95 36.92 36.90 36.85 36.75 36.59 36.44 36.32 36.21 36.03 35.90 35.75 35.47 34.69 34.14 33.58 33.42 33.26 33.05 32.84 32.69 32.53 32.43 32.34 29.13 31.19 31.37 31.38 30.90 29.79 29.68 31.20 31.51 31.64 31.56 31.52 31.46 31.35 31.20 31.11 31.07 31.04 31.02 30.94 30.84 30.73 30.71 30.63 30.65 30.60 30.55 30.50 —— 29.46 29.61 27.78 27.54 29.44 29.45 34.05 HTR YR 1997 MEAN 31.35 HIGHEST 23.94 JAN. 10, 1997 LOWEST 37.43 JULY 20, 36.07 1997 37.30 35.70 31.00 20 30 40 50 I I I I I I I I I I v ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO GRANDE DE LOIZA BASIN 501 182515065594100. Local number, 222. LOCATION.--Lat 18°25'15", long 65°59'41", Hydrologic Unit 21010005, 3.56 mi northwest of Carolina plaza, 1.21 mi northwest of Escuela Extension El Comandante, and 0.74 mi southwest of Escuela Vistamar. Owner: U.S. Geological Survey, WRD, Name: Campo Rico TW-1. AQUIFER.—Surficial Deposits. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m) . Depth 100 ft (30.5 m). INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 10.0 ft (3.05 m) above mean sea level, from topographic map. Measuring point: Hole on side of casing, 0.80 ft (0.24 m) above land-surface datum. Prior July 28, 1986, top of shelter floor, 3.10 ft (0.94 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.--February 1986 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 4.33 ft (1.32 m) below land-surface datum, Sept. 6, 1995; lowest water level recorded, 7.42 ft (2.26 m) below land-surface datum, Feb. 9, 1986. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV DEC JAN FEB MAR APR MAY JUN MEAN 5.35 5.41 WTR YR 1997 MEAN 5.67 5.64 5.70 5.71 5.71 5.71 5.78 5.83 HIGHEST 4.85 NOV. 18, 1996 LOWEST 6.19 JAN. 8, 1997 5.78 AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 5.24 5.27 5.41 5.51 5.51 5.57 5.55 5.42 5.27 5.26 5.21 5.15 5.14 5.13 5.23 5.40 5.47 5.51 5.46 5.48 5.43 5.53 5.43 5.32 5.23 5.20 5.24 5.23 5.26 5.39 5.50 5.55 5.64 5.59 5.55 5.58 5.52 5.42 5.29 5.23 5.23 5.29 5.29 5.26 5.44 5.41 5.44 5.55 5.30 5.23 5.26 5.21 5.20 5.13 5.28 5.40 5.52 5.56 5.55 5.71 5.58 5.77 5.79 5.66 5.62 5.65 5.75 5.63 5.55 5.48 5.49 5.39 5.50 5.68 5.79 5.71 5.73 5.69 5.60 5.64 5.63 5.56 5.55 5.52 5.58 5.63 5.66 5.71 5.70 5.63 5.78 5.81 5.78 5.78 5.75 5.75 5.71 5.64 5.61 5.61 5.51 5.55 5.56 5.68 5.82 5.86 5.78 5.73 5.66 5.63 5.70 5.71 5.71 5.63 5.61 5.65 5.64 5.70 5.72 5.75 5.84 5.83 5.82 5.71 5.74 5.75 5.64 5.58 5.59 5.58 5.59 5.61 5.66 5.68 5.73 5.81 5.84 5.84 5.83 5.77 5.74 5.68 5.75 5.67 5.70 5.70 5.74 5.70 5.68 5.77 5.78 ___ ___ —— 5.78 5.79 5.72 5.68 5.68 5.69 5.57 5.50 5.60 5.60 5.67 5.62 5.72 5.80 5.79 5.74 5.70 5.68 5.71 5.67 5.70 5.70 5.64 5.64 5.69 5.80 5.81 5.72 5.80 5.84 5.85 5.84 5.75 5.57 5.59 5.66 5.65 5.67 5.69 5.71 5.74 5.78 5.88 5.84 5.87 5.83 5.75 5.65 5.59 5.59 5.58 5.53 5.61 5.66 5.62 5.65 5.79 5.78 5.82 5.83 5.80 5.75 5.70 5.69 5.68 5.67 5.65 5.66 5.71 5.78 5.81 5.81 5.82 5.85 5.87 5.96 5.97 5.92 5.96 5.96 5.91 5.83 5.73 5.66 5.61 5.60 5.62 5.66 5.74 5.82 5.86 5.90 5.85 5.83 5.82 5.77 5.66 5.73 5.77 5.83 5.83 5.85 5.84 5.86 5.83 5.82 5.88 5.83 5.87 5.93 5.89 5.86 5.81 5.76 5.79 5.77 5.80 5.82 5.83 5.87 5.85 5.92 5.90 5.82 5.82 5.77 5.78 5.73 5.77 5.70 5.69 5.77 5.81 5.85 5.79 5.84 5.87 5.89 5.88 5.77 5.58 5.51 5.50 5.55 5.57 5.71 5.75 5.80 5.88 5.94 5.96 5.95 5.91 5.84 5.74 5.66 5.63 5.63 5.67 5.69 5.69 5.74 5.81 5.94 5.97 5.94 5.92 5.93 5.83 5.77 5.67 5.58 5.47 5.54 5.62 5.77 5.80 5.94 5.96 5.92 5.85 5.78 5.69 5.60 5.58 5.58 5.55 5.46 5.56 5.49 5.31 5.40 5.58 5.78 5.87 5.92 5.85 5.77 5.65 5.53 5.39 5.41 5.56 5.61 5.68 5.79 5.85 5.93 5.94 5.93 5.96 5.87 5.81 5.73 5.76 5.68 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 502 GROUND-WATER LEVELS RIO GRANDE DE LOIZA BASIN 181513065554601. Local number, CJ-TW3B. LOCATION.--Lat 18°15'13", long 65°55'46", Hydrologic Unit 21010005, 2.86 mi east of Gurabo plaza, 3.57 mi southwest of Hwy 186 km 4.7, and 1.39 mi southwest of Hwy 185 km 15.7. Owner: U.S. Geological Survey, WRD, Name: CJ-TW3B. AQUIFER.—Unconsolidated deposits of Quaternary Age. NELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-38 ft (0-11.6 m) screened 25-35 ft (7.62 m). Depth 38 ft (11.6 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 187 ft (57.0 m) above mean sea level, from topographic map. Measuring points Top of casing 2.95 ft (0.90 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—September 1991 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 10.64 ft (3.24 m) below land-surface datum, Sept. 11, 1996; lowest water level recorded, 20.31 ft (6.19 m) below land-surface datum, Sept. 19, 1994. WATER LEVEL, ZN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN MAR APR MAY JUN JUL AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN 12.29 12.40 12.47 12.58 12.69 12.76 12.87 12.94 13.05 13.12 13.13 13.29 13.37 13.44 13.54 13.62 13.66 13.73 13.78 13.89 13.95 14.03 14.07 14.11 14.17 14.22 14.27 14.29 14.28 14.30 14.33 13.50 HTR YR 1997 | 10 ———— f* §4i* E 15 H ?20 rI » I I 1 1 •mj 1 1 1 1 14. 14. 14. 14. 14. 14. 14. 14. 14. 14. 14. 14. 13. 13. 13. 13. 13. 13. 13. 13. 13. 13. 12. 12. 12. 12. 12. 12. 12. 12.- 13 MEAN I I I \J^ 1 1 1 36 12.73 36 12.77 28 12.83 28 12.90 32 12.96 37 13.03 32 13.07 27 13.10 27 13.23 32 13.32 39 13.35 20 13.35 75 13.37 51 13.40 44 13.44 45 13.50 45 13.55 35 13.63 27 13.69 26 13.71 25 13.78 25 13.85 75 13.88 62 13.93 56 14.00 52 14.05 53 14.08 59 62 —— 70 —— —— .55 13.43 —— 15.55 15.58 —— 15.62 —— 15.66 15.68 —— 15.70 —— 15.73 —— 15.77 15.83 15.84 15.87 —— 15.92 15.96 16.00 16.04 —— 16.07 —— 16.10 15.26 16.12 15.26 16.12 15.30 16.13 15.32 16.25 15.36 16.30 15.40 16.33 15.42 16.38 15.43 16.41 15.47 16.46 15.51 16.49 15.54 16.53 16.59 16.60 —— 16.63 —— 15.39 16.07 16.66 16.70 16.73 16.74 16.77 16.84 16.86 16.90 16.93 16.96 17.03 17.06 17.09 17.14 17.17 17.20 17.23 17.27 17.33 17.36 17.39 17.41 17.45 17.48 17.52 17.57 17.59 17.64 17.66 17.68 —— 17.18 17.72 17.73 17.76 17.79 17.83 17.85 17.89 17.93 17.94 17.96 17.99 18.02 18.07 18.09 18.10 18.12 18.14 18.15 18.16 18.16 18.17 18.19 18.23 18.25 18.26 18.28 18.31 18.33 18.34 18.37 18.38 18.08 16.81 HIGHEST 12.26 OCT. 1, 1996 LOWEST 19.47 AUG. 20, I 1 1 I I 1 1 I I ,A\ SjJ \/X. 1 1 1 1 1 1 1 1 1 ONDJFMAMJJASONDJFM 1 1 I I 1 I 1 1 1 1 1 1 ^—- --__r^---/ ^— i i i i i i i i i i i i AMJJASONDJFHAH III) J — •— X 1 1 1 1 J J A S 1 1 1 1 1 Vj\ 1 1 1 1 1 18.39 18.41 18.41 18.41 18.43 18.44 18.44 18.47 18.48 18.50 18.52 18.55 18.58 18.60 18.63 18.64 18.67 18.69 18.73 18.75 18.76 18.79 18.80 18.80 18.84 18.86 18.88 18.90 18.92 18.93 —— 18.64 18.96 18.97 18.99 19.02 19.05 19.08 19.08 19.11 19.12 19.13 19.15 19.16 19.17 19.18 19.19 19.19 19.21 19.22 19.24 19.25 19.26 19.28 19.28 19.31 19.31 19.31 19.32 19.33 19.34 19.34 19.34 19.19 19.35 19.35 19.35 19.35 19.37 19.38 19.39 19.40 19.41 19.42 19.43 19.44 19.44 19.44 19.45 19.45 19.46 19.46 19.46 19.47 19.47 19.47 19.44 19.43 19.39 19.35 19.33 19.33 19.33 19.33 19.32 19.40 19.29 19.27 19.25 19.22 19.17 19.15 19. 19. 19. 19. 19. 19. 14 13 13 13 15 16 19.16 19.16 19. 19. 17 17 19.15 19. 19. 19. 19. 19. 19. 19. 19. 19. 19. 19. 19. 19. - 19 15 15 15 16 17 20 21 22 24 25 25 25 26 — .19 21, 22, 1997 1 1 1 1 1 1 r> •-^r i i i i i i ONDJFMAMJJAS I I I \A i i i J 0 N D 1 1 I I 1 1 V 1 1 I 1 1 1 JFM A H J - - — .<-* I I J A S WATER YEAR GROUND-WATER LEVELS RIO GRANDE DE LOIZA BASIN 505 181352066025300. Local number, CJ-TW19A. LOCATION.—Lat 18°13'52", long 66°02'53", Hydrologic Unit 21010005, 0.96 mi southwest of Caguas plaza, 1.02 mi northwest of Escuela Antonio S. Pedreira, and 0.30 mi southeast of Hwy 156 km 59.1. Owner: U.S. Geological Survey, WRD, Name: CJ-TW19A, Bonneville. AQUIFER.—Unconsolidated deposits of Quaternary Age. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-67 ft (0-20.4 m), screened 50-65 ft (15.2-19.8 m). Depth 67 ft (20.4 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 262 ft (79.8 m) above mean sea level, from topographic map. Measuring point: Top of casing 3.00 ft (0.91 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.— June 1992 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 22.60 ft (6.89 m) below land-surface datum, Sept. 14, 1996; lowest water level recorded, 25.70 ft (7.83 m) below land-surface datum. May 31, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 23.37 23.39 23.41 23.47 23.50 23.53 23.55 23.58 23.62 23.64 23.66 23.69 23.72 23.75 23.78 23.80 23.81 23.83 23.85 23.89 23.92 23.95 23.98 24.01 24.04 24.05 24.07 24.07 24.08 24.10 24.11 24.12 24.13 24.14 24.15 24.17 24.17 24.18 24.16 24.15 24.18 24.19 24.19 24.14 24.09 24.06 24.05 24.06 24.05 24.06 —— ___ —— —— —— —— ___ —— —— —— —— —— MEAN 23.78 24.13 WTR YR 1997 MEAN 24.66 DEC JAN FEB MAR APR MAY JUN JUL —— 24.11 24.15 24.48 24.73 24.92 25.02 25.14 HIGHEST 23.35 OCT. 1, 1996 LOWEST 25.17 JULY 23-26, 30, 31, 1997 25.12 SEP — —— —— — _ _ —— —— —— — —— — — _ _ —— —— —— — _ _ 24.30 24.19 24.12 24.08 24.06 24.05 24.05 24.04 24.04 24.04 24.03 24.02 24.02 24.03 24.04 24.06 24.07 24.08 24.10 24.10 24.12 24.14 24.15 24.16 24.18 24.19 24.21 24.22 24.23 24.24 24.26 24.26 24.26 24.28 24.29 24.30 —— —— —— 24.31 24.31 24.32 24.34 24.35 24.36 24.38 24.39 24.42 24.43 24.44 24.45 24.48 24.49 24.49 24.49 24.51 24.52 24.52 24.53 24.54 24.55 24.56 24.57 24.58 24.58 24.58 24.58 24.59 24.60 24.60 24.61 24.62 24.64 24.64 24.66 24.67 24.67 24.67 24.67 24.71 24.71 24.71 24.72 24.72 24.73 24.73 24.74 24.74 24.75 24.76 24.77 24.79 24.80 24.80 24.82 24.83 24.83 24.84 24.84 24.85 —— 24.85 24.86 24.87 24.88 24.88 24.88 24.89 24.90 24.90 24.90 24.90 24.90 24.90 24.91 24.91 24.92 24.92 24.93 24.93 24.93 24.93 24.93 24.93 24.94 24.95 24.95 24.96 24.97 24.97 24.98 24.98 24.98 24.99 24.99 24.99 24.99 24.99 24.99 25.00 25.01 25.02 25.02 25.02 25.02 25.01 25.01 25.01 25.01 25.02 25.02 25.02 25.01 25.02 25.02 25.03 25.03 25.04 25.05 25.06 25.08 25.08 —— 25.09 25.09 25.10 25.11 25.12 25.12 25.12 25.12 25.12 25.13 25.13 25.13 25.13 25.15 25.15 25.15 25.14 25.15 25.15 25.16 25.16 25.16 25.16 25.17 25.17 25.17 25.16 25.16 25.16 25.17 25.17 25.16 25.16 25.15 25.14 25.14 25.14 25.13 25.12 25.12 25.12 25.12 25.12 25.12 25.12 25.13 25.14 25.14 25.14 25.15 25.15 25.16 25.16 25.16 25.14 25.11 25.08 25.05 25.04 25.02 25.01 24.99 24.99 24.99 24.99 24.99 24.99 24.99 24.99 25.01 25.02 25.05 25.06 25.06 25.06 25.05 25.04 25.04 25.03 25.01 25.01 25.01 25.01 25.01 25.01 25.01 25.01 25.02 25.01 24.98 24.95 24.92 25.01 26 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASO 1993 1994 1995 DJFMAMJJASONDJFMAMJJAS 1996 1997 WATER YEAR 504 GROUND-WATER LEVELS RIO HERRERA TO RIO ANTON RUIZ BASINS 181823065401900. Local number RF-04. LOCATION.—Lat 18°18'23", long 65°40'19", Hydrologic Unit 2101005, 1.72 mi southwest of the intersection of Hwy 3 with Hwy 976, 1.44 mi west of Hwy 3, 1.33 mi northwest of Hwy 982, and 0.49 mi south of Hwy 976. Owner: U.S. Geological Survey, WRD, Name: RF-04. AQUIFER.--Alluvium. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 6 in (0.15 m), cased 6 in (0.15 m) 0-40 ft (0-12.2 m), screened 20-40 ft (6.1-12.2 m). Depth 40 ft (12.2 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 86.29 ft (26.30 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.50 ft (1.07 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—August 31, 1993 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 10.92 ft (3.33 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 18.82 ft (5.74 m) below land-surface datum, July 21-25, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT DEC JAN FEB 1 2 3 4 5 14.95 15.06 15.21 15.36 15.47 17.31 17.31 17.31 17.31 17.31 13.77 13.77 13.78 13.85 14.02 16.48 16.47 16.46 16.46 16.46 6 7 8 9 10 15.60 15.74 15.88 15.99 16.10 17.31 17.23 16.19 15.59 15.10 14.22 14.40 14.56 14.71 14.87 16.35 16.29 16.25 16.23 16.23 11 12 13 14 15 16.20 16.31 16.39 16.50 16.59 14.64 13.81 12.47 12.18 12.23 15.05 15.21 15.38 15.50 15.60 16.22 16.22 16.24 16.28 16.31 16 17 18 19 20 16.67 16.82 16.82 16.86 16.98 12.54 12.77 12.99 13.15 13.20 15.69 15.75 15.80 15.91 15.99 16.35 16.38 16.40 16.44 16.51 21 22 23 24 25 17.06 17.15 17.23 17.31 17.36 12.99 12.68 12.68 12.80 12.96 16.06 16.13 16.19 16.26 16.31 16.54 16.56 16.56 16.48 16.33 17.08 26 27 28 29 30 31 17.40 17.43 17.46 17.47 17.34 17.31 13.07 13.24 13.41 13.59 13.73 —— 16.36 16.40 16.44 16.47 16.49 16.49 16.16 16.03 15.94 15.92 —— —— MEAN 16.52 14.30 15.40 16.33 —— 17.10 WTR YR 1997 MEAN 16.98 HIGHEST 12.18 NOV. 14, 15, 1996 MAY JUN JUL AUG 17.25 17.27 17.27 17.29 17.31 17.34 17.36 17.37 17.41 17.44 18.13 18.15 18.17 18.19 18.21 18.24 18.24 18.26 18.28 18.30 18.30 18.32 18.34 18.36 18.42 18.50 18.52 18.58 18.62 18.66 18.44 18.44 18.44 18.44 18.44 18.43 18.43 18.43 18.43 18.43 17.51 18.28 18.13 18.55 LOWEST 18.82 JULY 21-25, 1997 18.46 SEP 17.15 17.18 17.20 17.25 17.25 17.99 18.04 18.06 18.08 18.11 18.42 18.37 18.30 —— —— 18.16 18.18 18.22 18.24 18.28 18.52 18.51 18.49 18.47 18.46 17.95 17.84 17.70 17.57 17.45 17.39 17.32 17.27 17.24 17.23 17.22 17.22 17.21 17.20 17.20 17.47 17.50 17.53 17.59 17.65 18.32 18.33 18.34 18.36 18.37 —— —— 18.00 18.02 18.02 18.68 18.72 18.74 18.76 18.80 18.44 18.47 18.49 18.50 18.51 17.17 17.14 17.09 17.02 16.94 17.68 17.68 17.71 17.74 17.79 18.38 18.39 18.41 18.42 18.43 18.02 18.02 18.08 18.08 18.10 18.82 18.82 18.82 18.82 18.82 18.54 18.56 18.58 18.58 18.58 16.91 16.89 16.88 16.87 16.86 17.09 17.09 17.09 17.10 17.10 17.13 17.83 17.86 17.89 17.93 17.96 —— 18.43 18.43 18.43 18.43 18.43 18.43 18.12 18.12 18.12 18.14 18.16 —— 18.72 18.62 18.54 18.53 18.53 18.53 18.58 18.57 18.57 18.37 18.14 18.07 16.44 14.05 13.54 13.52 13.53 —— 16.73 JJASONDJFMAMJJASONDJFMAMJJAS 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO HERRERA TO RIO ANTON RUIZ BASINS SOS 181917065382701. Local number RF-12. LOCATION.—Lat 18°19'17", long 65°38'27", Bydrologic Unit 2101005, 1.20 mi northwest of Print a Barrancas, 0.81 mi east of Hwy 3, 0.82 mi south of Hwy 195, and 0.61 mi east of Hwy 194. Owner: U.S. Geological Survey, WRD, Name: RF-12. AQUIFER. —Alluvium. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-34 ft (0-10.4 m), screened 3.75-34 ft (1.14-10.4 m). Depth 34 ft (10.4 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 13.70 ft (4.18 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 4.16 ft (1.27 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—August 11, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 2.90 ft (0.88 m) below land-surface datum, Nov. 22, 1996; lowest water level recorded, 10.64 ft (3.24 m) below land-surface datum, Aug. 21, 22, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT 7.16 NOV DEC JAN FEB MAR APR MAY JUN JUL AUG 5.75 WTR YR 1997 MEAN 7.60 5.73 6.36 5.73 6.72 7.25 8.19 8.96 HIGHEST 2.90 NOV. 22, 1996 LOWEST 10.64 AUG. 21, 22, 1997 9.89 10.38 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 6.74 6.75 6.76 6.67 6.69 6.72 6.79 6.84 6.87 6.92 6.94 6.97 7.00 7.03 7.08 7.12 7.17 7.17 7.20 7.27 7.32 7.40 7.46 7.54 7.61 7.67 7.71 7.74 7.67 7.60 7.57 7.56 7.57 7.61 7.64 7.70 7.73 7.64 7.45 7.15 6.90 6.79 6.30 5.57 5.40 5.52 5.73 5.89 5.75 5.58 4.97 3.31 2.99 3.26 3.58 3.88 .17 .44 .67 .85 .96 —— 5.04 5.14 5.24 5.35 5.46 5.54 5.62 5.69 5.79 5.86 5.91 5.95 6.02 6.07 6.13 5.25 5.16 5.38 5.52 5.62 5.72 5.82 5.88 5.94 5.99 6.03 6.08 6.12 6.15 6.03 6.01 6.04 6.10 6.18 6.24 6.23 6.19 6.20 6.25 6.29 6.33 6.39 6.44 6.49 6.50 6.54 6.57 6.61 6.66 6.71 6.76 6.80 6.67 6.46 6.13 6.02 6.05 6.15 6.24 6.32 6.37 6.37 6.34 5.65 5.41 5.43 5.32 5.38 5.35 5.36 5.41 5.45 5.52 5.61 5.64 5.68 5.68 5.74 5.81 5.87 5.89 5.92 5.95 5.91 5.95 5.98 5.99 6.04 6.07 6.13 —— —— —— 6.17 6.21 6.25 6.28 6.32 6.35 6.40 6.46 6.48 6.52 6.58 6.60 6.62 6.64 6.64 6.68 6.74 6.80 6.84 6.87 6.90 6.94 6.97 7.03 7.06 7.10 7.14 7.16 7.17 7.19 7.23 7.13 7.01 6.96 6.98 6.99 7.02 7.03 7.04 7.07 7.11 7.15 7.18 7.20 7.24 7.26 7.23 7.23 7.25 7.25 7.29 7.32 7.37 7.43 7.51 7.43 7.49 7.53 7.56 7.60 7.66 —— 7.70 7.72 7.77 7.82 7.84 7.88 7.91 7.96 8.00 8.01 8.04 8.08 8.11 8.14 8.18 8.23 8.25 8.31 8.34 8.38 8.42 8.43 8.46 8.50 8.54 8.57 8.57 8.45 8.45 8.47 8.48 8.51 8.54 8.58 8.60 8.64 8.68 8.71 8.73 8.78 8.80 8.83 8.86 8.89 8.93 8.95 8.98 9.02 9.06 9.07 9.09 9.12 9.15 9.19 9.22 9.24 9.27 9.31 9.34 9.37 9.41 —— 9.43 9.46 9.52 9.55 9.59 9.60 9.64 9.66 9.68 9.68 9.76 9.82 9.85 9.89 9.94 9.97 10.00 10.03 10.06 10.09 10.11 10.08 10.08 10.10 10.12 10.13 10.14 10.16 10.16 10.17 10.18 10.18 10.21 10.23 10.24 10.27 10.30 10.32 10.34 10.36 10.37 10.38 10.39 10.43 10.47 10.50 10.52 10.53 10.55 10.57 10.59 10.62 10.64 10.61 10.62 10.60 10.60 10.51 10.39 10.07 9.82 9.60 9.48 9.22 9.15 9.07 9.01 8.96 8.89 8.86 8.81 8.80 8.83 8.87 8.89 8.90 8.91 8.90 8.92 8.94 8.97 9.00 9.03 9.06 9.06 9.08 9.11 8.94 8.34 8.12 8.04 7.99 —— 8.87 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1995 1996 1997 WATER YEAR 506 GROUND-WATER LEVELS RIO BERRERA TO RIO ANTON RUIZ BASINS 182131065241100. Local number RP-04 LOCATION.—Lat. 18*21-31", long. 65°24'11", Hydrologic Unit 21010005, 1.39 mi southeast of the intersection of Hwy 992 with Hwy 3, 0.40 mi southeast of the intersection of Hwy 983 with Hwy 3, 0.12 mi northwest of the intersection with Hwy 940 with Hwy 983, and 0.03 mi southwest of Hwy 983. Owner: U.S. Geological Survey, WRD, Name: RP-04. AQUIFER.--Alluvium. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-39 ft (0-11.9 m), screened 4-39 ft (1.2-11.9 m). Depth 39 ft (11.9 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 82.12 ft (25.03 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 4.18 ft (1.27 m) above land-surface datum. REMARKS.—Recording observation well. Water levels affected by nearby pumping well. PERIOD OF RECORD.--August 15, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 0.91 ft (0.28 m) below land-surface datum, Sept. 18, 1995; lowest water level recorded, 14.05 ft (4.28 m) below land-surface datum, Aug. 21, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 NOV 7.26 7.34 7.42 7.55 7.60 7.62 7.73 7.86 7.97 8.11 6.73 6.82 6.73 6.62 6.63 6.64 6.45 6.11 5.93 5.93 3.89 3.92 4.02 4.10 4.21 4.25 4.31 4.40 4.50 4.61 4.89 4.90 4.93 5.00 5.06 5.10 5.11 5.16 5.21 5.27 4.84 4.44 4.30 4.32 4.34 4.37 4.43 4.40 4.41 4.45 4.56 4.58 4.63 4.67 4.72 4.75 4.83 5.88 5.18 5.12 8.06 7.45 7.37 8.09 8.40 8.52 8.59 8.33 8.20 8.00 9.89 10.30 9.76 9.79 9.93 10.10 10.24 10.20 10.21 9.99 10.08 10.21 9.32 9.95 10.27 10.36 10.41 10.47 10.54 10.61 11.60 8.44 10.78 11.47 11.05 10.68 10.57 10.55 10.25 10.93 11.75 12.96 13.11 13.23 13.47 13.72 12.78 9.53 8.61 8.18 11.34 12.48 12.63 12.73 12.81 12.87 12.73 12.92 12.78 11.44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN 7.64 5.04 WTR YR 1997 MEAN 8.31 DEC MAR APR MAY JUN JUL AUG 4.86 5.90 4.55 6.09 8.38 10.45 10.70 HIGHEST 2.78 NOV. 23, 1996 LOWEST 14.05 AUG. 21, 1997 11.11 12.24 SEP 8.21 8.26 8.35 8.45 8.56 8.65 8.75 8.40 7.36 7.13 7.08 7.10 7.06 7.08 7.18 7.48 7.22 7.17 7.00 6.94 6.95 5.94 5.22 4.76 4.64 4.66 4.77 4.83 4.45 4.23 4.06 3.94 3.89 3.66 3.69 3.76 3.87 3.96 4.04 4.07 4.02 _ __ .67 5.36 .45 6.59 8.47 10.30 10.71 10.96 7.92 12.61 .73 5.43 .42 6.98 7.79 10.36 10.76 10.67 10.24 12.86 .82 5.49 .33 7.19 7.47 10.39 10.77 10.64 12.41 12.86 .88 4.80 .29 6.23 7.62 10.40 10.72 10.66 12.60 11.48 .95 5.23 .25 5.74 7.29 10.48 10.75 10.93 12.52 11.92 .94 6.93 .29 5.66 7.21 11.02 10.83 11.00 13.13 12.32 .93 7.51 .34 5.76 7.39 11.17 10.92 11.03 13.37 12.85 5.03 7.77 .42 5.89 8.02 11.21 11.07 11.07 13.50 12.94 5.12 7.96 .46 5.98 8.29 11.32 11.09 11.11 13.60 12.78 5.17 8.16 .53 6.54 8.56 11.38 11.13 11.14 13.65 13.20 5.22 8.24 .53 5.95 8.81 11.42 10.67 11.13 13.74 12.91 5.31 8.16 .43 6.44 9.49 12.46 8.83 8.73 13.72 13.03 5.39 7.81 .34 6.34 9.11 11.62 10.66 7.72 12.28 12.77 5.43 7.19 5.83 6.50 8.99 11.44 11.07 10.06 11.82 12.70 5.49 6.40 6.16 6.44 8.86 10.32 11.18 12.34 12.42 12.86 5.55 5.17 4.94 7.28 8.96 10.18 11.29 12.67 13.10 12.96 5.58 .95 4.61 7.63 9.14 10.06 11.62 12.74 11.63 12.38 5.60 .90 4.53 7.51 9.32 8.28 11.60 13.05 12.55 11.83 5.59 .91 —— 7.67 9.36 9.77 11.57 13.24 12.48 12.35 5.20 .90 —— 7.74 10.13 9.97 11.61 13.35 12.69 10.54 3.00 .90 —— 7.80 —— 10.07 —— 13.73 12.68 —— 12.50 I I I I I I I I I I I I I I I I I I I I I I I I I I I JJASONDJFMAMJJASONDJFMAMJJAS O N D J F M A 1995 WATER YEAR GROUND-WATER LEVELS 507 RIO HERRERA TO RIO ANTON ROIZ BASINS 182138065431800. Local number RS-02 LOCATION. --Lat 18°21'38", long 65°43'18", Hydrologic Unit 21010005, 0.87 mi southwest of Hwy 3, 0.39 mi south of the intersection of Bwy 992 with Hwy 991, 0.39 mi north of Hwy 983, and 0.07 mi east of Hwy 991. Owner: U.S. Geological Survey, WRD, Name: RS-02. AQUIFER.--Alluvium. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m) 0-56 ft (0-17.1 m), screened 2.56-56 ft (0.78-17.1 m). Depth 56 ft (17.1 m) . INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.--Elevation of land-surface datum is 33.90 ft (10.30 m) above mean sea level, from topographic survey. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.34 ft (1.02 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—August 22, 1995 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 1.39 ft (0.42 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 7.13 ft (2.17 m) below land-surface datum, July 9-13, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN 5.31 4.11 WTR YR 1997 MEAN 5.86 DEC JAN APR JUL 4.93 5.10 4.77 5.86 6.66 6.86 6.80 HIGHEST 2.77 NOV. 23, 1996 LOWEST 7.13 JULY 9-13, 1997 6.91 6.65 SEP .63 .69 .73 .79 .75 .77 .81 .87 .93 .97 .95 .97 5.01 5.05 5.05 5.17 5.37 5.47 5.61 5.73 5.85 5.93 6.01 6.01 6.07 6.09 6.09 6.05 5.41 5.35 5.47 5.29 5.31 5.47 5.41 5.49 5.57 4.71 4.37 4.41 4.65 4.57 3.39 3.13 3.51 3.91 4.19 4.41 3.59 3.47 3.01 3.25 3.43 2.79 3.03 3.23 3.57 3.83 4.03 4.15 4.13 ___ .03 .13 .27 .39 .51 .59 .67 .73 .81 .89 .91 .97 5.05 5.09 5.15 5.11 5.01 5.07 5.13 5.19 5.25 5.29 5.33 5.33 5.35 5.35 5.35 5.31 5.17 4.71 4.65 4.71 4.81 4.91 4.99 5.05 5.09 5.13 5.19 5.21 5.27 5.31 5.39 5.47 5.49 5.59 5.63 5.67 5.73 5.79 5.81 5.79 5.13 .83 .31 .03 .23 .47 .65 .77 .87 .93 .93 .43 .31 .45 .49 .59 .71 .63 .69 .69 .73 .77 .73 .73 .71 .75 .85 .95 .99 5.05 5.05 .79 .79 .85 .87 .92 .99 5.08 ___ 5.17 5.28 5.31 5.32 5.35 5.37 5.48 5.57 5.60 5.67 5.78 5.77 5.76 5.81 5.84 5.89 5.98 6.07 6.14 6.18 5.96 5.96 6.08 6.16 6.22 6.26 6.29 6.33 6.35 6.37 6.39 6.41 6.45 6.23 6.15 6.21 6.31 6.39 6.45 6.51 6.56 6.60 6.62 6.66 6.70 6.72 6.74 6.77 6.79 6.81 6.83 6.85 6.87 6.87 6.87 6.91 6.91 6.93 6.93 6.95 6.95 —— 6.97 6.99 7.01 7.01 7.04 7.04 7.06 6.92 6.72 6.74 6.80 6.82 6.82 6.84 6.88 6.92 6.94 6.96 7.02 7.04 7.06 7.08 7.08 7.07 6.61 6.65 6.54 6.36 6.46 6.55 6.63 6.62 6.66 6.70 6.71 6.77 6.81 6.82 6.86 6.88 6.89 6.93 6.95 6.68 6.50 6.59 6.69 6.79 6.80 6.86 6.86 6.85 6.87 6.89 6.82 6.78 6.82 6.82 6.88 6.92 6.94 6.96 6.98 7.02 7.05 7.07 7.09 7.09 7.11 7.11 7.13 7.13 7.13 7.13 6.93 6.93 6.95 6.97 7.01 7.03 7.05 6.94 6.52 6.40 6.46 6.54 6.62 6.66 6.76 6.79 6.83 6.73 6.69 6.73 6.77 6.81 6.83 6.87 6.91 6.93 6.95 6.95 6.95 6.87 6.85 6.85 6.89 6.91 6.95 6.93 6.93 6.95 6.99 6.99 6.75 6.76 6.12 6.18 5.86 5.90 5.71 5.71 5.77 5.93 5.99 6.14 6.24 6.34 6.42 6.50 6.57 6.65 6.65 6.71 6.75 6.78 6.76 6.70 6.60 6.64 6.71 6.77 6.79 6.81 6.85 6.86 6.78 6.64 5.22 3.64 4.10 4.46 4.86 —— 6.23 \f I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 3 ONDJFMAMJJA 1995 ONDJFMAMJJASONDJFMAMJJAS 1996 1997 WATER YEAR 508 GROUND-WATER LEVELS RIO HUMACAO TO RIO SECO BASINS 175858066100200. Local number, 6. LOCATION.—Lat 17°58'58", long 66°10'02", Hydrologic Unit 21010004, 4.23 mi northeast of Central Aguirre Church, 4.08 mi northeast of Colegio del Perpetuo Socorro Church, and 1.77 mi northwest of Hwy 3 km 144.2. Owner: Doctor Bruno, Name: Juana 5. AQUIFER.—Alluvium of Quaternary Age. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 16 in (0.41 m). Depth 173 ft (52.74 m) reported, 110 ft (33.54 m) measured. INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 127 ft (38.7 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 3.00 ft (0.91 m) above land-surface datum. After Aug. 7, 1981, top of 16 in (0.41 m) casing, 1.55 ft (0.47 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—November 1960 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 26.20 ft (7.99 m) below land-surface datum, Dec. 10, 1979; lowest water level recorded, 65.95 ft (20.10 m) below land-surface datum, June 2, 1968. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY MEAN OCT NOV DEC JAN APR MAY JUN JUL AUG 6 7 8 9 10 46.17 45.83 45.51 45.25 45.11 46.87 46.98 47.08 47.18 47.27 49.34 49.48 49.56 49.64 49.72 52.25 52.36 52.46 52.57 52.66 45.78 47.75 50.28 53.18 54.69 56.21 57.93 59.05 61.14 61.63 61.22 WTR YR 1997 MEAN 55.91 HIGHEST 44.98 OCT. 13, 1996 LOWEST 62.37 JULY 14, 15, 16, SEPT. 30, 1997 SEP 1 2 3 4 5 47.94 47.64 47.26 46.90 46.54 46.40 46.48 46.58 46.67 46.77 49.01 49.08 49.16 49.24 49.32 51.79 51.89 51.98 52.07 52.17 54.37 54.19 53.92 53.67 53.61 55.19 55.15 55.18 55.24 55.33 57.47 57.55 57.60 57.64 57.64 58.33 58.38 58.46 58.53 58.60 60.11 60.18 60.25 60.32 60.39 62.10 62.14 62.17 62.19 62.21 60.60 60.67 60.74 60.82 60.91 61.72 61.73 61.76 61.81 61.85 55.40 55.47 55.53 55.58 55.64 57.65 57.67 57.71 57.77 57.83 58.68 58.76 58.81 58.78 58.67 60.47 60.54 60.61 60.68 60.75 62.23 62.25 62.27 62.29 62.31 60.98 61.04 61.09 61.14 61.20 61.89 61.85 61.66 61.45 61.35 11 12 13 14 15 45.04 45.00 44.99 45.00 45.04 47.40 47.50 47.60 47.68 47.77 49.80 49.90 49.98 50.07 50.15 52.75 52.83 52.91 52.98 53.07 —— 54.19 54.30 54.40 54.50 55.72 55.80 55.88 55.95 56.07 57.89 57.92 57.94 57.95 57.99 58.59 58.56 58.59 58.65 58.73 60.83 60.91 60.98 61.06 61.13 62.33 62.34 62.35 62.36 62.37 61.26 61.33 61.39 61.35 61.26 61.31 61.33 61.37 61.43 61.50 16 17 18 19 20 45.09 45.14 45.20 45.27 45.34 47.86 47.94 48.01 48.09 48.18 50.23 50.32 50.41 50.51 50.61 53.16 53.26 53.35 53.45 53.54 54.59 54.68 54.79 54.88 54.98 56.16 56.25 56.34 56.44 56.54 58.03 58.04 58.03 58.02 58.02 58.81 58.88 58.97 59.06 59.15 61.20 61.27 61.35 61.42 61.49 62.35 62.26 62.08 61.86 61.57 61.18 61.11 61.07 61.07 61.11 61.57 61.64 61.71 61.78 61.85 21 22 23 24 25 45.41 45.48 45.56 45.63 45.72 48.26 48.34 48.42 48.50 48.58 50.71 50.80 50.89 50.99 51.10 53.65 53.73 53.83 53.92 54.01 55.09 55.18 55.25 55.31 55.34 56.64 56.74 56.84 56.93 57.03 58.03 58.05 58.08 58.12 58.14 59.25 59.36 59.46 59.55 59.63 61.56 61.63 61.69 61.75 61.83 61.22 60.92 60.71 60.59 60.50 61.16 61.24 61.31 61.38 61.46 61.91 61.97 62.03 62.08 62.14 26 27 28 29 30 31 45.82 45.90 46.00 46.08 46.18 46.29 48.65 48.72 48.79 48.86 48.94 —— 51.20 51.30 51.40 51.50 51.60 51.69 54.10 54.19 54.30 54.38 54.46 54.47 55.37 55.35 55.27 —— —— —— 57.10 57.17 57.21 57.26 57.32 57.39 58.15 58.17 58.20 58.23 58.27 —— 59.70 59.77 59.84 59.91 59.97 60.04 61.89 61.94 61.99 62.04 62.07 —— 60.42 60.39 60.40 60.43 60.48 60.54 61.54 61.61 61.69 61.75 61.77 61.73 62.19 62.24 62.28 62.32 62.35 —— 61.80 40 50 "60 70 i i i i i i i i i i i i i i i i i i i i i i J_ i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO HUMACAO TO RIO SECO BASINS 509 180415065513900. Local number, 96. LOCATION.--Lat 18004'15", long 65°51'39", Hydrologic Unit 21010005, 2.44 mi northwest of Escuela Eugenic Maria de Hostos 4.67 mi southwest of Escuela Segunda Unidad Luciano, and 3.93 mi southwest of Escuela Asuncion Lopez. Owner: P.R. Aqueduct and Sewer Authority, Name: US6S TH-2 or Yabucoa 7. AQUIFER.—Alluvium of Quaternary Age. WELL CHARACTERISTICS.—Drilled observation water-table well, diameter 16 in (0.41 m), cased 0-10 ft (0-3.05 m), diameter 6 in (0.15 m), cased about 0-183 ft (0-55.79 m), perforated 56-81 ft (17.07-24.70 m), 102-123 ft (31.10-37.50 m), 144-181 ft (43.90-55.18 m). Depth 181 ft (55.18 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 25 ft (7.62 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 4.00 ft (1.22 m) above land-surface. REMARKS.--Recording observation well. PERIOD OF RECORD.--April 25, 1978 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 13.10 ft (3.99 m) below land-surface datum, Dec. 2, 1987; lowest water level recorded, 28.29 ft (8.62 m) below land-surface datum, Sept. 20, 1980. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN MAY JUN JUL AU6 MEAN 16.06 17.07 17.41 17.99 18.49 19.23 20.76 21.04 21.31 WTR YR 1997 MEAN 19.41 HIGHEST 15.46 OCT. 1, 1996 LOWEST 21.72 JULY 9, 10, 1997 21.31 21.02 SEP 1 2 3 4 5 15.47 15.64 15.70 15.61 15.61 17.34 17.34 17.33 17.35 17.45 16.62 16.72 17.10 17.15 17.28 17.90 17.83 17.78 17.78 17.78 18.39 18.46 18.47 18.47 18.48 18.69 18.93 19.15 19.32 19.48 20.36 20.40 20.19 20.27 20.34 20.76 20.98 21.29 21.47 21.50 21.38 21.49 21.53 21.56 21.51 21.47 21.46 21.47 21.49 21.56 20.85 20.80 21.03 21.05 21.04 21.08 21.08 21.15 21.22 21.18 6 7 8 9 10 15.63 15.64 15.68 15.73 15.77 17.49 17.48 17.44 17.50 17.46 17.30 17.30 17.30 17.31 17.36 17.82 17.81 17.82 17.78 17.72 18.48 18.52 18.56 18.57 18.60 19.43 18.98 18.52 18.28 18.28 20.46 20.55 20.61 20.68 20.73 21.40 21.33 21.40 21.06 20.78 21.36 21.29 21.20 21.19 21.17 21.63 21.64 21.65 21.68 21.71 20.98 21.03 21.00 21.10 21.15 21.20 21.20 21.19 21.27 21.28 11 12 13 14 15 15.79 15.80 15.74 15.78 15.85 17.50 17.43 17.33 17.34 17.17 17.38 17.38 17.47 17.48 17.48 17.77 17.80 17.80 17.87 17.99 18.60 18.58 18.59 18.53 18.39 18.08 18.16 18.29 18.41 18.65 20.80 20.86 20.87 20.90 20.93 20.71 20.68 20.83 21.01 21.08 21.19 21.29 21.36 21.43 21.45 21.62 21.51 21.40 21.37 21.37 21.20 21.21 21.06 20.95 20.99 21.40 21.48 21.50 21.47 21.44 16 17 18 19 20 15.98 16.10 16.14 16.17 16.20 17.06 16.97 17.01 16.85 16.87 17.49 17.50 17.39 17.36 17.38 18.01 17.97 17.95 17.95 17.95 18.37 18.41 18.45 18.56 18.66 18.79 18.90 19.13 19.37 19.52 20.94 20.94 20.96 20.97 20.99 21.19 20.87 20.99 21.10 20.95 21.45 21.35 21.08 20.83 20.96 21.39 21.37 21.37 21.43 21.50 20.93 20.97 20.91 20.98 21.05 21.44 21.46 21.51 21.52 21.52 21 22 23 24 25 16.10 15.83 15.84 15.98 16.26 16.77 16.67 16.59 16.60 16.64 17.43 17.43 17.48 17.53 17.52 17.98 18.02 18.10 18.19 18.28 18.70 18.69 18.62 18.37 18.22 19.62 19.70 19.81 19.86 19.89 21.03 21.05 21.07 21.15 21.15 20.89 20.81 20.87 20.88 20.94 21.03 21.12 21.26 21.24 21.29 21.07 21.18 21.11 21.05 20.95 21.11 21.07 21.00 21.01 20.99 21.50 21.43 21.40 21.37 21.39 26 27 28 29 30 31 16.46 16.68 16.94 17.17 17.27 17.34 16.61 16.59 16.64 16.67 16.67 17.57 17.74 17.80 17.89 17.82 17.90 18.29 18.29 18.32 18.35 18.35 18.35 18.20 18.31 18.48 ___ ___ —— 20.04 20.07 20.08 20.14 20.26 20.35 20.79 20.68 20.68 20.79 20.69 —— 21.01 21.10 21.05 21.00 20.99 21.23 21.37 21.45 21.45 21.46 21.47 20.94 20.94 20.68 20.74 20.87 20.86 20.98 21.01 21.04 20.94 21.01 21.05 21.13 20.94 20.88 20.86 20.75 —— 21.27 10 15 25 \S i i i i i i i i i i i I I I I I I I I I I 1 I I I I I I I I I I I i i i i i i i i i i i i i i i i i i i i i i ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 510 GROUND-WATER LEVELS RIO HUMACAO TO RIO SECO BASINS 175719066085500. Local number P-13 LOCATION.--Lat 17°57'19", long 66°08'55", Hydrologic Unit 2101004, 1.0 mi east of the intersection of Hwy 3 with Hwy 707, 0.28 mi south of Hwy 3, and 0.25 mi northwest of the Philips Petroleum oil refinery* Owner: Phillips Petroleum, Name: Phillips Petroleum No. 13. AQUIFER.--Alluvium. WELL CHARACTERISTICS.—Drilled unused water-table well. INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.--Elevation of land-surface datum is about 33.0 ft (10.1 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.21 ft (0.98 m) above land-surface datum. REMARKS.--Recording observation well. Sampling performed on June 7, 1996 by private company. PERIOD OF RECORD.--September 25, 1991 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 14.47 ft (4.41 m) below land-surface datum. Mar. 22, 24, 1993; lowest water level recorded, 28.88 ft (8.80 m) below land-surface datum, Sept. 22, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY NOV DEC MAR MAY JUN AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 17.12 16.94 17.13 17.32 17.30 17.21 17.09 17.14 17.20 17.39 17.45 17.55 17.52 17.56 17.58 17.55 17.82 17.93 17.98 18.02 18.00 18.22 18.27 18.30 18.43 18.44 18.46 18.29 18.49 18.57 18.59 18.52 18.45 18.39 18.42 18.55 18.63 18.71 18.63 18.67 18.75 18.83 18.95 18.91 18.92 19.00 18.99 19.00 18.98 19.01 19.00 19.19 19.16 19.35 19.41 19.38 19.41 19.55 19.61 19.72 19.74 —— 19.75 19.81 19.85 20.01 20.10 20.21 20.17 20.18 20.21 20.23 20.20 20.20 20.09 20.20 20.30 20.36 20.27 20.40 20.57 20.67 20.79 20.85 20.96 21.09 21.15 21.22 21.39 21.43 21.52 21.56 21.60 21.65 21.71 21.79 21.91 21.95 22.02 22.08 22.18 22.22 22.28 22.37 22.08 22.33 22.35 22.39 22.45 22.51 22.53 22.56 22.56 22.68 22.68 22.70 22.80 22.90 22.90 22.96 23.05 23.12 23.14 23.23 23.18 23.13 23.16 23.18 23.24 23.25 23.21 23.17 23.17 23.24 23.27 23.23 23.20 23.18 23.17 23.20 23.32 23.43 23.53 23.58 23.64 23.64 23.71 23.63 23.64 23.65 23.68 23.72 ___ 23.76 23.77 23.81 23.88 23.78 23.62 23.57 23.55 23.55 23.56 23.61 23.59 23.48 23.40 23.37 23.37 23.38 23.37 23.32 23.28 23.34 23.35 23.40 23.47 23.59 23.69 23.72 23.75 23.79 23.85 23.94 24.00 24.13 24.21 24.26 24.31 24.36 24.39 24.42 24.46 24.49 24.30 24.40 24.44 24.41 24.43 24.55 24.56 24.61 24.65 24.73 24.73 24.70 24.77 24.82 24.81 24.92 24.99 25.05 25.05 24.96 ___ 24.93 24.98 24.95 24.95 24.99 25.08 25.15 25.25 25.31 25.36 25.39 25.43 25.48 25.65 25.97 25.94 25.98 26.03 26.14 26.16 26.14 26.15 26.25 26.33 26.39 26.39 26.45 26.47 26.54 26.56 26.52 26.73 26.58 26.59 26.76 26.63 26.82 26.90 26.84 26.84 26.92 26.94 26.83 26.80 26.62 26.60 26.70 26.91 27.02 27.08 27.08 27.12 27.17 27.25 27.31 27.34 27.43 27.51 27.50 27.48 27.55 ___ 27.61 27.76 27.78 27.86 27.93 28.00 28.06 28.07 28.06 28.13 28.17 28.17 28.22 28.25 28.27 28.36 28.42 28.46 28.50 28.53 28.55 28.57 28.57 28.51 28.62 28.65 28.69 28.69 28.74 28.78 28.80 28.83 28.86 28.89 28.91 28.86 28.85 28.94 28.97 29.00 29.03 29.04 29.04 29.03 29.02 29.02 29.02 28.92 28.85 28.94 28.99 29.03 29.04 29.03 29.02 29.13 29.25 29.39 29.34 29.36 29.46 29.53 29.49 29.53 29.61 29.60 29.59 29.64 29.61 29.62 29.68 29.59 29.62 29.52 29.33 29.31 29.30 29.43 29.34 29.19 29.17 29.10 28.97 28.86 28.96 28.91 29.08 29.03 29.07 28.86 28.74 28.81 —— MEAN 17.77 18.99 20.56 22.45 23.37 23.58 24.56 25.78 26.99 WTR YR 1997 MEAN 24.23 HIGHEST 16.92 OCT. 2, 1996 LOWEST 29.68 SEPT. 9, 1997 28.32 29.05 29.29 10 20 30 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 511 175829066232200. Local number, 87. LOCATION.—Lat 17°58'29", long 66°23'22*, Hydrologic Unit 21010004, 1.10 mi northeast of Santa Isabel plaza, 3.69 mi southeast of Escuela Playita Cortada, and 1.07 mi southeast of Estacion Experimental Santa Isabel. Owner: Francisco Alomar, Name: Alomar 1. AQUIFER.—Alluvium of Quaternary Age. HELL CHARACTERISTICS.--Drilled unused water-table well, diameter 20 in (0.51 m), iron cased. Depth 112 ft (34.14 in) INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 35.32 ft (10.77 m) above mean sea level. Measuring point: Bottom of clean-out shelter door, 2.50 ft (0.76 m) above land-surface datum. Prior to August 1981, top of recorder shelter floor, 4.00 ft (1.22 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—April 1967 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 8.45 ft (2.58 m) below land-surface datum, Dec. 10, 1970; lowest water level recorded, 49.18 ft (14.99 m) below land-surface datum, July 27, 1974. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN FEB MAR JUN JUL AUO 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 42.88 42.94 42.82 43.08 42.81 42.58 42.54 42.53 42.69 42.73 42.59 42.86 42.78 42.77 42.93 42.80 42.87 42.83 42.85 42.55 42.58 42.86 42.85 42.91 43.07 43.05 42.91 42.81 43.06 42.81 42.94 42.83 42.55 42.47 42.55 42.74 42.95 43.04 43.13 43.28 43.00 42.81 42.55 42.33 42.30 42.34 42.45 42.45 42.25 42.11 41.95 41.86 41.75 41.69 41.56 41.52 41.63 41.58 41.79 41.71 41.86 —— 41.73 41.63 41.89 41.96 42.16 42.29 42.28 42.18 41.97 42.26 42.25 42.41 42.43 42.54 42.36 42.16 42.34 42.41 42.45 42.54 42.42 42.28 42.47 42.52 42.46 42.28 42.39 42.56 42.37 42.39 42.42 42.41 42.33 42.56 42.72 42.49 42.50 42.43 42.61 42.82 42.84 42.58 42.33 42.30 42.53 42.53 42.49 —— —— —— —— ___ —— —— —— —— ___ —— —— —— —— —— MEAN 42.82 42.30 42.28 42.53 42.97 43.33 43.86 44.10 44.25 44.52 WTR YR 1997 MEAN 43.67 HIGHEST 41.47 NOV. 25, 1996 LOWEST 45.79 SEPT. 25, 26, 1997 44.71 SEP —— —— —— — — -_- —— —— —— — ___ —— —— —— — -__ —— —— —— — -__ —— —— —— 42.95 42.94 42.94 43.06 —— —— —— 43.17 43.03 42.92 43.04 43.07 43.10 43.14 43.20 43.19 43.00 43.23 43.29 43.44 43.39 43.36 43.29 43.33 43.71 43.33 43.51 43.54 43.56 43.47 43.36 43.48 43.53 43.67 43.60 43.41 43.34 43.49 43.72 43.69 43.82 43.82 43.77 43.61 43.57 43.52 43.55 43.71 43.68 43.63 43.68 43.78 43.82 43.89 44.00 43.95 43.98 43.89 43.88 44.03 44.04 44.10 44.11 44.06 44.03 44.06 44.16 44.19 —— 44.17 44.17 44.18 44.17 44.19 44.19 44.07 44.16 44.23 44.14 43.96 43.89 43.90 44.13 44.17 44.20 44.09 43.92 44.01 44.04 43.96 44.03 44.06 44.07 44.07 44.04 44.08 44.11 44.18 44.19 44.19 44.08 44.09 44.17 44.08 44.13 44.19 44.21 44.07 44.17 44.18 44.22 44.36 44.29 44.25 44.08 44.17 44.28 44.34 44.40 44.32 44.33 44.28 44.19 44.32 44.31 44.45 44.49 44.47 44.32 44.30 —— 44.45 44.55 44.53 44.61 44.59 44.47 44.55 44.72 44.66 44.69 44.73 44.76 44.61 44.66 44.76 44.84 44.87 44.84 44.89 44.73 44.45 44.29 44.17 44.11 44.12 44.06 44.09 44.19 44.31 44.36 44.48 44.55 44.42 44.39 44.38 44.51 ___ —— —— 44.54 44.54 44.58 44.65 44.54 44.49 44.53 44.53 44.72 44.77 44.82 44.76 44.77 44.88 45.06 45.17 45.09 44.88 44.73 44.76 44.85 44.89 44.96 45.17 45.30 45.21 45.09 45.13 45.20 45.32 45.35 45.31 45.31 45.50 45.45 45.45 45.52 45.38 45.14 45.06 45.13 45.24 45.35 45.22 45.36 45.40 45.47 45.59 45.62 45.33 45.17 45.08 45.17 —— 45.30 40 tt • S ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 512 GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 180002066132200. Local number, HW-TW-01. LOCATION.—Lat 18°00'02", long 66°13'22", Hydrologic Unit 21010004, 3.30 mi southwest of Cerro Guaraco, 8.71 mi southwest of Cayey plaza, and 2.80 mi southeast of Hwy 1 km 82.3 on Rabo del Buey. Owner: U.S. Geological Survey, HRD, Name: HW-TW-01. AQUIFER.—Fractured, volcanic rock, water-table aquifer. WELL CHARACTERISTICS.—Drilled observation well, diameter 7 in (0.18 m), 0-39.5 ft (0-12.0 m), cased 4 in (0.10 m), 0-38.2 ft (0-11.6 m), screened 32-37 ft (9.75-11.3 m). Depth 39.5 ft (12.0 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 190 ft (58.0 m) above mean sea level. Measuring point: Hole on side of 4 in (0.10 m) casing, 2.84 ft (0.87 m) above land-surface datum. Prior October 13, 1988, top of shelter floor, 3.48 ft (1.06 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.—April 14, 1988 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 19.34 ft (5.89 m) below land-surface datum, Dec. 18, 1990 to Jan. 26, 1991; lowest water level recorded, 37.45 ft (11.42 m) below land-surface datum, Sept. 10, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT DEC JAN FEB MAR APR MAY JUN 16 17 18 19 20 30.85 30.81 30.76 30.73 30.70 29.44 29.37 29.32 29.28 29.20 27.96 27.92 27.90 27.88 27.83 27.07 27.05 27.02 26.99 26.98 26.50 26.48 26.48 26.46 26.44 26.26 26.25 26.25 26.24 26.24 26.05 26.05 26.04 26.04 26.04 26.26 26.26 26.26 26.26 26.27 26.57 26.59 26.61 26.63 26.64 21 22 23 24 25 30.67 30.61 30.56 30.52 30.48 29.14 29.09 29.02 28.98 28.91 27.79 27.75 27.70 27.68 27.65 26.95 26.91 26.90 26.88 26.87 26.43 26.42 26.42 26.41 26.40 26.23 26.23 26.22 26.22 26.21 26.04 26.04 26.04 26.04 26.04 26.28 26.29 26.32 26.33 26.34 26.66 26.68 26.70 26.72 26.74 26 27 28 29 30 31 30.45 30.41 30.35 30.30 30.26 30.23 28.84 28.79 28.75 28.70 28.64 —— 27.63 27.60 27.56 27.53 27.50 27.47 26.85 26.82 26.81 26.77 26.77 26.75 26.40 26.40 26.39 —— —— —— 26.21 26.21 26.20 26.19 26.18 26.17 26.05 26.06 26.09 26.12 26.14 —— 26.35 26.36 26.37 26.39 26.40 26.41 26.76 26.79 26.82 26.85 26.89 —— MEAN 30.88 29.44 27.98 27.07 26.53 26.27 26.08 26.27 26.57 WTR YR 1997 MEAN 27.50 HIGHEST 26.04 APR. 18-25, 1997 LOWEST 31.83 OCT. 1, 1996 JUL 1 2 3 4 5 31.78 31.68 31.57 31.49 31.40 30.18 30.14 30.10 30.05 30.02 28.58 28.52 28.47 28.43 28.38 27.44 27.41 27.38 27.37 27.33 26.72 26.70 26.68 26.66 26.65 26.38 26.37 26.36 26.35 26.35 26.17 26.16 26.16 26.15 26.14 26.14 26.16 26.17 26.18 26.19 26.41 26.41 26.41 26.41 26.41 26.90 26.91 26.93 26.94 26.97 6 7 8 9 10 31.31 31.23 31.16 31.13 31.08 29.96 29.91 29.86 29.80 29.76 28.33 28.28 28.24 28.22 28.19 27.29 27.28 27.26 27.24 27.22 26.64 26.63 26.62 26.61 26.60 26.34 26.34 26.33 26.31 26.27 26.13 26.11 26.10 26.09 26.08 26.20 26.22 26.23 26.24 26.25 26.41 26.41 26.41 26.41 26.42 27.00 27.03 27.05 27.06 27.08 11 12 13 14 15 31.05 31.01 30.96 30.92 30.88 29.72 29.67 29.61 29.55 29.50 28.14 28.12 28.08 28.03 28.00 27.20 27.17 27.14 27.10 27.09 26.58 26.56 26.55 26.54 26.52 26.27 26.27 26.27 26.27 26.27 26.08 26.08 26.06 26.06 26.06 26.26 26.26 26.26 26.26 26.26 26.44 26.46 26.48 26.51 26.56 27.10 27.11 27.26 —— —— 27.03 AUG SEP 28.08 28.08 28.09 28.13 28.16 28.20 28.21 28.22 28.22 28.23 28.24 28.26 28.27 28.29 28.30 28.33 28.41 28.41 28.41 28.41 28.41 28.26 25 30 35 40 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 573 180001066122002 Local number, HW-TW-03C. LOCATION.—Lat 18°00'01", long 66C12'20", Hydrologic Unit 21010004, 8.27 mi southwest of Cayey plaza, 2.38 mi southwest of Cerro Garau, and 3.45 mi southeast of Hwy 1 km 82.3. Owner: U.S. Geological Survey, WRD, Name: HW-TW-03C. AQUIFER.—Fractured, volcanic rock, water-table aquifer. WELL CHARACTERISTICS.—Drilled observation well, diameter 7 in (0.18 m), 0-220 ft (0-67.0 m), cased 4 in (0.10 m), 0-150 ft (0-45.7 m), open hole 150-220 ft (45.7-67.0 m). Depth 220 ft (67.0 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is 270 ft (82.6 m) above mean sea level. Measuring point: Top of shelter floor, 3.32 ft (1.01 m) above land-surface datum. REMARKS.—Recording observation well. Aquifer test performed during May 24, 25, 26, 1989. PERIOD OF RECORD.—December 15, 1988 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 26.29 ft (8.01 m) below land-surface datum, Dec. 15, 1990; lowest water level recorded, 59.82 ft (18.23 m) below land-surface datum, Mar. 1, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV JAN MAR APR MAY JUN JUL AUG MEAN 55.25 51.84 49.76 49.73 50.25 50.78 WTR YR 1997 MEAN 51.77 HIGHEST 49.50 DEC. 24, 25, 1996 51.28 51.73 52.15 52.60 53.09 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 —— —— —— —— —— —— 55.92 55.84 55.78 55.74 55.69 55.65 55.63 55.59 55.53 55.48 55.43 55.40 55.39 55.33 55.25 55.15 55.05 54.92 54.76 54.56 54.39 54.23 54.08 53.92 53.75 53.60 53.46 53.33 53.15 52.98 52.82 52.67 52.52 52.41 52.25 52.07 51.86 51.70 51.59 51.47 51.34 51.25 51.15 51.05 50.92 50.82 50.73 50.65 50.53 50.43 50.34 50.27 50.22 —— 50.17 50.11 50.03 50.02 50.02 50.00 49.97 49.94 49.93 49.89 49.83 49.78 49.72 49.65 49.61 49.59 49.58 49.62 49.66 49.66 49.68 49.67 49.66 49.63 49.63 49.62 49.60 49.57 49.56 49.55 49.55 49.55 49.56 49.57 49.60 49.63 49.67 49.69 49.69 49.69 49.65 49.59 49.58 49.58 49.63 49.66 49.67 49.70 49.73 49.77 49.81 49.83 49.84 49.85 49.87 49.88 49.87 49.87 49.88 49.88 49.91 49.92 49.92 49.94 49.99 50.02 50.08 50.12 50.15 50.17 50.15 50.13 50.12 50.13 50.17 50.21 50.24 50.26 50.32 50.36 50.38 50.39 50.42 50.45 50.47 50.46 50.43 50.45 50.47 50.47 —— —— —— 50.49 50.49 50.53 50.59 50.64 50.67 50.71 50.74 50.76 50.72 50.67 50.65 50.67 50.68 50.69 50.70 50.73 50.78 50.81 50.84 50.88 50.92 50.96 50.98 51.00 r 51.01 50.98 50.98 50.95 50.96 50.97 50.99 51.04 51.08 51.15 51.21 51.24 51.24 51.24 51.23 51.16 51.17 51.17 51.19 51.22 51.25 51.27 51.29 51.32 51.35 51.39 51.41 51.42 51.42 51.42 51.43 51.42 51.43 51.46 51.46 51.48 —— 51.51 51.58 51.63 51.66 51.65 51.67 51.67 51.64 51.62 51.59 51.61 51.62 51.65 51.68 51.68 51.71 51.75 51.78 51.81 51.82 51.83 51.84 51.86 51.84 51.82 51.81 51.81 51.83 51.83 51.89 51.93 51.97 52.00 51.99 51.98 51.99 52.00 51.98 51.98 52.00 52.02 52.04 52.07 52.10 52.14 52.17 52.18 52.21 52.25 52.26 52.27 52.26 52.26 52.24 52.22 52.22 52.25 52.27 52.31 52.37 52.40 —— 52.43 52.45 52.48 52.48 52.49 52.49 52.48 52.46 52.46 52.47 52.50 52.52 52.52 52.57 52.62 52.64 52.67 52.67 52.70 52.70 52.68 52.65 52.64 52.63 52.64 52.65 52.69 52.74 52.80 52.84 52.87 52.92 52.92 52.93 52.91 52.93 52.93 52.91 52.91 52.93 52.96 52.97 53.02 53.05 53.10 53.13 53.17 53.20 53.19 53.19 53.17 53.16 53.13 53.12 53.14 53.16 53.20 53.24 53.28 53.31 53.31 53.34 53.35 53.39 53.38 53.38 53.38 53.37 53.35 53.38 53.45 53.48 53.55 53.60 53.62 53.66 53.66 53.68 53.65 53.64 53.63 53.61 53.62 53.66 53.67 53.70 53.76 53.77 53.76 53.76 53.78 53.80 —— 53.58 LOWEST 55.92 OCT. 9, 1996 60 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 514 GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 175947066130601 Local number, HW-TW-05B. LOCATION.--Lat 17°59'47", long 66°13'06", Hydrologic Unit 21010004, 2.70 mi northeast of Central Aguirre Church, 6.16 mi northwest of Escuela de Guayama, and 2.70 mi northeast of Hwy 3 km 151.3. Owner: U.S. Geological Survey, WRD, Name: HW-TW-05B. AQUIFER.--Fractured, volcanic rock, water-table aquifer. WELL CHARACTERISTICS.—Drilled observation well, diameter 7 in (0.18 m), 0-52 ft (0-15.8 m), cased 4 in (0.10 m), 0-51 ft (0-15.5 m), screened 41-46 ft (12.5-14.0 m). Depth 52 ft (15.8 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.--Elevation of land-surface datum is 145 ft (44.2 m) above mean sea level. Measuring point: Hole on side of casing, 3.00 ft (0.91 m) above land-surface datum. Prior October 13, 1989 top of shelter floor, 3.47 ft (1.06 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.--April 13, 1988 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 7.89 ft (2.40 m) below land-surface datum, May 26, 1992; lowest water level recorded, 28.55 ft (8.70 m) below land-surface datum, Aug. 14, 15, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER TEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN MAR MAY JUN JUL AUG MEAN 16.97 17.37 18.08 19.22 20.35 WTR YR 1997 MEAN 20.93 HIGHEST 16.89 OCT. 9-12, 21.30 21.76 22.21 22.51 23.17 1996 LOWEST 24.61 SEPT. 25, 26, 1997 23.81 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 16.95 16.93 16.90 16.90 16.91 16.90 16.90 16.90 16.89 16.90 16.89 16.89 16.90 16.90 16.93 16.94 16.95 16.96 16.97 16.97 16.98 16.98 17.01 17.02 17.07 17.08 17.12 17.12 17.13 17.13 17.15 17.17 17.18 17.22 17.27 17.29 17.33 17.34 17.36 17.36 17.38 17.39 17.40 17.38 17.38 17.38 17.39 17.42 17.42 17.42 17.43 17.43 17.40 17.39 17.39 17.39 17.39 17.41 17.44 17.46 17.51 ___ 17.53 17.57 17.61 17.65 17.73 17.74 17.77 17.81 17.86 17.90 17.90 17.93 17.97 17.99 18.03 18.05 18.06 18.10 18.18 18.21 18.23 18.28 18.33 18.36 18.39 18.43 18.48 18.51 18.55 18.59 18.62 18.67 18.70 18.74 18.78 18.81 18.89 18.94 18.98 19.00 19.02 19.07 19.07 19.09 19.20 19.20 19.22 19.23 19.29 19.33 19.38 19.42 19.43 19.44 19.47 19.50 19.55 19.59 19.64 19.71 19.74 19.78 19.82 19.83 19.90 19.93 19.98 20.02 20.05 20.11 20.13 20.16 20.19 20.23 20.28 20.35 20.37 20.42 20.48 20.52 20.55 20.59 20.64 20.66 20.69 20.73 20.76 20.80 20.86 20.89 —— 20.92 20.94 20.97 21.00 21.06 21.07 21.11 21.13 21.16 21.17 21.20 21.21 21.24 21.27 21.30 21.32 21.34 21.37 21.37 21.40 21.43 21.46 21.48 21.51 21.51 21.54 21.55 21.56 21.57 21.57 21.58 21.58 21.59 21.59 21.59 21.59 21.59 21.60 21.61 21.61 21.65 21.67 21.70 21.71 21.72 21.74 21.76 21.77 21.78 21.79 21.80 21.84 21.85 21.86 21.88 21.91 21.95 21.97 22.00 22.01 22.02 —— 22.03 22.04 22.06 22.08 22.10 22.12 22.14 22.18 22.18 22.19 22.19 22.19 22.19 22.19 22.20 22.21 22.22 22.23 22.24 22.25 22.27 22.27 22.29 22.30 22.31 22.31 22.31 22.32 22.33 22.34 22.34 22.35 22.36 22.37 22.37 22.36 22.35 22.35 22.35 22.35 22.36 22.42 22.42 22.44 22.45 22.46 22.48 22.50 22.52 22.54 22.55 22.57 22.63 22.65 22.66 22.69 22.72 22.75 22.78 22.81 22.83 ___ 22.85 22.88 22.92 22.94 22.98 23.00 23.02 23.04 23.06 23.08 23.11 23.12 23.14 23.17 23.19 23.21 23.23 23.24 23.26 23.29 23.30 23.30 23.30 23.30 23.30 23.30 23.30 23.30 23.32 23.33 23.37 23.40 23.41 23.44 23.46 23.50 23.54 23.58 23.62 23.65 23.69 23.70 23.75 23.76 23.78 23.82 23.86 23.89 23.91 23.93 23.97 24.01 24.04 24.04 24.04 24.04 24.04 24.04 24.04 24.04 24.05 24.06 24.08 24.10 24.13 24.14 24.18 24.20 24.22 24.26 24.30 24.31 24.34 24.39 24.40 24.43 24.46 24.46 24.46 24.46 24.47 24.49 24.52 24.53 24.54 24.55 24.59 24.61 24.56 24.50 24.46 24.44 —— 24.39 10 20 30 I I I I I I I I I I I I I I I I I I £ ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO SALINAS TO RIO JACAOUAS BASINS 575 175957066123400 Local number, HW-TW-13. LOCATION.--Lat 17°59'57", long 66°12'34", Hydrologic Unit 21010004, 3.11 northeast of Central Aguirre Church, 5.76 ml northwest of Escuela de Ouayama, and 2.03 ml northeast of Hwy 3 km 151.3. Owner: U.S. Geological Survey, NRD, Name: HW-TW-13. AQUIFER.—Fractured, volcanic rock, water-table aquifer. WELL CHARACTERISTICS.--Drilled observation well, diameter 7 in (0.18 m), 0-69 ft (0-21.0 m), cased 4 In (0.10 m), 0-69 ft (0-21.0 m), screened 4.0-69 ft (1.22-21.0 m). Depth 69 ft (21.0 m). INSTRUMENTATION.—Digital water level recorder—60-mlnute punch. DATUM.—Elevation of land-surface datum is 203 ft (61.9 m) above mean sea level. Measuring point: Hole on side of casing, 2.33 ft (0.71 m) above land-surface datum. Prior October 14, 1988, top of shelter floor, 3.47 ft (1.06 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.--Apr11 14, 1988 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 34.39 ft (10.5 m) below land-surface datum, Oct. 27, 1990; lowest water level recorded, 48.10 ft (14.7 m) below land-surface datum, Nov. 6, 7, 1992. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION Date Oct. 9 Nov. 13 Dec. 10 Water level 47.14 47.67 47.56 Date Jan. 14 Feb. 12 water level 47.72 47.82 Mar. 11 Apr. 9 Water level 47.77 47.47 Date May 14 June 11 Water level 47.47 47.47 45.6 45.8 - 48.0 ~ 48.2 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAM 1993 1994 1995 1996 1997 WATER YEAR 516 GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 175903066165000. Local number PG-07 LOCATION.--Lat 17°59'03", long. 66°16'50", Hydrologic Unit 21010004, 0.42 mi north of Hwy 3, 0.60 mi southeast of the intersection of Hwy 1 with Hwy 52, and 1.56 mi northeast of Punta Salinas. Owner: C. Godreau, Name: Pozo Godreau No. 7. AQUIFER.--Alluvium. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 20 in (0.51 m), cased 20 in (0.51 m) 0-120 ft (0-36.6 m), perforated 30-120 ft (9.1-36.6 m). Depth 120 ft (36.6 m). INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 54.0 ft (16.5 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 20 in (0.50 m) casing, 3.63 ft (1.11 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.--September 25, 1991 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 24.62 ft (7.50 m) below land-surface datum, Oct. 18, 1992; lowest water level recorded, 34.87 ft (10.63 m) below land-surface datum, Sept. 3, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV DEC JAN JUN JUL AUG MEAN 31.36 29.45 28.31 28.02 28.05 28.63 29.44 30.45 31.45 32.44 WTR YR 1997 MEAN 30.40 HIGHEST 27.99 JAN. 29 to FEB.12, 1997 LOWEST 34.10 SEPT. 26. 1997 33.27 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32.21 32.16 32.11 32.09 32.03 31.99 31.94 31.88 31.83 31.77 31.72 31.64 31.57 31.51 31.46 31.40 31.33 31.27 31.19 31.13 31.07 31.01 30.94 30.87 30.78 30.71 30.65 30.58 30.52 30.44 30.38 30.32 30.26 30.20 30.14 30.08 30.01 29.94 29.88 29.81 29.75 29.68 29.62 29.55 29.50 29.45 29.39 29.34 29.27 29.22 29.17 29.11 29.06 29.02 28.98 28.90 28.85 28.81 28.78 28.73 28.68 28.64 28.61 28.59 28.58 28.56 28.53 28.47 28.46 28.44 28.40 28.36 28.35 28.33 28.31 28.29 28.27 28.23 28.23 28.23 28.22 28.21 28.20 28.18 28.18 28.17 28.16 28.13 28.11 28.10 28.09 28.07 28.07 28.06 28.06 28.06 28.05 28.04 28.04 28.03 28.02 28.02 28.02 28.02 28.02 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 28.00 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 27.99 28.00 28.00 28.00 28.01 28.01 28.02 28.03 28.04 28.06 28.09 28.13 28.15 28.17 28.21 28.23 28.26 ___ 28.29 28.33 28.34 28.36 28.38 28.40 28.44 28.49 28.50 28.50 28.52 28.55 28.57 28.59 28.60 28.61 28.63 28.65 28.67 28.70 28.73 28.76 28.79 28.82 28.83 28.84 28.86 28.88 28.93 28.95 28.96 28.98 29.01 29.02 29.04 29.10 29.13 29.16 29.19 29.25 29.25 29.27 29.34 29.36 29.38 29.41 29.45 29.48 29.51 29.54 29.58 29.61 29.64 29.68 29.71 29.77 29.80 29.84 29.87 29.90 29.93 —— 29.96 30.00 30.03 30.07 30.10 30.13 30.16 30.20 30.24 30.27 30.30 30.32 30.35 30.38 30.38 30.39 30.42 30.46 30.54 30.58 30.62 30.65 30.69 30.72 30.76 30.79 30.80 30.83 30.87 30.90 30.93 30.96 30.98 31.01 31.06 31.09 31.12 31.16 31.20 —— ___ 31.28 31.31 31.35 31.38 31.41 31.46 31.49 31.52 31.56 31.60 31.64 31.68 31.73 31.77 31.79 31.81 31.86 31.90 31.94 31.98 32.03 32.05 32.09 32.12 32.16 32.20 32.22 32.26 32.26 32.26 32.29 32.33 32.37 32.40 32.44 32.47 32.51 32.55 32.57 32.60 32.63 32.65 32.68 32.71 32.72 32.75 32.78 32.82 32.85 32.91 32.92 32.94 32.96 32.97 32.99 33.02 33.05 33.07 33.09 33.13 33.15 33.22 33.23 33.25 33.27 33.30 33.32 33.35 33.38 33.40 33.42 33.42 33.46 33.47 33.49 33.52 33.55 33.60 33.60 33.61 33.61 33.62 33.73 33.76 33.80 33.82 33.83 33.85 33.87 33.87 33.87 33.89 33.91 33.96 34.02 34.03 34.05 34.06 34.07 34.08 34.09 34.09 34.09 34.09 34.09 34.09 34.09 34.09 34.09 34.09 —— 33.95 20 30 40 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO SALINAS TO RIO JACAOUAS BASINS 517 175943066224800. Local number PS-07 LOCATION.--Lat 17°59'43", long 66°22'48", Hydrologic Unit 2101004, 0.74 mi east of Hwy 153, 1.45 mi northeast of Estaci6n Santa Isabel, and 1.98 mi north of Hwy 1. owner: Luce and Company, Name: Paso Seco No. 7. AQUIFER. —Alluvium. WELL CHARACTERISTICS.--Drilled unused water-table well. Depth 235 ft (71.6 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 89.0 ft (27.1 m) above mean sea level, from topographic map. Measuring point: Side of the casing, 0.80 ft (0.24 m) above land-surface datum. REMARKS.—Recording observation well. Water levels affected by nearby pumping wells. PERIOD OF RECORD.—March 27, 1992 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 81.11 ft (24.72 m) below land-surface datum, Dec. 3, 4, 6, 7, 1992; lowest water level recorded, 101.28 ft (30.87 m) below land-surface datum, Sept. 13, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION Date Oct. 16 Nov. 26 Dec. 16 Jan. 17 Water level 89.47 87.74 86.88 87.09 Date Feb 21 Mar. 27 Apr. 21 Water level 87.13 87.44 87.44 Date May 20 June 17 July 25 Water level 88.08 88.34 89.29 Date Aug. 6 Sept. 12 Sept. 17 Water level 89.47 90.95 91.23 80 82 84 86 88 90 92 94 96 98 100 102 d> I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJA 1993 1994 1995 1996 1997 WATER YEAR 518 GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 180206066135500. Local number, RM # 5. LOCATION.--Lat 18°02'06", long 66°13'55", Hydrologic Unit 21010004, 6.98 mi southwest of Cayey plaza, 0.63 mi east of Hwy 1 km 82.3 on Rabo del Buey, and 1.75 mi southeast of Capilla de Santa Marta. Owner: U.S. Geological Survey, WRD, Name: RM # 5. AQUIFER.--Quaternary alluvium. WELL CHARACTERISTICS.--Drilled observation water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-34 ft (0-10.4 m), screened 24-34 ft (7.32-10.7 m). Depth 34 ft (10.4 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.--Elevation of land-surface datum is 276.35 ft (84.2 m) above mean sea level. Measuring point: Top of shelter floor, 3.28 ft (1.0 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--March 9, 1989 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 5.56 ft (1.69 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 24.24 ft (7.39 m) below land-surface datum, Sept. 20, 1994. WATER LEVEL, IN FEET BELOW LAND- SURFACE DATUM INSTANTANEOUS DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT 11.27 11.29 11.31 11.33 11.34 11.36 11.36 11.37 11.37 11.37 11.37 11.37 11.37 11.39 11.39 11.40 11.40 11.42 11.39 11.39 11.40 11.41 11.43 11.44 11.46 11.49 11.49 11.49 11.50 11.51 11.51 NOV 11.52 11.52 11.54 11.56 11.56 11.56 11.58 11.59 11.60 11.60 11.60 11.53 11.50 11.51 11.54 11.57 11.58 11.54 11.57 11.57 11.57 11.48 11.53 11.55 11.57 11.60 11.62 11.63 11.63 11.64 DEC 11.65 11.65 11.67 11.69 11.70 11.71 11.71 11.73 11.73 11.74 11.72 11.62 11.65 11.67 11.68 11.67 11.70 11.71 11.72 11.72 11.73 11.73 11.73 11.75 11.75 11.75 11.74 11.74 11.75 11.76 11.74 JAN 11.74 11.76 11.77 11.77 11.78 11.78 11.79 11.79 11.79 11.80 11.80 11.80 11.82 11.82 11.82 11.82 11.82 11.82 11.82 11.82 11.82 11.77 11.70 11.73 11.76 11.78 11.79 11.82 11.83 11.84 11.84 FEB 11.84 11.79 11.79 11.80 11.80 11.82 11.82 11.83 11.83 11.83 11.85 11.85 11.85 11.77 11.77 11.80 11.80 11.81 11.82 11.83 11.83 11.83 11.83 11.83 11.82 11.82 11.82 11.82 —— ___ , WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 OBSERVATION AT 1200 MAR 11.82 11.82 11.83 11.84 11.85 11.85 11.85 11.86 11.86 11.87 11.91 11.91 11.91 11.91 11.92 11.93 11.93 11.93 11.91 11.91 11.91 11.91 11.91 11.91 11.91 11.92 11.94 11.95 11.95 11.96 11.98 APR 12.01 12.03 12.01 12.02 12.00 11.99 11.99 11.99 11.99 12.10 12.19 12.26 12.35 12.43 12.55 12.64 12.73 12.81 12.91 13.02 13.12 13.22 13.31 13.45 13.59 13.71 13.84 13.94 14.03 14.12 —— MAY 14.22 14.31 14.42 14.52 14.62 14.73 14.86 14.94 15.00 15.07 15.14 15.20 15.25 15.29 15.36 15.36 15.36 15.36 15.36 15.31 15.03 14.71 14.48 14.31 14.20 14.15 14.13 13.99 13.99 13.99 14.07 JUN 14.16 14.31 14.37 14.51 14.56 14.61 14.69 14.82 14.87 14.92 14.92 14.92 14.94 14.94 14.94 14.97 15.07 15.18 15.28 15.40 15.50 15.62 15.74 15.82 15.93 16.01 16.12 16.21 16.31 16.38 —— JUL 16.50 16.57 16.65 16.77 16.85 16.92 17.00 17.07 17.10 17.21 17.28 17.35 17.43 17.50 17.59 17.67 17.74 17.80 17.89 17.96 18.01 18.05 18.07 18.13 18.18 18.24 18.31 18.36 18.43 18.50 18.57 AUG 18.64 18.70 18.78 18.89 18.96 19.00 19.04 19.08 19.11 19.14 19.18 19.18 19.21 19.24 19.28 19.31 19.33 19.38 19.42 19.47 19.52 19.56 19.58 19.63 19.66 19.70 19.73 19.76 19.79 19.83 19.87 SEP 19.91 19.95 19.99 20.03 20.08 20.11 20.14 20.18 20.22 20.27 20.34 20.36 20.41 20.44 20.49 20.54 20.57 20.66 20.69 20.75 20.79 20.84 20.89 20.93 20.96 20.99 21.00 21.00 21.00 20.99 —— MEAN 11.40 11.57 11.71 11.79 11.82 11.90 12.74 14.73 15.20 WTR YR 1997 MEAN 14.20 HIGHEST 11.27 OCT. 1, 1996 LOWEST 21.01 SEPT. 30, 1997 17.60 19.32 20.52 30 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO SALINAS TO RIO JACAGUAS BASINS 519 180104066152300. Local number, RM * 10. LOCATION.--Lat 18001'04", long 66015'23", Hydrologic Unit 21010004, 8.00 ml southeast of Coamo plaza, 1.07 mi northeast of Escuela de Coco, and 0.70 mi southwest of Escuela Sabana Liana. Owner: U.S. Geological Survey, WRD, Name: RM * 10. AQUIFER.--Quaternary alluvium. WELL CHARACTERISTICS.—Drilled observation water-table well, diameter 4 in (0.10 m), cased 4 in (0.10 m), 0-37 ft (0-11.3 m), screened 27-37 ft (8.23-11.3 m). Depth 37 ft (11.3 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.—Elevation of land-surface datum is 164.13 ft (50.0 m) above mean sea level, from leveling survey. Measuring point: Top of shelter floor, 3.62 ft (1.10 m) above land-surface datum. REMARKS.—Recording observation well. Pumping test performed on February 8, 1990. Well dry at 35.77 ft (10.9 m). PERIOD OF RECORD.--March 13, 1989 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 18.0 ft (5.49 m) below land-surface datum, Nov. 9, 1990; lowest water level recorded, 35.77 ft (10.9 m) below land-surface datum, Sept. 14 to Oct. 5, 1994 WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC FEB APR MAY JUN JUL AUG 6 7 8 9 10 21.38 21.40 21.48 21.55 21.58 22.59 22.63 22.65 22.67 22.70 23.28 23.38 23.43 23.49 23.57 26.16 26.24 26.32 26.43 26.51 27.87 27.91 27.96 27. SB 28.02 28.87 28.93 28.97 29.03 29.07 30.21 30.24 30.26 30.30 30.35 31.34 31.37 31.40 31.45 31.49 32.51 32.57 32.61 32.64 32.69 33.64 33.67 33.70 33.75 33.75 MEAN 21.80 22.74 24.12 26.87 28.18 29.32 30.57 31.70 32.87 WTR YR 1997 MEAN 29.29 HIGHEST 21.08 OCT. 1, 1996 LOWEST 35.64 SEPT. 9-14, 1997 33.98 35.25 SEP 1 2 3 4 5 21.11 21.17 21.23 21.28 21.32 22.42 22.45 22.47 22.51 22.54 23.06 23.09 23.12 23.17 23.23 25.83 25.88 25.94 26.02 26.07 27.67 27.71 27.74 27.78 27.83 28.67 28.71 28.75 28.80 28.84 30.02 30.05 30.10 30.13 30.17 31.15 31.18 31.24 31.27 31.31 32.32 32.34 32.37 32.40 32.46 33.43 33.47 33.51 33.56 33.61 34.56 34.61 34.65 —— —— 35.63 35.63 35.63 35.63 35.62 35.63 35.63 35.63 35.63 35.64 11 12 13 14 15 21.59 21.60 21.63 21.66 21.69 22.74 22.73 22.69 22.67 22.68 23.64 23.64 23.59 23.61 23.68 26.62 26.71 26.79 26.85 26.93 28.08 28.09 28.12 28.16 28.21 29.09 29.13 29.17 29.21 29.24 30.39 30.42 30.46 30.50 30.55 31.53 31.56 31.59 31.62 31.67 32.71 32.75 32.78 32.81 32.88 33.79 33.83 33.88 33.91 33.96 —— 34.99 35.02 35.05 35.13 35.64 35.64 35.64 35.63 35.63 16 17 18 19 20 21.72 21.76 21.85 21.93 21.97 22.74 22.78 22.79 22.81 22.85 23.76 23.86 23.99 24.13 24.29 26.98 27.03 27.08 27.14 27.22 28.23 28.26 28.31 28.36 28.40 29.27 29.32 29.38 29.44 29.49 30.59 30.64 30.69 30.72 30.76 31.70 31.73 31.77 31.81 31.85 32.93 32.96 32.99 33.02 33.04 33.99 34.03 34.05 34.08 34.12 35.19 35.22 35.25 35.29 35.34 35.63 35.63 35.63 35.63 35.63 21 22 23 24 25 22.04 22.10 22.13 22.19 22.24 22.85 22.83 22.83 22.86 22.88 24.46 24.63 24.79 24.91 25.03 27.26 27.30 27.35 27.40 27.43 28.43 28.46 28.48 28.51 28.53 29.54 29.59 29.63 29.68 29.72 30.80 30.84 30.88 30.91 30.94 31.88 31.93 31.97 32.01 32.05 33.07 33.10 33.13 33.17 33.22 34.15 34.19 34.23 34.25 34.28 35.42 35.44 35.45 35.46 35.47 35.62 35.62 35.62 35.62 35.62 26 27 28 29 30 31 22.28 22.32 22.34 22.37 22.39 22.40 22.91 22.93 22.95 22.99 23.02 —— 25.16 25.28 25.42 25.53 25.65 25.76 27.46 27.51 27.55 27.59 27.62 27.65 28.56 28.60 28.64 —— —— —— 29.78 29.82 29.86 29.91 29.95 29.99 30.97 31.01 31.04 31.08 31.12 —— 32.07 32.10 32.14 32.18 32.21 32.26 33.26 33.29 33.31 33.37 33.39 —— 34.33 34.38 34.40 34.44 34.48 34.52 35.49 35.51 35.53 35.55 35.58 35.61 35.62 35.62 35.61 35.61 35.61 —— 35.63 20 30 40 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 520 GROUND-WATER LEVELS RIO INABON TO RIO LOCO BASINS 180133066503300. Local number, 132. LOCATION. —Lat 18°01'33", long 66°50'33", Hydrologic Unit 21010004, 0.90 mi southeast of Yauco plaza, 3.46 mi west of Guayanilla plaza, and 1.32 mi north of Escuela Segunda Unidad Barinas. Owner: Pittsburg Plate Glass 4, Name: Yauco 2. AQUIFER.--Limestone of Tertiary Age. WELL CHARACTERISTICS.—Drilled observation well, cased 20 in (0.51 m) 0-20 ft (0-6.1 m), 12 in (0.30 m) perforated pipe 20-84 ft (6.1-25.61 m), 10 in (0.25 m) perforated pipe 84-190 ft (25.61-57.93 m). Depth 190 ft (57.93 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 75 ft (22.87 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 2.35 ft (0.72 m) above land-surface datum. REMARKS.—Recording observation well. [+, above land-surface datum]. PERIOD OF RECORD.—July 1972 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, +0.12 ft (0.04 m) below land-surface datum, July 19, 1979; lowest water level recorded, 36.91 ft (11.25 m) below land-surface datum, June 27, 1974. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN APR MAY JUN 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 14.56 14.77 15.00 15.01 15.01 15.00 15.04 15.16 15.30 15.37 15.37 15.47 15.54 15.54 15.65 15.67 15.85 15.93 15.93 15.88 15.84 15.73 15.60 15.55 15.43 15.43 15.46 15.37 15.34 15.17 15.16 15.18 15.25 15.47 15.57 15.64 15.73 15.87 15.87 15.84 15.84 15.85 16.00 16.00 15.94 15.94 15.94 15.94 15.59 15.27 15.15 15.19 15.15 15.12 15.08 15.07 15.11 15.03 15.10 15.23 15.24 15.32 15.36 15.53 15.71 15.82 15.95 15.95 16.03 16.03 16.38 16.41 16.52 16.60 16.64 16.72 16.77 —— 16.76 16.94 16.98 17.00 17.00 17.01 17.01 17.01 17.01 17.01 17.01 17.01 17.01 17.57 17.30 17.21 17.08 17.06 17.04 17.03 17.03 17.08 17.16 17.27 17.31 17.38 17.45 17.56 17.62 17.79 17.90 17.96 18.01 18.06 18.15 18.21 18.20 18.39 18.54 18.54 18.49 18.81 18.94 19.01 19.08 19.15 19.22 19.27 19.32 19.40 19.40 19.65 19.74 19.80 19.86 19.98 20.07 20.14 20.30 20.40 20.41 20.42 20.46 20.48 20.58 20.74 20.82 20.89 21.11 21.23 21.28 21.37 21.44 —— ___ 21.54 21.59 21.71 21.85 21.94 22.02 22.10 22.16 22.29 22.44 22.63 22.85 23.02 23.14 23.21 23.21 23.35 23.55 23.67 23.71 23.71 23.80 23.88 23.94 23.96 24.06 24.11 24.18 24.23 24.23 24.26 24.33 24.38 24.42 24.41 24.40 24.35 24.34 24.47 24.65 24.80 24.99 25.07 25.17 25.15 25.31 25.42 25.46 25.62 25.76 25.85 25.96 26.05 26.18 26.24 26.29 26.31 26.37 26.45 26.53 26.62 —— 26.66 26.81 26.93 26.97 26.98 27.00 27.03 27.15 27.26 27.39 27.52 27.75 27.85 27.99 27.95 28.05 28.15 28.34 28.49 28.62 28.77 28.91 28.98 29.01 29.04 29.11 29.25 29.34 29.40 29.55 29.65 29.69 29.59 29.64 29.86 30.00 30.11 29.97 30.30 30.41 30.52 30.67 30.80 30.93 31.07 31.22 31.24 31.25 31.34 31.42 31.43 31.45 31.45 31.37 31.45 —— —— —— —— ___ MEAN 15.39 15.51 16.54 17.83 20.25 23.11 25.38 28.13 30.72 WTR YR 1997 MEAN 22.98 HIGHEST 14.56 OCT. 1, 1996 LOWEST 33.89 AUG. 30, 31, 1997 JUL AUG 33.00 SEP — — ___ —— —— —— — ___ —— —— 32.79 32.95 32.86 32.80 32.73 32.64 32.69 32.79 32.78 32.86 32.87 32.79 32.87 33.10 33.35 33.57 33.82 33.75 33.51 33.59 33.54 33.40 33.18 32.83 32.60 31.41 31.15 32.05 32.65 32.77 32.91 32.93 32.94 32.90 32.80 32.70 32.86 32.93 33.03 33.12 33.16 33.30 33.32 33.32 33.14 33.12 32.94 —— 32.90 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS RIO INABON TO RIO LOCO BASINS 521 175950066354200. Local number, 141. LOCATION.--Lat 17 059'50', long 66°35'42', Hydrologic Unit 21010004, 1.71 mi southeast of Plaza Degetau at Ponce, 1.31 mi southeast of the intersection between Bwy 10 and Hwy 2, and 2.60 mi notheast of Muellle de Ponce. Owner: P.R. Aqueduct and Sewer Authority, Name: Restaurada 8A. AQUIFER.--Alluvium of Quaternary Age. WELL CHARACTERISTICS.--Drilled unused public supply well, diameter 16-10 in (0.41-0.25 m), cased 16 in (0.41 m) 2-20 ft (0.6-6.1 m), perforated 20-130 ft (6.10-39.6 m), 10 in (0.25 m) 128-165 ft (39.0-50.3 m), perforated. Depth 165 ft (50.3 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 24 ft (7.30 m) above mean sea level, from topographic map. Measuring point: Bottom edge of hole on side of casing 1.90 ft (0.58 m) above land-surface datum, 26.2 ft (7.67 m), above mean sea level. REMARKS.—Recording observation well. Discontinued on Nov. 8, 1994 due to apparent collapsed casing, repair on August 7, 1996. PERIOD OF RECORD.—October 1981 to March 1, 1986, discontinued, November 18, 1991 to November 8, 1994, discontinued, August 7, 1996 to September 30, 1996. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 11.2 ft (3.41 m) below land-surface datum, Oct. 9, 1985; lowest water level recorded, 28.6 ft (8.71 m) below land-surface datum, July 9, 1982. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN FEB MAR MAY JUN JUL AUO MEAN 23.98 23.70 21.46 22.17 23.24 25.51 26.07 26.63 26.39 WTR YR 1997 MEAN 24.82 HIGHEST 20.70 DEC. 17, 1996 LOWEST 27.08 MAY 22, 1997 26.24 26.18 SSP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 23.03 23.31 23.42 23.49 23.44 23.45 23.44 23.43 24.20 24.15 24.12 24.20 24.26 24.30 24.29 24.29 24.20 24.13 24.16 24.17 24.18 24.03 24.03 24.02 25.03 24.23 24.12 24.10 24.04 23.92 24.16 24.19 24.28 24.33 24.36 24.29 24.25 24.21 24.16 24.20 24.17 24.20 24.07 23.98 23.97 23.85 23.61 23.65 23.43 23.40 23.35 23.27 23.25 23.16 23.15 23.10 23.08 23.05 23.02 23.05 23.02 —— 23.00 23.01 23.06 22.38 21.43 21.22 21.13 21.05 21.04 20.95 20.89 20.86 20.84 20.80 20.78 20.76 20.75 20.86 20.94 20.97 21.33 21.42 21.52 21.66 21.73 21.79 21.83 21.79 21.83 21.90 21.87 21.83 21.84 21.93 21.99 21.98 22.00 22.01 22.04 22.06 22.01 22.02 21.96 21.95 22.00 21.95 21.93 22.07 22.17 22.19 22.21 22.21 22.15 22.13 22.22 22.41 22.53 22.59 22.64 22.69 22.74 22.81 22.88 22.92 22.90 22.85 22.81 22.30 —— —— —— —— ___ —— 22.07 22.07 22.08 22.08 22.12 22.21 22.19 22.20 22.92 24.25 24.66 24.91 25.06 25.23 25.31 25.35 —— —— —— 25.39 25.47 25.24 25.00 25.05 25.03 25.10 25.19 25.21 25.73 25.25 25.28 25.25 25.47 25.45 25.51 25.51 25.52 25.42 25.50 26.53 25.68 25.65 25.67 25.64 25.72 25.69 25.78 25.89 25.95 26.03 26.01 26.01 25.95 26.08 26.13 26.17 26.22 26.20 26.24 26.24 26.27 25.50 25.38 25.29 25.19 25.14 25.81 25.93 26.03 26.12 26.18 26.21 26.27 26.36 26.43 26.46 26.49 26.53 26.55 26.58 —— 26.58 26.60 26.65 25.17 26.21 26.49 26.59 26.65 26.68 25.91 26.48 26.59 26.59 26.69 26.75 26.83 26.76 26.78 26.83 26.88 26.92 27.03 26.95 26.95 26.95 26.95 26.93 26.92 26.58 26.44 26.31 26.28 26.31 26.24 26.19 26.22 26.21 26.26 26.25 26.26 26.23 26.16 26.24 26.28 26.35 26.29 26.37 26.38 26.37 26.48 26.51 26.53 26.56 26.57 26.56 26.58 26.59 26.55 26.60 26.63 26.56 —— 26.58 26.60 26.62 26.65 26.65 26.66 26.64 26.60 26.09 26.57 25.68 24.38 26.03 26.18 26.21 26.26 26.30 26.34 26.34 26.30 26.31 26.22 26.20 26.17 26.10 26.13 26.13 26.09 26.08 26.15 26.26 26.32 26.37 26.38 26.42 26.41 26.41 26.43 26.46 26.46 26.49 26.39 26.00 26.47 26.47 26.47 26.40 26.38 26.37 26.28 26.26 26.12 25.98 25.94 25.89 25.81 25.71 25.78 25.72 25.65 25.65 25.66 25.65 25.63 25.68 25.72 25.76 25.78 25.76 25.84 25.81 25.82 25.77 25.83 25.82 25.84 25.92 25.92 25.89 25.87 25.91 25.92 25.92 25.93 25.94 25.94 25.93 25.85 26.07 26.10 26.07 26.12 —— 25.87 10 120 30 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASO 1993 1994 1995 DJFMAMJJASONDJFMAMJJAS 1996 1997 WATER YEAR 522 GROUND-WATER LEVELS RIO INABON TO RIO LOCO BASIN 180045066381600. Local number AN-1 LOCATION.—Lat 18°00'45", long 66°38'16", Hydrologic Unit 21010004, 0.27 mi east of the intersection of Hwy 10 with Hwy 132, 0.60 mi northwest of Paro^ie Montaner, and 0.04 mi south of Hwy 132. Owner: Albergue de Nines de Ponce, Name: Albergue de Ninos. AQUIFER. - -Al luvium. WELL CHARACTERISTICS.—Drilled unused water-table well. INSTRUMENTATION.—Digital water level recorder--60-minute punch. DATUM.—Elevation of land-surface datum is about 49.0 ft (14.90 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 5.42 ft (1.65 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—March 30, 1992 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 35.29 ft (10.76 m) below land-surface datum, June 22, 1992; lowest water level recorded, 51.88 ft (15.81 m) below land-surface datum, Aug. 30, 1994. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN JUN JUL AUO MEAN 37.13 35.62 34.11 33.27 32.94 32.27 31.08 31.91 32.35 WTR YR 1997 MEAN 32.99 HIGHEST 29.44 APR. 8, 1997 LOWEST 38.21 OCT. 15, 1996 32.43 31.66 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 37.57 37.47 37.36 37.77 37.31 37.19 37.57 37.35 37.74 37.14 37.07 37.04 36.98 36.99 37.93 37.49 37.18 36.85 36.74 36.68 36.59 36.51 37.74 36.79 37.11 37.00 36.87 36.78 36.68 36.59 37.09 36.43 36.38 36.27 36.34 36.24 36.22 36.10 36.01 35.99 35.90 35.94 35.83 35.79 36.14 35.62 35.55 35.46 35.39 35.51 35.29 35.24 35.23 35.19 35.14 35.17 34.99 34.88 34.81 34.78 34.70 —— 34.57 35.17 34.54 34.53 35.10 34.58 34.42 34.34 34.43 34.30 34.20 34.15 34.32 34.08 34.02 33.79 33.91 33.56 33.92 34.58 33.88 33.81 33.80 33.77 33.63 33.62 33.68 33.67 33.44 34.04 33.45 33.36 33.34 34.04 33.32 33.24 33.20 33.80 33.27 33.20 33.88 33.18 33.11 33.15 33.69 33.09 33.05 33.66 33.05 33.02 33.07 33.33 33.04 33.05 33.02 33.01 32.95 33.00 33.61 32.97 32.99 33.57 33.02 32.95 32.94 33.37 32.98 32.94 33.57 33.02 32.97 33.50 33.01 33.58 33.50 33.07 32.82 32.72 32.72 33.25 32.68 32.63 33.33 32.57 32.52 32.45 32.43 33.01 32.41 32.42 —— —— 32.30 32.24 32.81 32.28 32.25 32.87 32.94 32.27 32.20 32.51 32.17 32.15 33.06 32.91 32.14 32.10 32.78 32.81 32.55 32.52 32.18 32.01 31.94 32.70 32.59 32.25 32.60 31.98 30.97 30.39 30.80 31.41 31.66 31.42 30.37 30.04 29.79 29.73 29.47 31.51 31.37 31.12 30.96 31.01 31.04 31.16 31.10 31.11 31.30 31.15 31.18 31.24 31.30 31.88 31.34 31.39 31.38 31.38 31.45 31.48 31.51 —— 31.47 32.30 31.71 31.64 32.33 31.67 31.52 31.81 31.92 31.48 31.57 31.89 31.93 31.99 32.09 32.10 31.87 31.82 32.05 32.10 32.11 32.09 32.55 31.95 31.92 31.16 31.95 31.95 31.86 32.41 31.87 31.94 32.13 31.91 31.80 31.93 32.49 31.86 31.84 31.88 32.02 32.05 32.58 32.30 32.19 32.11 32.53 32.54 33.11 33.03 32.38 32.30 32.17 32.57 32.92 32.46 33.10 33.13 32.41 32.37 32.57 —— 32.62 32.59 32.47 32.42 32.43 32.38 32.50 32.44 32.51 32.66 33.21 32.47 32.40 32.78 32.80 32.78 32.83 33.09 32.43 32.38 32.30 32.17 32.13 32.12 31.98 31.96 31.93 32.27 32.03 32.20 32.08 32.21 31.99 31.94 32.03 32.02 31.90 32.06 32.00 31.81 31.76 31.81 31.80 31.91 31.78 31.79 31.57 31.48 31.61 31.63 31.62 31.61 31.50 31.30 31.20 31.37 31.50 31.37 31.56 31.37 31.06 30.99 30.97 30.98 31.48 31.56 31.11 30.86 30.75 30.78 30.83 31.39 31.05 31.07 30.88 30.86 31.07 31.40 31.11 30.88 30.93 30.68 30.58 31.14 30.98 30.85 30.56 31.33 31.01 30.93 31.09 31.07 —— 31.01 20 40 60 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 523 RIO GUANAJIBO BASIN 180132067033800. Local number, 143. LOCATION.--Lat 18°01'32", long 67°03'38", Hydrologic Unit 21010003, 1.86 mi south of Lajas plaza, 1.27 mi southeast of the Estacion Experimental Agricola, and 1.30 mi northwest of the intersection of Hwy 116 with Hwy 305. Owner: Pedro P. Vivoni, Name: vivoni, Hacienda Amistad. AQUIFER.—Limestone of unknown age. WELL CHARACTERISTICS.—Drilled unused irrigation well, diameter 12 in (0.30 m) . Depth 200 ft (60.98 m). INSTRUMENTATION.—Digital water level recorder—15-minute punch. DATUM.--Elevation of land-surface datum is about 52.5 ft (16.0 m) above mean sea level, from topographic map. Measuring point: Hole side of casing, 0.80 ft (0.24 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—December 1981 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 37.36 ft (11.39 m) below land-surface datum, Nov. 20, 1985; lowest water level recorded, 40.70 ft (12.40 m) below land-surface datum, Sept, 26, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 NOV JAN APR MAY MEAN 39.95 39.88 39.86 39.85 39.89 40.21 40.28 40.39 40.52 WTR YR 1997 MEAN 40.23 HIGHEST 39.72 FEB. 6, 1997 LOWEST 40.70 SEPT. 26, 1997 40.59 40.63 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 39.94 39.92 39.87 39.92 39.95 39.94 39.96 40.00 39.97 39.97 39.94 39.95 39.94 39.95 39.98 39.99 39.97 39.94 39.93 39.98 40.00 40.01 39.98 39.96 39.98 39.98 39.96 39.91 39.90 39.92 39.93 39.93 39.94 39.93 39.94 39.96 39.96 39.93 39.88 39.87 39.90 39.96 39.98 39.93 39.88 39.88 39.89 39.89 39.85 39.85 39.84 39.84 39.83 39.82 39.85 39.85 39.83 39.80 39.80 39.80 39.80 —— 39.78 39.77 39.76 39.79 39.82 39.81 39.80 39.82 39.83 39.85 39.85 39.83 39.82 39.80 39.79 39.78 39.79 39.83 39.87 39.86 39.87 39.90 39.94 39.94 39.96 40.00 40.04 39.99 39.96 39.97 39.93 39.92 39.91 39.87 39.87 39.85 39.88 39.89 39.89 39.87 39.85 39.85 39.86 39.86 39.83 39.82 39.80 39.81 39.83 39.85 39.88 39.86 39.87 39.87 39.84 39.83 39.83 39.81 39.79 39.80 39.80 39.79 39.76 39.77 39.78 39.81 39.79 39.80 39.81 39.84 39.84 39.82 39.81 39.74 39.77 39.82 39.81 39.81 39.84 39.91 39.93 39.93 39.96 40.01 40.10 40.06 40.01 40.08 40.12 40.12 —— —— —— 40.12 40.09 40.07 40.08 40.10 40.16 40.17 40.19 40.20 40.19 40.19 40.20 40.24 40.27 40.26 40.24 40.24 40.25 40.25 40.23 40.23 40.25 40.27 40.27 40.28 40.28 40.25 40.25 40.24 40.23 40.21 40.21 40.26 40.24 40.26 40.29 40.28 40.28 40.24 40.23 40.25 40.30 40.25 40.27 40.30 40.29 40.27 40.26 40.25 40.26 40.29 40.31 40.30 40.31 40.30 40.34 40.34 40.33 40.35 40.34 40.33 —— 40.32 40.35 40.38 40.37 40.36 40.36 40.37 40.36 40.37 40.37 40.37 40.36 40.38 40.41 40.37 40.37 40.41 40.41 40.43 40.42 40.41 40.41 40.44 40.41 40.42 40.41 40.39 40.41 40.43 40.45 40.46 40.46 40.46 40.48 40.45 40.49 40.50 40.51 40.54 40.56 40.55 40.52 40.48 40.50 40.52 40.51 40.51 40.51 40.55 40.55 40.54 40.52 40.55 40.54 40.51 40.52 40.53 40.54 40.54 40.57 40.58 —— 40.57 40.56 40.58 40.58 40.61 40.61 40.61 40.56 40.54 40.59 40.61 40.59 40.56 40.60 40.60 40.60 40.62 40.60 40.60 40.61 40.62 40.60 40.60 40.60 40.57 40.55 40.57 40.60 40.63 40.63 40.64 40.65 40.63 40.62 40.61 40.61 40.63 40.60 40.60 40.61 40.62 40.62 40.63 40.64 40.66 40.67 40.68 40.67 40.66 40.65 40.65 40.65 40.65 40.65 40.61 40.61 40.62 40.64 40.65 40.65 40.63 40.61 40.62 40.66 40.62 40.57 40.58 40.55 40.51 40.50 40.53 40.58 40.61 40.61 40.61 40.62 40.65 40.65 40.64 40.63 40.62 40.60 40.62 40.62 40.61 40.63 40.64 40.69 40.68 40.68 40.65 40.64 —— 40.61 I I I I I I I I I I I I I I I I I I I I I I I_I I I I I I I I I I | | | | I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 524 GROUND-WATER LEVELS RIO GUANAJIBO BASIN 180628067084300. Local number, CR-TW-9A. LOCATION. --Lat 18°06'28", long 67°08'43", Hydrologic Unit 21010003, 1.29 mi north of Cabo Rojo plaza, 1.54 mi northwest of Escuela Segunda Unidad Antonio Acar6n Correa, and 1.23 mi southeast of Escuela Sabana Alta. Owner: U.S. Geological Survey, WRD, Name: CR-TW-9A. AQUIFER. --Sandy and clay. WELL CHARACTERISTICS. --Dril led unused water-table well, diameter 4 in (0.10 m) , cased 4 in (0.10 m) , 0-24 ft (0-7.32 m), screened 19-24 ft (5.79-7.32 m) . Depth 24 ft (7.32 m) . INSTRUMENTATION. --Digital water level recorder- -60 -minute punch. DATUM. — Elevation of land-surface datum is about 33.21 ft (10.1 m) above mean sea level, from topographic map. Measuring point: Hole on shelter floor, 4.51 ft (1.37 m) above land-surface datum. REMARKS. — Observation well. Drilled on Mar. 25, 1992, Automatic Digital Recorder (ADR) re-installed on May 29, 1996. PERIOD OF RECORD. --JUly 1992 to January 1994, discontinued. May 27, 1996 to September 30, 1996. EXTREMES FOR PERIOD OF RECORD. — Highest water level recorded, +0.24 ft (+0.07 m) below land-surface datum, Oct. 12, 1992; lowest water level recorded, 7.22 ft (2.20 m) below land-surface datum, Aug. 14, 1997. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 NOV DEC JAN FEB MAR APR MAY JUN JUL AUG 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN 2.67 2.02 WTR YR 1997 MEAN 4.22 3.01 3.06 2.16 1.92 1.99 2.10 2.17 2.28 2.34 2.42 2.49 2.53 2.60 2.66 2.71 2.77 2.79 2.82 2.85 2.88 2.92 2.92 2.96 2.96 3.00 3.03 3.01 2.92 2.80 2.82 2.86 2.86 2.88 2.92 2.98 2.98 2.97 2.97 2.97 2.74 2.23 2.08 2.11 1.42 1.27 1.46 1.64 1.71 1.58 1.51 1.51 1.47 1.21 1.07 1.27 1.46 1.63 1.76 1.89 1.98 2.01 —— 2.09 2.15 2.21 2.29 2.23 2.26 2.30 2.47 2.59 2.70 2.74 2.83 2.86 2.92 2.97 2.99 3.10 3.12 3.14 3.19 3.23 3.26 3.31 3.35 3.41 3.45 3.48 3.48 3.48 3.54 3.55 3.46 3.51 3.59 3.21 3.17 3.22 3.29 3.34 3.32 3.09 3.06 3.06 3.07 3.06 3.08 3.12 3.17 3.20 3.25 3.29 3.30 3.30 3.22 3.20 3.19 3.20 3.23 3.26 3.24 3.26 3.28 3.30 3.32 3.38 3.39 3.09 2.83 2.88 2.95 3.00 3.06 3.10 3.15 3.18 3.23 3.27 3.35 3.42 3.49 3.50 3.60 3.62 3.67 3.74 3.78 3.83 3.86 3.92 3.96 —— —— ___ 4.01 4.01 4.07 4.12 4.16 4.21 4.23 4.26 4.28 4.32 4.39 4.42 4.47 4.51 4.56 4.61 4.66 4.64 4.66 4.65 4.71 4.76 4.81 4.85 4.90 4.94 4.97 5.01 5.01 4.89 4.96 4.97 5.00 5.03 5.05 5.08 5.14 5.18 5.20 5.24 5.30 5.35 5.36 5.42 5.48 5.54 5.60 5.64 5.71 5.78 5.83 5.89 5.90 5.95 6.04 6.11 6.19 6.24 5.87 6.08 6.20 6.31 6.38 6.44 6.51 6.58 6.62 6.67 6.74 6.81 6.88 6.90 6.99 7.06 7.07 7.09 ___ ___ ___ —— ___ —— —— ___ ___ —— ___ 2.93 3.23 3.39 4.55 5.58 6.74 HIGHEST 1.07 NOV. 22, 1996 LOWEST 7.22 AUG. 14, 1997 6.80 6.81 6.65 6.56 6.52 6.52 6.52 6.53 6.55 6.58 6.53 6.61 6.74 6.80 6.88 6.94 6.03 6.62 SEP 6.24 6.37 6.41 6.42 6.52 6.60 6.67 6.78 6.88 6.95 7.04 7.07 7.07 7.07 7.06 7.07 7.07 7.10 7.10 7.10 7.10 7.10 7.10 7.10 7.10 7.10 7.10 7.10 7.10 5.34 6.86 10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 525 RIO CULEBRINAS BASIN 182442067091700. Local number, 200. LOCATION.— Lat 18°24'42", long 67°09'17", Hydrologic Unit 21010002, 1.40 mi south of Aguadilla plaza, 3.04 mi northeast of Aguada plaza, and 0.20 mi north of Hwy 2 km 146.4. Owner: Carmelo Sanchez, Name: Aguadilla Cement well. AQUIFER.—Surficial deposits. WELL CHARACTERISTICS.—Abandoned water-table industrial well, diameter 4 in (0.10 m), cased 0-20 ft (0-6.10 m), perforated 11-20 ft (3.35-6.10 m). Depth 20 ft (6.10 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 10 ft (3.05 m) above mean sea level, from topographic map. Measuring point: Shelter floor on top of 4 in (0.10 m) casing, 3.25 ft (0.99 m) above land-surface datum. REMARKS.—Recording observation well, water levels affected by nearby pumping well. PERIOD OF RECORD.—October 1985 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 2.24 ft (0.68 m) below land-surface datum, Aug 25, 1988; lowest water level recorded, 9.60 ft (2.93 m) below land-surface datum, Feb. 20, 1992. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN FEB MAR APR JUN JUL AUG SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 5.54 5.63 5.68 5.74 5.78 5.84 5.54 5.94 6.00 5.70 5.53 5.64 5.53 5.38 5.51 5.33 5.45 5.60 5.61 5.69 5.82 5.86 5.91 5.98 6.06 6.06 6.07 6.18 6.20 6.24 6.29 6.33 6.34 6.34 6.45 6.46 6.56 6.61 6.64 6.65 6.66 6.57 6.55 6.55 6.66 6.69 6.14 5.97 5.55 5.50 5.51 5.52 5.56 5.55 5.66 5.84 5.93 5.96 6.02 6.17 6.17 —— 6.18 6.28 6.32 6.37 6.46 6.49 6.49 6.54 6.61 6.71 6.58 6.59 6.67 6.67 6.73 6.79 6.83 6.89 6.91 6.93 6.95 6.96 6.98 6.99 7.13 7.21 7.25 7.25 7.25 7.28 7.30 7.30 7.31 7.34 7.33 7.33 7.34 7.41 7.41 7.43 7.46 7.47 7.47 7.49 7.52 7.54 7.56 7.58 7.58 7.58 7.60 7.27 6.12 5.36 5.13 5.09 5.08 5.16 5.30 5.41 5.50 5.60 5.59 5.64 5.71 5.82 5.88 5.95 6.03 5.95 6.01 6.08 6.16 6.23 6.28 6.36 6.36 6.42 6.51 6.56 6.62 6.65 6.73 6.71 6.73 6.82 6.86 6.88 6.95 6.96 —— —— —— 6.96 6.97 6.99 7.10 7.11 7.16 7.16 7.20 7.20 7.27 7.28 7.29 7.33 7.36 7.36 7.37 7.44 7.48 7.48 7.51 7.56 7.57 7.57 7.66 7.69 7.74 7.77 7.77 7.77 7.80 7.82 7.91 7.95 7.95 7.98 7.98 7.98 8.04 8.11 8.12 8.14 8.18 8.18 8.17 8.17 8.17 8.18 8.19 8.19 8.20 8.19 8.22 8.25 8.25 8.27 8.27 8.27 8.26 8.28 8.29 8.29 —— 8.30 8.29 8.30 8.29 8.31 8.31 8.31 8.00 8.01 7.91 7.93 7.82 7.69 7.51 7.46 7.52 7.52 7.42 7.54 7.64 7.71 7.80 7.81 7.81 7.82 7.91 7.98 7.69 7.52 7.42 7.42 7.34 7.36 7.47 7.54 7.54 7.63 7.63 7.65 7.75 7.78 7.84 7.84 7.86 7.79 7.79 7.88 7.89 7.91 7.95 7.98 7.98 7.98 8.01 7.90 7.93 8.02 8.06 8.07 8.07 8.07 —— 8.08 8.11 8.12 8.12 8.12 8.14 8.20 8.22 8.23 8.24 8.25 8.25 8.26 8.22 8.25 8.08 8.06 8.06 8.06 8.07 8.02 8.03 8.03 8.04 8.04 8.04 8.05 7.33 7.34 7.30 7.37 7.24 7.23 7.25 7.33 7.25 6.96 6.97 7.01 7.05 7.13 7.21 7.28 7.20 7.24 7.29 7.30 7.09 7.13 7.19 7.26 7.30 7.19 7.19 7.19 6.66 6.63 6.67 6.47 6.47 6.48 6.49 6.24 6.26 6.29 6.36 6.44 6.46 6.52 6.58 6.65 6.71 6.78 6.81 6.82 6.82 6.87 6.90 6.91 7.01 7.01 7.02 7.01 7.03 7.07 7.15 7.19 6.92 7.00 7.07 7.20 7.22 —— MEAN 5.78 6.17 WTR YR 1997 MEAN 7.08 6.79 6.78 6.34 7.41 8.15 7.84 HIGHEST 4.88 OCT. 10, 1996 LOWEST 8.31 MAY 5, 6, 7, 7.82 1997 8.02 7.04 6.81 10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 526 THIS PAGE WAS LEFT BLANK INTENTIONALLY 527 528 ST. THOMAS, U.S. VIRGIN ISLANDS 50252000 BONNE RESOLUTION OUT AT BONNE RESOLUTION, ST. THOMAS, VI LOCATION. —Lat 18°21'57-, long 64°57'34", Hydrologic Unit 21020001, on right bank near Hull Bay Road, 0.5 mi (0.8 km) upstream from mouth, and 2.5 mi (4.0 km) northwest of Fort Christian, Charlotte Amalie. DRAINAGE AREA.—0.49 mi 3 (1.27 km2 ). PERIOD OF RECORD.--December 1962 to February 1967, March 1979 to April 1981, May 1982 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 280 ft (85 m), from topographic map. December 1962 to February 1967 and March 1979 to April 1981 at site about 100 ft (30 m) upstream at different datum. REMARKS.--Records poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB APR MAY JUN JUL AUG SEP 1 .01 .01 2 .01 .01 3 .01 .01 4 .01 .01 5 .01 .01 6 .01 .01 7 .01 .01 8 .01 .01 9 .01 .01 10 .01 .01 11 .01 .02 12 .01 1.0 13 .01 .08 14 .01 .03 15 .01 .02 16 .01 .01 17 .01 .01 18 .02 .05 19 .01 .05 20 .01 .07 21 .01 e!9 22 .01 e.23 23 .01 e.15 24 .01 e.30 25 .01 e.09 26 .01 e.06 27 .01 e.10 28 .02 e.12 29 .01 e.08 30 .01 e.08 31 .01 —— .06 .06 .06 .06 .08 .08 .08 .08 .08 .07 .07 .07 .08 .08 .08 .08 .08 .08 .09 .09 .08 .09 .09 .09 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .10 .12 .12 .12 .12 .15 .14 .12 .12 .12 .11 .12 .12 .12 .12 .12 TOTAL 0.33 21.65 2.56 3.44 MEAN .011 .72 .083 .11 MAX .02 19 .10 .15 MIN .01 .01 .06 .10 AC-FT .7 43 5.1 6.8 CFSM .02 1.47 .17 .23 IN. .03 1.64 .19 .26 .20 .03 .15 .03 .14 .03 .15 .02 .16 .02 .15 .02 .15 .02 .15 .02 .15 .02 .16 .02 .16 .01 .14 .01 .12 .01 .11 .01 .10 .01 .10 .01 .10 .01 .08 .01 .08 .01 .06 .01 .10 .01 .08 .01 .07 .01 .05 .01 .05 .00 .04 .01 .04 .01 .03 .02 .01 —— .01 —— .01 3.07 0.44 .11 .014 .20 .03 .03 .00 6.1 .9 .22 .03 .23 .03 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1986 - 1997 MEAN .48 .76 .062 .068 MAX 3.09 4.22 .30 .35 (WY) 1986 1988 1993 1992 MIN .011 .011 .002 .016 (WY) 1997 1995 1995 1986 .061 .051 .38 .31 1992 1987 .005 .001 1995 1995 SUMMARY STATISTICS FOR 1996 CALENDAR YEAR ANNUAL TOTAL 63.17 ANNUAL MEAN .17 HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN 32 LOWEST DAILY MEAN .01 ANNUAL SEVEN- DAY MINIMUM .01 INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) 125 ANNUAL RUNOFF (CFSM) .35 ANNUAL RUNOFF (INCHES) 4.80 10 PERCENT EXCEEDS .08 50 PERCENT EXCEEDS .01 90 PERCENT EXCEEDS .01 Sep 10 Jan 1 Jan 1 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 — 0.30 .010 .01 .01 .6 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 0.31 .010 .01 .01 .6 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 — 0.30 .010 .01 .01 .6 .02 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 0.32 .010 .02 .01 .6 .02 .02 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .07 .01 .01 .01 .01 .01 .01 .01 .02 .04 .02 .05 .05 .05 .05 .05 .05 .05 .05 0.75 .024 .07 .01 1.5 .05 .06 .06 .05 .05 .04 .04 .05 .41 .14 .07 .05 .04 .04 .04 .04 .05 .06 .04 .04 .04 .04 .04 .03 .04 .03 .04 .06 .07 .06 .04 .04 1.84 .061 .41 .03 3.6 .13 .14 , BY WATER YEAR (WY) .063 .34 1986 .000 1995 .33 2.06 1987 .002 1995 .13 .89 1987 .004 1995 FOR 1997 WATER YEAR 35.31 .097 19 .00 .01 884 6.18 70 .20 2.68 .11 .01 .01 NOV 21 Mar 25 Mar 19 NOV 21 NOV 21 .043 .18 1988 .010 1994 WATER 169 1650 7 186 6 .054 .23 1988 .010 1994 YEARS 1963 - .25 .77 .026 Apr 18 .00 Apr 11 .00 Jan 31 Apr 18 .00 Apr 18 .51 .93 .11 .02 .01 .98 8.91 1989 .009 1994 1997 1989 1964 1983 1980 1986 1983 1983 e Estimated ST. THOMAS, U.S. VIRGIN ISLANDS 529 50274000 TURPENTINE RUN AT MOUNT ZION, ST. THOMAS, VI LOCATION.--Lat 18°19'55", long 64°53'20", Hydrologic Unit 21020001, on left bank at Mount Zion, 0.6 ml (0.9 km) east southeast from Donoe school, 0.5 ml (0.8 km) northwest from Mariendal, and 0.4 ml (0.6 km) southeast from conjunction of roads 38 and 32. DRAINAGE AREA.--2.33 ml 2 (6.03 km 2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—January 1963 to December 1969, October 1992 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 120 ft (36 m), from topographic map. Datum of gage for period of October 1992 to current year is 1.62 ft (0.49 m), higher than previous record. REMARKS.—Records poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC MAR APR MAY JUN JtJL AUG SEP 1 .88 .43 2 e.55 .41 3 e.63 .55 4 .86 .54 5 .58 .42 6 e.49 .89 7 .71 .40 8 .47 .36 9 .57 .41 10 e.53 .41 11 e.43 e.58 12 .49 e5.2 13 .49 .84 14 .42 .54 15 .45 .45 16 .37 .74 17 .42 .57 18 .40 .70 19 .42 .93 20 .40 .67 21 .43 53 22 .40 3.0 23 .44 3.5 24 .36 4.9 25 .30 1.5 26 .51 el.O 27 .40 e.92 28 1.1 el. 6 29 .54 1.3 30 .46 1.2 31 .39 TOTAL 15.89 87.96 MEAN .51 2.93 MAX 1.1 53 MIN .30 .36 AC -FT 32 174 CFSM .22 1.26 IN. .25 1.40 STATISTICS OF MONTHLY MEAN MEAN .23 .96 MAX 2.04 6.49 (WY) 1993 1993 MIN .23 .37 (WY) 1997 1996 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN LOWEST DAILY MEAN ANNUAL SEVEN- DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC -FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .91 .78 .86 .81 .80 .86 e.72 e.81 .76 .70 1.1 .62 .60 .74 1.3 .86 .66 .76 .75 .77 .61 .69 .64 .57 .56 .75 1.1 .63 1.7 2.0 e.86 26.28 .85 2.0 .56 52 .36 .42 DATA .59 4.79 1993 .23 1994 e.77 .96 .67 .67 .51 .53 .62 .72 .52 .51 .50 .61 .56 .54 .52 .46 .57 .51 .47 .82 3.3 4.9 .97 el. 3 e.71 e.54 e.54 e.48 e.59 e.46 el. 8 27.63 .89 4.9 .46 55 .38 .44 e6.3 e2.0 e.82 e.89 e.72 e.62 e.92 el. 2 e.48 e.45 e2.3 el.l .63 .59 .48 .71 .68 .59 .57 .49 .48 .51 .96 e.48 e.53 e.40 e.34 .32 ___ —— 26.56 .95 6.3 .32 53 .41 .42 FOR WATER YEARS 1964 .08 .89 1997 .086 1997 .05 .95 1997 .047 1997 e.35 e.49 .78 .51 .38 e.47 e.40 e.63 e.43 e.31 .31 .71 .53 .39 .39 .30 .32 .33 .30 .22 .21 .27 .18 .23 .27 .27 .27 .29 .37 .27 .27 11.45 .37 .78 .18 23 .16 .18 - 1997 .12 .37 1997 .076 1995 FOR 1996 CALENDAR YEAR 465 1 205 924 7 .72 .27 .04 .11 .55 .44 .91 .39 .16 Sep 10 Jul 6 Jun 24 .32 .38 .31 .26 .34 .26 .25 .21 .20 .24 .25 .29 .31 .26 .25 .24 .24 .22 .27 .35 .31 .24 .26 .38 .25 .28 .25 .26 .28 .32 —— 8.28 .28 .38 .20 16 .12 .13 .33 .32 .29 .31 .30 .30 .31 .26 1.2 .42 .33 .35 .32 .30 .27 .41 .37 .21 .20 .15 .16 .21 .41 .31 e.25 el. 4 el. 3 e.54 e.35 e.32 e.33 12.53 .40 1.4 .15 25 .17 .20 e.37 e3.1 e.32 .22 .20 .22 .21 .23 .20 .26 .19 .21 .21 .26 .28 .32 .32 .29 .29 .30 .29 .24 .57 .29 .23 .21 .20 .14 .14 .19 —— 10.50 .35 3.1 .14 21 .15 .17 .17 .15 .12 .12 .12 .13 .16 .18 .43 .16 .19 .17 .16 .19 .12 .40 .17 .41 .65 .91 .66 .32 .19 .14 .23 .15 .14 .15 .13 .10 .09 7.41 .24 .91 .09 15 .10 .12 .10 .13 .20 .11 .28 .36 .31 .31 .37 .77 .46 .17 8.3 1.2 .29 .31 .20 .14 .12 .16 .31 .94 .30 1.5 .48 .33 .31 .33 .23 .27 .24 19.53 .63 8.3 .10 39 .27 .31 .22 .27 .19 .17 .16 .25 5.1 1.3 .51 .38 .36 .31 .36 .43 1.2 1.5 .67 .46 .48 .33 .32 .37 .42 .43 .38 1.0 .43 .48 .37 .28 —— 19.13 .64 5.1 .16 38 .27 .31 , BY WATER YEAR (WY) .04 .92 1993 .025 1995 FOR 1997 273 53 1370 5 542 4 1 .73 .77 1993 .15 1995 WATER YEAR .15 .75 Nov 21 .09 Jul 31 .12 Jul 27 Nov 21 .71 Nov 21 .32 .36 .0 .40 .19 .32 3.16 1993 .18 1994 .08 .74 1996 .078 1997 WATER 3 802 10500 7 565 8 .07 .63 1997 .074 1997 YEARS 1964 .78 .43 .00 Sep .01 Apr .01 Apr Sep .28 Sep .33 .87 .93 .28 .09 .47 38.0 1995 .25 1994 - 1997 1995 1965 16 1995 5 1995 3 1995 16 1995 16 1995 e Estimated 530 ST. JOHN, U.S. VIRGIN ISLANDS 50295000 GUINEA GOT AT BETHANY, ST. JOHN, VI LOCATION.—Lat 18°19'55", long 64°46'50', Hydrologic Unit 21020001, 600 ft (183 m) southeast of Bethany Church, and 1.0 ml (1.6 km) east of Government House at Cruz Bay. DRAINAGE AREA.—0.37 mi* (0.96 km2 ). PERIOD OF RECORD.—January 1963 to October 1967, September 1982 to current year. GAGE.—Water-stage recorder and concrete control. Elevation of gage is 260 ft (79 m), from topographic map. Prior to September 1982, at datum 1.00 ft (0.30 m) higher. REMARKS.—Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 .05 .02 ,07 2 .05 .02 .06 3 .05 .02 4 .05 .02 5 .04 .03 6 .04 .04 7 .04 .04 8 .04 .03 9 .04 .03 10 .04 .03 11 .04 .03 12 .04 1.8 13 .03 .68 14 .03 .24 15 .03 .13 16 .03 .08 17 .03 .03 18 .03 .03 19 .03 .03 20 .03 .03 21 .03 12 22 .03 1.1 23 .02 .25 24 .02 7.3 25 .02 .65 26 .02 .09 27 .02 .06 28 .03 .80 29 .03 .30 30 .03 .14 31 .02 —— .06 .06 .07 .07 .07 .07 .07 .05 .05 .05 .06 .06 .06 .06 .06 .06 .07 .07 .04 .04 .04 .04 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .05 .06 .06 .06 .06 .06 .06 .06 .07 .07 .05 .05 .05 .04 .04 .04 .04 .04 .04 TOTAL 1.03 26.05 1.76 1.60 MEAN .033 .87 .057 .052 MAX .05 12 .07 .07 MIN .02 .02 .04 .04 AC-FT 2.0 52 3.5 3.2 CFSM .09 2.35 .15 .14 IN. .10 2.62 .18 .16 .06 .05 .04 .05 .05 .05 .05 .05 .05 .05 .05 .04 .04 .03 .02 .02 .02 .01 e.Ol e.Ol .02 .02 .02 .02 .02 .02 .02 .02 —— —— 0.91 .032 .06 .01 1.8 .09 .09 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1983 MEAN .048 .35 .028 .016 MAX .23 2.52 .11 .052 (WY) 1986 1985 1989 1997 MIN .000 .000 .000 .000 (WY) 1992 1992 1987 1992 .008 .032 1997 .000 1992 .02 .02 .02 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .00 .00 .00 .00 .00 .00 0.29 .009 .02 .00 .6 .03 .03 - 1997 .005 .023 1996 .000 1986 SUMMARY STATISTICS FOR 1996 CALENDAR YEAR ANNUAL TOTAL 49.77 ANNUAL MEAN .14 HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN 12 LOWEST DAILY MEAN .00 ANNUAL SEVEN- DAY MINIMUM .00 INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) 99 ANNUAL RUNOFF (CFSM) .37 ANNUAL RUNOFF (INCHES) 5.00 10 PERCENT EXCEEDS .07 50 PERCENT EXCEEDS .02 90 PERCENT EXCEEDS .01 Nov 21 Jun 17 Jun 17 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 — 0.30 .010 .01 .01 .6 .03 .03 .01 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .02 .02 .02 .02 .02 .01 .01 .03 .03 .03 .03 .04 .04 .04 .04 .04 .03 0.62 .020 .04 .01 1.2 .05 .06 .03 .03 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 — 0.35 .012 .03 .01 .7 .03 .04 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 0.31 .010 .01 .01 .6 .03 .03 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .01 .01 .01 .01 .01 .01 .01 .00 0.07 .002 .01 .00 .1 .01 .01 .00 .01 .01 .01 .01 .00 .01 .01 .01 .01 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 —— 0.29 .010 .02 .00 .6 .03 .03 , BY WATER YEAR (WY) .29 4.03 1983 .000 1995 FOR 1997 33 12 319 3 67 3 .089 .89 1986 .000 1994 WATER YEAR .58 .092 Nov 21 .00 Mar 26 . 00 Aug 1 Nov 21 .74 Nov 21 .25 .38 .06 .01 .01 .010 .031 1987 .000 1991 .011 .041 1996 .000 1987 WATER . . . 110 . . 946 5. 56 . 2. . . . .015 .082 1983 .000 1991 YEARS 1963 - 078 35 00 Apr 18 00 Oct 3 00 Jan 9 Apr 18 33 Apr 18 21 86 04 01 00 .30 2.35 1989 .000 1991 1997 1983 1967 1983 1982 1983 1983 1983 e Estimated 531 ST. CROIX, U.S. VIRGIN ISLANDS 50345000 JOLLY HILL GUT AT JOLLY HILL, ST. CROIX, VI LOCATION.—Lat 17°44'00", long 64°51'47", Hydrologic Unit 21020002, on Mahogany Road at Jolly Hill, 1.8 mi (2.9 km) northeast of Frederiksted. DRAINAGE AREA.—2.10 mi 2 (5.44 km2 ). PERIOD OF RECORD.—January 1963 to December 1968. Monthly measurements, 1962-69. October 1982 to current year. GAGE.—Water-stage recorder, crest-stage gage and sharp-crested concrete control. Elevation of gage is 140 ft (43 m), from topographic map. REMARKS.—Records poor. Low-water diversions upstream from station. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 DAILY MEAN VALUES DAY OCT NOV DEC JAN 1 .30 e.15 .30 .26 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 .19 e.14 .21 e.19 .29 e.18 .20 e.15 .17 e.30 .29 e.14 .16 e.12 .19 e.14 .18 e.14 .15 e.20 .16 el. 7 .16 e.29 .14 e.18 .15 e.16 .13 e.25 .14 e.20 .14 e.24 .14 e.32 .14 e.23 . 15 e!7 .14 el . 0 .15 el. 2 .12 el. 6 .11 e.50 .17 e.34 .14 e.32 .37 e.54 .18 e.45 .11 e.41 .13 .27 .30 .28 .28 .29 .25 .28 .27 .24 .37 .22 .21 .21 .21 .21 .21 .21 .23 .23 .21 .23 .23 .23 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .26 .31 .31 .31 .31 .31 .31 .31 .39 .37 .31 .31 .31 .29 .31 .31 .26 .31 .26 .31 .26 .31 TOTAL 5.40 28.78 7.79 9.08 MEAN .17 .96 .25 .29 MAX .37 17 .37 .39 MIN .11 .12 .21 .26 AC-FT 11 57 15 18 CFSM .08 .46 .12 .14 IN. .10 .51 .14 .16 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN .92 .77 .50 .29 MAX 5.92 2.33 2.34 .88 (WY) 1996 1988 1988 1988 MIN .000 .000 .000 .000 (WY) 1987 1992 1992 1992 FEB .32 .29 .27 .29 .30 .29 .29 .29 .29 .29 .29 .30 .29 .29 .29 .29 .29 .29 .29 .28 .28 .28 .27 .27 .27 .27 .24 e.24 - — 7.94 .28 .32 .24 16 .14 .14 YEARS 1986 .19 .55 1988 .000 1989 MAR .25 .24 .23 .22 .22 .21 .22 .22 .21 .20 .18 .18 .18 .18 .19 .18 .17 .14 .18 .13 .13 .13 .13 .12 .12 .11 .11 .12 .12 .11 .11 5.24 .17 .25 .11 10 .08 .09 - 1997 .096 .34 1990 .000 1989 SUMMARY STATISTICS FOR 1996 CALENDAR YEAR ANNUAL TOTAL 150. ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAILY MEAN 62 LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS PEAK FLOW INSTANTANEOUS PEAK STAGE ANNUAL RUNOFF (AC-FT) 298 ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 2. 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 33 41 Sep 10 00 Jun 4 00 Jun 4 20 66 41 14 01 APR .10 .10 .10 .10 .09 .09 .09 .09 .09 .08 .08 .08 .08 .09 .11 .10 .09 .08 .08 .07 .07 .07 .07 .07 e.07 e.09 e.06 e.07 e.06 e.06 —— 2.48 .083 .11 .06 4.9 .04 .04 MAY e.06 .05 .06 .05 .05 .05 .06 .09 .07 .07 .07 .07 .06 .07 .07 .10 .07 .12 .11 .07 .07 .05 .06 .07 .13 .10 .08 .17 .16 .07 .04 2.42 .078 .17 .04 4.8 .04 .04 JUN JXJL e.04 .00 .04 .00 .04 .00 e.05 .00 e.03 .00 .03 .00 e.04 .00 e.04 .00 e.04 e.04 e.04 e.05 e.03 e.02 e.Ol e.OO e.OO .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 AUG SEP .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 e.OO .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 —— .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 0.54 0.00 0.00 0.00 .018 .000 .05 .00 .00 .00 1.1 .00 .01 .00 .01 .00 .000 .000 .00 .00 .00 .00 .00 .00 .00 .00 .00 .00 , BY WATER YEAR (WY) .068 .23 1990 .000 1989 FOR 1997 69 17 11 1 138 1 .093 .46 1992 .000 1989 WATER YEAR .67 .19 Nov 21 .00 Jun 16 .00 Jun 16 Nov 21 .62 Nov 21 .091 .23 .30 .11 .00 .17 .084 1.43 .52 .030 .74 .18 3.80 1987 1987 1987 1995 .000 .000 .000 .000 1989 1989 1989 1991 WATER YEARS 1964 - 1997 .19 .94 .00 62 .00 .00 937 5.38 159 .10 1.42 .64 .04 .00 1996 1965 Sep 10 1996 Oct 1 1985 Sep 4 1986 Sep 15 1995 Sep 15 1995 e Estimated 532 THIS PAGE WAS LEFT BLANK INTENTIONALLY 533 534 GROUND-WATER LEVELS ST. CROIX, U.S. VIRGIN ISLANDS 174225064472000. Local number, 2. LOCATION.—Lat 17°42 1 25", long 64047'20", Hydrologic Unit 21020002, 0.90 mi southeast of the Experimental Station, 0.6 mi southwest of Christiansted Plaza, and 0.18 mi northeast of the Alexander Hamilton Airport entrance on Hwy 64. Owner: U.S. Virgin Islands Government, Name: USGS-10, Fairplains 2 (FP2). AQUIFER.—Alluvium and marl. NELL CHARACTERISTICS.—Drilled unused water-table well, diameter 6 in (0.15 m), cased 6 in (0.15 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 20 ft (6.10 m) above mean sea level, from topographic map. Measuring point: Top of 0.5 in (0.01 m) hole at concrete base wall, 3.00 ft (0.91 m) above land-surface datum. REMARKS.—Recording observation well. Nearby pumping well. PERIOD OF RECORD.—June 1983 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 19.02 ft (5.80 m) below land-surface datum, Feb. 8, 1997; lowest water level recorded, 26.46 ft (8.06 m) below land-surface datum, Aug. 25, 1990. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT 21.14 21.06 20.99 20.92 20.83 20.82 NOV DEC JAN APR JUN JUL 19.35 19.38 19.44 19.56 19.58 19.53 19.49 19.46 19.42 19.81 19.79 19.80 19.92 20.03 20.07 20.01 20.14 20.19 20.24 MEAN 20.96 —— —— —— 19.19 19.43 19.68 19.97 20.16 WTR YR 1997 MEAN 19.94 HIGHEST 19.02 FEB. 8, 1997 LOWEST 21.14 OCT. 1, 1996 20.20 20.08 20.10 20.23 20.13 20.25 20.24 20.26 20.30 20.34 20.31 20.22 20.26 20.24 SEP 19.21 19.16 19.16 19.16 19.13 19.39 19.33 19.28 19.30 19.34 19.57 19.58 19.58 19.60 19.60 19.79 19.91 19.89 19.77 19.80 20.09 20.09 20.19 20.18 20.09 20.27 20.21 20.24 20.14 20.11 20.32 20.25 20.26 20.26 20.27 20.31 20.32 20.36 20.37 20.36 19.07 19.10 19.08 19.07 19.16 19.34 19.35 19.33 19.25 19.26 19.63 19.63 19.63 19.61 19.60 19.88 19.99 19.91 19.90 19.93 20.21 20.22 20.07 20.11 20.22 20.22 20.21 20.21 20.24 20.37 20.25 20.25 20.23 20.20 20.24 20.34 20.25 20.32 20.36 20.36 19.15 19.18 19.10 19.15 19.12 19.33 19.39 19.40 19.47 19.44 19.67 19.66 19.57 19.71 19.66 19.87 19.97 19.95 19.95 20.08 20.14 20.15 20.19 20.16 20.07 20.34 20.36 20.25 20.37 20.38 20.23 20.18 20.20 20.20 20.22 20.39 20.46 20.37 20.40 20.36 19.04 19.18 19.12 19.25 19.26 19.32 19.47 19.52 19.56 19.51 19.65 19.74 19.71 19.69 19.60 19.95 19.95 19.99 20.02 20.02 20.12 20.10 20.22 20.17 20.20 20.30 20.32 20.39 20.33 20.24 20.23 20.13 20.18 20.22 20.22 20.29 20.38 20.28 20.38 20.33 19.32 19.28 19.20 19.28 19.35 19.54 19.52 19.54 19.54 19.60 19.75 19.83 19.81 19.78 19.83 19.99 20.08 20.08 20.04 19.95 20.19 20.19 20.21 20.20 —— 20.15 20.20 20.22 20.17 20.20 20.22 20.22 20.19 20.14 20.32 20.22 20.33 20.39 20.33 20.32 20.36 20.35 20.23 20.33 20.32 20.34 24 •**v^ ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 535 ST. CROIX, U.S. VIRGIN ISLANDS 174243064475100. Local number, 3. LOCATION.--Lat 17°42 1 43", long 64°47'51", Hydrologic Unit 21020002, 0.75 mi northwest of the Alexander Hamilton Airport entrance on Hwy 64, 6.45 mi southwest of Christiansted Plaza, and 0.57 mi southwest of the Experimental Station. Owner: U.S. Virgin Islands Government, Name: Golden Grove - 6 (PW6). AQUIFER.--Alluvium and marl. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 8 in (0.20 m), cased 8 in (0.20 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 40 ft (12.2 m) above mean sea level, from topographic map. Measuring point: Upper edge of hole at 8 in (0.20 m) casing, 4.20 ft (1.28 m) above land-surface datum. REMARKS.--Recording observation well. PERIOD OF RECORD.—March 1982 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 12.99 ft (3.96 m) below land-surface datum, Nov. 10, 1990; lowest water level recorded, 41.05 ft (12.51 m) below land-surface datum, Sept. 15, 1995. OCT DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN WTR YR 1997 WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 NOV DEC JAN FEB MAR APR MAY JUN JUL AUG —— —— —— 24.43 24.51 24.52 —— —— —— 24.52 —— —— —— 24.50 —— —— —— 24.45 24.46 —— —— 24.41 —— —— 24.41 24.48 25.65 25.96 27.23 27.23 MEAN 27.01 HIGHEST 24.32 JAN. 31, 1997 LOWEST 28.18 MAY 22, 1997 27.38 27.45 SEP 25.69 25.74 25.75 25.79 25.81 26.21 26.26 26.28 26.67 26.76 27.19 27.18 27.18 27.15 27.19 27.30 27.31 27.35 27.34 27.41 27.38 27.28 27.30 27.30 27.38 27.62 27.63 27.60 27.61 27.63 25.85 25.83 25.82 25.86 25.90 26.44 26.41 26.41 26.56 27.23 27.19 27.19 27.19 27.21 27.22 27.42 27.40 27.36 27.36 27.42 27.39 27.37 27.36 27.39 27.40 27.61 27.58 27.63 27.65 27.68 25.93 25.92 25.94 25.98 25.98 27.09 26.68 27.55 27.65 27.74 27.20 27.21 27.23 27.24 27.23 27.42 27.41 27.41 27.44 27.43 27.39 27.41 27.41 27.42 27.44 27.76 27.76 27.77 27.79 27.77 25.96 25.96 25.98 26.01 26.03 27.85 27.91 27.95 28.04 28.08 27.22 27.22 27.24 27.25 27.25 27.41 27.43 27.42 27.41 27.43 27.47 27.47 27.45 27.47 27.49 27.76 27.74 27.76 27.75 27.71 26.03 26.04 26.05 26.07 26.16 28.13 28.18 27.62 27.48 27.40 27.24 27.26 27.26 27.25 27.26 27.41 27.41 27.40 27.40 27.38 27.51 27.51 27.51 27.51 27.55 27.73 27.71 27.70 27.70 27.71 —— 25.61 25.63 25.66 25.68 25.68 26.16 26.16 26.17 26.17 26.18 —— 27.29 27.25 27.24 27.23 27.22 27.21 27.26 27.27 27.27 27.30 27.31 —— 27.32 27.28 27.33 27.37 27.36 27.38 27.55 27.56 27.58 27.58 27.56 27.59 27.75 27.72 27.69 27.69 27.69 —— 27.70 20 30 '40 50 /V ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJA 1993 1994 1995 1996 1997 WATER YEAR 536 GROUND-WATER LEVELS ST. CROIX, U.S. VIRGIN ISLANDS 174316064480800. Local number, 13. LOCATION.—Lat 17°43'16", long 64°48 1 08", Hydrologic Unit 21020002, 5.25 mi east of Fort Frederick at Frederickstead, 0.95 mi southeast of Holy Cross Church, and 0.65 mi northeast of Adventure Ruins. Owner: U.S. Virgin Islands Water and Power Authority, Name: WAFA-17 at Adventure well field. AQUIFER.—Kingshill Limestone. WELL CHARACTERISTICS.--Drilled observation well, diameter 4 in (0.10 m), cased 0-95 ft (0-29.0 in), screened 10-40 ft (3.05-12.2 m). Depth 95 ft (29.0 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 75 ft (22.9 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 2.33 ft (0.71 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.--February 28, 1990 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 0.27 ft (0.08 m) below land-surface datum, Sept. 10, 1996; lowest water level recorded, 27.88 ft (8.50 m) below land-surface datum, Sept. 6, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV DEC JAN MAY JUN JUL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN WTR YR 1997 —— —— 6.86 —— —— 6.86 6.64 7.06 7.91 9.19 10.63 MEAN 9.81 HIGHEST 6.61 FEB. 7-10, 1997 LOWEST 13.02 SEPT. 30, 1997 11.75 12.33 SEP 6.75 6.64 6.64 6.63 6.63 6.67 6.72 6.73 6.75 6.75 7.52 7.54 7.56 7.58 7.60 8.66 8.68 8.69 8.70 8.74 9.95 9.97 9.97 9.99 10.04 11.34 11.36 11.44 11.49 11.54 11.73 11.78 11.83 11.87 11.92 12.72 12.73 12.75 12.75 12.77 6.62 6.61 6.61 6.61 6.61 6.78 6.81 6.84 6.84 6.88 7.62 7.65 7.67 7.69 7.71 8.78 8.82 8.84 8.85 8.89 10.10 10.16 10.22 10.32 10.37 11.58 11.63 11.67 11.71 11.75 11.97 12.02 12.05 12.09 12.13 12.77 12.78 12.79 12.79 12.81 6.62 6.62 6.62 6.62 6.63 6.91 6.94 6.96 6.96 7.01 7.74 7.76 7.78 7.81 7.84 8.93 8.98 9.02 9.06 9.09 10.42 10.47 10.54 10.59 10.63 11.79 11.82 11.86 11.92 11.95 12.16 12.21 12.23 12.27 12.32 12.88 12.92 12.93 12.95 12.95 6.63 6.63 6.63 6.64 6.64 7.03 7.06 7.09 7.10 7.13 7.86 7.88 7.90 7.93 7.96 9.13 9.19 9.23 9.29 9.35 10.67 10.74 10.80 10.84 10.90 11.98 12.03 12.06 12.11 12.14 12.34 12.40 12.44 12.47 12.51 12.26 12.41 12.58 12.69 12.77 6.64 6.64 6.65 6.65 6.65 7.20 7.24 7.29 7.32 7.35 7.98 8.01 8.05 8.15 8.22 9.38 9.43 9.47 9.52 9.57 10.96 10.99 11.05 11.10 11.12 12.12 12.13 12.13 11.44 11.53 12.57 12.60 12.64 12.66 12.68 12.82 12.84 12.84 12.85 12.88 6.66 6.66 6.67 —— —— —— 7.38 7.41 7.43 7.45 7.47 7.50 8.30 8.38 8.46 8.52 8.59 —— 9.61 9.66 9.70 9.77 9.85 9.90 11.12 11.14 11.19 11.24 11.34 —— 11.58 11.65 11.71 11.60 11.61 11.69 12.69 12.69 12.70 12.70 12.71 12.71 12.92 12.93 12.96 12.97 12.99 —— 12.80 10 ? 20 30 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS 537 ST. THOMAS, U.S. VIRGIN ISLANDS 182038064550300. Local number, 6. LOCATION.—Lat 18°20'38", long 64°55'03", Hydrologic Unit 21020001, 1.12 mi east of Charlotte Amalie, 0.75 mi southwest of Winterberg Peak, and 1.08 mi southeast of Canaan. Owner: U.S. Virgin Islands Government, Name: Grade School 3. AQUIFER.--Volcanic breccia. WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 6 in (0.15 m), cased 6 in (0.15 m). Depth 70 ft (21.3 m). INSTRUMENTATION.—Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 60 ft (18.3 m) above mean sea level, from topographic map. Measuring point: Top of 0.5 in (0.01 m) hole at 6 in (0.15 m) casing, 1.30 ft (0.40 m) above land-surface datum. Prior to June 27, 1983, top of 6 in (0.15 m) casing, 2.90 ft (0.88 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—March 1982 to current year. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 1.53 ft (0.47 m) below land-surface datum, Oct. 1, 1989; lowest water level recorded, 35.38 ft (10.79 m) below land-surface datum, July 21, 1982. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 MEAN WTR YR 1997 DEC JAN FEB APR MAY JUN JUL AUG —— —— —— 22.00 23.91 26.03 27.94 29.22 MEAN 27.22 HIGHEST 20.84 FEB. 12, 1997 LOWEST 30.98 AUG. 13, 1997 30.23 29.55 SEP 22.70 22.83 22.94 22.98 23.03 25.11 25.17 25.22 25.27 25.33 26.98 27.07 27.15 27.23 27.31 28.63 28.66 28.57 28.62 28.67 29.86 29.90 29.93 29.97 30.01 30.42 30.50 30.55 30.60 30.64 28.18 28.36 28.53 28.69 28.86 23.10 23.19 23.27 23.33 23.42 25.38 25.44 25.50 25.57 25.64 27.38 27.46 27.55 27.62 27.69 28.73 28.80 28.86 28.92 28.96 30.06 30.10 30.15 30.19 30.24 30.69 30.74 30.78 30.82 30.88 29.03 29.17 26.87 25.62 25.37 —— —— 20.99 21.16 21.36 23.53 23.65 23.72 23.79 23.85 25.70 25.77 25.85 25.93 26.00 27.75 27.82 27.87 27.91 27.98 29.02 29.07 29.13 29.19 29.24 30.28 30.32 30.35 30.39 30.42 30.92 30.95 30.97 30.63 29.84 25.41 25.56 25.76 26.00 26.21 21.54 21.72 21.89 22.02 22.13 23.92 24.01 24.09 24.17 24.26 26.07 26.14 26.22 26.30 26.38 28.04 28.07 28.10 28.13 28.18 29.29 29.35 29.41 29.47 29.52 30.47 30.50 30.52 30.51 30.42 29.31 29.04 28.94 28.93 28.98 26.12 25.51 25.37 25.47 25.66 22.24 22.31 22.34 22.33 22.37 24.36 24.44 24.54 24.62 —— 26.46 26.52 26.58 26.63 26.65 28.25 28.31 28.33 28.36 28.40 29.50 29.50 29.53 29.57 29.62 30.33 30.26 30.18 30.17 30.20 29.07 29.20 28.99 28.81 28.29 25.87 25.99 26.08 26.18 26.06 22.43 22.50 22.60 —— —— —— 24.76 24.84 24.92 24.98 25.02 25.06 26.69 26.74 26.79 26.84 26.88 —— 28.43 28.48 28.53 28.51 28.53 28.57 29.65 29.70 29.74 29.78 29.82 30.21 30.19 30.20 30.23 30.30 30.35 27.73 27.58 27.60 27.69 27.83 27.99 25.78 24.42 23.88 23.80 23.88 —— 26.26 > 40 S ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 538 GROUND-WATER LEVELS ST. THOMAS, U.S. VIRGIN ISLANDS 182038064580000. Local number, 8. LOCATION.—Lat 18°20'38", long 64°58'00", Hydrologic Unit 21020001, 2.08 mi northwest of Charlotte Amalie, 0.50 mi northeast of Harry S. Truman Airport entrance on Hwy 302, and 1.15 mi southwest of Dorothea. Owner: U.S. Virgin Islands Water and Power Authority, Name: Kirwan Terrace, VIEO-6. AQUIFER.--Alluvial deposits, volcanic rock. WELL CHARACTERISTICS.—Drilled observation well, diameter 4 in (0.10 m), cased 0-56 in (0-17.1 m), screened 56-76 ft (17.1-23.2 m). Depth 76 ft (23.2 m) . INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 35 ft (10.7 m) above mean sea level, from topographic map. Measuring point: Top of shelter floor, 3.00 ft (0.91 m) above land-surface datum. REMARKS.—Observation well. Drilled on July 1, 1991. Automated digital recorder installed on October 2, 1991. PERIOD OF RECORD.—October 2, 1991 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 14.34 ft (4.37 m) below land-surface datum, Dec. 6, 7, 1996; lowest water level recorded, 32.67 ft (9.96 m) below land-surface datum, July 27, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV DEC JAN FEB APR JUL AUG MEAN 25.62 23.34 15.06 17.75 19.03 WTR YR 1997 MEAN 24.61 HIGHEST 14.34 DEC. 6, 7, 21.69 24.85 27.23 28.83 1996 LOWEST 31.12 SEPT. 7, 1997 30.06 30.74 SEP 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 25.31 25.32 25.34 25.38 25.40 25.42 25.43 25.47 25.52 25.52 25.51 25.51 25.48 25.47 25.51 25.56 25.59 25.64 25.66 25.70 25.69 25.71 25.76 25.81 25.85 25.90 25.91 25.91 25.93 25.96 25.98 26.02 26.06 26.07 26.08 26.13 26.17 26.15 26.13 26.15 26.17 26.18 26.10 25.91 25.76 25.68 25.65 25.55 25.47 25.38 25.33 24.63 22.07 20.32 19.01 17.64 16.69 16.04 15.55 15.18 14.91 —— 14.66 14.50 14.42 14.39 14.37 14.35 14.35 14.37 14.43 14.52 14.55 14.61 14.65 14.73 14.78 14.83 14.93 15.02 15.13 15.20 15.30 15.40 15.50 15.62 15.73 15.83 15.94 16.06 16.15 16.19 16.28 16.49 16.51 16.64 16.76 16.89 17.02 17.17 17.31 17.38 17.45 17.52 17.64 17.76 17.89 18.01 18.15 18.29 18.42 18.55 18.69 18.73 18.53 18.09 17.88 17.83 17.85 17.93 18.04 18.17 18.29 18.40 18.48 18.27 18.13 18.09 18.12 18.18 18.27 18.33 18.40 18.50 18.59 18.82 18.92 19.00 19.09 19.14 19.24 19.34 19.42 19.52 19.60 19.68 19.75 19.81 19.88 19.98 20.10 20.20 —— —— 20.32 20.42 20.51 20.63 20.71 20.78 20.87 20.96 21.03 21.08 21.18 21.27 21.36 21.45 21.53 21.61 21.70 21.81 21.92 22.03 22.13 22.25 22.35 22.45 22.55 22.64 22.75 22.88 22.99 23.10 23.22 23.33 23.48 23.62 23.75 23.85 23.96 24.06 24.17 24.29 24.40 24.50 24.59 24.69 24.79 24.88 24.96 25.06 25.14 25.22 25.31 25.39 25.46 25.55 25.64 25.72 25.77 25.85 25.92 26.00 26.16 —— 26.25 26.33 26.42 26.48 26.54 26.60 26.69 26.76 26.85 26.91 26.98 27.04 27.11 27.15 27.21 27.27 27.33 27.41 27.47 27.52 27.57 27.63 27.70 27.75 27.79 27.81 27.85 27.89 27.93 27.97 28.02 28.05 28.09 28.24 28.28 28.36 28.43 28.48 28.53 28.57 28.61 28.65 28.70 28.75 28.80 28.85 28.90 28.95 29.01 29.06 29.10 29.14 29.15 29.16 29.17 29.20 29.24 29.28 29.33 29.38 29.43 —— 29.49 29.53 29.58 29.63 29.67 29.73 29.76 29.80 29.83 29.87 29.91 29.95 29.99 30.04 30.07 30.11 30.14 30.18 30.21 30.25 30.28 30.31 30.34 30.36 30.38 30.40 30.42 30.43 30.43 30.42 30.44 30.46 30.49 30.52 30.55 30.58 30.62 30.65 30.69 30.72 30.75 30.79 30.82 30.85 30.86 30.85 30.83 30.81 30.80 30.82 30.83 30.83 30.84 30.84 30.84 30.80 30.76 30.74 30.73 30.73 30.76 30.82 30.84 30.89 30.94 31.00 31.05 31.09 31.12 31.06 30.98 30.93 30.90 30.88 30.85 30.85 30.84 30.81 30.79 30.75 30.73 30.72 30.73 30.72 30.70 30.71 30.69 30.66 30.62 30.61 30.57 30.56 —— 30.82 30 40 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 5 ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR GROUND-WATER LEVELS ST. JOHN, U.S. VIRGIN ISLANDS 539 181956064464500. Local number, 11. LOCATION. --Lat 18°19'56", long 64°46 1 45", Hydrologic Unit 21020001, 1.05 mi southeast of Cruz Bay plaza, 0.25 mi southeast of Bethany Church, and 0.48 mi southeast of Margaret Hill. Owner: U.S. Virgin Islands Government, Name: Guinea Gut Well. AQUIFER.--Louisenhoj Formation (Donnelly, 1959). WELL CHARACTERISTICS.—Drilled unused water-table well, diameter 6 in (0.15 m), cased 6 in (0.15 m). Depth 85 ft (25.9 m). INSTRUMENTATION.--Digital water level recorder—60-minute punch. DATUM.—Elevation of land-surface datum is about 280 ft (85.36 m) above mean sea level, from topographic map. Measuring point: Bottom of 0.5 in (0.01 m) hole at 6 in (0.15 m) casing, 1.50 ft (0.46 m) above land-surface datum. Prior to June 28, 1983, top of 6 in (0.15 m) casing, 1.80 ft (0.55 m) above land-surface datum. REMARKS.—Recording observation well. PERIOD OF RECORD.—March 1982 to current year. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 2.71 ft (0.79 m) below land-surface datum, Jan. 3, 1990; lowest water level recorded, 34.18 ft (10.42 m) below land-surface datum, Sept. 6, 1995. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997 INSTANTANEOUS OBSERVATION AT 1200 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OCT 6.54 6.53 6.48 6.50 6.50 6.52 6.55 6.58 6.59 6.59 6.60 6.62 6.67 6.74 6.84 6.93 7.02 7.14 7.30 7.56 7.77 7.97 8.15 8.38 8.62 8.78 8.83 8.83 8.80 8.79 8.91 NOV 9.04 9.15 9.25 9.37 9.46 9.47 9.27 9.23 9.21 9.07 9.02 7.04 5.53 5.19 5.11 5.12 5.17 5.20 5.21 5.13 4.10 4.05 3.99 3.62 3.79 3.82 3.84 3.85 3.76 3.71 DEC 3.75 3.78 3.78 3.75 3.74 3.71 3.69 3.65 3.63 3.62 3.58 3.60 3.58 3.56 3.54 3.53 3.58 3.59 3.56 3.55 3.52 3.55 3.53 3.56 3.56 3.56 3.60 3.63 3.55 3.38 3.42 JAN 3.50 3.39 3.44 MAY AUG SEP 4.65 4.74 4.77 4.83 4.84 8.64 8.83 9.02 9.19 9.38 12.76 12.90 12.99 13.14 13.28 16.12 16.18 16.32 16.41 16.54 19.17 19.32 19.40 19.51 19.59 21.09 21.16 21.25 21.33 21.43 22.99 23.07 23.14 23.19 23.28 4.86 4.92 4.98 4.97 5.03 9.57 9.76 9.90 10.03 10.16 13.40 13.56 13.73 13.83 13.87 16.71 16.82 16.95 17.09 17.20 19.70 19.78 19.86 19.94 19.98 21.52 21.59 21.70 21.76 21.83 23.33 23.38 23.40 23.43 23.47 .__ 05 10 5.12 5.18 5.29 5.37 5.42 10.29 10.40 10.53 10.64 10.77 13.94 14.04 14.15 14.28 14.39 17.32 17.41 17.54 17.67 17.77 20.04 20.09 20.14 20.25 20.34 21.88 21.93 21.98 22.00 22.06 23.50 23.53 23.58 23.61 23.65 20 24 31 35 22 5.53 5.67 5.80 5.85 6.07 10.88 11.01 11.12 11.25 11.34 14.53 14.67 14.79 14.94 15.09 17.90 17.99 18.11 18.18 18.30 20.39 20.43 20.46 20.49 20.50 22.12 22.18 22.26 22.33 22.39 23.62 23.59 23.56 23.55 23.53 17 16 20 20 33 6.30 6.52 6.77 6.98 7.25 11.46 11.60 11.74 11.85 12.03 15.19 15.31 15.36 15.36 15.49 18.37 18.50 18.60 18.59 18.67 20.45 20.47 20.50 20.54 20.59 22.48 22.55 22.59 22.66 22.70 23.54 23.55 23.53 23.54 23.55 43 48 56 .__ 7.53 7.69 7.91 8.09 8.23 8.44 12.17 12.31 12.45 12.52 12.64 ___ 15.52 15.60 15.70 15.78 15.90 16.00 18.74 18.83 18.92 18.99 19.10 —— 20.64 20.70 20.79 20.87 20.94 21.01 22.73 22.77 22.80 22.83 22.87 22.93 23.55 23.50 23.44 23.42 23.41 ___ MEAN 7.38 6.29 WTR YR 1997 MEAN 12.68 3.60 3.44 4.27 5.99 10.78 14.50 17.73 HIGHEST 3.33 DEC. 30, 1996 LOWEST 23.65 SEPT. 15, 1997 20.22 22.12 23.45 20 40 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJASONDJFMAMJJAS 1993 1994 1995 1996 1997 WATER YEAR 540 THIS PAGE WAS LEFT BLANK INTENTIONALLY 541 INDEX Page Page Access to U.S. Geological Survey Water Data................................ 29 Acre-foot, definition of.................................................................... 30 Adenosine triphosphate, definition of.............................................. 30 Adjuntas, Lago Garzas near............................................................. 58 Adjuntas, Lago Garzas No. 1 near dam near............451-454,459-461 Adjuntas, Rio Cidra at.................................................................... 436 Adjuntas, Rio Grande de Arecibo near................................ 59,60,436 Adjuntas, Rio Vacas near............................................................. 436 Aguada, Rio Cano near.................................................................. 446 Aguada, Rio Culebrinas near.................................................. 433,434 Aguas Buenas, Quebrada Grande near.......................................... 444 Aguas Buenas, Rio Cagiiitas near...........................................235-241 Aguas Buenas, Rio de Bayamdn near..................................... 178,179 Aguas Verdes basin, Quebrada, ground-water records in.............................................. 512-515 Aibonito, at Llanos near Aibonito, Rio.......................................... 443 Algae growth potential, definition of............................................... 30 Almirante Sur, Rio Unibon off Highway 160 near........................ 441 Annual 7-day minimum, definition of............................................. 32 Anasco, Rio Grande de Anasco near...................................... 426,427 Aquifer, definition of.....................................................................:. 30 Arecibo, Rio Grande de Arecibo above...................................... 91-97 Arecibo, Rio Tanama above Observatorio de................................ 438 Arenas near Utuado, Quebrada...................................................... 437 Arenas, Rio de Bayamon at........................................................... 168 Arroyatas on Highway 171 at Cidra, Rio....................................... 443 Arroyatas at mouth near Comerio, Rio.......................................... 443 Arroyatas on Highway 775 near Cidra, Rio................................... 443 Artesian, definition of...................................................................... 30 Artificial substrate, definition of...................................................... 37 Ash mass, definition of.................................................................... 31 B Bacteria, definition of...................................................................... 30 Bahia de San Juan No. 5 at San Juan............................................. 192 Bairoa at Bairoa, Rio............................................................... 257-262 near Caguas........................................................................ 263,264 Barranquitas at Barranquitas, Rio.................................................. 443 Barranquitas, Rio Grande de Manati, near.....................................438 Barranquitas, Rio Usabon on Highway 162, near.......................... 442 Bauta at Pozas, Rio........................................................................ 440 Bauta near Divisoria, Rio............................................................... 440 Bauta near Orocovis, Rio............................................................... 120 Bayamdn at Hood Channel at Bayamon, Rio de..........................................................................183,184 at Arenas.................................................................................... 168 near Aguas Buenas.................................................................... 444 near Bayamon............................................................................ 444 Bayamon basin, Rio de, gaging station records in..................................................................... 168-184 low-flow partial-records stations in............................ 444,445 water-quality records in...................................................... 172-184. water-quality partial record analysis of samples collected at .........................................448-461 Bayamtfn below Lago de Cidra, Rio de.................................. 171-177 Bayamdn Mouth, Lago de Cidra near.....................................448-450 near Aguas Buenas............................................................. 178,179 near Bayamdn............................................................................ 180 Bayamtfn, Quebrada Cerro Gordo at La Aldea at.......................... 444 Bayamtfn, Quebrada Santa Olaya on Highway 174 near............... 445 Bayamtfn near Minillas, Rio.......................................................... 445 Bayamon, Rio Guaynabo near................................................ 181,182 Bayaney, Rio Camuy near............................................................... 56 Beatriz on Highway 1 near Cayey, Quebrada................................ 442 Bed material, definition of................................................................31 Bed load, definition of......................................................................36 Bed load discharge, definition of .....................................................36 Biochemical oxygen demand, definition of .....................................31 Biomass, definition of ......................................................................31 Blanca at El Jagual, Quebrada................................................. 197-203 Blanco basin, Rio, gaging station records in.........................................................................344,345 Blasina near Carolina, Quebrada............................................. 194,195 Blue-green algae, definition of......................................................... 35 Bonne Resolution Gut at Bonne Resolution, St. Thomas, VI....................................................528 Borinquen, Rio Turabo above .................................................219-225 Botijas near Botijas, Rio.................................................................439 near Cairo...............................................................................439 Bottom material, definition of..........................................................31 Bucana at Highway 14 bridge near Ponce, Rio..............................388 Bucana basin, Rio, gaging station records in........................................................................383-388 water-quality records in .......................................................386,387 Bucarabones near Toa Alta, Rio.....................................................444 Cacao, Rio Toro Negro on Highway 157 at................................... 439 Caguana, Rio Tanama near ............................................................438 Caguana, on Highway 10 near Utuado, Rio. ................................. .437 Caguas, Lago Loiza No. 4 near mouth Caguas, Rio Bairoa near. ....................................................... ..263,264 Caguas, Rio Cagiiitas at Highway 30 at .................................255,256 Caguas, Rio Cagiiitas at Villa Blanca at.. ........................... .....248-254 Caguas, Rio Caguitas near........... .................................... ........242-247 Caguas, Rio Grande de Loiza at............................................. 226-234 Caguitas at Highway 30 at Caguas, Rio............................ ...... 255,256 at Villa Blanca at Caguas ............................................... ......248-254 near Caguas..................................... ................................... ..242-247 near Aguas Buenas...............................................................235-241 Caimito, Quebrada Las Curias Tributary near ...............................445 Campo Rico, Rio Candvanas near.................................................. 306 Camuy basin, Rio, gaging station records in....... ...................................................................... 55,56 low-flow partial-records stations in .......................................436 Camuy near Bayaney, Rio................................................................ 56 near Lares.... ................................................................................ 436 off Highway 129 near Lares .......................................................436 Canal Principal de Diversiones at Lago deGuajataca............................................................... 50,51 CanoVanas near Campo Rico, Rio................................................. 306 Canas at Achiote near Naranjito, Rio... .......................................... 443 at Rio Cafias........... ......................................................... .....288-294 Canas basin, Rio, gaging station records in. ........................................................................... ....288 water-quality records in.... ......................................... ......289-294 Cano near Aguada, Rio ..................................................................446 Caonillas above Lago Caonillas, Rio .............................................438 Caonillas above Lago Caonillas near Jayuya, Rio ......................86,87 Caonillas at Paso Palma, Rio. ................................................ ......74-85 Caonillas, Lago Caonillas at Damsite near Utuado.......................... 88 Caricaboa at Jayuya, Rio ................................................................437 Carolina, Quebrada Blasina near............................................. 194,195 Cairo, Rio Botijas near. ............................................................. .....439 Castaner, Lago Guayo at Damsite near .......................................... 420 Catano, Rio Hondo at Hood Channel near.............................. 166,167 Cayaguas at Cerro Gordo, Rio ...................................................... 21 1 Cayey, Lago Carite at Gate Tower near......................................... 140 Cayey, Lago Carite No. 1 near dam near ................. 451-454,459-461 542 INDEX Page Page Cayey, Lago Carite No. 3 on Rio de La Plata near................................................................ 448-460 Cayey, Quebrada Beatriz on Highway 1, near............................... 442 Cayey, Quebrada Santo Domingo at.............................................. 442 Cayey, Rio de La Plata on Highway 171, near.............................. 442 Cayey, Rio de La Plata on Highway 738, near.............................. 442 Cayey, Rio Guavate on Highway 52, near..................................... 442 Cells/volume, definition of.............................................................. 31 Central Cambalache, Rio Grande de Arecibo at..................... 108-110 Central Pellejas, Rio Pellejas at..................................................... 436 Central Pellejas, Rio Vivi near....................................................... 437 Central Rufma, Rio Guayanilla at........................................... 395,396 Cerrillos above Lago Cerrillos near Ponce, Rio ............................ 383 near Ponce..........................................................................385-387 Cerro Gordo at La Aldea at Bayamon, Quebrada.......................... 444 Cerro Gordo, Rio Cayaguas at....................................................... 211 Charco Hondo, Rio Tanama at....................................................... 107 Chemical oxygen demand, definition of.......................................... 31 Chico at Providencia, Rio....................................................... 358,359 Chico basin, Rio, water-quality records in.............................. 358,359 Chlorophyll, definition of............................................................... 31 Ciales, Rio Cialitos at Highway 649 at .......................... 124,125,440 Ciales, Rio Cialitos on Highway 614, near.................................... 440 Ciales, Rio Grande de Manati at.................................................... 121 Ciales, Rio Grande de Manati at Highway 149 at.................. 122,123 Ciales,Rio Toro Negro, near.......................................................... 440 Cialitos at Cialitos, Rio.................................................................. 440 Cialitos at Highway 649 at Ciales, Rio............................ 124,125,440 Cialitos on Highway 614 near Ciales, Rio..................................... 440 Cibuco at Vega Baja, Rio....................................................... 135-137 at Cibuco................................................................................... 441 below Corozal................................................................... 132-134 on Highway 620 near Vega Alta............................................... 441 Cibuco basin, Rio, gaging-station records in.....................................................................132-137 ground-water records in ..................................................... 477-482 low-flow partial-record stations in..................................... 440-442 water-quality records in...................................................... 133-137 Cidra at Adjuntas, Rio.................................................................... 436 Cidra, Lago de Cidra at Damsite near.............................. 455-461,170 Cidra, Rio Arroyataon Highway 171 at........................................ 443 Cidra, Rio Arroyatas on Highway 775 near................................... 443 Coamo basin, Rio, gaging station records in........................................................................ 368-370 ground-water records in .............. .............................................. 511 water-quality records in....................................................... 369,370 Coamo at Coamo, Rio.................................................................... 368 near Coamo......................................................................... 369,370 Color unit, definition of................................................................... 31 Comerio, Rio Arroyatas at mouth near.......................................... 443 Comerio, Rio de La Plata at.................................................... 143-149 Comerio, Rio de La Plata near................................................ 150,151 Contents, definition of..................................................................... 31 Control, definition of....................................................................... 32 Control structure, definition of........................................................ 32 Cooperation........................................................................................ 2 Corozal, Rio Cibuco below..................................................... 132-134 Corozal, Rio Corozal above Sewage plant, at................................ 440 Corozal, Riodelos Negros at mouth, at........................................440 Corozal, Rio Grande de Manati, near............................................ 439 Corozal, Rio Mavillaon Highway 164, near................................. 441 Criminales near Lares, Rio ............................................................ 436 Cruz near Toa Alta, Quebrada....................................................... 444 Cubic foot per second, definition of................................................ 32 Cubic foot per second-day, definition of......................................... 32 Cubic feet per second per square mile, definition of............................................................................ 32 Cuesta Arriba on Highway 816 at Nuevo, Rio...............................443 Culebrinas at Highway 404 near Moca, Rio ..................................432 at Perchas No. 1 ..........................................................................446 at San Sebastian ..........................................................................446 near Aguada......................................................................... 433,434 near San Sebastian ...............................................................430,431 Culebrinas basin, Rio, gaging station records in ....................................................................432 ground-water records in.............................................................. 525 low-flow partial-record stations in..............................................446 water-quality records in .......................................................430-434 D Definition of terms ......................................................................30-39 Descalabrado basin, Rio, gaging station records in ....................................................................371 Descalabrado near Los Llanos, Rio................................................371 Diatoms, definition of.......................................................................35 Discharge at low-flow partial-record stations in Puerto Rico ...........................................................435 Discharge, definition of.................................................................... 32 Dissolved, definition of ....................................................................32 Dissolved-solids concentrations, definition of .................................32 Divisoria, Rio Bauta near ...............................................................440 Diversity index, definition of ...........................................................32 Drainage area, definition of..............................................................32 Drainage basin, definition of ............................................................33 Dry mass, definition of.....................................................................31 E El Jagual, Quebrada Blanca at................................................. 197-203 El Mang6, Rio Gurabo below..................................................265-271 El Verde, Quebrada Sonadora near......................................... 308,309 El Verde, Rio Grande near............................................................. 313 Esperanza, Rio Tanama at..............................................................438 Espiritu Santo basin, Rio, gaging station records in..........................................................308-313 water-quality records in ......................................................311,312 Espiritu Santo near Rio Grande, Rio.......................................310-312 Explanation of records........................................................................9 Fajardo above Fajardo, Rio .....................................................322-332 below Fajardo .....................................................................342,343 near Fajardo........................................................................333-341 Fajardo basin, Rio, gaging station records in .....................................................................322-343 ground-water records in ......................................................504-507 water-quality records in ......................................................324-343 Fecal coliform bacteria, definition of ..............................................31 Fecal streptococcal bacteria, definition of........................................31 Florida, Rio Grande de Arecibo below Lago Dos Bocas near.......................................................89,90 Frailes on Highway 169 at Guaynabo, Quebrada...........................445 Fronton, Rio Yunes at ....................................................................438 Gage-height, definition of ................................................................33 Gaging station, definition of.............................................................33 Grande de Anasco basin, Rio, gaging station records in..........................................................420-427 water-quality records in ......................................................421-427 INDEX Page 543 Page Grande de Anasco near Anasco, Rio...................................... 426,427 near Lares........................................................................... 421,422 near San Sebastian.............................................................. 423-425 Grande de Arecibo at Central Cambalache, Rio........................................ 108-110 above Arecibo........................................................................91-97 below Lago Dos Bocas near Florida...................................... 89,90 below Utuado.........................................................................61-70 near Adjuntas.................................................................. 71,72,436 near Utuado..................................................................... 71,72,437 Grande de Arecibo basin, Rio, gaging station records in........................................................... 58-110 ground-water records in .....................................................466-470 low-flow partial-record station in....................................... 436-438 water-quality partial-record stations, analyses of samples collected at..................................................................448-461 water-quality records in.......................................................... 59-72 Grande de Jayuya at Jayuya, Rio................................................... 437 Grande de Loiza at Caguas, Rio ............................................. 226-234 at Highway 183 near San Lorenzo.....................................212-218 at Quebrada Arenas................................................................... 196 below Damsite....................................................................297-303 below Trujillo Alto............................................................. 304,305 Grande de Loiza basin, Rfo, gaging station records in......................................................... 194-306 ground-water records in ..................................................... 500-503 water-quality partial-record stations, analyses of samples collected at.................................................................. 448-461 water-quality records in...................................................... 194-305 Grande deManati at Ciales, Rio.................................................... 121 at Highway 2 near Manati................................................... 126-128 at Highway 149 at Ciales .................................................... 122,123 near Barranquitas........................................................................... 438 near Corozal............................................................................... 439 near Manati................................................................................. 440 near Morovis ....................................................................... 115-117 Grande de Manati basin, Rio, gaging station records in............................................................. 112-129 ground-water records in ......................................................471-476 low-flow partial-record stations in...................................... 439,440 water-quality records in....................................................... 113-129 Grande de Patillas near Patillas, Rio....................................... 360-362 Grande de Patillas basin, Rio, gaging station records in .....................................................360-363 water-quality records in....................................................... 361,362 Grande near Aguas Buenas, Quebrada.......................................... 444 Grande near Moca, Quebrada........................................................ 446 Grande near El Verde, Rio............................................................. 313 Graphs: Ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands.................................... 7 Monthly-mean discharge of selected streams in Puerto Rico............................................................... 4 Green algae, definition of................................................................ 35 Grid showing system for numbering wells and miscellaneous sites (latitude and longitude)............................................................ 19 Ground-water level, records of ...................................................27,28 Ground-water quality, records of................................................ 28,29 Ground-water records for Puerto Rico.................................... 463-525 Ground-water records for U.S. Virgin Islands........................533-539 Ground-water station, definition of.................................................. 33 Ground-water stations in Puerto Rico, map showing location of.......................................................... 16 Ground-water stations in U.S. Virgin Islands, map showing location of .......................................................... 18 Guaba near Naguabo, Quebrada..................................................... 344 Guadiana above Sewage plant at Naranjito, Rio. .......................... .443 Guadiana near Naranjito, Rio... ............................................... 152,153 Guajataca above mouth near above Sewage plant at Lares.... ................................................... 436 at Lares. ............................................................................. .......46-48 Guajataca basin, Rio, gaging station records in. ......................................................................... ...46-53 ground-water records in.. ................................................... ..464,465 low-flow partial-record stations in....... ....................................... 436 water-quality partial-record stations, analyses of samples collected at... ................................. ..448-461 water-quality records in ...........................................................47-53 Guanajibo at Highway 1 19 at San German, Rio ............................402 near Hormigueros ................................................................413-415 near San German. ................................................................ .403,404 Guanajibo basin, Rio, gaging station records in.... ............................................................. ........402-415 ground-water records in .......................................................523,524 water-quality records in .......................................................403-415 Guanica, Rio Loco at............................................................... 399,400 Guaonica near Utuado, Rio ............................................................437 Guatemala at San Sebastian, Rio... ............................................... ..446 Guavateon Highway 52 nearCayey, Rio. ..................................... 442 Guayanes above mouth at Playa de Guayanes, Rio.....................................................................353,354 at Yabucoa .............. ......................................................... ...351,352 Guayanes basin, Rio, ground- water records in............................... 508 water-quality records in... ............................................ 351-354 Guayanilla at Central Rufina, Rio ........................................ ...395,396 near Guayanilla.......................................................................... 394 Guayanilla basin, Rio, gaging station records in..........................................................394-396 water-quality records in..................................................... 395,396 Guaynabo at Highway 836 near Guaynabo, Rio.... ........................ 445 Guaynabo below Guaynabo, Rio.................................................... 445 Guaynabo near Bayamon, Rio................................................. 181,182 Guaynabo, Quebrada Frailes on Highway 169 at........................... 445 Guinea Gut at Bethany, St. John, VI. .......................................... ...530 Gurabo at Gurabo, Rio ............................................................279-285 below El Mango..................................................................265-271 near Gurabo ................... .....................................................286-287 H Hardness, definition of .....................................................................33 Hato Rey, Rio Piedras at .........................................................188-190 Hondas at mouth at proyecto La Plata, Quebrada..........................442 Hondo at Flood Channel near Catano, Rio.............................. 166,167 on Highway 776 at Rio Hondo...........................................443 Hondo II at Sabana Seca, Rio.........................................................444 Hondo basin, Rio, water-quality records in.............................166,167 Hormigueros, Rio Guanajibo near...........................................413-415 Hormigueros, Rio Rosario near...............................................405-412 Humacao at Highway 3 at Humacao, Rio............................... 349,350 at Las Piedras.............................................................................348 Humacao basin, Rio, gaging station records in.....................................................................348-350 water-quality records in...................................................... 349,350 Hydrologic Bench-Mark Network, definition of ..........................................................................33 Hydrologic conditions, summary of ................................................3-8 Hydrologic unit, definition of...........................................................33 544 INDEX Page Page Icacos near Naguabo, Rfo.............................................................. 345 Identification numbers, stations....................................................... 10 Inabon at Real Abajo, Rio.............................................................. 382 Inabon basin, Rfo, gaging station records in ................................. 382 ground-water records in..................................................... 521 Indio, on Highway 22 at Rfo Abajo, Rfo....................................... 442 Instantaneous discharge, definition of............................................. 32 Introduction........................................................................................ 1 Jacaguas at JuanaDfaz, Rfo........................................................... 380 Jacaguas basin, Rfo, gaging station records in..................................................................... 372-380 water-quality records in...................................................... 373-378 Jauca at mouth near Jayuya, Rfo.................................................... 437 Jauca near Jayuya, Rfo................................................................... 437 Jayuya, Rfo Caonillas above Lago Caonillas near...................... 86,87 Jayuya, Rfo Caricaboa at................................................................ 437 Jayuya, Rfo Grande de Jayuya at................................................... 437 Jayuya, Rfo Jauca at mouth near.................................................... 437 Jayuya, Rfo Jauca near................................................................... 437 Jayuya, Rfo Saliente at Coabey near................................................ 73 Jolly Hill Gut at Jolly Hill, St. Croix, VI....................................... 531 Juana Dfaz, Lago Guayabal at Damsite near................................. 379 Juana Dfaz, Rfo Jacaguas at........................................................... 380 Juncos, Rfo Valenciano near...................................................272-278 Lago Caonillas, Rfo Caonillas above............................................. 438 Lago Caonillas at Damsite near Utuado.......................................... 88 Lago Carite at Gate Tower near Cayey.......................................... 140 Lago Carite No. 1 near dam near Cayey...................451-454,459-461 No. 3 on Rfo de La Plata near Cayey ..................................448-450 Lago Cerrillos at Damsite near Ponce ........................................... 384 Lago Cerrillos near Ponce, Rfo Cerrillos above............................ 383 Lago de Cidra at Damsite near Cidra............................................. 170 Lago deCidra near Dam.........................................................455-461 Lago de Cidra near Rfo de Bayamon Mouth.......................... 448-450 Lago de Cidra, Rfo de Bayamon below.................................. 171-177 Lago de Guajataca, at Damsite near Quebradillas........................... 49 Canal Principal de Diversiones at........................................... 50,51 No. 1 near dam near Quebradillas.........................451-454,459-461 No. 3 near mouth near Quebradillas.................................... 448-450 Lago Dos Bocas No. 1 near dam near Utuado..........451-454,459-461 No. 3 at west branch near Utuado....................................... 448-450 Lago El Guineoat Damsite near Villalba...................................... 118 Lago Garzas near Adjuntas.............................................................. 58 Lago Garzas No. 1 near dam near Adjuntas.............451-454,459-461 Lago Guayabal at Damsite near Juana Dfaz.................................. 379 Lago Guayo at Damsite near Castafier........................................... 420 Lago La Plata at Damsite nearToa Alta........................................ 154 Lago La Plata No. 3 near dam near Naranjito ........................455-461 Lago Las Curias at Damsite near Rfo Piedras................................................................. 185 No. 5 near mouth near Naranjito.........................................448-450 Lago Loco at Damsite near Yauco................................................. 398 Lago Lofza at Damsite near Trujillo Alto .............................. 295,296 No. 4 near mouth near Caguas............................................ 448-450 No. 7 near dam near Trujillo Alto....................................... 455-461 Lago Lucchetti at Damsite near Yauco.......................................... 397 Lago de Mat nil las at Damsite near Orocovis................................ 119 Lago Patillas at Damsite near Patillas............................................ 363 Lago Toa Vaca, Rfo Toa Vaca above..................................... 372-378 Laguna San Jos6 No. 2 at San Juan................................................ 191 Laguna Tortuguero basin, water quality records in........................ 129 Laguna Tortuguero outlet near Vega Baja..................................... 129 Lajas at Toa Alta, Rfo.....................................................................444 Land-surface datum, definition of....................................................33 Lapas near Rabo del Buey, Rfo...................................................... 366 La Plata at Proyecto La Plata, Rfo de.............................................................................. 141,142 at Comerio...........................................................................143-149 at Highway 2 near Toa Alta................................................. 161-163 below La Plata Dam.............................................................155-160 near Comerio........................................................................ 150,151 on Highway 738 near Cayey.......................................................442 La Plata basin, Rfo de, gaging station records in.......................................................... 140-163 ground-water records in......................................................483-491 low-flow partial-record stations in......................................442-444 water-quality partial-record stations, analyses of samples collected at....................448-461 water-quality records in......................................................141-163 La Plena, Rfo Majada at .................................................................367 Lares, Rfo Camuy near...................................................................436 Lares, Rfo Camuy off Highway 129 near.......................................436 Lares, Rfo Criminales near.............................................................436 Lares, Rfo Grande de Anasco near..........................................421,422 Lares, Rfo Guajataca above sewage plant at..................................436 Lares, Rfo Guajataca at ...............................................................46-48 Las Carreras atUnibdn, near Morovis, Rfo....................................441 Las Curias Tributary near Caimito, Quebrada ...............................445 Las Piedras, Rfo Humacao at .........................................................348 Levels for Puerto Rico, ground water .....................................463-525 Levels for U.S. Virgin Islands, ground water..........................533-539 Limon above confluence with Rfo Yunes, Rfo ..............................438 Limon on Highway 613 near Tetuan, Rfo......................................438 Lizas, Rfo Maunabo at....................................................................355 Loco at Guanica, Rfo............................................................... 399,400 Loco basin, Rfo, gaging-stations records in ............................398-400 Loco basin, Rfo, water-quality records in ...............................399,400 Los Guanos near Rfo Piedras, Quebrada........................................445 Los Llanos, Rfo Descalabrado near................................................371 Los Morones near Moca, Quebrada ...............................................446 Los Negros at mouth at Corozal, Rfo de ........................................440 Low-flow partial-record stations in Puerto Rico, Discharge at.................................................................436-446 Low-flow partial-record in North Central Puerto Rico, map showing location of................................. 15 M Majada at La Plena, Rfo .................................................................367 Majada basin, Rfo, ground-water records in ...........................517-519 Mameyes basin, Rfo, gaging station records in.......................314-320 water-quality records in......................................................315-320 Mameyes Abajo, Rfo Yunes at mouth near....................................438 Mameyes near Sabana, Rfo .....................................................314-320 Manatf, Rfo Grande de Manatf at Highway 2 near............................................................126-128 Manatf, Rfo Grande de Manatf near...............................................440 Maps: Location of surface-water stations in Puerto Rico....................... 13 Location of ground-water stations in Puerto Rico....................... 16 Location of ground-water stations in the U.S. Virgin Islands............................................................... 18 Location of low-flow partial-record stations in North Central Puerto Rico.................................................... 15 545 INDEX Page Page Location of maximum concentration of fecal coliform bacteria at sample sites.......................................................................... 11 Location of maximum concentration of fecal streptococci bacteria at sample sites ...................................................................... 12 Location of surface-water stations in the U.S. Virgin Islands..................................................... 17 Location of water-quality stations in Puerto Rico....................... 14 Rio Camuy basin......................................................................... 55 Rio Cibuco basin....................................................................... 131 Rio Culebrinas basin................................................................. 429 Rio Grande de Arecibo basin...................................................... 57 Rio Grande de Loiza basin........................................................ 193 Rio Grande de Manati basin...................................................... 111 Rio Guajataca basin...................................................................... 45 Rio Guanajibo basin................................................................... 401 Rio Herrera to the Rio Ant6n Ruiz basins.................................. 307 Rio Hondo to the Rio Puerto Nuevo basins ............................... 165 Rio Humacao to the Rio Seco basins......................................... 347 Rio Inab6n to the Rio Loco basins............................................. 381 Rio de La Plata basin.................................................................. 139 Rio Salinas to the Rio Jacaguas basins....................................... 365 Rio Yagiiez and the Rio Grande de Afiasco basins............................................................................. 417 Maricao, Rio Mavillaon Highway 821 near................................. 441 Maton on Highway 14 at Maton Abajo, Rio.................................. 442 Matrullaat mouth, Rio................................................................... 439 Maunabo at Lizas, Rio................................................................... 355 at Maunabo..........................................................................356,357 Maunabo basin, Rio, gaging stations records in........................................................................ 355-357 water-quality records in.................................................. 356,357 Mavilla, on Highway 164nearCorozal, Rio................................. 441 Mavilla, on Highway 821 near Maricao, Rio ................................441 Maximum concentrations of fecal coliform bacteria at sampled sites, map showing location of.......................................................... 11 Maximum concentrations of fecal streptococci bacteria at sampled sites, map showing location of.......................................................... 12 Mayagiiez, Rio Yagiiez near................................................... 418,419 Mean concentration, definition of.................................................... 37 Mean discharge, definition of.......................................................... 32 Measuring point, definition of......................................................... 33 Metamorphic stage, definition of..................................................... 33 Methylene blue active substances, definition of.............................. 33 Micrograms per gram, definition of................................................. 33 Micrograms per liter, definition of................................................... 33 Milligrams of carbon per area or volume per unit time or periphyton and macrophytes and for phytoplankton, definition of........................................ 36 Milligrams of oxygen per area or volume per unit time for periphyton and macrophytes and for phytoplankton, definition of........................................ 36 Milligrams per liter, definition of.................................................... 33 Minillas, Rio Bayamon near.......................................................... 445 Minillas, Rio Minillas on Highway 174 near................................. 445 Moca, Quebrada Grande near........................................................ 446 Moca, Quebrada Los Morones near............................................... 446 Moca, Rio Culebrinas at Highway near......................................... 432 Morovis above Sewage Plant near Morovis, Rio........................... 441 Morovis, Quebrada Grande de Morovis on Highway 634 near.................................................................. 442 Morovis, Quebrada Grande near.................................................... 439 Morovis, Rio Grande de Manati near..................................... 115-117 Morovis, Rio Las Carreras at Unib6n, near................................... 441 N Naguabo, Quebrada Guaba near.....................................................344 Naguabo, Rio Icacos near...............................................................345 Naranjito, Lago La Plata No. 3 near dam near........................455-461 Naranjito, Lago La Plata No. 5 near mouth near.....................448-450 Naranjito, Rio Canas at Achiote, near............................................443 Naranjito, Rio Guadiana above Sewage Plant at............................443 Naranjito, Rio Guadiana near.................................................. 152,153 National Stream-Quality Accounting Network, definition of.......................................................... 34 National Trends Network, definition of ...........................................34 Natural substrate, definition of.........................................................37 Networks and programs, special ........................................................9 Nuevo, Rio Cuestas Arribaen Highway 816 at .............................443 O Organic mass, definition of ..............................................................31 Organism, definition of ....................................................................34 Organism count/area, definition of................................................... 34 Organism count/volume, definition of .............................................34 Orocovis, Lago de Matrullas at Damsite near................................ 119 Orocovis, Rio Bauta near............................................................... 120 Orocovis, Rio Orocovis at....................................................... 112,439 Orocovis, Rio Orocovis near................................................... 113,114 Orocovis, Rio Sana Muertos near...................................................439 Parameter code, definition of ...........................................................34 Partial record station, definition of................................................... 34 Partial-record stations in Puerto Rico, Discharge at.................................................................436-446 Partial-record stations in North Central Puerto Rico, map showing location of low-flow............................. 15 Partial record station in Puerto Rico, water quality at ............................................................447-461 Particle size, definition of.................................................................35 Particle-size classification, definition of ..........................................35 Paso Palma, Rio Caonillas at.......................................................74-85 Patillas, Lago de Patillas Damsite near..........................................363 Patillas, Rio Grande de Patillas near.......................................360-362 Pellejas, Rio Pellejas at Central......................................................436 Pellejas, Rio Vivi near Central .......................................................437 Percent composition, definition of ...................................................35 Perchas, no. 1, Rio Culebrinas at....................................................446 Periphyton, definition of...................................................................35 Pesticides, definition of.................................................................... 35 Phytoplankton, definition of.............................................................35 Picocurie, definition of.....................................................................35 Piedras, Basin, Rio low flow partial-record stations in......................................445 Piedras at Hato Rey, Rio .........................................................188-190 near Rio Piedras..................................................................186,187 Plankton, definition of...................................................................... 35 Playa de Guayanes, Rio Guayanes above mouth at............................................................ 353,354 Polychlorinated biphenyls, definition of ..........................................36 Ponce, RioBucanaat Highway 14 Bridge near............................. 388 Ponce, Rio Cerrillos above Lago Cerrillos near.............................383 Ponce, Lago Cerrilos at Damiste near............................................384 Ponce, Rio Cerrillos near.........................................................385-387 Ponce, Rio Portugues at...........................................................392,393 Ponce, Rio Pol-fugue's near.......................................................389-391 Portugue"z at Ponce, Rio......................................................392,393 546 INDEX Page Page Portugues basin, Rio, gaging station records in............................................................. 389-393 ground-water records in ............................................................. 522 water-quality records in....................................................... 390-393 Pozas, Rfo Bauta, at....................................................................... 440 Primary productivity, definition of.................................................. 36 Programs, special networks and ........................................................ 9 Providencia, Rio Chico at....................................................... 358,359 Proyecto La Plata, Quebrada Honda at mouth, at.......................... 442 Proyecto La Plata, Rio de La Plata at..................................... 141,142 Publications on techniques of water-resources investigations............................................40-42 Puerto Nuevo basin, Rio, gaging station records in............................................................. 185-192 ground-water records in ......................................................492-499 water-quality records in....................................................... 186-192 Quality of water records of Puerto Rico, surface- and....................................................................... 43-434 Quebrada Aguas Verdes basin, ground-water records in.................................................. 512-515 Quebrada Arenas, Rio Grande de Lofza at.................................... 196 near Utuado................................................................................ 437 Quebrada Grande de Morovis on Highway 634 near Morovis..........................................................................442 Quebrada Grande near Morovis..................................................... 439 Quebrada Riachuelo at mouth........................................................ 439 Quebrada Santo Domingo at Cayey............................................... 442 Quebradillas, Lago Guajataca at Damsite near................................ 49 Quebradillas, Lago Guajataca No. 1 near dam near....................................................451-454,459-461 Quebradillas, Lago Guajataca No. 3 near mouth near.............................................................. 448-450 Quebradillas, Rio Guajataca above mouth near.......................................................................... 52,53 R Rabo del Buey, Rio Lapas near...................................................... 366 Radiochemical program, definition of............................................. 36 Real Abajo, Rio Inabon at.............................................................. 382 Records, explanation of ................................................................9,10 Records of ground-water levels.................................................. 27,28 Records of ground-water quality................................................ 28,29 Records of stage and water discharge......................................... 19-24 Records of surface-water quality................................................ 24-27 Recoverable from bottom material, definition of............................ 36 Return period, definition of.............................................................. 36 Rio Abajo, Rio Indio on Highway 22 at........................................ 442 Rio Cafias, Rio Canas at.......................................................... 288-294 Rio Grande, El Verde near............................................................. 313 Rio Grande, Rfo Espfritu Santo near....................................... 310-312 Rio Piedras, Lago Las Curias at Damsite near.............................. 185 Rfo Piedras, Quebrada Los Guanos near....................................... 445 Rfo Piedras, Rfo Piedras near.................................................. 186,187 at Hato Rey..................................................................... 188-190 Rosario near Hormigueros, Rfo ..............................................405-412 Runoff, in inches, definition of........................................................ 36 Sabana at Vista Monte, Rfo........................................................... 169 Sabana Hoyos................................................................................. 477 Sabana basin, Rfo, gaging station records in................................. 321 ground-water records in..................................................... 506-507 at Sabana....................................................................................321 Sabana, Rio Mameyes near.....................................................314-320 Sabana Seca, Rfo Hondo II, at........................................................444 Saliente at Coabey near Jayuya, Rfo................................................73 Salinas, Rfo gaging station records in .....................................366,367 Salvatierra near San Lorenzo, Quebrada.................................204-210 Sana Muertos, near Orocovis .........................................................439 San German, Rfo Guanajibo at Highway 119 at ............................402 San German, Rfo Guanajibo near............................................403,404 San Juan, Bahfa de San Juan No. 5 at............................................ 192 San Juan, Laguna San Jose" No. 2 at .............................................. 191 San Lorenzo, Quebrada Salvatierra near.................................204-210 San Lorenzo, Rfo Grande de Lofza at Highway 183 near........................................................210-218 San Sebastian, Rfo Culebrinas at....................................................446 San Sebastian, Rfo Culebrinas near.........................................430,431 San Sebastian, Rfo Guatemala at....................................................446 San Sebastian, Rfo Sonador near....................................................446 San Sebastian, Rfo Grande de Afiasco near ............................423-425 Santa Olaya on Highway 174 near Bayamon, Quebrada.............................................................................445 Sediment, definition of..................................................................... 36 7-day 10-year low flow, definition of ..............................................37 Sodium-adsorption-ratio, definition of.............................................37 Solute, definition of..........................................................................37 Sonadora near El Verde, Quebrada......................................... 308,309 Sonadora, Quebrada Sonadora at ...................................................444 Sonador near San Sebastian, Rfo....................................................446 Special network and programs ...........................................................9 Specific conductance, definition of ..................................................37 Stage-discharge relation, definition of .............................................37 Station identification numbers.......................................................... 10 St. Croix, VI, Jolly Hill Gut at Jolly Hill .......................................531 St. John, VI, Guinea Gut at Bethany.............................................. 530 Streamflow, definition of .................................................................37 St. Thomas, VI, Bonne Resolution Gut at Bonne Resolution ...................................................528 St. Thomas, VI, Turpentine Run at Mount Zion ............................529 Substrate, definition of..................................................................... 37 Summary of hydrologic conditions .................................................3-8 Surface and quality-of-water records for Puerto Rico...............43-434 Surface area, definition of ................................................................38 Surface-water quality, records of ................................................24-27 Surface-water records for U.S. Virgin Islands ........................527-531 Surface-water stations in Puerto Rico, map showing location of...................................................... 13 Surface-water stations in U.S. Virgin Islands, map showing location of...................................................... 17 Surficialbed material, definition of .................................................38 Suspended, definition of...................................................................38 Suspended-recoverable, definition of ..............................................38 Suspended sediment, definition of ...................................................36 Suspended-sediment concentration, definition of ............................37 Suspended-sediment discharge, definition of................................... 37 Suspended-sediment load, definition of ...........................................37 Suspended-total, definition of.......................................................... 38 Tanamd above Observatorio de Arecibo........................................438 Tanama at Charco Hondo, Rfo....................................................... 107 at Esperanza................................................................................438 near Caguana...............................................................................438 near Utuado............................................................................98-106 Taxonomy, definition of...................................................................38 Techniques of water-resources investigations, publications on............................................40-42 547 INDEX Page Page Terms, definition of.................................................................... 30-39 Tetuan, Rio Limon on Highway 613 near..................................... 438 Thermograph, definition of.............................................................. 38 Time-weighted average, definition of............................................. 38 Toa Alta, Lago La Plata at Damsite near....................................... 154 Toa Alta, Quebrada Cruz, near...................................................... 444 Toa Alta, Rio Bucarabones, near................................................... 444 Toa Alta, Rio de La Plata at Highway 2 near......................... 161-163 Rio Lajas at................................................................................. 444 Toa Vaca above Lago Toa Vaca, Rio..................................... 372-378 Tons per acre-foot, definition of...................................................... 38 Tons per day, definition of............................................................... 39 Toro Negro near Ciales, Rio.......................................................... 440 Toro Negro on Highway 157 at Cacao, Rio.................................. 439 Total, definition of........................................................................... 39 Total coliform bacteria, definition of.............................................. 30 Total discharge, definition of........................................................... 39 Total organism count, definition of................................................. 34 Total-recoverable, definition of....................................................... 39 Total sediment discharge, definition of .......................................... 37 Total-sediment load, definition of.................................................... 37 Tritium network, definition of......................................................... 39 Trujillo Alto, Lago Loiza at Damsite near.............................. 295,296 Trujillo Alto, Lago Loiza No. 7 near dam near...................... 455-461 Trujillo Alto, Rio Grandede Loiza below.............................. 304,305 Turabo above Borinquen, Rio................................................. 219-225 Turpentine Run at Mount Zion, St. Thomas, VI............................ 529 U Unibdn above Sewage Plant at Unibon, Rio.................................. 441 Unib6n off Highway 160 near Almirante Sur, Rio.................................................................................. 441 Usabon on Highway 162 near Barranquitas, Rio........................... 442 Utuado, Quebrada Arenas near...................................................... 437 Utuado, Rio Guaonica near............................................................ 437 Utuado, Lago Caonillas at Damsite near......................................... 88 Utuado, Lago Dos Bocas No. 1 near dam near.........451-454,459-461 Utuado, Rio Caguana on Highway 10 near................................... 437 Utuado, Lago Dos Bocas No. 3 at west branch near............................................................. 448-450 Utuado, Rio Grande de Arecibo below.......................................61-70 Utuado, Rio Grande de Arecibo near................................... 71,72,437 Utuado, Rio Tanamd near......................................................... 98-106 Vacas near Adjuntas, Rio............................................................... 436 Valenciano near Juncos, Rio...................................................272-278 Vega Alta, Rio Cibuco on Highway 620 near............................... 441 VegaBaja, Laguna Tortuguero outlet near.................................... 129 Vega Baja, Rio Cibuco at........................................................ 135-137 Vicente at mouth, Quebrada.......................................................... 444 Villalba, Lago El Guineo at Damsite near..................................... 118 Vista Monte, Rio Sabana at........................................................... 169 Vivi near Central Pellejas, Rio....................................................... 437 W Water-discharge, records of stage and........................................ 19-24 Water-quality partial-record stations in Puerto Rico ................................................447-461 Water-quality stations in Puerto Rico, map showing location of............................................ 14 Water-resources investigations, publications on techniques of.......................................... 40-42 Water year, definition of.................................................................. 39 U.S. Geological Survey Water Data, Access to ...............................29 WDR, definition of......................................................................... ..39 Weighted average, definition of .......................................................39 Wells - Puerto Rico: Cibuco basin, Rio Well 70 - Sabana Hoyos .....................................................477 Well 211 - Rosario No. 2....................................................478 Well 212 - Ponderosa TW-1 ...............................................479 Well 213 - Pampano No. 2 .................................................480 Well PA-2 Palo Alto#2......................................................481 Well TO-3 Tortuguero TW-3 .............................................482 Culebrinas basin, Rio Well 200 - Aguadilla Cement north ...................................525 Grande de Arecibo basin, Rio Well 204 - Gilberto Rivera ........................................ ..466,467 Well EN-1 Encantada #1 PRASA ......................................468 Well FL-1 Florida #1 ..........................................................469 Well TI-1 Tiburones#l ......................................................470 Grande de Loiza basin, Rio Well 50 - USGS #50 Experimental Gurabo ....................... 500 Well 222 - Campo Rico TW-1 ...........................................501 Well CJ-TW-3B - Gurabo Oeste ........................................ 502 Well CJ-TW-19A - Bonneville ..........................................503 Grande de Manati basin, Rio Well 166 Manati USGS #166.............................................471 Well 206 - Plazuela No. 2...................................................472 Well 207 - Cantito La Luisa. .............................................. 473 Well 210 - Gelo Martinez...................................................474 Well CS-7 Cotto Sur#7......................................................475 Well HI-2 Hill OBO #2 ......................................................476 Guajataca basin, Rio Well 165 - Mateo Perez, Bo. Saltos ...................................464 Well 202 - Carmelo Barreto-Garcia. ................................. .465 Guanajibo basin, Rio Well 143 - Vivoni, Hacienda Amistad ...............................523 Well CR-TW-9A - Bajura#9A....... ....................................... 524 Herrera to Rio Anton Ruiz basin, Rio Hondo to Rio Puerto Nuevo basins, Rio Well 219 - Fort Buchanan No. 1 ............................................492 Humacao to Rio Seco basins, Rio Well 6 - Juana 5......................................................................508 Well 96 - USGS TW-2 or Yabucoa 7 ................................... 509 Well P-13 ............................................................................... 510 Inabon to Rio Loco basins, Rio Well 132 - Yauco 2 ................................................................520 Well 141 - RestauradaSA......... ............................................ .521 Well AN-1 .............................................................................. 522 La Plata basin, Rio de Well 216 - Pozo Navy - Campanulas...................... .............. .483 Well 217 - Monserrate TW - 2 ..............................................484 Well DA - 1 ............................................................................485 Well HG - 4............................................................................486 Well SA - 1.............................................................................487 Well SA - 3.............................................................................488 Well MA - 2 ...........................................................................489 Well SR - 2.............................................................................490 548 INDEX Page Page Well TB -1.............................................................................491 Y Salinas to Rio Jacaguas basins, Rio Well - 87 Alomar 1 ................................................................511 Yabucoa, Rio Guayane's at...................................................... 351,352 WellHW-TW-01 ...................................................................512 Yagiiez near Mayaguez, Rio................................................... 418,419 Well HW-TW-03C.................................................................513 Yaguez basin, Rio, water-quality records in........................... 418,419 Well HW-TW-05B.................................................................514 Yauco basin, Rio, gaging station records in .................................. 397 Well HW-TW-13 ...................................................................515 Yauco, Lago Loco at Damsite near................................................ 398 Well PG - 07...........................................................................516 Yauco, Lago Lucchetti at Damsite near......................................... 397 Well PS - 07 ...........................................................................517 Yunes at Fronton, Rio.................................................................... 438 Well RM - 05 .........................................................................518 Yunes, Rio Limon above confluence with, Rio............................. 438 WellRM - 10.........................................................................519 Yunes at mouth near Mameyes Abajo, Rio................................... 438 Wells - U.S. Virgin Islands St. Croix Z Well 2 - USGS-10, Fairplains 2 (FP2) ...................................534 Well 3 - Golden Grove 6 (PW6) ............................................535 Zooplankton, definition of............................................................... 35 Well 13 - WAPA - 17.............................................................536 St. John Well 11-Guinea Gut Well....................................................539 St. Thomas Well 6 - Grade School 3.........................................................537 Well 8 - VEO-6.....................................................................538 Wet mass, definition of.....................................................................31 WSP, definition of ...........................................................................39 CONVERSION FACTORS AND VERTICAL DATUM Multiply inch (in.) foot (ft) mile (mi) acre *-\ square mile (mi ) gallon (gal) million gallons (Mgal) cubic foot (ft3) cubic-foot-per-second day [(ft /s) d] acre-foot (acre-ft) cubic foot per second (ft /s) gallon per minute (gal/min) million gallons per day (Mgal/d) ton (short) By Length To obtain 2.54X10 1 2.54x1 0-2 3.048x10-* 1.609x10° Area 4.047x103 4.047x10-' 4.047x10"3 2.590x10° 3.785x10° 3.785x10° 3.785xlO'3 3.785xl03 3.785xlO'3 2.832X10 1 2.832xlO-2 2.447x103 2.447x10-3 1.233xl03 1.233xlO~3 1.233xlO'6 Flow 2.832x10' 2.832x10' 2.832x10-2 6.309x10-2 6.309x10-2 6.309xl(T5 4.381x10' 4.381x10-2 Mass 9.072x10- millimeter meter meter kilometer square meter square hectometer square kilometer square kilometer liter cubic cubic cubic cubic cubic cubic cubic cubic cubic cubic cubic decimeter meter meter hectometer decimeter meter meter hectometer meter hectometer kilometer liter per second cubic decimeter per second cubic meter per second liter per second cubic decimeter per second cubic meter per second cubic decimeter per second cubic meter per second megagram or metric ton Sea level: In this report "sea level" refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic datum derived from a general adjustment for the first-order level nets of both the United States and Canada, formerly called Sea Level Datum of 1929. U.S. DEPARTMENT OF THE INTERIOR U.S. Geological Survey, WRD GSA Center 651 Federal Dr. Suite 400-15 Guaynabo, Puerto Rico 00965