Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1996 St Thomas I Isla de \P Culebra Isla de Vieques PUERTO RICO St John I U. S. V I R G I N ISLANDS Saint Croix I HSTRICT LIBRARY COPY U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-96-1 Prepared in cooperation with the Commonwealth of Puerto Rico, the Government of the U.S. Virgin Islands and other agencies CALENDAR FOR WATER YEAR 1996 1995 OCTOBER S M 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 31 NOVEMBER S M T W T F S 1234 5 6 7 8 9 10 11 112 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 DECEMBER S M T W T F S 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 1996 JANUARY S M T W T F S 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 31 APRIL S M T W T F S 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 JULY S M T W T F S 123456 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2 22 23 24 25 26 27 28 29 30 31 FEBRUARY S M T W T F S 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 MAY S M T W T F S 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 AUGUST S M T W T F S 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 MARCH S M T W T F S 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 JUNE S M T W T F S 1 2345678 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 SEPTEMBER S M 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 US GEOLOGICAL SURVEY, WRD GSA CENTER 651 FEDERAL DR SUITE 400-15 GUAYNABO PR 00965 Water Resources Data Puerto Rico and the U.S. Virgin Islands Water Year 1996 by P.L. Dfaz, Z. Aquino, C. Figueroa-Alamo, R.J. Vachier, and A.V. Sanchez St Thomas I Culebra Isla de Vieques PUERTO RICO StJohnl U. S. V I R G I N ISLANDS Saint Croix I U.S. GEOLOGICAL SURVEY WATER-DATA REPORT PR-96-1 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 1997 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 Carlos Narvaez George Arroyo Rafael Pefia-Cortez Gregory Cherry Carlos C. Rodrfguez Iris M. Concepcidn Julio A. Rodrfguez Israel Cruz Miguel Rodrfguez Angel G. Ferrer Rafael M. Rodrfguez Robert Fitzhugh Jos6 Ren6 Sanchez Pedro Galindo Luis Santiago-Rivera Wilfredo Garcfa Luis Soler Hector Guardiola Angel Torres Evelyn S. Guevara Heriberto Torres-Sierra Sen6n Guzman-Rfos James Torres Felipe Hernandez Jose" A. Torres Sandra Lagares Ahmed Valencia Jos6 Merced 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 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, 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 May 20, 1997 3. REPORT TYPE AND DATES COVERED Annual - October 1, 1995 to September 30,1996 4. TITLE AND SUBTITLE Water Resources Data for Puerto Rico and the U.S. Virgin Islands Water Year 1996 6. AUTHOR(S) Pedro L. Diaz, Zaida Aquino, Carlos Figueroa-Alamo, Ricardo J. Vachier, Ana V. Sanchez 5. FUNDING NUMBERS 8. PERFORMING ORGANIZATION REPORT NUMBER USGS-WDR-PR-96-1 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 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-96-1 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 1996 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 75 streamflow-gaging stations; stage only for 5 gaging stations, daily sediment records for 25 streamflow stations; 95 partial-record or miscellaneous streamflow stations; stage records for 15 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 67 obser- vation 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 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT 15. NUMBER OF PAGES 564 16. PRICE CODE 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..................................................................................................................................................................................1 Cooperation...........................................................^ Summary of hydrologic conditions..............................................................................................................................................3 RainfeU............................................^ Surface water........................................................................................................................................................................3 Ground water ..............................................................................................................................................................^ Water quality................................................................^ Special networks and programs .................................................................................................................................................10 Explanation of records...............................................................................................................................................................10 Station identification numbers............................................................................................................................................11 Downstream order system............................................................................................................................................ 11 Latitude-longitude system............................................................................................................................................ 11 Records of stage and water discharge.................................................................................................................................21 Data collection and computation.............................................................................................................................21 Data Presentation .....................................................................................................................................................22 Station manuscript ................................................................................................................................................22 Data table of daily mean values ............................................................................................................................23 Statistics of monthly mean data............................................................................................................................24 Summary statistics ................................................................................................................................................24 Identifying estimated daily discharge ..........................................................................................................................25 Accuracy of the records...............................................................................................................................................25 Records of surface-water quality ........................................................................................................................................26 Classification of records...................................................................................................................^^ Arrangement of records...............................................................................................................................................26 On-site measurements and sample collection..............................................................................................................26 Water temperature..................................................................................................^ Sediment............................................................................................................................................................. Laboratory measurements............................................................™ Data presentation..............................................................................................._ Remark codes...............................................................................................................................................................29 Recordsof ground-water levels...................................^^ Data collection and computation .................................................................................................................................2 Data presentation..................................................................................................................................................^ Records of ground-water quality.......................................................................................................................................30 Data collection and computation.................................................................................................................................31 Data presentation..............................................................................................................^^ Access to WATSTOREdata...........................................................^ Definition of terms.....................................................................................................................................................................32 Publications on Techniques of Water-Resources Investigations ...............................................................................................42 Surface- and quality-of-water records for Puerto Rico..............................................................................................................45 Discharge at partial-record stations in Puerto Rico .................................................................................................................429 Water-quality at partial-record stations in Puerto Rico ...........................................................................................................441 Ground-water records for Puerto Rico.....................................................................................................................................463 Surface-water records for the U.S. Virgin Islands...................................................................................................................525 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........................................................................................................................................................8 3. Map showing location of fecal coliform bacteria concentration at sampled sites................................................. 12 4. Map showing location of fecal streptococci bacteria concentration at sampled sites............................................ 13 5. Map showing location of surface-water stations in Puerto Rico........................................................................... 14 6. Map showing location of water-quality stations in Puerto Rico............................................................................ 15 7. Map showing location of low-flow partial-record stations in North-central Puerto Rico..................................... 16 8. Map showing location of ground-water stations in Puerto Rico............................................................................ 17 9. Map showing location of surface-water stations in U.S. Virgin Islands............................................................... 18 10. Map showing location of ground-water stations in the U.S. Virgin Islands......................................................... 19 11. Map showing location of surface-water stations in Vieques Island..................................................................... 20 12. Grid showing system for numbering wells and miscellaneous site (latitude and longitude)................................ 21 13. Map showing the Rfo Guajataca basin..................................................................................................................47 14. Map showing the Rfo Camuy basin...................................................................................................................... 57 15. Map showing the Rfo Grande de Arecibo basin................................................................................................... 61 16. Map showing the Rfo Grande de Manatf basin..................................................................................................... 93 17. Map showing the Rfo Cibuco basin.................................................................................................................... 113 18. Map showing the Rfo de la Plata basin............................................................................................................... 121 19. Map showing the Rfo Hondo to the Rfo Puerto Nuevo basins........................................................................... 155 20. Map showing the Rfo Grande deLoiza basin..................................................................................................... 189 21. Map showing northeastern river basins the Rfo Herrera to the Rfo Ant6n Rufz basins..................................... 307 22. Map showing southeastern river basins the Rfo Humacao to the Rfo Seco basins............................................. 337 23. Map showing south coast river basins the Rfo Salinas to the Rfo Jacaguas basins............................................ 355 24. Map showing south coast river basins the Rfo Inabdn to the Rfo Loco basins ..................................................371 25. Map showing the Rfo Guanajibo basin............................................................................................................... 393 26. Map showing the Rfo Yagiiez and the Rfo Grande de Anasco basins................................................................ 409 27. Map showing the Rfo Culebrinas basin ..............................................................................................................421 TABLES Page Table 1. Island-wide monthly precipitation and annual averages for 1996 water year and the 30-year reference period, 1961-90.................................................................................................................. 3 2. Summary of peak stages and discharges prior to and during September 10,1996, at selected U.S. Geological Survey streamflow-gaging stations in Puerto Rico.................................................. 6 3. Highest water level recorded during water year 1996 and previous highest ground- water levels at selected ground-water wells in Puerto Rico and the U.S. Virgin Islands ...................................................................................................................................................................7 4. Lowest ground-water levels recorded during water year 1996 and previous lowest ground-water levels at selected wells in Puerto Rico .......................................................................................... 7 5. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1996....................................................................................................... 9 6. Factors for conversion of chemical constituents in milligrams per liter to milli- equivalents per liter............................................................................................................................................. 36 VII SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, 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 48 Lago Guajataca at Damsite near Quebradillas (e)........................................................................ 50010800 51 Canal Principal de Diversiones at Lago Guajataca (c,b).............................................................. 50011000 52 Rio Guajataca above mouth near Quebradillas (c,b).................................................................... 50011400 54 RIO CAMUY BASIN Rio Camuy at Tres Pueblos Sinkhole (d)...................................................................................... 50014600 58 Rio Camuy near Bayaney (d)........................................................................................................ 50014800 59 Rio Camuy near Hatillo (d)........................................................................................................... 50015700 60 RIO GRANDE DE ARECIBO BASIN Lago Garzas near Adjuntas (e)............................................................................................. 50020100 62 Rio Grande de Arecibo near Adjuntas (c,b).................................................................................. 50020500 63 Rio Grande de Arecibo near Utuado (c,b).................................................................................... 50025000 65 Rfo Saliente at Coabey near Jayuya (d)................................................................................ 50025155 67 Rio Caonillas above Lago Caonillas near Jayuya (c,b)................................................................ 50026050 68 Lago Caonillas at Damsite near Utuado (e).......................................................................... 50026140 70 Rio Grande de Arecibo below Lago Dos Bocas near Florida (c,b).............................................. 50027250 71 Rio Grande de Arecibo above Arecibo (d,s)................................................................................. 50027750 73 Rio Tanama near Utuado (d,c,b,s)........................................................................................ 50028000 80 Rio Tanama at Charco Hondo (d) ........................................................................................ 50028400 89 Rio Grande de Arecibo at Central Cambalache (c,b)................................................................... 50029000 90 RIO GRANDE DE MANATI BASIN Rio Orocovis at Orocovis (d)................................................................................................ 50030460 94 Rio Orocovis near Orocovis (c,b)......................................................................................... 50030700 95 Rio Grande de Manati near Morovis (d,c,b)................................................................................. 50031200 97 Lago El Guineo at Damsite near Villalba (e)........................................................................ 50032290 100 Lago de Matrullas at Damsite near Orocovis (e).................................................................. 50032590 101 Rio Bauta near Orocovis (d)................................................................................................. 50034000 102 Rio Grande de Manati at Ciales (d).............................................................................................. 50035000 103 Rio Grande de Manati at Highway 149 at Ciales (c,b)................................................................. 50035500 104 Rio Cialitos at Highway 649 at Ciales (c,b)......................................................................... 50035950 106 Rio Grande de Manati at Highway 2 near Manati (d,c,b,p).......................................................... 50038100 108 LACUNA TORTUGUERO BASIN Laguna Tortuguero Outlet near Vega Baja (c,b).......................................................................... 50038200 111 RIO CIBUCO BASIN Rio Cibuco below Corozal (d,c,b)................................................................................................ 50038320 114 Rio Cibuco at Vega Baja (d,c,b)................................................................................................... 50039500 117 RIO DE LA PLATA BASIN Lago Carite at Gate Tower near Cayey (e)................................................................................... 50039990 122 Rio de La Plata at Proyecto La Plata (d,c,b)................................................................................. 50043000 124 Rio de La Plata at Comerio (d,s)................................................................................................... 50043800 126 Rio de La Plata near Comerio (c,b).............................................................................................. 50044000 133 Rio Guadiana at Guadiana (d,s)............................................................................................ 50044830 135 Rio Guadiana near Naranjito (c,b)........................................................................................50044850 142 Lago La Plata at Damsite near Toa Alta (e)................................................................................. 50045000 144 Rio de La Plata below La Plata Dam (d,s).................................................................................... 50045010 145 Rio de La Plata at Highway 2 near Toa Alta (d,c,b,s,p)............................................................... 50046000 152 RIO HONDO BASIN Rio Hondo at Flood Channel near Catano (c,b)............................................................................ 50047530 156 VIII 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 Bayam6n at Arenas (d)...................................................................................................... 50047535 158 Rio Sabana at Vista Monte (d).............................................................................................. 50047540 159 Lago de Cidra at Damsite near Cidra (e)...................................................................................... 50047550 160 Rio de Bayam6n below Cidra Dam (d,s)...................................................................................... 50047560 161 Rio de Bayam6n near Aguas Buenas (c,b)................................................................................... 50047600 168 Rio de Bayam6n near Bayam6n (d).............................................................................................. 50047850 170 Rio Guaynabo near Bayam6n (c,b)....................................................................................... 50047990 171 Rio de Bayam6n at Rood Channel at Bayam6n (c,b,p)............................................................... 50048510 173 RIO PUERTO NUEVO BASIN Rio Piedras: Rio Piedras at El Senorial (d,s)..................................................................................................... 50048770 175 Rfo Piedras near Rio Piedras (c,b,p)............................................................................................. 50048800 182 Rfo Piedras at Hato Rey (d,c,b).................................................................................................... 50049100 184 Laguna San Jose: Laguna San Jose No 2 at San Juan (c,b)....................................................................................... 50049820 187 Bahia de San Juan: Bahfa de San Juan No 5 at San Juan (c,b)..................................................................................... 50049920 188 QUEBRADA BLASINA BASIN Quebrada Blasina near Carolina (c,b)........................................................................................... 50050300 190 RIO GRANDE DE LOIZA BASIN Rio Grande de Loiza at Quebrada Arenas (d)............................................................................... 50050900 192 Quebrada Blanca at El Jagual(d,s)....................................................................................... 50051150 193 Quebrada Salvatierra near San Lorenzo (d,s)....................................................................... 50051180 200 Rio Cayaguas at Cerro Gordo (d)......................................................................................... 50051310 207 Rfo Grande de Loiza at Highway 183 near San Lorenzo (d,s)..................................................... 50051800 208 Rfo Turabo above Borinquen (d,s)........................................................................................ 50053025 215 Rfo Grande de Lofza at Caguas (d,c,b,s)...................................................................................... 50055000 222 Rfo Caguitas near Aguas Buenas (d,s).................................................................................. 50055100 231 Rfo Caguitas near Caguas (d,s)............................................................................................. 50055170 238 Rfo Caguitas at Villa Blanca at Caguas (d,s)........................................................................ 50055225 245 Rfo Caguitas at Highway 30 at Caguas (c,b)........................................................................ 50055250 252 Rfo Bairoa at Bairoa (d,s)..................................................................................................... 50055390 254 Rfo Bairoa near Caguas (c,b)................................................................................................ 50055400 261 Rfo Gurabo: Rfo Gurabo below El Mang6 (d,s)........................................................................................ 50055750 263 Rfo Valenciano near Juncos (d,s)..................................................................................... 50056400 270 Rfo Gurabo at Gurabo (d,s)................................................................................................... 50057000 277 Rfo Gurabo near Gurabo (c,b).............................................................................................. 50057025 284 Rfo Caftas at Rfo Canas (d,s)................................................................................................ 50058350 286 Lago Lofza at Damsite near Trujillo Alto (c,b,e).......................................................................... 50059000 293 Rfo Grande de Lofza below Damsite (d,s).................................................................................... 50059050 295 Rfo Grande de Lofza below Trujillo Alto (c,b)............................................................................. 50059100 302 Rfo Grande de Lofza at Carolina (e)............................................................................................. 50061000 304 Rfo Can6vanas near Campo Rico (d).................................................................................... 50061800 305 RIO ESPIRITU SANTO BASIN Quebrada Toronja at El Verde (d)........................................................................................ 50063500 308 Rfo Espfritu Santo near Rio Grande (d.c.b).................................................................................. 50063800 309 Rfo Grande near El Verde (d)............................................................................................... 50064200 312 RIO MAMEYES BASIN Rfo Mameyes near Sabana (d)...................................................................................................... 50065500 313 RIO SABANA BASIN Rfo Sabana at Sabana (d).............................................................................................................. 50067000 320 IX SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number RIO FAJARDO BASIN Rio Fajardo near Fajardo (d,c,b,p)................................................................................................ 50071000 321 Rfo Fajardo below Fajardo (c,b)................................................................................................... 50072500 332 RIO BLANCO BASIN Quebrada Guaba near Naguabo (d)..................................................,............................................ 50074950 334 Rfo Icacos near Naguabo (d)......................................................................................................... 50075000 335 RIO HUMACAO BASIN Rio Humacao at Las Piedras (d)................................................................................................... 50081000 338 Rio Humacao at Highway 3 at Humacao (c,b)............................................................................. 50082000 339 RIO GUAYANES BASIN Rio Guayane"s at Yabucoa (c,b,p)................................................................................................. 50083500 341 Rfo Guayane"s above mouth at Playa de Guayanes (c,b).............................................................. 50086500 343 RIO MAUN ABO BASIN Rfo Maunabo at Lizas (d)............................................................................................................. 50090500 345 Rfo Maunabo at Maunabo (c,b).................................................................................................... 50091000 346 RIO CHICO BASIN Rfo Chico at Providencia (c,b)...................................................................................................... 50091800 348 RIO GRANDE DE PATILLAS BASIN Rfo Grande de Patillas near Patillas (d,c,b).................................................................................. 50092000 350 Lago Patillas at Damsite near Patillas (e)..................................................................................... 50093045 353 RIO SALINAS BASIN Rfo Lapas near Rabo del Buey (d)................................................................................................ 50100200 356 Rfo Majada at La Plena (d)........................................................................................................... 50100450 357 RIO COAMO BASIN Rfo Coamo at Coamo (d).............................................................................................................. 50106100 358 Rfo Coamo near Coamo (c,b)....................................................................................................... 50106500 359 RIO DESCALABRADO BASIN Rfo Descalabrado near Los Llanos (d).......................................................................................... 50108000 361 RIO JACAGUAS BASIN Rfo Toa Vaca above Lago Toa Vaca (d,s)............................................................................ 50110900 362 Lago Guayabal at Damsite near Juana Dfaz (e)............................................................................ 50111300 369 Rfo Jacaguas at Juana Dfaz (d)..................................................................................................... 50111500 370 RIO INABON BASIN Rfo Inabon at Real Abajo (d)........................................................................................................ 50112500 372 RIO BUCANA BASIN Rfo Bucana: Rfo Cerrillos above Lago Cerrillos near Ponce (d)....................................................................... 50113800 373 Lago Cerrillos at Damsite near Ponce (e)..................................................................................... 50113950 374 Rfo Cerrillos near Ponce (d,c,b).................................................................................................... 50114000 377 Rfo BucanS at Hwy 14 Bridge near Ponce (d).............................................................................. 50114390 380 RIO PORTUGUES BASIN Rfo Portugues near Ponce (d,c,b).................................................................................................. 50115000 381 Rfo Portugues at Ponce (c,b,p)...................................................................................................... 50116200 384 SURFACE-WATER AND WATER-QUALITY STATIONS, IN DOWNSTREAM ORDER, FOR WHICH RECORDS ARE PUBLISHED IN THIS VOLUME-Continued Station number Page RIO GUAYANILLA BASIN Rio Guayanilla near Guayanilla (d).............................................................................................. 50124200 386 Rio Guayanilla at Central Rufma (c,b,p)...................................................................................... 50124700 387 RIO YAUCO BASIN Lago Lucchetti at Damsite near Yauco (e)................................................................................... 50125780 389 RIO LOCO BASIN Lago Loco at Damsite near Yauco (e).......................................................................................... 50128900 390 Rio Loco at Guanica (c,b,p).......................................................................................................... 50129700 391 RIO GUANAJIBO BASIN Rio Guanajibo at Highway 119 at San German (d)...................................................................... 50131990 394 Rio Guanajibo near San German (c,b).......................................................................................... 50133600 395 Rfo Rosario near Hormigueros (d,c,b,s)............................................................................... 50136400 397 Rio Guanajibo near Hormigueros (d,c,b,p)................................................................................... 50138000 406 RIO YAGUEZ BASIN Rio Yagiiez near Mayaguez (c,b).................................................................................................. 50138800 410 RIO GRANDE DE ANASCO BASIN Lago Guayo at Damsite near Castaner (e)............................................................................ 50141500 412 Rfo Grande deAnasco near Lares (c,b)........................................................................................50143000 413 Rfo Grande de Anasco near San Sebastian (d,c,b,s)..................................................................... 50144000 415 Rfo Grande de Anasco near Anasco (c,b,p).................................................................................. 50146000 418 RIO CULEBRINAS BASIN Rfo Culebrinas near San Sebastian (c,b)....................................................................................... 50147600 422 Rfo Culebrinas at Highway 404 near Moca (d)............................................................................ 50147800 424 Rfo Culebrinas near Aguada (c,b,p).............................................................................................. 50149100 425 VIEQUES, P.R. Quebrada La Mina near Esperanza (e).......................................................................................... 50232000 427 Quebrada Pildn at Colonia Puerto Real (e)................................................................................... 50233000 428 Discharge at partial-record stations and miscellaneous sites Low-flow partial-record stations................................................................................................................... 430 Analyses of samples collected of water-quality partial-record stations and miscellaneous sites............................................................................................................ 442 ST THOMAS, US VIRGIN ISLANDS Bonne Resolution Gut at Bonne Resolution (d)........................................................................... 50252000 526 Turpentine Run at Mount Zion (d)................................................................................................ 50274000 527 ST JOHN, US VIRGIN ISLANDS Guinea Gut at Bethany(d)............................................................................................................50295000 528 ST CROIX, US VIRGIN ISLANDS River Gut at Hwy 66 at Fairplanes (d).......................................................................................... 50333700 529 Bethlehen Gut at Hwy 66 at Fairplanes (d).................................................................................. 50334500 530 Jolly Hill Gut at Jolly Hill (d)....................................................................................................... 50345000 531 XI GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED 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 ..................................................................................................................467 Well 182209066340600 Local number FL-1 ..................................................................................................................468 Well 182626066345100 Local number TI-1 ...................................................................................................................469 RIO GRANDE DE MANATI BASIN Well 182549066304300 Local number 166 ....................................................................................................................470 Well 182757066325600 Local number 206 ....................................................................................................................471 Well 182710066303700 Local number 207 ....................................................................................................................472 Well 182308066260400 Local number 210 ....................................................................................................................473 Well 182548066265700 Local number CS-7 ..................................................................................................................474 Well 182506066280200 Local number HI-2...................................................................................................................475 RIO CIBUCO BASIN Well 182647066201700 Local number 70 ......................................................................................................................476 Well 182615066235300 Local number 211 ....................................................................................................................477 Well 182515066194000 Local number 212 ....................................................................................................................478 Well 182330066185700 Local number 213 ....................................................................................................................479 Well 182614066261500 Local number PA-2..................................................................................................................480 Well 182712066251700 Local number TO-3..................................................................................................................481 RIO DE LA PLATA BASIN Well 182530066135400 Local number 216 ....................................................................................................................482 Well 182655066142400 Local number 217 ....................................................................................................................483 Well 182804066173500 Local number DA-1 .................................................................................................................484 Well 182620066163403 Local number HG-4 .................................................................................................................485 Well 182657066162700 Local number SA-1 ..................................................................................................................486 Well 182657066162701 Local number SA-3..................................................................................................................487 Well 182548066164401 Local number MA-2.................................................................................................................488 Well 182526066165001 Local number SR-2 ..................................................................................................................489 Well 182654066150600 Local number TB-1 ..................................................................................................................490 RIO HONDO TO RIO PUERTO NUEVO BASINS Well 182441066082600 Local number 219 ....................................................................................................................491 Well 182511066045401 Local number PN-2..................................................................................................................492 Well 182435066052701 Local number PN-5 ..................................................................................................................493 Well 182445066043401 Local number PN-6..................................................................................................................494 Well 182443066041502 Local number PN-8c ................................................................................................................495 Well 182417066042700 Local number PN-10................................................................................................................496 Well 182349066032600 Local number PN-13 ................................................................................................................497 Well 182406066034700 Local number PN-19................................................................................................................498 XII GROUND-WATER WELLS, BY BASIN, FOR WHICH RECORDS ARE PUBLISHED-Continued Page RIO GRANDE DE LOIZA BASIN Well 181550065593201 Local number 50 ......................................................................................................................499 Well 182515065594100 Local number 222 ....................................................................................................................500 Well 181513065554601 Local number a-TW3B..........................................................................................................501 Well 181352066025300 Local number a-TW19A........................................................................................................502 RIO HERRERA TO RIO ANTON RUIZ BASINS Well 181823065401900 Local number RF-04 ................................................................................................................503 Well 181917065382701 Local number RF-12 ................................................................................................................504 Well 182131065241100 Local number RP-04 ................................................................................................................505 Well 182138065431800 Local number RS-02 ................................................................................................................506 RIO HUMACAO TO RIO SECO BASINS Well 175858066100200 Local number 6 ........................................................................................................................507 Well 180415065513900 Local number 96 ......................................................................................................................508 Well 175719066085500 Local number P-13 ...................................................................................................................509 RIO SALINAS TO RIO JACAGUAS BASINS Well 175829066232200 Local number 87 ......................................................................................................................510 Well 180002066132200 Local number HW-TW-01 .......................................................................................................511 Well 180001066122002 Local number HW-TW-03C ....................................................................................................512 Well 175947066130601 Local number HW-TW-05B ....................................................................................................513 Well 175957066123400 Local number HW-TW-13.......................................................................................................514 Well 175903066165000 Local number PG-07 ................................................................................................................515 Well 175943066224800 Local number PS-07.................................................................................................................516 Well 180206066135500 Local number RM-05...............................................................................................................517 Well 180104066152300 Local number RM-10...............................................................................................................518 RIO INABON TO RIO LOCO BASINS Well 180133066503300 Local number 132 ....................................................................................................................519 Well 175900066354200 Local number 141 ....................................................................................................................520 Well 180045066381600 Local number AN-1 .................................................................................................................521 RIO GUANAJIBO BASIN Well 180132067033800 Local number 143 ....................................................................................................................522 Well 180628067084300 Local number CR-TW-9A .......................................................................................................523 RIO CULEBRINAS BASIN Well 182442067091700 Local number 200 ....................................................................................................................524 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, 1996 DISCONTINUED STREAMFLOW STATIONS XIII 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 Guajatac 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 50016000 Rio Camuy near Camuy 50021000 Rio Pellejas at Central Pellejas 50021050 Rio Pellej as below Central Pellej as 50021500 Rio Pellej as near Utuado 50023000 Rio Vivf near Central Pellejas 50027200 Rio Grande de Arecibo blw. Lago dos Bocas 50029000 Rio 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 RioIndioatVegaBaja 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 Bayamon 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 50059000 Rio Piedras at Rio Piedras 50061300 Rio Canovanillas near Loiza 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 — 12.5 14.40 Period of record 1970 1984-89 1970 1969-70,1984-87 1969-70,1984-89 1969-71 1969-70 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 1971-82,1987-93 1968-73 XIV WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 DISCONTINUED STREAMFLOW STATIONS-Continued Station Station name number 50062500 Rio Herrera near Colonia Dolores 50063300 Rio Espiritu Santo near 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 Rio Blanco at Florida 50076000 Rio Blanco near Florida 50077000 Rio Blanco at Rio Blanco 50077400 Rio Blanco at Colonia La Fe 50078500 Rio Anton Ruiz at Central Pasto Viejo 50081500 Rio Humacao near Humacao 50082000 Rio Humacao at Hwy 3 at Humacao 50082200 Rio Humacao near La Suiza 50082800 Rio Guayan6s near Colonia Laura 50083500 Rio Guayane~s near Yabucoa 50084000 Rio Li mones near Yabucoa 50085100 Rio Guayane~s at Central Roig 50086100 Rio del Ingenio at Comunas 50086500 Rio Guayan6s at Playa Guayane~s 50087200 Cano Santiago near Central Roig 50091000 Rio Maunabo at Maunabo 50091200 Rio Maunabo near Maunabo 50091400 Rio Jacaboa near Lamboglia 50091700 Rio Chico at Patillas 50091800 Rio Chico at Providencia 50094200 Rio Grande de Patillas at Patillas 50094300 Rfo Grande de Patillas at Providencia 50094400 Rio Nigua at Pitahaya 50095200 Rio Guamani at Guayama 50095500 Rio Guamani near Guayama 50099000 Quebrada Aguas Verdes near Salinas 50106500 Rio Coamo near Coamo 50106900 Rio Coamo below Lago Coamo near Coamo 50107200 Rio Coamo at mouth near Santa Isabel 50108200 Rio Descalabrado at Las Ollas 50108500 Rio Descalabrado near Santa Isabel 50111200 Rio Toa Vaca near Villalba 50111700 Rio Jacaguas near Juana Diaz 50111750 Rio Jacaguas below Quebrada Guana"bana 50112100 Rio Jacaguas near Anis 50112600 Rio Inabon at Goto Laurel 50113100 Rio Guayo near Goto Laurel 50113500 Rio Inabon near Anis Drainage area (mi2) 2.75 2.23 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 — 11.80 30.20 Period of record 1968-72 1968-73 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 1967-71 1965, 1968-71 1964-65 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 DISCONTINUED STREAMFLOW STATIONS-Continued XV Station Station name number 50114400 Rio Bucana near Ponce 50114700 Rio Bucana near Playa de Ponce 50115900 Rio Portugues 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 Rio Guay anilla nr Guay anilla 50124500 Rio Guayanilla at Guayanilla 50125900 Rio Duey above Diversion near Yauco 50126150 Rio Yauco above Diversion Monserrate near Yauco 50128000 Rio Yauco near Yauco 50129000 Rio Loco near Yauco 50129500 Rio Loco near Guanica 50129900 Laguna Cartagena near Boqueron 50130320 Quebrada Mamey at Joyuda 50136000 Rio Rosario at Rosario 50141000 Rio Yahuecas near Adjuntas 50145000 Rio Grande de Anasco at El Espino 50147000 Rio Culebrinas at San Sebastian 50214500 Quebrada Resaca near Monte Resaca, Culebra 50215000 Drainage Canal at Culebra Airport, Culebra 50231000 Quebrada Confresi Tributary near Isabel II, 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 50337500 Gut 4.5 at Cane Valley 50348000 Salt River at Canaan 50349000 Gut 10 near Altona Drainage area (mi2) 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 2.97 0.38 1.48 0.09 1.42 5.40 0.2 0.36 0.13 Period of record 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 1963-69,1978-86 1992-94 1992-94 1992-93 1991-93 1990-93 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, 1996 ' 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, 1996." This report includes records on both surface and ground water. Specifically, it contains: (1) Discharge records for 75 streamflow-gaging stations, stage only for 5 gaging stations, daily sediment records for 25 streamflow stations, 95 partial-record or miscellaneous streamflow stations, stage records for 15 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, and 1995 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-96-1." 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, 1996 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 and 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, 1996 SUMMARY OF HYDROLOGIC CONDITIONS Rainfall Rainfall throughout Puerto Rico during the water year 1996 (October 1995 to September 1996) averaged about 112 percent of normal. During the months of January, February, April, and June to September rainfall was above normal (table 1). Significant above normal rainfall conditions were recorded during January and September as rainfall averaged 234 and 202 percent of normal, respectively. During the month of October, November, December, March, and May rainfall was deficient with averages below normal fluctuating between 24 to 35 percent below. Rainfall averaged about 114 percent of normal in northern Puerto Rico, 103 percent of normal in southern Puerto Rico, 103 percent of normal in western Puerto Rico, and 130 percent of normal in eastern Puerto Rico. Monthly average rainfall islandwide for the 1996 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 and annual averages for the 1996 water year and the 30-year reference period, 1961-1990 Month October November December January February March April May June July August September 1996 Water Year (inches) 5.52 4.24 3.23 6.68 4.16 2.29 5.65 4.66 6.20 6.73 7.22 14.42 30-year normal (inches) 8.29 6.55 4.38 2.86 2.52 3.01 4.46 6.96 4.99 5.08 6.89 _U4 TOTAL 71.00 63.13 Surface Water Streamflow in Puerto Rico was, in general, above normal in water year 1996, based on the index stations with monthly- mean discharges largest than the long-term monthly median flow during several months. A monthly comparison of the monthly- mean flows during the 1996 water year, the long-term median of the monthly-mean flows, and the maximum and minimum 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. Historical maximum monthly-mean flows were recorded at the four stations. In the northern area, the Rio Grande de Manatf index station recorded historical maximum monthly-mean flow during September. During the rest of the year, the Streamflow conditions at this index station were generally near normal. In the eastern area, the index station on the Rio Fajardo, recorded monthly-mean flows below the median of the monthly-mean flows for the months of October, November, April, and May. During January, the previous maximum monthly- mean flow was exceeded. A new historical maximum was recorded at this index station. The rest of the year, monthly-mean flows, were above the median of monthly-mean flows. NOPTH RIO GRANGE DE MANATI AT HWY 2 NEAR MANATf (50038100) 10,000 1,000 - 100 ————1996 MONTHLY MEAN _ _ _ . 1964-95 MEDIAN OF MONTHLY-MEAN ONDJFMAMJJAS SOUTH RIO INABON AT REAL ABAJO (50112500) 1996 MONTHLY MEAN _ _ _ . 1962-95 MEDIAN OF MONTHLY-MEAN O N D J F M A MJj———A!3 EAST RIO FAJARDO NEAR FAJARDO (50071000) 1,000 100 — 1996 MONTHLY MEAN _ _ _ - 1965-95 MEDIAN OF MONTHLY-MEAN °NDJFMAMJJA WEST RIO GRANGE DE ANASCO NEAR SAN SEBASTIAN (50144000) 10,000 1,000 - 100 1996 MONTHLY MEAN _ _ _ . 1964-95 MEDIAN OF MONTHLY-MEAN ONDJFMAMJJAS Unshaded area indicates range between highest and lowest monthly-mean discharges for the period of record to water year 1996. Figure 1 .-Monthly-mean discharge of selected streams in Puerto Rico. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 In the southern area, the index station on the Rio Inabdn, recorded monthly-mean flows below the median of the monthly-mean flow only during the first quarter of the year (October, November, and December). During February, historical maximum monthly-mean flow was recorded at this index station. The rest of the year, monthly-mean flows were above the media of the monthly-mean flows. In the western area, the index station on the Rio Grande de Anasco, recorded historical maximum monthly-mean flow during February. Monthly-mean flows below the median of monthly mean flows were recorded during November, December, January, and July. During the rest of the year, the monthly-mean flows were well above the median of monthly mean flows. The most important hydrologic event that happened during water year 1996 was the passage of Hurricane Hortense through the Caribbean area. During the early morning of September 10,1996, Hurricane Hortense passed over the southwestern part of Puerto Rico. The eye of Hurricane Hortense moved over the towns of Guayanilla, Yauco, Guanica, Lajas, San German, Cabo Rojo, Hormigueros, and Mayagiiez. Hurricane Hortense produced heavy rains over Puerto Rico, especially in the eastern half of the island. This heavy rain produced moderate to severe floods in more than 40 towns through the island. The most affected areas were the north and east. Floodwaters inundated downtown areas and neighborhoods, washing away homes, businesses, vehicles, bridges, and parts of roads. These floods resulted in 18 deaths, of which 15 drowned as floodwaters inundated their homes or swept away their vehicles when they attempted to cross flooded bridges and roads. The U.S. Geological Survey data network was highly affected with about 25 percent of the stations destroyed or severely damaged. High-water marks were surveyed shortly after the event to determine the peak stages at sites where recording instruments failed or were damaged during the flood. Historical maximum peak stages and flows were recorded during this event. Peak stages and discharges for 30 selected streamflow-gaging stations in Puerto Rico are listed in table 2. Ground-Water Levels Ground-water levels in most aquifers in Puerto Rico and the U.S. Virgin Islands followed seasonal fluctuations associated to rainfall patterns during water year 1996. Early and late into the water year, the ground-water levels increased in response to above normal rainfall associated to the passage of Hurricane Marilyn, September 1995, and Hortense, September 1996, through the area. Ground-water levels in Puerto Rico declined during the summer months, in response primarily to ground- water withdrawals for public and industrial use in the north coast and irrigation use in the south coast. Record-low and record- high water levels were recorded at several wells in Puerto Rico and the U.S. Virgin Islands (tables 3 and 4). Ground-water levels in the north coast limestone aquifer of Puerto Rico fluctuated during the first half of water year 1996 in response to above normal rainfall in the area (fig. 2). From March to September the water levels declined in respond to less rainfall recharge and sustained ground-water withdrawals. At the Sabana Hoyos index well, the water levels declined about 2.00 ft. This declining trend was reversed by the rainfall produced by Hurricane Hortense in early September which caused the water levels to rise significantly. At the south coast alluvial aquifer of Puerto Rico, the ground water levels decreased from October to May in response to below average rainfall in the area and sustained ground-water withdrawals for agricultural, public, and industrial use (fig. 2). By mid May, the water levels began to rise in response to aquifer recharge from above average rainfall and streamflow infiltration. A significant rise in water level was recorded during September when Hurricane Hortense affected the area. At the Alomar index well, water levels rose about 2.00 ft. during September 1996. In the U.S. Virgin Islands, ground water levels followed similar fluctuations as those in Puerto Rico (fig. 2). The ground-water levels generally declined from October to June as rainfall diminished in the area. At the Guinea Gut index well in St. John, U.S. Virgin Islands, the water levels declined about 16.00 ft. for the same period of record. The declining trend was attenuated by various rainfall events which produced water level rises. After July, the ground-water levels increased as rainfall events became more frequent. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 Table 2. Summary of peak stages and discharges prior to and during September 10, 1996, at selected U.S. Geological Survey streamflow-gaging stations in Puerto Rico [mi2, square miles; ft, feet; ft3/s, cubic feet per second; >, greater than] Previous maximum discharge Station number 50014600 50025155 50030460 50031200 50034000 50035000 50038100 50039500 50043800 50045010 50046000 50047560 50047850 50048770 50050900 50051180 50051800 50053025 50055000 50055170 50055225 50055390 50057000 50058350 50059050 50100200 50100450 50106100 50110900 50113800 Station name Rio Camuy at Tres Pueblos Sinkhole Rio Saliente at Coabey near Jayuya Rio Orocovis at Orocovis Rio Grande de Manati near Morovis Rio Bauta near Orocovis Rio Grande de Manatf at Ciales Rio Grande de Manatf at Hwy 2 near Manatf Rfo Cibuco at Vega Baja Rfo de la Plata at Comerio Rfo de la Plata below La Plata Dam Rfo de la Plata at Hwy 2 near Toa Alta Rfo de Bayamon below Lago Cidra Rfo de Bayamon near Bayamon Rfo Piedras at El Senorial Rfo Grande de Lofza at Quebrada Arenas Quebrada Salvatierra near San Lorenzo Rfo Grande de Loiza at Hwy 1 83 near San Lorenzo Rfo Turabo above Borinquen Rfo Grande de Lofza at Caguas Rfo Cagiiitas near Caguas Rfo Cagiiitas at Villa Blanca at Caguas Rfo Bairoa at Bairoa Rfo Gurabo at Gurabo Rfo Canas at Rfo Canas Rfo Grande de Lofza below Damsite Rfo Lapa near Rabo del Buey Rfo Majada at La Plena Rfo Coamo at Coamo Rfo Toa Vaca above Lago Toa Vaca Rfo Cerrillos above Lago Cerrillos near Ponce Drainage area (mi2) -- 9.25 5.03 55.2 16.7 128 197 99.1 109 173 208 8.32 41.8 7.49 6.00 3.74 25.0 7.14 89.8 8.27 16.9 5.08 60.2 7.53 209 9.92 16.7 43.5 7.64 15.4 Period of record 1990-96 1990-96 1981-82 1989-96 1965-96 1970-82 1989-96 1946-53 1960-96 1970-96 1973-96 1989-96 1989-96 1960-96 1991-96 1965-70 1988-96 1988-96 1978-96 1984-96 1990-96 1990-96 1960-96 1992-96 1991-96 1991-96 1960-96 1990-96 1987-96 1989-96 1989-96 1987-96 1989-96 1989-96 Date 10/1991 06/1994 01/1992 05/1985 10/1970 10/1970 10/1985 04/1987 01/1992 01/1992 01/1992 07/1993 10/1970 08/1988 01/1992 05/1985 01/1992 01/1992 09/1960 09/1993 01/1992 01/1992 09/1960 10/1990 11/1987 01/1992 01/1992 01/1992 01/1992 01/1992 Peak stage (ft) 12.42 13.92 11.53 17.89 21.90 24.00 33.79 19.10 29.22 34.76 26.39 16.56 20.20 16.08 17.52 17.20 31.37 21.07 31.17 26.10 19.91 12.32 27.70 20.55 39.57 17.82 17.19 13.49 13.24 9.65 Maximum discharge (ft3/s) 1,030 5,900 2,320 48,000 17,800 125,000 97,500 34,000 127,000 127,000 118,000 2,090 28,000 4,680 18,200 9,320 40,700 12,000 71,500 3,010 13,400 1,580 74,600 3,830 124,000 15,700 15,200 9,290 8,700 8,140 Flood of September 10, 1996 Peak stage (ft) 19.58 19.29 16.85 18.83 25.14 25.20 36.36 18.74 27.78 42.26 27.40 27.34 29.07 15.46 25.93 20.87 35.62 22.60 32.32 31.60 23.89 18.16 31.44 24.60 49.31 18.65 18.69 19.94 18.65 10.62 Peak discharge (ft3/s) 3,650 14,500 8,070 53,000 25,900 128,000 > 140,000 29,400 118,000 197,000 >1 18,000 15,000 65,000 5,400 >20,000 15,000 56,800 15,200 83,000 9,040 >20,000 7,200 62,100 7,500 223,000 18,100 17,700 26,300 > 15,000 10,600 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 Table 3. Highest ground-water levels recorded during water year 1996 and previous highest ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands [PR, Puerto Rico; St.C, St. Croix; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year; +, above land-surface datum] Well name or number Manati 3 Dorado Airport Well Higuillar No. 4 Maguayo No. 2 San Antonio No. 1 San Antonio No. 3 Santa Rosa No. 2 ToaBajaTW-1 Luis Munoz Marin 1C Jardin Botanico No. 1 Jardin Botanico No. 3 CJ-TW3B CJ-TW19A RF-04 RF-12 RS-02 RM#5 WAPA-17 Local number 166 DA-1 HG-4 MA-2 SA-1 SA-3 SR-2 TB-1 PN-8c PN-13 PN-19 CJ-TW3B CJ-TW19A RF-04 RF-12 RS-02 RM#5 13 Location PR PR PR PR PR PR PR PR PR PR PR PR PR PR PR PR PR ST.C 1996 Highest water level (ft-blsd) 22.43 56.67 31.84 24.89 13.97 13.95 60.42 3.04 8.80 6.96 3.06 10.64 22.60 10.92 4.64 1.39 5.56 0.27 Date (mm-dd-yy) 09-20-96 09-11-96 09-11-96 09-18-96 09-19-96 09-11-96 09-11-96 09-20-96 09-10-96 09-10-96 09-10-96 09-11-96 09-11-96 09-14-96 09-10-96 01-15-96 09-10-96 09-10-96 09-10-96 Previous highest water level (ft-blsd) 22.90 57.62 4.03 27.58 17.13 16.76 62.79 7.90 10.35 8.75 3.35 13.40 22.78 11.74 5.70 3.10 7.48 4.68 Date (mm-dd-yy) 03-03-83 06-06-95 09-17-95 09-18-95 09-26-95 09-16-95 09-16-95 09-30-95 09-16-95 09-25-89 09-18-89 12-30-92 06-13-92 06-14-92 12-03-92 12-04-92 07-27-93 09-18-95 09-17-95 09-18-95 09-17-95 05-26-92 10-14-90 Period of record (mm-yy) 02-82 to 09-96 02-95 to 09-96 01-95 to 09-96 06-95 to 09-96 10-94 to 09-96 10-94 to 09-96 02-95 to 09-96 11-92 to 09-96 02-89 to 09-96 03-89 to 09-96 06-91 to 09-96 09-91 to 09-96 06-92 to 09-96 08-93 to 09-96 08-95 to 09-96 08-95 to 09-96 03-89 to 09-96 02-90 to 09-96 Table 4. Lowest ground-water levels recorded during water year 1996 and previous lowest ground-water levels at selected wells in Puerto Rico [PR, Puerto Rico; mm-dd-yy, month-day-year; ft-blsd, feet below land-surface datum; mm-yy, month-year] Well name or number RF-04 RF-12 RP-04 RS-02 HW-TW-01 HW-TW-03C HW-TW-05B Godreau No. 7 Vivoni, Col. Amistad Local number RF-04 RF-12 RP-04 RS-02 HW-TW-01 HW-TW-03C HW-TW-05B PG-07 143 Location PR PR PR PR PR PR PR PR PR 1996 Highest water level (ft-blsd) 18.22 10.45 9.66 6.95 37.45 59.82 28.55 34.87 40.09 Date (mm-dd-yy) 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 09-10-96 03-01-96 08-14-96 08-15-96 09-03-96 07-21-96 07-22-96 07-28-96 Previous highest water level (ft-blsd) 17.11 8.14 2.93 6.22 34.44 59.10 27.13 34.58 40.00 Date (mm-dd-yy) 08-15-95 08-17-95 08-18-95 08-16-95 08-17-95 09-05-95 09-08-95 to 09-16-95 09-28-95 09-07-95 08-18-95 to 08-21-95 06-09-90 to 06-11-90 06-08-94 Period of record (mm-yy) 08-93 to 09-96 08-95 to 09-96 08-95 to 09-96 08-95 to 09-96 04-88 to 09-96 12-88 to 09-96 04-88 to 09-96 09-91 to 09-96 12-81 to 09-96 8 I UJ o: to 25 30 35 WELL 70, SABANA HOYOS, PUERTO RICO I______I______I ___L OCT NOV OCC JAN FEB MAR APR MAY JUN JUL AU6 SEP 1995 1996 l T WELL 87, ALOMAR 1, PUERTO RICO z _r OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AU6 SEP 1995 1996 14 24 WELL 11. GUINEA GUT ST. JOHN, U.S. VIRGIN ISLANDS I I I L OCT NOV'DEC JAN FEB MAR APR MAY JUN JUL AU6 SEP 1995 1996 Figure 2.—Ground-water levels at selected wells in Puerto Rico and the U.S. Virgin Islands. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 19% Water Quality In water year 1996 the U.S. Geological Survey, in cooperation with several local government agencies, collected water- quality data at 83 surface-water stations in Puerto Rico. The water-quality data collected at these stations included the major chemical constituents and several constituents that are listed in table 5. The highest concentration of each of these constituents detected during water year 1996 and the station where it was detected are summarized in table 5. Table 5. Surface-water quality stations in Puerto Rico with highest concentration of selected constituents during water year 1996 [All constituent concentrations are in milligrams per liter; MBAS, Methylene blue active substance] Station number Station name Constituent Concentration 50049100 50116200 50049100 50049100 50049100 50055250 50055250 50143000 50055250 Rio Piedras at Hato Rey Rfo Portugues at Ponce Rio Piedras at Hato Rey Rio Piedras at Hato Rey Rfo Piedras at Hato Rey Rio Cagiiitas at Caguas Rio Cagiiitas at Caguas Rfo Grande de Afiasco near Lares Rfo Caguitas at Caguas Sulfide Boron Manganese Iron Zinc Cyanide Phenols Phenols MBAS 1.0 2.0 8.5 16 2.0 0.02 0.08 0.08 1.1 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 1996. The highest concentrations observed during this year were in stations 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 the upper basin sewage treatment plants. 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 of the Island. Suspended sediment concentrations were monitored at 25 stations in Puerto Rico during the 1996 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 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. 10 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 1996 water year that began October 1,1995 and ended September 30, 1996. 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 11. 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. 11 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 12). 67'15' 67W 65'30' 18°30' - 18W ATLANTIC EXPLANATION FECAL COLIFORM • < 1000 • 1000-10,000 • 10,000-100,000 100,000-1,000,000 30 KILOMETERS SEA Figure 3.--Maximum concentration of fecal coliform bacteria at the water-quality sampling sites in Puerto Rico. 67" 15' 67-00' 45 30' 15' 66'QO' 45' 65"30' ATLANTIC OCEAN 03$* 15' - 18 C00' SE/i EXPLANATION FECAL STREPTOCOCCI 4 < 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'QQ ! 45' 30' 15' 66W 45' 65'30' 18 V3CT - 15' - 18'00' Rio Cuietnnss R(o Gusyabc Rio Granite ATLANTIC OCEAN CARIBBEAN SEA fl!o Fujfiido .?fo Deguao .. lebiada Palms , ,'fc Santiago to Blanco '^-J { Rto Gusysiws EXPLANATION 0920 CONTINOUS STREAMFLOW STATION AND NUMBER , 0930 LAKE-ELEVATION STATION I AND NUMBER 0564 DAYLY SEDIMENT STATION ^ AND NUMBER Figure 5.--Location of surface-water stations in Puerto Rico. 67" 15' 67'GG' 18 =3G' - 18W ATLANTIC OCEAN \Wo Daguao A ' ~"/"V X 71 X Quetoarfa'PdAna 0509 IN ' ' V 0820 V^ "/" Sa/-i/«f;o -^1* / I VWT A ? ° Sfe"co .--^ T \~~~-—•/ ^x/ "fo A'!-'«'! ^-^ EXPLANATION QUALITY OF WATER STATIONS BIOLOGICAL CHEMICAL 0280 SEDIMENT (Daily) CARIBBEAN SEA Figure 6.-Location of water-quality stations in Puerto Rico. 0> 67'15' 67"QO ! 45 ! 30' 15' 66"GQ ! 18*30' Rio Cuiebrin^s 1485 18*00' 45' 65"30 ! 0474/5 04787 .2647970 AQ48760 . -47953 b48750 895 047750 047810 0476 047598 043998 043950 10 20 KILOMETERS SEA 10 20 MILES EXPLANATION A LOW-FLOW PARTIAL-RECORD STATION 043850 STATION IDENTIFICATION NUMBER I____________ !_____________ Figure 7.--Location of low-flow partial-record stations in northcentral Puerto Rico. 67" 15' 67"00' 45' 30' 15' 66W 45 65'30' ATLANTIC OCEAN 18 =30' 15' 18"00' Y222 / _x ^^ft ( ^ fj £ / T 0 10 20 10 N c^T^^/c^V; ^^ ,^^«^o f,vO pjO 1%^:^",^" ,^=^v:> v^" ^ ^" *o c>v ff#v EXPLANATION 01234 0 1 2 3,4 64°50' 45! 40' 64*35' 17*45* ST. CROIX 17*40* L EXPLANATION 01234 KILOMETERS ^34g0 SURFACE-WATER STATION 1 -i1 -----J -- AND NUMBER __ 0 1 234 j____________,_____ Figure 9.--Location of surface-water stations in the U.S. Virgin Islands. 65°05' 65W 18"24! - 18°20! 64"50' 45' 18"22! ST. JOHN 01234 KILOMETERS _J__I__II. 0 1 2 3,4 64 <)50' 45' 40' 19 64'50' 01234 KILOMETERS 1 1 01234 64"40' rs 64'35 ! ST. CRO1X 17*45' 17'40' 01234 KILOMETERS .III____ EXPLANATION WELL AND WELL NUMBER I 01234 Figure 10.--Location of ground-water stations in the U.S. Virgin Islands. IS) Isla de P.R, EXPLANATION 2320 SURFACE-WATER STATION AND NUMBER Hi 0 1 Figure 11.--Location of surface-water stations in Vieques Island. WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 21 66»SJ* SI* SI* 50' 4T 48' 6«»47* ll»02' — or— H«00'— - I7°S9 134 «4| 131* \ v .* /f ' •27 •74 C/ C COORDINATES FOR WELLS 27 (180160066474000) AND 74 (160136066471000) COORDINATES FOR WELLS 132 (160133066603300) ~~ AND 1S4 (180120066603200) COORDINATES FOR WELL 131 (180066066602700) COORDINATES FOR WELL 16 (176922066466600) Figure 12.--Grid showing 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 com pi etc-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. 22 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 23 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. REM ARKS.--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. 24 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 the 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). WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 ft3/s. 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. 26 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 27 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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, andA4. 28 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 29 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 30 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 31 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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-drgit 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 WATSTORE DATA The U.S. Geological Survey is the principal Federal water-data agency and, as such, collects and disseminates about 70 percent of the water data currently being used by numerous State, local, private, and other Federal agencies to develop and manage our water resources. As part of the U.S. Geological Survey's program of releasing water data to the public, a large-scale computerized system has been developed for the storage and retrieval of water data collected through its activities. The National Water-Data Storage and Retrieval System (WATSTORE) was established in 1972 to provide an effective and efficient means for the processing and maintenance of water data collected through the activities of the U.S. Geological Survey and to facilitate release of the data to the public. A variety of useful products, ranging from data tables to complex statistical analyses such as Log Pearson Type III, can be produced using WATSTORE. The system resides on the central computer facilities of the U.S. Geological Survey at its National Center in Reston, Virginia, and consists of related files and data bases. * Station Header File - Contains descriptive information on over 440,000 sites throughout the United States and its territories where the U.S. Geological Survey collects or has collected data. * Daily Values Files - Contains over 220 million daily values of streamflow, stages, reservoir contents, water temperatures, specific conductances, sediment concentrations, sediment discharges, and ground-water level. * Peak Flow File - Contains approximately 500,000 maximum (peak) streamflow and gage-height values at surface-water sites. * Water-Quality Data - Contains approximately 2 million analyses of water samples that describe the chemical, physical, biological, and radio-chemicals characteristics of both surface and ground water. * Ground-Water Site Inventory Data Base - Contains inventory data for over 900,000 wells, springs, and other sources of ground water. The data includes site location, geohydrologic characteristics, well-construction history, and one-time field measurements such as water temperature. 32 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 In 1976, the U.S. Geological Survey opened WATSTORE to the public for direct access. The signing of a Memorandum of Agreement with the Survey is required to obtain direct access to WATSTORE. The system can be accessed either synchronously or asynchronously. The requestor will be expected to pay all computer costs he/she incurs. Direct access may be obtained by contacting: U.S. Geological Survey National Water Data Exchange 421 USGS National Center Reston, Virginia 22092 In addition to providing direct access to WATSTORE, data can be provided in various machine-readable formats on magnetic tape or 5-1/4 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's offices. (See address on the back of the title page). 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. 33 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 b 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. 34 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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: 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. 35 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 (G.H.) 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 (Isd) 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 (ug/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 (UG/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. 36 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 Table 6. Factors for conversion of chemical constituents in milligrams per liter to milliequivalents per liter Ion Multiply by Ion Aluminum (Al+3)* ................ 0.1 1 1 19 Iodide (1-1 .............................. Ammonia as NH4+1 .............. .05544 Iron (Fe+3). ............................ Barium (Ba+2) ....................... .01456 Lead (Pb+2) ........................... Bicarbonate (HCO3-1)........... .01639 Lithium (Li+1) ....................... Bromide (Br-1).. ..................... .01251 Magnesium (Mg+2) ............... Calcium (Ca+2)...................... .04990 Manganese (Mn+2)*.. ............ Carbonate (CO3-2).. ............... .03333 Nickel (Ni+2). ........ ................ Chloride (CM).... ................... .02821 Nitrate (N03-1)............ ........... Chromium (Cr+6)* ................ .11539 Nitrite (NO2-1) ...................... Cobalt (Co+2)* ...................... .03394 Phosphate (PO4-3) ................. Copper (Cu+2)* ..................... .03148 Potassium (K+l) .................... Cyanide (CN-1)..... ................. .03844 Sodium (NA+1) ..................... Fluoride (F-l)................ ......... .05264 Strontium (Sr+2). ................... Hydrogen (H+l)...... ............... .99209 Sulfate (SO4-2). ..................... Hydroxide (OH-1)... ............... .05880 Zinc (Zn+2)*... ....................... Constituent reported in micrograms per liter; multiply by factor and divide results by 1,000. National Stream Oualitv Accounting Network (NASOAN) is a nationwide data-collection Multiply by 0.00788 .05372 .00965 .14411 .08226 .03640 .03406 .01613 .02174 .03159 .02557 .04350 .02283 .02082 .03060 network designed by th 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. 37 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 1010 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. Phytoplankton 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. 38 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 [mg C/(m2.time)] for periphyton and macrophytes and Tmg C/(m2.time)1 for phytoplankton 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 / (m2.timeVI for periphyton and macrophytes and fmgO /(m2.time)T for phytoplankton 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. 39 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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 (S AR) 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. 40 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. Surficial 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 part 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 Order... ...................... ..Ephemeroptera 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. 41 WATER RESOURCES DATA FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS, 1996 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. 42 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 Cl. 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 Al. 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. 44 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 of streamflow 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. Srnoot and C. E. Novak: USGS-TWRI Book 8, Chapter B2. 1968. 15 pages. 45 46 THIS PAGE WAS LEFT BLANK INTENTIONALLY ATLANTIC OCEAN Igntout and "~""\ sedimtntory rock* ^ ^V^' •-.——t .0 Ki'o Cfij(?<»t d* \ £ ARosco bo»in x ^0105 EXFtANATION SURFACE-WATER STATION AND NUMBER Toios QUALITY-OF-WATER STATION AND NUMBER V0io72o QUALITY-OF-WATER PARTIAL RECORD STATION AND NUMBER 10108 '165 LAKE-ELEVATION STATION AND NUMBER WELL AND WELL NUMBER 01 23456 KILOMETERS II II I I ,__! I f n 01234 MILES 47 Figure 13.--Rio Guajataca basin. 48 RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR LOCATION.—Lat 18°18'01", long 66°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* (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). May 1969 to December 1970 (February to May 1971 and March 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV DEC JAN FEB MAR MAY JUN JUL ADO SEP 1 35 11 2 37 10 3 46 9.7 4 36 8.5 5 25 7.5 6 19 8.0 7 14 8.3 8 13 26 9 11 11 10 11 8.6 11 9.1 6.8 12 13 6.2 13 24 5.6 14 8.7 5.1 15 30 7.0 16 43 5.5 17 56 4.9 18 36 4.7 19 27 4.4 20 22 4.1 21 49 4.3 22 32 3.9 23 27 3.6 24 27 10 25 40 4.0 26 20 29 27 18 10 28 17 6.2 29 13 5.5 30 12 8.7 31 11 —— TOTAL 781.8 248.1 MEAN 25.2 8.27 MAX 56 29 MIN 8.7 3.6 AC-FT 1550 492 CFSM 7.98 2.62 IN. 9.20 2.92 5.6 4.7 4.3 4.2 4.1 4.0 3.7 3.7 3.8 5.9 5.6 4.1 3.4 3.1 3.8 3.0 2.9 3.6 3.2 2.9 3.1 2.9 3.2 3.1 3.9 2.9 2.6 2.5 2.4 2.3 2.1 110.6 3.57 5.9 2.1 219 1.13 1.30 2.1 2.0 1.8 1.7 1.7 1.7 1.6 1.4 1.5 1.5 1.5 1.3 1.2 4.0 4.7 4.0 2.0 1.4 1.5 2.2 1.5 1.4 1.4 1.4 2.3 2.3 2.4 2.4 3.0 1.7 1.5 62.1 2.00 4.7 1.2 123 .63 .73 2.1 2.0 2.0 2.1 2.3 2.3 5.8 4.7 11 20 4.7 2.2 2.1 2.0 1.8 1.9 1.9 5.0 2.0 4.9 11 27 27 31 11 6.4 5.8 3.9 3.3 —— —— 209.2 7.21 31 1.8 415 2.28 2.46 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1969 MEAN 17.1 8.35 MAX 33.7 16.7 (WY) 1991 1971 MIN 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 3.69 7.31 1971 1.35 1991 FOR 2.80 6.83 1971 .66 1991 2.71 7.21 1996 .93 1992 2.5 2.7 2.6 2.4 2.3 2.4 2.3 2.2 2.0 2.0 2.0 2.1 2.2 6.5 9.7 2.5 2.0 1.6 2.3 2.5 2.4 1.8 2.4 2.4 2.1 2.3 2.3 2.4 2.4 2.3 11 90.6 2.92 11 1.6 180 .92 1.07 - 1996 2.25 6.38 1971 .92 1994 1995 CALENDAR YEAR 3475.32 9.52 66 .89 .97 6890 3.01 40.91 26 5.5 1.3 May 14 Apr 16 Apr 19 14 2.8 1.8 2.6 19 11 4.2 2.9 3.3 3.1 2.9 3.5 3.0 2.6 2.7 2.5 2.7 2.9 12 4.0 2.6 2.6 2.5 2.5 2.3 2.8 2.4 2.0 2.6 1.9 —— 127.7 4.26 19 1.8 253 1.35 1.50 2.1 1.8 2.3 1.6 1.6 2.9 1.9 1.6 1.5 1.4 11 5.4 1.6 7.5 2.7 2.2 9.9 2.9 3.7 3.2 2.2 2.0 1.9 1.8 1.9 26 13 24 9.0 40 17 207.6 6.70 40 1.4 412 2.12 2.44 34 11 6.3 13 12 11 7.0 7.2 5.3 4.8 4.2 3.7 8.1 4.3 5.1 3.9 4.6 4.4 4.3 5.4 5.4 5.1 4.5 16 5.2 3.9 20 8.0 4.6 4.2 —— 236.5 7.88 34 3.7 469 2.49 2.78 4.1 3.5 3.9 3.0 4.3 3.3 3.2 19 17 4.9 9.6 13 5.9 4.4 4.0 3.8 4.4 3.7 6.9 4.1 3.6 3.2 2.8 3.0 2.9 2.8 2.7 2.8 3.1 3.5 6.2 162.6 5.25 19 2.7 323 1.66 1.91 5.6 18 10 5.5 4.7 5.0 5.0 6.3 5.4 12 27 19 7.3 16 4.7 4.6 4.8 22 7.4 10 4.8 7.7 5.8 33 12 8.7 8.4 32 12 11 9.8 345.5 11.1 33 4.6 685 3.53 4.07 11 11 12 43 63 24 11 20 14 129 46 28 20 17 16 14 30 21 13 11 12 8.8 8.8 15 30 41 19 15 11 27—— 741.6 24.7 129 8.8 1470 7.82 8.73 , BY WATER YEAR (WY) 3.59 7.63 1993 1.09 1994 10.1 20.2 1995 3.86 1992 7.85 16.4 1995 3.18 1992 FOR 1996 WATER YEAR 3323.9 9.08 129 1.2 1.4 915 12.52 6590 2.87 39.13 24 4.4 1.9 Sep 10 Jan 13 Jan 7 Sep 5 Sep 5 4.38 9.85 1969 2.01 1994 6.10 11.1 1996 3.34 1970 WATER YEARS 1969 6.53 9.08 4.13 216 .47 .51 5300 21.30 4730 2.07 28.08 15 3.6 .97 Oct Jan Jan Oct Oct 12.3 24.7 1996 5.95 1993 - 1996 1996 1994 7 1990 13 1991 9 1991 7 1990 7 1990 49 RIO QDAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°18'01», long 66«52'24», at bridge on Highway 111 (km 32.9), 0.1 mi (0.2 km) Quebrada Anon, and 0.4 mi (0.6 km) northeast of Lares plaza. DRAINAGE AREA.—3.16 mi* (8.18 km'). PERIOD OF RECORD.—Water years 1958-71, 1974 to current year. upstream from DATE NOV 1995 01... JAN 1996 22... FEE 13... APR 09... JUN 10... AUG 20... TIME 1245 0945 1210 1145 1330 1530 WATE DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 10 1.5 2.5 3.6 5.4 31 R-QUALITY SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 198 238 270 242 239 230 DATA, WATER YEAR OCTOBER 1 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.5 8.8 7.8 7.6 7.6 7.5 TEMPER- ATURE WATER (DEG C) (00010) 23.0 21.0 21.0 22.5 23.5 24.0 TUR- BID- ITY (NTU) (00076) 5.1 2.5 3.7 7.3 1.9 180 .995 TO SB: OXYGEN, DIS- SOLVED (MG/L) (00300) 8.2 5.0 7.2 7.3 7.5 7.3 rTJSMBSK 1 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 96 56 83 86 90 89 990 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 16 13 <10 61 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K11000 K9000 2200 3200 5500 220000 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 29000 3800 3200 2800 8200 230000 DATE NOV 1995 01... JAN 1996 22... FEB 13... APR 09... JUN 10... AUG 20... HARD- NESS TOTAL (MG/L AS CACO3) (00900) 74 — __ 97 — 68 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 21 -- — 29 — 22 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 5.2 -- -- 6.0 -- 3.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 10 -- -- 11 -- 6.2 SODIUM AD- SORP- TION RATIO (00931) 0.5 — -- 0.5 -- 0.3 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.0 — — 2.8 -- 2.8 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 72 98 100 90 93 110 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 5.0 — -- 10 -- 8.0 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 11 — -- 12 -- 8.4 non-ideal count 50 DATE NOV 1995 01... JAN 1996 22... FEB 13... APR 09... JUN 10... AUG 20... DATE NOV 1995 01... JAN 1996 22... FEB 13... APR 09... JUN 10... AUG 20... DATE NOV 1995 01... JAN 1996 22... FEB 13... APR 09... JUN 10... AUG 20... RIO GUAJATACA BASIN 50010500 RIO GUAJATACA AT LARES, PR—Continued MATER-QUALITY DATA, MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 FLUO- RIDE, DIS- SOLVED (MQ/L AS P) (00950) <0.10 — — <0.10 — <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MQ/L AS N) (00625) 0.27 <0.24 <0.20 <0.20 <0.30 <0.26 IRON, TOTAL RECOV- ERABLE (UO/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 32 — — 27 — 16 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.8 2.4 1.9 l.B 2.3 2.1 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SON OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 129 — — 152 — 132 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 12 11 8.3 7.9 10 1.6 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 3.67 — — 1.48 — 11.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.070 0.030 0.080 0.070 0.040 0.020 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 5 9 5 13 6 356 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — — 1 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- G&N* NITRATE TOTAL (MG/L AS N) (00620) 2.49 2.19 1.69 1.59 1.98 1.49 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — — <100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 0.010 0.020 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — — 20 — -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 2.50 2.20 1.70 1.60 2.00 1.50 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — — <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.040 0.050 0.030 0.100 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — — <1 — — PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.24 <0.20 <0.20 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — — <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 290 370 <1 <1 40 40 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.02 <0.02 51 RIO GUAJATACA BASIN 50010800 LAGO GUAJATACA AT DAMSITE NEAR QUEBRADILLAS, PR LOCATION.--Lat 18°24'02", long 66°55'25 B , 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 de Padua and 2.8 mi (4.5 km) from Escuela Segunda Unidad Baldorioty de Castro. DRAINAGE AREA.--24.6 mi' (63.71 km2 ) 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) height, 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, 620.43 ft (189.1 m) May 8, 1995. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 645.48 ft (196.7 m), Oct. 18; minimum elevation, 629.00 ft (191.7 m). May 26. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 593 0 625 15,295 600 2,405 650 36,403 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 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 MAX MIN 642.90 642.67 642.48 642.11 641.88 641.96 641.99 641.99 641.97 641.96 642.00 641.99 642.46 642.65 643.08 644.65 645.47 645.14 644.47 643.71 643.30 642.64 642.37 642.65 643.58 643.41 643.27 643.23 643.29 643.29 643.28 645.47 641.88 643.24 643.21 643.17 643.13 643.05 643.01 642.94 642.99 643.06 643.02 642.95 642.88 642.80 642.70 642.67 642.59 642.52 642.41 642.32 642.22 642.33 642.26 642.15 642.11 642.02 642.17 642.09 642.00 641.89 641.86 —— 643.24 641.86 641.78 641.68 641.56 641.46 641.37 641.26 641.13 641.03 640.92 640.80 640.70 640.58 640.45 640.34 640.22 640.11 640.00 639.95 639.84 639.72 639.60 639.49 639.37 639.25 639.32 639.24 639.10 638.98 638.84 638.69 638.55 641.78 638.55 638.40 638.27 638.12 637.97 637.83 637.69 637.54 637.39 637.25 637.13 637.07 636.95 636.84 636.85 636.79 636.69 636.57 636.45 636.39 636.25 636.11 635.96 A A A A 635.56 A 635.59 635.46 635.34 ___ ___ 635.19 635.01 634.85 634.65 634.47 634.28 634.72 634.78 634.71 634.78 634.76 634.65 634.52 634.37 634.26 634.15 634.01 633.96 633.86 633.78 633.85 634.47 635.31 635.94 636.12 636.11 636.05 635.97 635.88 ___ —— 636.12 633.78 635.78 635.68 635.57 635.46 635.35 635.23 635.11 634.99 634.89 634.77 634.64 634.52 634.43 634.50 634.98 634.99 634.91 634.82 634.69 634.56 634.42 634.29 634.14 633.99 633.84 633.70 633.56 633.40 633.31 633.18 633.07 635.78 633.07 633.06 632.97 632.88 632.75 632.69 632.62 632.60 632.57 632.45 632.31 632.17 632.08 631.94 631.79 631.65 631.50 631.37 631.26 631.41 631.35 631.22 631.06 630.90 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 629.46 629.39 629.40 629.40 629.32 629.21 629.08 629.44 629.90 630.90 631.94 634.20 635.53 ___ ___ 636.15 636.46 636.57 636.96 637.32 638.28 A 639.16 638.99 638.61 638.29 638.09 638.32 638.38 638.38 638.50 638.85 638.97 638.95 638.90 638.83 638.79 638.74 638.77 638.73 638.68 639.24 639.71 640.56 641.11 --- ___ 641.18 641.03 640.80 640.49 640.11 639.72 639.22 638.92 639.02 638.40 637.98 638.36 638.55 638.61 638.59 638.55 638.48 638.40 638.48 638.55 638.50 638.43 638.34 638.26 638.16 638.05 637.92 637.87 637.74 637.63 637.53 641.18 637.53 637.44 637.55 637.71 637.80 637.74 637.63 637.65 637.63 637.58 637.52 637.76 637.99 637.97 637.96 637.93 638.19 639.41 640.10 640.34 640.11 639.62 639.11 638.59 639.09 638.77 638.06 637.48 A 636.57 A 635.52 ___ 635.23 635.17 635.32 636.47 637.76 638.24 638.35 639.01 A 642.66 642.99 642.64 642.18 641.66 641.27 641.70 641.40 641.15 640.60 640.04 639.77 639.47 639.34 639.36 639.71 640.21 640.32 A 640.28 640.30 —— ___ CAL YR 1995 MAX 645.47 MIN 620.53 WTR YR 1996 MAX 645.47 MIN 629.08 A No gage-height record 52 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 1995 TO SEPTEMBER 1996 NOV 06 JAN 17 FEB 22 APR 15 JUN 05 AUG 21 DATE 1995 1996 ... ... ... ... ... NOV 06 JAN 17 FEB 22 APR 15 JUN 05 AUG 21 E » 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) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1300 E65 270 6.8 25.0 1.6 — — <10 K10 K12 1320 *65 1230 *65 1445 *65 1400 *65 0630 "65 HARD- NESS TOTAL (MG/L DATE AS CACO3 ) (00900) 1995 140 1996 ... ... 130 150 estimate non-ideal count 265 7.5 25.0 0.70 290 7.6 25.0 0.50 287 7.5 25.5 1.0 307 7.2 25.5 1.1 314 7.0 26.0 1.1 MAGNE- SODIUM POTAS- CALCIUM SIUM, SODIUM, AD- SIUM, DIS- DIS- DIS- SORP- DIS- SOLVED SOLVED SOLVED TION SOLVED (MG/L (MG/L (MG/L RATIO (MG/L AS CA) AS MG) AS NA) AS K) (00915) (00925) (00930) (00931) (00935) 50 3.7 5.3 0.2 2.3 __ __ 47 4.1 6.3 0.2 2.1 __ 53 3.2 5.1 0.2 2.0 2.6 1.7 1.6 0.3 0.6 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 130 140 130 130 150 150 32 <10 21 <10 20 16 4 18 7 11 SULFATE SULFIDE DIS- TOTAL SOLVED (MG/L (MG/L AS S) AS S04) (00745) (00945) <0.5 5.8 __ __ <0.5 8.3 __ 6.5 K4 K2 K6 58 240 28 K8 68 600 K140 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 6.0 -- -- 8.2 -- 8.1 Discharge values provided by Puerto Rico Electric and Power Authority. RIO GUAJATACA BASIN 50011000 CANAL PRINCIPAL DE DIVERSIONES AT LAGO DE GUAJATACA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 53 NOV 1995 06... JAN 1996 17... FEB 22... APR 15... JUN 05... AUG 21... NOV 1995 06... JAN 1996 17.. . FEB 22.. . APR 15... JUN 05... AUG 21... 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) 0.38 0.42 0.25 0.50 0.55 0.23 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 6.8 -- — 7.7 — 7.1 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.57 0.42 0.35 0.41 0.55 0.39 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 158 — — 162 — 175 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 2.5 1.9 1.5 1.3 2.4 2.1 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) E28.2 -- — 28.4 — 30.7 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.020 0.020 0.020 0.020 <0.020 <0.020 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 2 7 5 7 2 ARSENIC TOTAL (UG/L AS AS) (01002) 1 — — <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.190 0.010 0.090 <0.010 <0.010 0.070 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 0.010 <0.010 <0.010 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — — 20 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.190 <0.020 0.100 <0.020 <0.020 0.080 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — — <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.140 0.050 0.210 0.240 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 — — PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.35 0.28 0.20 0.29 0.31 0.23 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — — <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) NOV 1995 06... JAN 1996 17... FEB 22... APR 15... JUN 05. .. AUG 21... 50 80 70 140 <0.10 <0.10 <0.010 <0.010 <0.02 0.02 54 RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR--Continued WATER-QUALITY RECORDS LOCATION.--Lat 18°28'31", long 66°57'46", Hydrologic Unit 21010002, on left bank at ford 1.7 mi (2.7 km) upstream from bridge on highway 2, 1.6 mi (2.6 km) west of Quebradillas plaza, 2.1 mi (3.4 km) upstream from Atlantic Ocean, and 6.6 mi (10.6 km) downstream from Lago Quaj ataca. DRAINAGE AREA.--Indeterminate PERIOD OF RECORD.—Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NOV 07 JAN 17 FEB 23 APR 17 JUN 05 AUG 30 DATE 1995 1996 ... ... ... DATE NOV 1995 07... JAN 1996 17. .. FEB 23. .. APR 17... JUN 05.. . AUG 30... 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) 1330 E10 *970 1430 15 *867 0950 13 426 0820 5.8 561 1610 34 363 1130 E250 302 HARD- MAGNE- NESS CALCIUM SIUM, TOTAL DIS- DIS- (MG/L SOLVED SOLVED AS (MG/L (MG/L CACO3) AS CA) AS MG) (00900) (00915) (00925) 250 71 17 __ _- 250 80 11 _. 150 53 3.7 7.6 26.5 1.6 7.4 24.0 4.2 7.6 23.0 4.7 7.4 24.0 0.40 7.6 26.0 7.0 7.6 27.0 2.4 SODIUM POTAS- SODIUM, AD- SIUM, DIS- SORP- DIS- SOLVED TION SOLVED (MG/L RATIO (MG/L AS MA) AS K) (00930) (00931) (00935) 99 3 4.9 __ __ 26 0.7 2.2 __ 5.5 0.2 2.0 4.2 3.9 5.9 5.0 6.0 8.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 180 210 190 220 180 190 51 45 68 59 73 100 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- 16 450 <10 580 14 R6000 <10 310 10 K1100 <10 480 CHLO- SULFATE RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS S04) AS CL) (00945) (00940) 28 200 __ __ 8.0 43 __ 7.6 8.7 390 3500 310 250 2000 370 E = estimate * = Sample was collected at hwy #2, 2 miles donwstream of regular sampling site. K = non-ideal count 55 NOV 1995 07... JAN 1996 17... FEB 23... APR 17... JUN 05... AUG 30... DATE NOV 1995 07... JAN 1996 17... FEB 23... APR 17.. . JUN 05... AUG 30... NOV 1995 07.. . JAN 1996 17... FEB 23... APR 17... JUN 05... AUG 30... RIO GUAJATACA BASIN 50011400 RIO GUAJATACA ABOVE MOUTH NEAR QUEBRADILLAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE 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) <0.22 0.38 <0.24 0.28 0.33 0.51 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 100 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 6.4 — — 9.0 — 6.7 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.7 1.8 1.8 1.2 1.1 1.4 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) (26.2 km2 ). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 02... JAN 1996 12... FEB 12... APR 04... JUN 18... AUG 27... TIME 1440 0835 1300 0950 0740 1140 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 14 8.9 8.0 17 7.5 5.5 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 275 294 313 218 336 333 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 8.0 8.3 8.0 7.3 8.0 8.0 TEMPER- ATURE WATER (DEG C) (00010) 24.0 20.5 21.0 20.5 22.5 24.5 TUR- BID- ITY (NTU) (00076) 4.0 2.2 2.1 39 1.1 2.7 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.5 8.1 8.1 8.1 7.9 7.9 OXYGEN, OXYGEN DIS- DEMAND, SOLVED CHEM- (PER- ICAL CENT (HIGH SATUR- LEVEL) ATION) (MG/L) (00301) (00340) 92 <10 92 <10 96 <10 94 16 95 <10 99 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 2700 K1700 3800 K10000 <10 2000 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 860 870 K200 2800 830 390 DATE NOV 1995 02.. . JAN 1996 12... FEE 12... APR 04... JUN 18. .. AUG 27. .. HARD- NESS TOTAL (MG/L AS CAC03 ) (00900) 120 -- -- 100 -- 150 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 30 -- — 26 -- 37 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 11 -- -- 8.5 -- 13 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 12 -- -- 12 -- 14 SODIUM AD- SORP- TION RATIO (00931) 0.5 -- -- 0.5 -- 0.5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.7 -- -- 2.5 -- 2.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 110 130 140 74 150 150 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.6 -- -- 10 -- 8.7 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -- -- 14 -- 17 non-ideal count 96 RIO GRANDE DE MANATI BASIN 50030700 RIO OROCOVTS NEAR OROCOVIS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE NOV 1995 02. .. JAN 1996 12... FEB 12... APR 04... JUN 18... AUG 27. .. NOV 1995 02... JAN 1996 12.. . FEB 12.. . APR 04. .. JUN 18. .. AUG 27. .. NOV 1995 02... JAN 1996 12.. . FEB 12... APR 04. .. JUN 18... AUG 27. .. FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) 0.10 — — <0.10 -- <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.24 0.29 1.2 0.61 0.24 0.71 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 31 -- -- 25 -- 35 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.2 2.5 2.0 1.4 1.9 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 179 -- -- 142 -- 213 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.8 5.4 11 8.9 6.4 8.5 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 6.89 — — 6.36 — 3.22 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.080 0.090 0.760 0.140 0.100 0.190 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) <1 6 1 46 8 2 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — -- <1 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.840 0.890 1.19 1.36 1.19 1.11 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.040 0.110 0.040 0.010 0.090 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- — 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.850 0.930 1.30 1.40 1.20 1.20 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.150 0.720 0.160 0.020 0.200 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — -- 3 — -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.21 0.14 0.48 0.45 0.22 0.51 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- — 30 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 270 2100 <1 <1 40 100 <0.10 <0.10 <1 <1 <1 <0.010 <0.010 <1 <0.02 <0.02 97 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR HOROVIS, PR LOCATION.--Lat 18°17'45", long 66°24'47", Hydrologic 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 Huerto, 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN MAR APR MAY JUN JUL AUG SEP 1 41 73 2 75 93 3 131 138 4 60 105 5 42 94 6 34 179 7 33 143 8 35 114 9 29 315 10 28 e920 11 34 e200 12 32 e!40 13 28 6112 14 28 6150 15 24 6112 16 24 6200 17 96 6150 18 52 6120 19 46 6107 20 33 688 21 185 686 22 217 elOO 23 112 682 24 278 670 25 246 670 26 168 666 27 185 664 28 203 662 29 192 57 30 109 57 31 87 TOTAL 2887 4267 MEAN 93.1 142 MAX 278 920 MIN 24 57 AC -FT 5730 8460 CFSM 1.69 2.58 IN. 1.95 2.88 STATISTICS OF MONTHLY MEAN MEAN 155 145 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 53 52 52 47 48 46 46 48 52 45 45 44 54 52 45 46 63 169 204 101 69 57 57 53 46 49 49 55 45 43 38 1873 60.4 204 38 3720 1.09 1.26 37 36 36 34 33 54 44 43 47 44 37 47 38 35 6200 670 650 643 656 670 680 647 642 640 654 elOO e!42 6210 e!30 e66 e60 2025 65.3 210 33 4020 1.18 1.36 652 647 642 640 637 637 637 660 6140 696 672 654 46 45 44 41 41 51 47 645 680 ellO 6140 6170 6180 670 650 645 640 —— 1959 67.6 180 37 3890 1.22 1.32 DATA FOR WATER YEARS 1965 109 522 1966 8.65 1995 FOR 77.5 191 1992 10.4 1995 63.0 179 1969 15.3 1994 e39 e37 636 636 637 38 32 32 29 27 28 34 26 32 38 31 27 25 24 24 23 22 22 21 21 22 27 23 22 24 22 881 28.4 39 21 1750 .51 .59 - 1996 64.5 226 1972 12.7 1984 1995 CALENDAR YEAR 22210.1 60.8 1340 3.5 4.1 44050 1.10 14.97 150 26 5.6 Sep 16 May 1 Apr 26 25 22 95 150 154 131 70 40 31 26 28 103 173 93 88 82 63 49 49 48 37 36 36 34 30 27 26 26 27 33 —— 1832 61.1 173 22 3630 1.11 1.23 26 24 23 22 21 21 23 29 54 34 31 25 23 23 74 158 64 95 44 77 40 28 26 24 22 ellO e!42 e!40 e66 678 690 1657 53.5 158 21 3290 .97 1.12 e62 e73 e40 e38 e43 e42 635 632 630 628 628 627 627 628 635 650 642 638 41 30 24 22 21 19 18 17 22 22 18 17 —— 969 32.3 73 17 1920 .59 .65 16 15 15 15 14 13 13 627 6250 650 633 631 631 643 649 643 44 33 27 24 22 20 19 19 23 22 19 19 20 20 21 1010 32.6 250 13 2000 .59 .68 21 20 21 30 34 25 22 27 20 20 20 19 21 25 35 72 80 34 26 23 24 22 22 62 30 23 21 21 22 21 20 883 28.5 80 19 1750 .52 .60 49 95 26 6103 6300 6250 674 688 elOO 7500 772 6450 6390 6350 6330 6370 6300 6210 6170 e!60 6120 ellO elOO 83 80 78 76 73 81 70 —— 12958 432 7500 26 25700 7.82 8.73 , BY WATER YEAR (WY) 108 412 1969 8.80 1995 FOR 1996 33201 90 7500 13 14 47700 18 65850 1 22 151 43 21 161 915 1985 15.7 1994 WATER YEAR .7 Sep 10 Jul 6 JUl 1 Sep 10 .83 Sep 10 .64 .37 61.4 173 1987 6.75 1994 46.3 157 1979 5.54 1994 WATER 95 248 24 17100 3 4 48000 17 69250 1 23 172 48 21 55.1 435 1979 9.70 1984 YEARS 1965 .6 .2 May .5 May .0 Jul May .89 May .73 .53 104 432 1996 6.87 1994 - 1996 1971 1994 18 1985 1 1995 22 1994 18 1985 18 1985 e Estimated 98 PERIOD RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR HOROVIS, PR—Continued WATER-QUALITY RECORDS OF RECORD.—Water years 1968 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 02... JAN 1996 12... FEB 12... APR 08... JUN 18. .. AUG 27. .. NOV 02 JAN 12 FEB 12 APR 08 JUN 18 AUG 27 NOV 02 JAN 12 FEB 12 APR 08 JUN 18 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) 1245 65 265 8.0 25.0 8.3 7.8 94 <10 570 260 1025 47 270 8.3 23.0 7.2 8.4 97 <10 290 K160 1140 45 278 8.1 23.5 7.4 8.7 104 15 K720 220 0930 42 240 7.6 24.0 77 7.0 84 16 3400 K1200 1025 40 0940 21 HARD- NESS TOTAL (MG/L DATE AS CAC03 ) (00900) 1995 100 1996 ... ... 99 120 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1995 0.20 1996 . . . 0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- -- 24 -- 28 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 26 -- -- 25 -- 235 265 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.2 -- -- 9.4 -- 11 SOLIDS, SUM OF CONSTI- TUENTS , DIS- SOLVED (MG/L) (70301) 164 -- -- 150 __ 7.8 8.1 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- -- 11 -- 12 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 28.8 -- -- 17.0 -- 26.0 64 26.0 2 SODIUM AD- SORP- TION RATIO (00931) 0.5 -- -- 0.5 — 0.5 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 4 12 10 74 47 .1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 -- -- 2.7 -- 2.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.790 0.720 0.490 1.17 0.890 7.4 7.9 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 110 110 110 89 89 130 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 0.030 0.040 92 98 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.800 0.730 0.500 1.20 0.930 15 K10 K1500 <10 K130 200 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 8.9 -- -- 9.9 -- 8.2 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.030 0.030 0.080 0.070 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 15 -- -- 15 -- 15 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.28 0.32 0.56 0.46 0.51 AUG 27 K = 0.10 non- ideal count 25 179 10.2 5 0.450 0.010 0.460 0.050 0.32 RIO GRANDE DE MANATI BASIN 50031200 RIO GRANDE DE MANATI NEAR MOROVIS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 99 DATE NOV 1995 02... JAN 1996 12... FEE 12... APR 08... •TON 18... AUG 27... NOV 1995 02. .. JAN 1996 12... FEB 12... APR 08... JUN 18. . . AUG 27... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.30 0.35 0.59 0.54 0.58 0.37 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.1 1.1 1.7 1.5 0.83 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.9 4.8 4.7 7.7 6.7 3.7 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.040 0.050 0.140 0.130 0.050 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- — <1 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- 100 — -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- -- 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 — — 6 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- 20 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 470 2800 40 130 <0.10 <0.10 <1 <0.010 <0.010 <1 <0.02 <0.02 100 RIO GRANDE DE MANATI BASIN 50032290 LAGO EL GUINEO AT DAMSITE NEAR VILLALBA, 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 Villalba plaza and 1.9 mi (3.1 km) northeast of Cerro Haravillas. The reservoir itself fixes the territorial limits between the Municipality of Ciales and Orocovis. DRAINAGE AREA.--1.64 mi 2 (4.25 km2 ). ELEVATION RECORDS PERIOD OF RECORD.--Hay 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; minimun elevation, 2,919.79 ft (899.95 m), May 27, 1988. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 2,961.39 ft (902.63 m), Sep. 10; minimun elevation, 2,936.59 ft (895.07 m), July 5. 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 Ut OCT 1 2959.58 2 2959.35 3 2959.54 4 2960.14 5 A NOV ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES DEC JAN FEB MAR APR MAY JUN SEP 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 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 A A A A A —— —— —— A A A A A A A A A A 2959.75 2959.34 2959.02 2958.65 2958.57 2958.64 2958.74 2958.22 2957.89 2957.83 2957.79 2957.76 2957.86 2957.95 2958.03 2958.01 2958.10 2957.89 2957.31 2957.39 2957.44 ___ 2957.52 2957.43 2957.50 2957.58 2957.64 2957.73 2957.81 2957.98 2957.86 2957.71 2957.52 2957.59 2957.73 2958.52 2958.76 2958.87 2958.84 2958.25 2958.42 2958.55 2958.65 2958.73 2958.65 2958.63 2958.66 2958.68 2958.91 2959.06 2959.15 2959.04 2959.00 2959.15 2957.43 2958.91 2958.67 2958.76 2958.82 2958.41 2957.78 2957.22 2956.58 2956.03 2956.50 2956.64 2956.20 2955.60 2955.19 2954.79 2954.44 2954.79 2955.04 2955.24 2955.36 2956.86 2957.89 2958.10 2958.31 2958.41 2958.46 2958.52 2958.55 2958.59 ___ —— 2958.91 2954.44 2958.62 2958.64 2958.66 2958.71 2958.73 2958.77 2958.85 2958.92 2959.08 2959.19 2959.42 2959.54 2959.64 2959.73 2959.80 2959.91 2959.63 2959.53 2958.99 2959.06 2958.25 2957.44 2957.52 2957.59 2957.05 2956.50 2955.95 2955.39 2955.21 2955.29 2955.41 2959.91 2955.21 2954.85 2954.28 2955.55 2956.32 2956.57 2956.75 2956.89 2956.19 2955.29 2954.38 2953.95 2953.47 2953.60 2953.76 2953.87 2953.37 2952.81 2952.21 2951.28 2951.39 2951.49 2950.75 2949.98 2949.19 2948.85 2948.03 2948.13 2948.21 2947.57 2946.91 --- 2956.89 2946.91 2946.23 2945.82 2945.16 2945.24 2945.32 2944.86 2943.79 2942.70 2941.90 2941.15 2941.25 2941.36 2940.47 2939.21 2938.66 2939.35 2938.78 2939.09 2940.74 2944.17 2944.21 2943.66 2944.18 2943.59 2943.80 2943.99 2944.20 2943.58 2942.89 2943.03 2942.94 2946.23 2938.66 2943 2943 2943 2943 2944 2944 2944 2943 2942 2942 2942 2941 2941 2941 2944 2944 2944 2944 2945 2945 2945 2945 2945 2945 2945 2944 2943 2942 2941 2940 2945 2940 .17 .38 .39 .67 .14 .33 .02 .40 .80 .39 .59 .91 .90 .90 .01 .34 .39 .97 .15 .27 .32 .56 .77 .79 .12 .33 .54 .69 .37 .02 —— .79 .02 2938.91 2937.73 2937.33 2936.81 2936.85 2937.01 2937.18 2939.71 2941.41 2941.92 2941.55 2941.23 2941.51 2942.42 2943.07 2942.84 2942.75 2942.90 2942.82 2943.08 2943.32 2942.48 2942.11 2941.80 2941.65 2941.42 2941.62 2942.39 2942.28 2941.93 2941.72 2943.32 2936.81 2943.23 2943.62 2943.96 2944.22 2944.07 2943.71 2943.03 2943.16 2942.81 2943.08 2943.56 2942.90 2942.83 2942.72 2942.35 2942.15 2942.34 2942.59 2942.44 2942.56 2942.43 2942.42 2942.20 2942.48 2942.68 2942.85 2942.90 2942.56 2942.30 2941.78 2941.95 2944.22 2941.78 2942.11 2942.26 2943.48 2943.07 2942.54 2941.91 2942.08 2942.31 2941.61 2961.05 2960.93 2960.82 2960.86 2960.88 2960.82 2960.75 2960.77 2960.77 2960.75 2960.41 2960.70 2960.71 2960.09 2959.56 2959.11 2958.57 2958.32 2958.60 2958.02 2957.29 —— 2961.05 2941.61 A No gage-height record 101 RIO GRANDE DE MANATI BASIN 50032590 LAGO DE MATRULLAS AT DAHSITE NEAR OROCOVIS, PR LOCATION.—Lat 18°12'46", long 66°28'50", Hydrologic Unit 21010001, in shelter house at damsite, and 5.8 mi (9.3 km) southwest of Orocovis. DRAINAGE AREA.—4.46 mi' (11.55 km2 ). ELEVATION RECORDS PERIOD OF RECORD.—May 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 hm3 ) 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, 2,419.90 ft (737.58 m), Sept. 10; minimum elevation, 2,411.45 ft (735.01 m), May 17. 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 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES 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 MAX MIN NOV DEC JAN FEB MAR APR MAY JUL SEP 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 A A A A A .__ A A A A A A 2413.03 2413.06 2413.27 2413.48 2413.57 2413.67 2413.75 2413.83 2413.69 2413.89 2414.12 2414.47 2414.68 2414.53 2414.38 2414.24 2414.42 2414.59 2414.76 2414.63 2414.54 2414.45 2414.38 A A A A A A A A A A A A A A A A A 2415.28 2415.17 2415.01 2414.92 2415.11 2415.26 2415.11 2415.02 2414.92 2414.93 2414.99 2415.38 2415.41 2415.27 2415.18 2415.10 2414.99 2414.89 2415.05 2415.20 2415.03 2414.87 2414.72 2414.54 2414.37 2414.56 2414.71 2414.52 2414.35 2414.17 2413.98 2413.78 2414.07 2414.23 2414.40 2414.21 2414.37 2414.38 2415.38 2415.54 2415.41 2415.12 2414.91 2414.77 2414.62 ___ ___ A 2414.66 2414.82 2414.63 2414.41 2414.23 2414.03 2413.88 2414.05 2414.21 2414.11 2413.96 2413.77 2413.60 2413.47 2413.62 2413.76 2413.60 2413.37 2413.19 2412.96 2412.73 2412.85 2412.96 A 2412.51 2412.31 2412.09 2411.92 2412.05 2412.17 2411.94 2411.71 2412.68 2412.79 2413.40 2413.66 2413.84 2413.65 A A 2413.43 2413.83 2414.15 2414.40 A 2414.49 2414.33 2414.15 2414.23 A A A A A A A A A A A ___ A A A A A A A A A A A A A 2412.03 2411.90 2411.68 2411.50 2412.09 2412.88 2414.47 2414.54 2414.71 2414.73 2414.64 2414.78 2414.95 2415.09 2414.96 2414.71 2414.94 2414.77 2414.92 A A A 2414.65 2414.48 2414.55 2414.67 2414.47 2414.32 2414.13 2413.90 2413.67 2413.48 2413.96 2414.18 2414.03 2414.23 2414.14 2413.99 2413.86 2414.02 2414.15 2413.94 2414.00 2414.13 2413.94 2413.73 2413.50 2413.21 ___ 2412 2412 2412 2412 2412 2412 2412 2414 2414 2414 2414 2414 2414 2415 2415 2415 2415 2414 2414 2415 .99 .76 .54 .29 .05 .16 .29 .04 .66 .70 .66 .62 .83 .26 .32 .19 .09 .97 .88 .03 A A A A A A A A A A A A A A A A A A A 2413.51 2413.67 2413.97 2413.90 2413.82 2413.74 2413.70 2413.63 2413.76 2413.88 2413.79 2413.86 2413.79 2413.73 2413.71 2413.84 2413.95 2413.77 2413.62 2413.41 2413.18 2412.99 2413.10 2413.40 2413.53 2413.41 2413.39 2413.19 2412.95 2413.08 2413.31 2413.04 2416.52 2416.09 2415.69 2415.86 2415.85 A A A A A A A A 2415.51 2415.46 2415.43 2415.42 2415.37 A 2415.40 2415.36 2415.54 2413.78 A No gage-height record 102 RIO GRANDE DE MANATI BASIN 50034000 RIO BAUTA NEAR OROCOVIS, PR LOCATION.--Lat 18°14'10", long 66°27'18", Hydrologic Unit 21010001, (12.1 km), and 4.2 ml (6.8 km) west of Orocovis. DRAINAGE AREA.—16.7 mi* (43.3 km*). on left bank, at bridge on Highway 157 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 47 38 2 76 38 3 74 40 4 87 33 5 109 34 6 60 43 7 45 39 8 36 46 9 32 35 10 34 32 11 39 29 12 36 27 13 36 68 14 30 64 15 28 106 16 32 91 17 41 57 18 49 43 19 63 35 20 182 31 21 140 28 22 85 30 23 70 26 24 164 25 25 159 25 26 112 24 27 86 23 28 90 22 29 71 21 30 52 21 31 43 TOTAL 2208 1174 MEAN 71.2 39.1 MAX 182 106 MIN 28 21 AC-FT 4380 2330 CFSM 4.27 2.34 IN. 4.92 2.62 STATISTICS OF MONTHLY MEAN MEAN 87.5 53.2 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 20 20 19 19 18 18 18 17 17 17 17 17 18 16 16 16 18 29 28 19 17 16 16 19 15 15 19 17 15 14 13 553 17.8 29 13 1100 1.07 1.23 DATA 27.6 108 1971 4.29 1995 13 13 13 13 13 14 13 13 15 13 13 12 13 27 107 34 21 17 15 17 18 15 14 14 13 20 43 91 77 54 26 794 25.6 107 12 1570 1.53 1.77 FOR WATER 20.0 83.4 1992 3.66 1995 19 17 16 15 15 15 15 14 14 15 14 13 13 13 13 12 13 14 13 13 141 89 174 179 131 63 41 30 e29 —— 1163 40.1 179 12 2310 2.40 2.59 YEARS 1969 14.7 40.1 1996 5.70 1994 e27 e25 e23 e21 e!9 e!7 elS 14 14 13 15 15 13 13 13 13 13 12 12 11 11 11 11 10 10 11 11 11 11 11 11 437 14.1 27 10 867 .84 .97 - 1996 15.0 59.9 1972 4.18 1994 FOR 1995 CALENDAR YEAR 13707. 37. 850 3. 3. 27190 2. 30. 85 14 3. 8 6 Sep 16 0 Jan 6 0 Jan 18 25 53 3 10 10 102 74 72 66 32 20 16 15 16 88 97 47 36 27 23 22 39 38 24 20 19 18 17 16 15 15 15 15 —— 1024 34.1 102 10 2030 2.04 2.28 14 14 13 13 14 14 14 14 14 14 14 13 13 13 17 16 14 58 73 189 88 e33 e24 e20 e!7 e!4 e!4 e!4 e!3 e!3 e!3 821 26.5 189 13 1630 1.59 1.83 e!3 e!3 e!3 e!3 e!2 e!2 e!2 e!2 e!2 e!2 e!2 12 12 11 13 15 14 13 14 11 11 10 9.8 9.5 9.5 9.6 10 9.9 9.5 9.9 —— 349.7 11.7 15 9.5 694 .70 .78 9.4 9.3 9.2 8.7 8.4 8.3 8.3 106 165 63 30 26 21 29 83 34 19 14 12 11 11 11 11 10 11 11 10 10 11 11 11 792.6 25.6 165 8.3 1570 1.53 1.77 11 9.3 11 11 11 9.3 11 41 10 76 9.9 27 9.9 14 9.7 21 9.7 22 10 e!9500 12 e7600 12 e3000 9.9 elOOO 9.8 e350 10 e200 11 e!20 11 94 9.9 98 9.3 98 13 102 16 96 10 87 13 82 13 77 10 73 9.7 68 9.4 67 9.4 61 9.3 55 9.0 52 8.8 328.7 33110.6 10.6 1104 16 19500 8.8 9.3 652 65670 .63 66.1 .73 73.76 , BY WATER YEAR (WY) 26.9 80.2 1980 4.92 1995 FOR 1996 42755 117 19500 8 8 25900 25 84810 7 95 87 16 10 50.7 179 1981 4.24 1994 WATER YEAR .6 Sep 10 .3 Jul 6 .8 Jul 1 Sep 10 .14 Sep 10 .00 .24 19.2 78.6 1979 3.59 1994 16.5 104 1979 3.22 1994 20.4 105 152 1104 1979 1996 3.97 3.55 1994 1994 WATER YEARS 1969 - 1996 38.1 117 6.56 19500 2.8 2.8 25900 25.14 2.6 27570 2.28 30.96 65 13 5.3 1996 1994 Sep 10 1996 Jul 23 1994 Jul 23 1994 Sep 10 1996 Sep 10 1996 Jul 26 1994 e Estimated 103 RIO GRANDE DE MANATI BASIN 50035000 RIO GRANDE DE MANATI AT CIALES, PR 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 2 (332 km2 ), excludes 6.0 mi 2 (15.5 km 2 ), the runoff from which is diverted through El Guineo and de Hatrullas 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 2 ). 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC APR 1 232 241 2 261 236 3 388 334 4 347 263 5 374 240 6 236 409 7 192 354 8 173 307 9 155 1750 10 147 903 11 175 346 12 205 253 13 197 252 14 155 355 15 139 341 16 242 452 17 299 291 18 215 255 19 268 206 20 332 185 21 784 216 22 654 190 23 335 158 24 969 152 25 976 151 26 651 141 27 727 138 28 576 132 29 571 127 30 318 128 31 269 —— TOTAL 11562 9506 MEAN 373 317 MAX 976 1750 MIN 139 127 AC-FT 22930 18860 CFSM 2.91 2.48 IN. 3.36 2.76 STATISTICS OF MONTHLY MEAN MEAN 429 343 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 e Estimated 124 124 120 115 117 113 107 107 110 105 106 105 118 109 105 102 108 270 433 178 133 116 113 111 103 102 109 115 104 97 93 3972 128 433 93 7880 1.00 1.15 DATA 256 1296 1966 29.7 1995 FOR 91 90 88 84 84 102 100 88 132 105 91 95 89 102 596 254 156 121 112 180 228 141 117 107 113 149 444 573 409 238 171 5450 176 596 84 10810 1.37 1.58 FOR WATER 187 678 1952 26.2 1995 141 124 116 111 103 102 118 206 307 200 125 108 101 101 95 91 89 139 107 92 165 284 340 475 498 210 145 122 115 —— 4930 170 498 89 9780 1.33 1.43 YEARS 1946 168 1392 1950 41.6 1957 102 95 93 92 95 104 94 87 84 82 82 93 83 85 114 91 82 77 75 73 72 71 71 69 69 69 78 75 73 79 76 2585 83.4 114 69 5130 .65 .75 - 1996 138 477 1969 29.7 1994 1995 CALENDAR YEAR 77457 212 6160 11 13 153600 1. 22. 431 84 21 Sep 16 Jan 25 Jan 19 66 51 82 70 251 417 285 318 147 100 84 76 83 315 464 201 175 152 124 114 143 222 125 106 91 82 74 70 67 67 65 69 —— 4639 155 464 65 9200 1.21 1.35 65 60 60 60 60 58 59 63 88 74 68 63 61 63 82 6269 e!59 e!77 e!76 449 326 140 118 108 106 382 418 6204 e!23 e!67 e!42 4448 143 449 58 8820 1.12 1.29 6162 6129 691 el05 6115 6113 688 678 672 e77 e80 e70 65 64 90 151 142 108 148 103 88 83 80 74 73 71 75 77 73 71 —— 2816 93.9 162 64 5590 .73 .82 69 67 67 67 67 67 68 263 928 287 146 116 114 105 226 174 126 107 94 88 84 77 73 71 72 71 65 61 66 65 63 4014 129 928 61 7960 1.01 1.17 65 64 65 67 66 62 63 85 75 73 78 93 76 59 72 93 113 75 65 68 107 78 76 130 102 80 74 72 78 71 66 2411 77.8 130 59 4780 .61 .70 94 123 74 503 770 347 184 265 316 626400 61850 e974 6824 6722 6676 6790 6610 425 383 343 287 261 242 219 208 198 187 192 201 173 —— 38841 1295 26400 74 77040 10.1 11.29 , BY WATER YEAR (WY) 260 1174 1969 28.5 1984 FOR 1996 95174 260 26400 58 60 128000 25 54 188800 2 27 384 113 68 422 2293 1985 29.6 1994 WATER YEAR Sep 10 May 6 May 2 Sep 10 .20 Sep 10 Aug 14 .03 .66 154 458 1979 17.8 1994 106 438 1979 14.1 1994 WATER 244 520 47 42700 8 9 128000 25 11 176800 1 25 440 113 51 150 1212 1979 27.0 1994 YEARS 1946 .3 May .5 Jul .5 Jul Sep .20 Sep .00 Jan .91 .90 304 1295 1996 23.9 1994 - 1996 1971 1994 18 1985 28 1994 24 1994 10 1996 10 1996 24 1995 104 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 a (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 1995 TO SEPTEMBER 1996 OCT 11 JAN 11 FEE 09 APR 08 JUN 20 AUG 08 DATE 1995 . . . 1996 . . . . . . OCT 11 JAN 11 FEB 09 APR 08 JUN 20 AUG 08 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) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (316.79) 1000 196 1040 136 1005 226 1205 133 0935 105 1035 94 HARD- NESS TOTAL (MG/L DATE AS CAC03) (00900) 1995 86 1996 . . . 84 93 non- ideal count 220 8.0 25.0 9.3 239 8.0 23.0 1.0 212 7.5 22.0 160 216 7.5 26.0 61 233 7.6 26.5 1.5 235 7.5 26.0 4.4 MAGNE- SODIUM POTAS- CALCIUM SIUM, SODIUM, AD- SIUM, DIS- DIS- DIS- SORP- DIS- SOLVED SOLVED SOLVED TION SOLVED (MG/L (MG/L (MG/L RATIO (MG/L AS CA) AS MG) AS NA) AS K) (00915) (00925) (00930) (00931) (00935) 22 7.6 11 0.5 2.1 .. -_ 21 7.6 10 0.5 2.2 __ 23 8.6 10 0.5 1.8 8.4 100 8.1 92 7.8 89 7.9 97 8.1 100 8.1 99 ALKA- LINITY WAT WH TOT FET SULFIDE FIELD TOTAL MG/L AS (MG/L CAC03 AS S) (00410) (00745) 85 <0.5 100 75 75 <0.5 98 96 <10 K950 K1100 <10 2600 2100 35 46000 46000 12 2300 700 17 26000 2800 <10 2700 970 CHLO- SULFATE RIDE, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS SO4) AS CL) (00945) (00940) 8.7 13 __ __ 9.6 12 __ 8.7 14 RIO GRANDE DB MANATI BASIN 50035500 RIO GRANDE DE MANATI AT HIGHWAY 149 AT CIALES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 105 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- DATE OCT 1995 11... JAN 1996 11... FEB 09... APR 08... JUN 20... AUG 08... DATE OCT 1995 11... JAN 1996 11. .. FEB 09... APR 08... JUN 20... AUG 08... OCT 1995 11... JAN 1996 11... FEB 09... APR 08... JUN 20... AUQ 08... 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 0.70 0.43 0.40 0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) DIS- SOLVED (MG/L AS SIO2) (00955) 24 -- — 23 — 22 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.59 0.85 0.93 1.4 0.81 1.7 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 139 — — 130 — 146 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 2.6 3.8 4.1 6.2 3.6 7.5 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) DIS- SOLVED (TONS PER DAY) (70302) 73.8 — — 46.7 — 37.1 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.070 0.090 0.110 0.060 0.130 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 14 5 128 40 8 15 ARSENIC TOTAL (UG/L AS AS) (01002) 1 — -- <1 -- — SELE- NIUM, TOTAL (UG/L AS SE) (01147) GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.380 0.640 0.17 0.930 0.400 1.49 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- — 100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.060 0.030 0.010 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — — 10 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.390 0.650 0.230 0.960 0.410 1.50 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — — <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.030 0.480 0.080 0.070 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — — 5 — -- PHENOLS TOTAL (UG/L) (32730) GEN/ ORGANIC TOTAL (MG/L AS N) (00605) <0.17 <0.17 0.22 0.35 0.33 0.18 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- — <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 510 2700 60 110 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <0.02 <0.02 106 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, 0.7 mi (1.1 km) upstream from mouth, and about 0.4 mi (0.6 km) west of Ciales plaza. DRAINAGE AREA.--17.0 mi 2 (44.0 km2 ). PERIOD OP RECORD.--Water years 1969-71, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 11 JAN 10 FEE 09 APR 04 JUN 20 AUG 08 DATE 1995 1996 . . . . . . DATE OCT 1995 11.. . JAN 1996 10.. . FEE 09.. . APR 04. . . JUN 20. . . AUG 08. .. 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) 1130 24 1130 14 1110 55 1200 20 1115 12 1245 15 HARD- NESS CALCIUM TOTAL DIS- (MG/L SOLVED AS (MG/L CACO3) AS CA) (00900) (00915) 95 27 __ _- 96 27 __ 98 29 207 8.4 24.5 3.2 241 8.0 22.5 3.5 203 7.4 21.5 150 234 7.9 23.0 1.9 240 7.8 25.0 1.3 242 7.8 26.5 4.7 MAGNE- SODIUM POTAS- SIUM, SODIUM, AD- SIUM, DIS- DIS- SORP- DIS- SOLVED SOLVED TION SOLVED (MG/L (MG/L RATIO (MG/L AS MG) AS NA) AS K) (00925) (00930) (00931) (00935) 6.8 10 0.4 1.8 __ __ 7.0 11 0.5 1.7 __ 6.2 9.4 0.4 1.8 8.4 8.7 8.2 8.5 8.6 8.1 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 94 100 74 97 100 100 99 <10 98 <10 K840 3100 370 2900 93 35 57000 49000 98 <10 103 11 100 <10 SULFATE SULFIDE DIS- TOTAL SOLVED (MG/L (MG/L AS S) AS SO4) (00745) (00945) <0.5 6.1 __ __ <0.5 6.1 __ 7.1 390 K940 5400 CHLO- RIDE, DIS- 360 540 2800 SOLVED (MG/L AS CL) (00940) 11 -- -- 11 -- 12 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 1995 TO SEPTEMBER 1996 107 SOLIDS, RESIDUE FLUO- SILICA, SUM OF SOLIDS, TOTAL NITRO- NITRO- NITRO- NITRO- OTTRO- DATE OCT 1995 11... JAN 1996 10... FEE 09... APR 04... JUN 20... AU6 08... DATE OCT 1995 11. .. JAN 1996 10. .. FEB 09... APR 04... JUN 20... AU6 08... DATE OCT 1995 11... JAN 1996 10... FEB 09... APR 04... JUN 20... AU6 08... RIDE, DIS- SOLVED (M6/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 <0.21 0.33 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) DIS- SOLVED (MG/L AS SIO2) (00955) 29 — — 31 — 25 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.75 0.93 1.1 0.80 0.61 0.87 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 148 — — 153 — 150 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 3.3 4.1 5.1 3.5 2.7 3.9 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) DIS- SOLVED (TONS PER DAY) (70302) 9.63 — — 8.16 — 5.91 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.100 0.070 0.030 0.080 0.080 0.090 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) AT 105 DBG. C, SUS- PENDED (MG/L) (00530) 1 11 140 7 2 18 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — — <1 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.610 0.710 0.920 0.560 0.400 0.540 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — — 100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — — <10 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.620 0.720 0.930 0.570 0.400 0.540 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — -- <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.020 0.010 0.020 0.010 0.040 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — — <1 — — PHENOLS TOTAL (UG/L) (32730) GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.19 0.22 0.21 <0.21 0.29 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — — 20 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 150 190 <1 10 30 <0.10 <0.10 <1 <1 <1 <0.010 <0.010 <1 <1 <0.02 0.02 108 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 km2 ), approximately, of which about 38 mi 2 (98 km2 ) is partly or entirely noncontributing, excludes 6.0 mi 2 (15.5 km2 ) 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES FEB JUN JUL AUG 1 249 306 2 322 281 3 426 404 4 285 339 5 496 281 6 269 467 7 208 440 8 178 444 9 158 1390 10 148 3250 11 180 624 12 202 449 13 182 365 14 154 502 15 140 374 16 204 689 17 339 413 18 387 389 19 276 313 20 189 275 21 589 285 22 1210 336 23 386 241 24 1160 230 25 1070 227 26 1200 210 27 1040 205 28 826 193 29 833 184 30 454 184 31 356 TOTAL 14116 14290 MEAN 455 476 MAX 1210 3250 HIN 140 184 AC -FT 28000 28340 CFSH 2.31 2.42 IN. 2.67 2.70 STATISTICS OF MONTHLY MEAN MEAN 738 543 MAX 2958 1803 (WY) 1971 1971 HIN 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 e!80 e!80 e!80 e!70 e!80 e!70 e!60 e!60 e!70 e!60 elSO e!51 e!61 e!55 e!51 el48 el60 e350 e620 e260 e210 e!79 168 172 159 154 156 171 163 150 145 5843 188 620 145 11590 .96 1.10 141 139 139 136 135 144 165 142 154 194 184 164 152 139 e900 e400 e250 e!90 elSO e280 e360 6230 e!90 e!70 elSO 6240 6700 6900 6700 6400 6260 8658 279 900 135 17170 1.42 1.63 6240 6210 e!90 elSO e!70 6160 6190 6350 6490 6350 6230 6180 6160 6160 6150 e!40 e!40 e220 6180 6150 6230 6450 6520 6740 6780 6320 238 200 185 ___ --- 7903 273 780 140 15680 1.38 1.49 DATA FOR WATER YEARS 1970 361 1498 1971 71.8 1995 FOR 247 771 1992 59.1 1995 201 444 1988 72.0 1994 173 164 160 156 155 164 149 144 140 135 133 140 134 128 163 156 132 126 117 111 107 104 100 98 95 95 e!20 ellO elOO e!20 ellO 4039 130 173 95 8010 .66 .76 - 1996 186 521 1972 56.2 1994 1995 CALENDAR YEAR 122560 336 14700 31 33 Sep 16 Jan 24 Jan 18 6120 elOO 6400 6660 6460 6510 6250 6160 6140 6120 99 200 6619 6305 233 208 188 167 160 6282 6195 163 153 145 134 127 124 122 121 124 6789 226 660 99 13470 1.15 1.28 120 113 110 110 107 106 111 116 137 137 122 113 117 110 109 6290 6181 6303 6226 6286 6526 6200 153 145 127 6284 6504 6492 6227 6252 6316 6250 202 526 106 12400 1.02 1.18 6213 6262 6151 131 152 147 130 113 104 98 99 96 93 93 98 e!79 6155 130 155 124 101 93 88 83 79 74 79 92 100 694 --- 3606 120 262 74 7150 .61 .68 81 78 75 74 71 70 71 120 61300 6436 232 167 158 154 222 249 170 140 123 113 106 98 92 91 96 92 84 81 82 86 84 5096 164 1300 70 10110 .83 .96 92 84 98 93 97 92 81 121 123 88 88 98 101 107 103 131 6184 6130 101 91 156 110 104 193 150 113 97 89 105 99 85 3404 110 193 81 6750 .56 .64 81 144 123 374 1050 851 246 284 338 642000 617100 61600 61400 61200 ellOO 1300 elllO 6709 6598 554 442 382 340 298 281 266 246 268 267 237 --- 75189 2506 42000 81 149100 12.7 14.20 , BY WATER YEAR (WY) 361 1037 1993 49.9 1995 FOR 1996 155183 424 42000 70 74 674 3178 1985 93.7 1989 WATER YEAR Sep 10 Jul 6 Jul 1 236 747 1987 63.8 1994 Not determined Sep 10 243100 1.70 23.14 648 142 38 36 307800 2 29 522 164 95 .39 Sep 10 .15 .30 158 577 1979 53.0 1994 WATER 369 756 96. 55900 31 33 212 1644 1979 67.9 1984 YEARS 1970 5 May Jan Jul Not determined Sep 36. 28 267100 1. 25. 646 166 85 39 Sep Jan 87 43 525 2506 1996 67.4 1994 - 1996 1971 1994 18 1985 24 1995 23 1994 10 1996 10 1996 23 1995 e Estimated 109 RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1969 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 31... JAN 1996 10... FEB 26.. . APR 22... JUN 27... AUG 29... DATE OCT 1995 31. .. JAN 1996 10.. . FEB 26... APR 22... JUN 27... AUG 29... DATE OCT 1995 31... JAN 1996 10... FEB 26... APR 22... JUN 27... AUG 29... TIME 1130 0935 1305 1130 1130 1140 HARD- NESS TOTAL (MG/L AS CAC03 ) (00900) 94 -- -- 98 -- 120 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 22 -- -- 21 -- 21 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 360 190 305 162 84 102 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- -- 28 -- 37 SOLIDS, RESIDUE AT 180 DEC. C DIS- SOLVED (MG/L) (70300) 156 -- -- -- -- -- SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 218 265 189 240 316 305 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.0 -- -- 6.7 -- 7.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 142 -- -- 143 -- 173 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.7 7.7 7.4 7.6 7.6 7.7 SODIUM, DIS- SOLVED (MG/L AS MA) (00930) 10 -- -- 10 -- 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 141 -- -- 62.5 -- 47.4 TEMPER- ATURE WATER (DEG C) (00010) 25.5 25.0 24.0 26.0 28.5 29.5 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- -- 0.4 -- 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) -- 22 200 32 14 13 TUR- BID- ITY (NTU) (00076) 55 6.5 200 61 1.1 6.0 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.1 -- -- 2.2 -- 2.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.09 0.670 1.25 0.14 0.440 0.460 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.2 7.3 7.1 7.3 6.5 7.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 87 120 68 90 140 120 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.050 0.010 0.010 0.070 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 86 87 83 89 83 91 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.10 0.680 1.30 0.150 0.450 0.530 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 16 <10 24 12 26 <10 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 12 -- -- 12 -- 13 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.340 0.030 0.090 0.120 0.420 0.340 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 3300 4700 K13000 K1100 33000 3900 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 8.9 -- -- 8.6 -- 8.7 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.42 0.28 0.72 0.57 1.2 1.6 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 640 590 5900 700 10000 570 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) 0.76 0.31 0.81 0.69 1.6 1.9 K » non-ideal count Ho RIO GRANDE DE MANATI BASIN 50038100 RIO GRANDE DE MANATI AT HIGHWAY 2 NEAR MANATI, PR--Continued HATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 31... JAN 1996 10... FEE 26... APR 22... JUN 27... AUG 29... DATE OCT 1995 31... JAN 1996 10... FEB 26... APR 22... JUN 27... AUG 29... NITRO- GEN, TOTAL (HG/L AS N) NITRO- PHOS- GEN, PHORUS TOTAL (HG/L AS P) TOTAL (HG/L AS N03) BARIUM, BARIUM, TOTAL ARSENIC DIS- RECOV- TOTAL SOLVED ERABLE (UG/L (UG/L (UG/L AS AS) AS BA) AS BA) BORON, CADMIUM TOTAL TOTAL RECOV- ERABLE (UG/L AS B) RECOV- ERABLE (UG/L AS CD) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (00600) (71887) (00665) (01002) (01005) (01007) (01022) (01027) (01034) 1.6 0.99 2.1 0.84 2.0 2.4 7.1 4.4 9.3 3.7 8.9 11 0.150 0.090 0.260 0.060 0.460 1.0 47 COBALT, DIS- SOLVED (UG/L AS CO) (01035) <3 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <1 <100 30 <1 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) IRON, DIS- SOLVED (UG/L AS FE) (01046) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS UN) (01055) MANGA- NESE, DIS- SOLVED (UG/L AS UN) (01056) MOLYB- DENUM, DIS- SOLVED (UG/L AS HO) (01060) NICKEL, DIS- SOLVED (UG/L AS NI) (01065) SILVER, DIS- SOLVED (UG/L AS A6) (01075) SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) STRON- TIUM, DIS- SOLVED (UG/L AS SR) (01080) VANA- DIUM, DIS- SOLVED (UG/L AS V) (01085) 91 15 10 <1 150 <6 1200 70 DATE OCT 1995 31. .. JAN 1996 10... FEB 26... APR 22.. . JUN 27... AUG 29... ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) ALUM- INUM, DIS- SOLVED (UG/L AS AL) (01106) LITHIUM DIS- SOLVED (UG/L AS LI) (01130) SELE- NIUM, DIS- SOLVED (UG/L AS SE) (01145) SELE- NIUM, TOTAL (UG/L AS SE) (01147) MERCURY DIS- SOLVED (UG/L AS HG) (71890) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 50 <1 <0.10 <1 <0.10 <0.010 <1 <0.02 111 LACUNA TORTUGUERO BASIN 50038200 LACUNA TORTUGUERO 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 Manati, and 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. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 12... JAN 1996 16... FEB 08... APR 03... JUN 17... AUG 14.. . DATE OCT 1995 12... JAN 1996 16... FEB 08... APR 03... JUN 17... AUG 14. .. DATE OCT 1995 12... JAN 1996 16... FEB 08... APR 03... JUN 17... AUG 14... PH OXYGEN, OXYGEN COLI- ALKA- SPE- WATER DIS- DEMAND, FORM, STREP- LINITY CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI WAT 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 SATUR- 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) 0810 1330 7.4 27.5 5.4 67 36 K750 690 120 0800 891 7.8 25.5 5.9 71 27 K40 K120 120 0900 1009 7.7 25.0 5.9 71 28 K32 80 130 0730 1150 7.8 27.0 4.8 60 35 74 K1000 150 1400 1260 8.1 30.0 5.3 70 42 <4 K40 110 0700 1330 7.6 29.0 4.1 53 41 K120 K110 95 RESIDUE NITRO - TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO - SULFIDE DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, TOTAL SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L PENDED (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 7 0.180 0.010 0.190 0.410 0.99 1.4 1.6 7.0 9 0.220 0.010 0.230 0.220 0.98 1.2 1.4 6.3 2 0.190 0.010 0.200 0.150 0.75 0.90 1.1 4.9 <0.5 11 0.210 0.010 0.220 1.10 0.90 2.0 2.2 9.8 4 0.350 0.010 0.360 0.140 1.3 1.4 1.8 7.8 <1 0.290 0.010 0.300 0.180 1.5 1.7 2.0 8.9 HANGA- 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 CU) AS FE) AS MN) AS ZN) AS CN) (UG/L) (MG/L) (00665) (01022) (01042) (01045) (01055) (01092) (00720) (32730) (38260) 0.020 80 <10 60 10 <10 <0.010 5 0.03 <0.020 <0.020 0.030 60 <10 150 <10 <10 <0.010 <1 0.05 <0.020 <0.020 K » non-ideal count 112 THIS PAGE WAS LEFT BLANK INTENTIONALLY 113 ATLANTIC OCEAN Dr TO SEPTEM MEAN DISCHARGE (CFS) 7.0 6.7 6.8 6.9 12 7.3 6.8 7.3 7.3 6.0 8.5 7.6 6.4 8.3 17 10 7.9 7.4 7.3 7.4 6.9 6.8 5.6 4.7 5.1 5.7 8.4 6.2 6.2 5.4 5.2 BER 1996 MEAN CONCEN- TRATION (MO/L) MARCH 10 9 8 8 17 4 5 6 5 5 6 6 5 16 57 28 17 14 12 11 9 6 4 4 6 6 23 12 9 6 5 SEDIMENT DISCHARGE (TONS/DAY) .19 .16 .15 .14 .86 .07 .09 .12 .09 .09 .14 .12 .09 .66 4.9 .81 .36 .29 .25 .22 .17 .11 .05 .05 .08 .10 .60 .20 .15 .09 .06 TOTAL 752.8 668.08 438.1 2849.93 228.1 11.46 138 50044830 RIO DE LA PLATA BASIN RIO GDADIANA AT GOADIANA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 5.0 5.0 12 13 12 8.2 5.9 5.3 5.1 4.8 4.9 31 21 8.5 8.3 12 7.4 6.6 6.2 6.3 6.4 19 15 14 9.6 8.5 8.4 7.7 11 9.6 APRIL 3 6 41 45 36 35 15 7 8 11 13 119 50 16 10 50 41 18 17 17 16 78 47 44 23 18 17 16 26 15 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MAY .05 .08 2.9 2.4 1.4 .81 .25 .11 .11 .15 .17 20 3.7 .36 .23 1.7 .83 .31 .28 .29 .28 13 2.4 1.7 .59 .42 .37 .33 .88 .42 —— 7.9 7.4 7.2 6.9 6.3 6.9 11 9.9 18 11 9.1 7.4 7.7 6.9 10 9.4 7.3 7.2 7.6 8.5 6.3 6.0 5.7 5.3 7.6 44 15 7.6 5.7 29 10 5 3 2 2 2 2 52 30 84 26 18 17 17 17 30 18 7 5 7 42 51 57 24 7 16 424 50 15 7 101 29 .11 .07 .04 .04 .03 .04 2.5 .80 7.6 .80 .45 .34 .35 .32 1.3 .51 .13 .09 .18 .94 .86 .93 .36 .10 .55 193 2.3 .33 .10 30 .83 7.1 6.1 5.2 136 51 22 30 14 10 10 9.3 11 9.0 8.6 19 24 19 11 8.0 6.3 6.0 8.7 5.4 5.1 4.3 4.2 4.9 4.3 4.0 3.6 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE ' 7.1 6.1 5.2 136 51 22 30 14 10 10 9.3 11 9.0 8.6 19 24 19 11 8.0 6.3 6.0 8.7 5.4 5.1 4.3 4.2 4.9 4.3 4.0 3.6 15 12 10 683 216 83 129 18 10 7 7 6 5 14 62 86 53 33 22 12 6 24 9 6 5 4 6 7 4 4 .29 .20 .14 534 88 6.0 16 .67 .26 .20 .16 .17 .12 .35 3.9 9.7 3.9 1.1 .48 .21 .10 .79 .13 .08 .06 .04 .10 .08 .04 .04 297.7 56.52 315.8 246.00 467.1 667.31 50044830 RIO DE LA PLATA BASIN RIO GUADIANA AT GUADIANA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 139 MEAN MEAN CONCEN- DISCHARGE TRATION DAY (CFS) (MG/L) 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 3.5 3.4 3.4 3.2 3.1 3.3 3.7 62 28 8.1 6.1 6.6 6.5 53 28 10 11 6.9 5.8 5.7 4.5 4.1 4.0 5.3 5.7 4.2 3.9 3.7 4.0 3.8 6.1 310.6 8181.1 JULY 5 5 6 5 4 5 14 231 117 26 18 15 15 801 89 16 28 10 15 13 15 27 23 18 11 10 13 5 4 3 13 —— SEDIMENT DISCHARGE (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .05 .05 .05 .04 .04 .04 .16 72 15 .57 .29 .27 .26 273 7.9 .44 1.2 .19 .25 .20 .18 .30 .25 .28 .18 .11 .13 .05 .04 .03 .28 373.83 116079.24 5.7 3.7 3.6 3.6 8.6 4.0 8.7 4.8 3.5 3.3 4.4 3.8 4.8 33 44 85 15 7.8 6.5 5.9 5.5 4.6 8.4 6.8 5.7 6.1 6.2 55 20 16 15 409.0 26 29 24 13 42 9 26 14 9 9 24 34 15 149 245 268 28 7 7 11 8 5 23 12 7 6 8 199 69 26 8 —— .68 .29 .23 .13 1.4 .10 1.3 .19 .08 .08 .42 .36 .24 31 82 91 1.3 .15 .13 .17 .12 .06 .86 .24 .11 .10 .13 87 3.8 1.1 .34 305.11 MEAN MEAN CONCEN- DISCHARGE TRATION (CFS) (MG/L) SEDIMENT DISCHARGE (TONS/DAY) SEPTEMBER 17 16 13 90 22 10 9.5 74 117 2400 52 42 49 83 64 60 24 19 14 11 11 11 12 13 14 11 8.7 15 12 18—— 3312.2 39 33 8 422 124 20 20 292 752 9200 723 473 465 329 304 298 118 56 44 34 27 21 17 14 15 15 19 52 38 31 —— —— 2.4 1.5 .26 336 6.9 .57 .75 64 1850 105000 102 54 62 75 52 48 8.0 2.8 1.6 .99 .78 .65 .56 .48 .54 .44 .50 2.2 1.3 1.5 —— 107677.72 140 RIO DE UV PLATA BASIN 50044830 RIO GUADIANA AT GUADIANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1995 10... NOV 06... 06... FEE 1996 09... 09... JUN 04... 04... AUG 15... DATE OCT 1995 10... NOV 06... 06... FEE 1996 09... 09... JUN 04... 04... AUG 15... TIME 1650 1200 1415 1527 1557 0632 0732 1615 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) — 70 64 41 48 67 69 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 25 55 61 868 1020 407 412 263 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 84 76 76 52 60 78 79 SEDI- MENT, SUS- PENDED (MG/L) (80154) 2510 4450 4010 25000 13200 3840 3120 2690 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 92 89 65 72 86 93 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 169 661 660 58600 36400 4220 3470 1910 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 100 96 93 83 90 96 97 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 47 42 40 18 21 26 36 40 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 100 98 95 91 95 99 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 59 50 47 29 33 42 49 46 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 99 97 94 98 100 99 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 72 59 53 34 38 52 57 57 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 98 96 99 100 100 68 78 91 98 99 100 100 141 RIO DE LA PLATA BASIN 50044830 RIO GUADIANA AT GUADIANA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT DATE DEC 1995 11... JAN 1996 16... FEB 09... MAY 09... JUN 04... 04... AU6 14... SEP 05... 14... TIME 1550 1552 1647 1515 0702 1157 1625 1300 1745 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 39 26 412 37 399 279 68 18 74 SEDI- MENT, SUS- PENDED (MG/L) (80154) 2200 110 3860 858 3670 1860 405 139 284 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 232 7.7 4290 86 3950 1400 74 6.8 57 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 98 91 90 96 92 96 92 90 97 142 RIO DE LA PLATA BASIN 50044850 RIO GUADIANA NEAR NARANJITO, PR WATER-QUALITY RECORDS LOCATION.--Lat 188 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* (10.3 km'). PERIOD OF RECORD.--Water year 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 04 DEC 07 FEB 05 APR 10 JUN 04 AUG 26 DATE 1995 ... 1996 ... ... DATE OCT 1995 04.. . DEC 07. .. FEB 1996 05. . . APR 10. . . JUN 04. .. AUG 26. . . 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 8.0 350 1040 7.4 304 1125 13 343 0840 5.3 333 1330 115 183 0950 6.0 381 HARD- MAGNE- NESS CALCIUM SIUM, TOTAL DIS- DIS- (MG/L SOLVED SOLVED AS (MG/L (MG/L CACO3) AS CA) AS MG) (00900) (00915) (00925) 140 31 14 __ __ 150 35 15 -- 160 38 16 7.4 27.0 1.8 8.0 23.5 2.5 7.6 23.0 2.5 7.7 23.0 0.60 7.4 25.5 150 7.6 25.5 0.50 SODIUM POTAS- SODIUM, AD- SIUM, DIS- SORP- DIS- SOLVED TION SOLVED (MG/L RATIO (MG/L AS NA) AS K) (00930) (00931) (00935) 17 0.6 3.9 __ __ 17 0.6 2.4 __ 17 0.6 2.6 6.9 7.4 7.9 7.5 7.8 7.3 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 170 130 130 150 140 85 25 330 85 <10 K10000 91 <10 K6600 87 <10 2000 K30 2500 930 2100 95 57 30000 37000 89 <10 4000 CHLO- SULFATE RIDE, SULFIDE DIS- DIS- TOTAL SOLVED SOLVED (MG/L (MG/L (MG/L AS S) AS SO4) AS CL) (00745) (00945) (00940) <0.5 13 23 __ __ <0.5 14 23 __ 18 24 3400 K = non-ideal count RIO DE LA PLATA BASIN 50044850 RIO GUADIANA NEAR NARANJITO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1994 TO SEPTEMBER 1995 143 DATE OCT 1995 04... DEC 07... FEB 1996 05... APR 10... JUN 04... AUG 26... DATE OCT 1995 04... DEC 07.. . FEB 1996 05... APR 10... JUN 04... AUG 26... OCT 1995 04... DEC 07... FEB 1996 05... APR 10... JUN 04... AUG 26... FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) <0.10 — — 0.20 — 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.27 0.28 0.20 0.54 2.3 0.63 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 26 — -- 25 -- 0.10 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.22 2.8 2.1 1.8 3.9 2.4 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 206 -- — 210 -- 200 NITRO- GEN, TOTAL (HG/L AS NO3) (71887) 0.97 12 9.3 8.1 17 11 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.45 — — 2.99 — 3.24 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.180 0.250 0.140 0.210 0.880 0.330 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (HG/L) (00530) 6 12 19 2 564 <1 ARSENIC TOTAL (UG/L AS AS) (01002) 2 -- -- 2 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.130 2.49 1.89 1.28 1.54 1.77 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 — -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 0.010 0.020 0.060 0.030 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- -- 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.150 2.50 1.90 1.30 1.60 1.80 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.070 0.030 0.040 0.020 0.180 0.210 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.20 0.25 0.16 0.52 2.1 0.42 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — -- <10 -- — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 190 140 <1 100 50 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 0.04 <0.02 144 RIO DE LA PLATA BASIN 50045000 LAGO LA PLATA AT DAMSITE NEAR TOA ALT A, PR LOCATION.--Lat 18°20'40", long 66°14'10", Hydrologie Unit 21010005, 2.9 ml (4.7 km) at northeast of Plaza da Naranjito, 2.7 ml (4.3 km) Wast of Road 167, km 15.3, Buena vista, Bayamon, 5.2 mi (8.4 km) aast of Plaza da Corozal. DRAINAGE AREA.—181 mi 1 (469 km'). ELEVATION RECORDS PERIOD OF RECORD.—February 1989 to current yaar. Prior to October 1994, published as Lago La Plata at Damaita. 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 hm} ) 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, 170.90 ft (52.09 m), Sept. 10; minimum elevation, 159.07 ft (48.48 m), Jun. 4. 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 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES 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 MAX MIN OCT NOV DEC JAN MAY JUN JUL AUG SEP 163.73 163.80 163.62 163.71 163.61 163.70 163.89 163.90 164.00 164.05 164.53 164.58 164.34 164.54 164.41 164.35 164.55 164.47 164.48 164.41 164 164 164 164 164 164 164 163 163 163 .43 .38 .32 .25 .20 .12 .05 .99 165.81 165.81 165.84 165.85 165.82 165.85 165.85 165.82 .93 164.97 165.89 .89 165.19 165.84 165.10 164.99 164.91 164.84 164.87 164.78 164.69 164.61 164.48 164.37 162.97 162.84 162.94 163.69 164.02 164.23 164.30 164.26 164.15 164.01 162.30 162.15 161.99 161.81 161.64 161.48 161.45 161.34 161.29 161.25 159.39 159.27 159.09 159.63 159.73 159.85 160.09 160.73 160.88 160.92 163.72 163.57 163.41 163.24 163.09 162.91 162.30 160.50 162.35 162.97 164.87 164.79 164.72 165.01 165.28 165.33 165.33 165.27 165.17 165.10 165.47 165.47 165.46 165.98 165.81 165.83 165.81 164.46 162.73 160.81 164.09 164.09 164.20 164.02 164.10 A A A 164.65 164.82 164.50 164.37 164.51 164.39 164.39 164.70 164.48 164.77 164.48 164.56 164.65 164.45 164.42 164.25 164.58 164.39 164.48 164.53 164.50 164.44 164.47 164.52 164.48 164.49 164.57 164.67 164.58 164.61 164.55 164.54 164.52 164.67 164.25 163. 9 165.05 165.25 165.39 165.42 165.43 165.44 165.26 165.54 165.49 165.67 165.67 165.63 165.59 165.76 165.72 165.80 165.90 165.88 165.80 165.78 165.76 165.55 165.52 165.48 165.46 165.44 165.40 165.38 165.35 165.31 165.43 164.30 164.31 164.29 164.30 164.27 164.81 164.93 164.65 164.59 164.50 164.40 164.29 164.16 164.02 163.87 163.89 164.00 164.03 163.99 163.97 163.95 163.89 163.79 163.66 163.50 163.37 163.31 163.29 163.22 163.09 161.15 161.01 160.88 160.72 160.68 160.57 160.46 160.42 160.33 160.40 160.30 160.15 160.00 159.82 159.66 160.85 160.82 160.95 161.01 162.95 164.07 164.07 164.09 164.07 164.09 164.16 164.34 164.42 164.40 164.34 163.24 163.37 163.67 165.26 164.86 164.90 165.13 164.85 164.96 165.03 165.10 165.11 165.10 165.14 165.02 165.05 164.95 164.90 165.81 165.76 165.76 165.80 165.81 165.91 166.01 165.69 165.70 165.73 165.75 165.79 164.11 164.02 164.94 165.43 165.36 165.47 165.61 165.37 165.53 165.78 165.76 166.19 165.68 165.91 166.12 165.85 165.84 165.82 165.84 165.81 165.76 165.40 165.33 165.25 165.19 —— 163.76 163.63 163.52 163.39 163.24 163.11 162.98 162.84 162.68 162.56 162.45 —— 159.70 159.95 159.98 159.82 159.72 159.56 164.25 164.17 164.11 164.01 163.87 —— 164.94 164.88 164.87 164.84 164.81 164.88 165.76 165.73 A 165.73 A 165.52 166.30 165.74 A 166.30 166.18 —— 165.90 165.19 165.10 163.11 164.30 162.45 162.30 159.56 164.42 159.09 165.26 160.50 A No gage-height record 145 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR 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 1 (448 km» ) . 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 Aqueduct and Sewer Authority reservoir upstream from gage. Gage-height satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV DEC SEP 1 152 2 25 3 105 4 1.9 5 57 6 1.3 7 .97 8 50 9 1.6 10 21 11 69 12 85 13 2.0 14 89 15 2.5 16 25 17 3.4 18 69 19 2.6 20 19 21 360 22 145 23 20 24 182 25 99 26 2.4 27 181 28 154 29 417 30 56 31 18 TOTAL 2416.67 MEAN 78.0 MAX 417 MIN . 97 AC-FT 4790 CFSM .45 IN. .52 STATISTICS OF MEAN 212 MAX 1107 (WY) 1991 HIN .048 (WY) 1992 78 34 180 7.1 127 265 51 71 249 293 61 60 88 4.7 159 72 85 47 45 2.4 1.5 33 .54 .34 .13 35 2.3 23 1.6 1.0 —— 2077.61 69.3 293 .13 4120 .40 .45 12 1.2 .94 .92 .91 .76 .66 .54 .60 .46 44 1.7 1.3 .86 .75 .84 1.2 136 221 55 161 18 1.2 .89 .69 .63 56 184 31 1.9 1.4 938.35 30.3 221 .46 1860 .18 .20 MONTHLY MEAN DATA 79.2 225 1993 .004 1995 SUMMARY STATISTICS ANNUAL TOTAL ANNUAL MEAN 42.1 161 1993 .000 1995 1.1 1.0 32 20 1.8 1.4 1.1 .90 106 2.0 1.8 1.2 .92 247 940 297 3.2 86 91 398 373 186 49 97 60 75 242 440 346 142 105 4348.42 140 940 .90 8630 .81 .94 FOR WATER 275 1581 1992 .19 1990 31 34 20 23 74 93 54 103 189 112 1.2 6.2 28 .96 .66 57 1.5 1.2 1.0 1.1 2.0 1.6 1.1 1.0 1.0 .89 .80 .80 .85 —— 841.86 29.0 189 .66 1670 .17 .18 YEARS 1989 42.0 222 1991 .14 1995 .82 .77 .73 1.4 1.2 .80 .73 .73 .65 .60 .60 .60 .60 .69 .8? .64 .51 89 2.0 1.6 1.4 1.3 1.2 1.0 .84 .77 .67 .60 .60 .53 .49 114.89 3.71 89 .49 228 .02 .02 - 1996 20.1 83.2 1990 .022 1995 FOR 1995 CALENDAR YEAR 31780. 87. 48 1 .49 .51 .70 1.0 .98 .90 .85 .85 .82 .67 .66 1.0 1.2 1.0 1.1 1.1 1.1 1.1 1.1 1.0 .97 .97 1.2 1.1 1.1 .97 .97 .99 1.0 1.1 —— 28.50 .95 1.2 .49 57 .01 .01 1.0 1.0 1.0 1.0 1.0 .96 1.4 .84 .80 .74 .60 .60 .60 .58 .48 .45 .45 .45 .50 .60 .60 .64 .66 .51 .45 .46 1.2 .89 .71 .66 .72 22.55 .73 1.4 .45 45 .00 .00 , BY WATER YEAR 39.6 231 1993 .011 1995 FOR 1996 261223 714 140 494 1993 .000 1994 .65 .51 .47 .64 .76 .77 3.5 5.1 3.7 3.0 1.8 1.9 1.6 2.2 2.2 115 377 119 258 84 1.5 1.2 .91 .82 .80 .73 .73 .74 .62 .57 —— 990.42 33.0 377 .47 1960 .19 .21 (WY) 49.0 220 1993 .002 1994 WATER YEAR .23 HIGHEST ANNUAL MEAN LOWEST ANNUAL HIGHEST DAILY MEAN MEAN 9990 LOWEST DAILY MEAN ANNUAL SEVEN-DAY MINIMUM INSTANTANEOUS INSTANTANEOUS ANNUAL RUNOFF ANNUAL RUNOFF ANNUAL RUNOFF PEAK FLOW PEAK STAGE (AC-FT) (CFSM) (INCHES) 10 PERCENT EXCEEDS 63040 . 6. 131 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS Sep 16 00 Jan 1 00 Jan 1 50 84 03 00 141000 197000 42 518100 4 56 173 1 Sep . 13 Nov .49 Jun Sep .26 Sep .13 .24 .6 .60 10 25 30 10 10 .52 .45 .45 .40 .45 .57 170 786 43 4.8 4.5 4.4 4.0 362 1780 462 111 258 2.1 1.6 1.0 .98 .99 .99 42 16 .86 .71 .68 .61 .77 4061.83 131 1780 .40 8060 .76 .87 83.1 384 1993 .037 1994 .85 .67 .66 .47 .51 .41 .57 .59 10 1.8 1.2 1.1 1.2 1.3 1720 1200 332 156 29 1.7 98 3.5 168 117 2.0 2.1 1.6 47 98 2.3 1.9 4001.43 129 1720 .41 7940 .75 .86 33.4 129 1996 .020 1989 WATER YEARS 193 714 16 141000 197000 42 139500 1 15 184 .0 .00 .00 .26 .11 .14 1.6 1.3 1.1 229 201 7.0 5.9 741 1170 e!41000 e97700 e70 e32 e!7 e25 e21 e22 e!8 e!3 elO e4.8 e!5 e7.0 e!3 e!6 e7.9 e!2 ell e3.6 e4.5 —— 241380.7 8046 141000 1.1 478800 46.6 51.96 1268 8046 1996 .001 1991 1989 - 1996 1996 1994 Sep 10 1996 Jul 14 1989 Jul 14 1989 Sep 10 1996 Sep 10 1996 1.0 .00 e Estimated 146 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 OP 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 days. 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 days. EXTREMES FOR CURRENT YEAR 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 4,390 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several days. 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 days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 31 152 25 105 1.9 57 1.3 .97 50 1.6 21 69 85 2.0 89 2.5 25 3.4 69 2.6 19 360 145 20 182 99 2.4 181 154 417 56 18 37 23 22 5 13 5 4 11 4 7 16 24 5 13 4 9 6 12 6 7 53 22 8 32 15 5 32 13 51 12 6 16 1.7 35 .03 13 .02 .01 8.9 .02 2.3 11 14 .03 16 .03 2.9 .06 17 .04 3.9 80 39 1.2 49 30 .03 36 22 112 9.9 1.6 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 78 34 180 7.1 127 265 51 71 249 293 61 60 88 4.7 159 72 85 47 45 2.4 1.5 33 .54 .34 .13 35 2.3 23 1.6 1.0 17 5 17 5 18 36 9 13 29 48 27 24 23 6 26 14 15 11 9 5 2 10 5 3 2 6 4 7 5 3 11 1.2 29 .21 24 58 5.9 14 73 66 4.4 3.9 16 .08 31 16 14 9.9 10 .03 .01 4.7 .01 .00 .00 6.0 .03 2.0 .02 .01 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 12 1.2 .94 .92 .91 .76 .66 .54 .60 .46 44 1.7 1.3 .86 .75 .84 1.2 136 221 55 161 18 1.2 .89 .69 .63 56 184 31 1.9 1.4 6 5 4 3 3 2 2 2 1 1 8 6 5 4 4 3 3 19 37 17 27 11 5 4 3 2 12 41 8 5 4 .94 .02 .01 .01 .01 <.01 <.01 <.01 <.01 <.01 8.1 .03 .02 .01 .01 .01 .01 37 38 5.3 28 1.2 .02 .01 .01 .00 7.9 38 5.3 .03 .02 2416.67 522.67 2077.61 400.40 938.35 169.97 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM 147 SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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) JANUARY 1.1 1.0 32 20 1.8 1.4 1.1 .90 106 2.0 1.8 1.2 .92 247 940 297 3.2 86 91 398 373 186 49 97 60 75 242 440 346 142 105 3 3 7 9 7 5 5 4 13 6 5 4 3 33 108 51 4 18 19 64 75 31 17 22 15 16 50 67 64 29 26 .01 .01 5.8 2.6 .03 .02 .01 .01 23 .03 .02 .01 .01 59 411 49 .09 11 13 89 80 25 5.1 14 7.0 7.3 35 86 61 20 11 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) FEBRUARY 31 34 20 23 74 93 54 103 189 112 1.2 6.2 28 .96 .66 57 1.5 1.2 1.0 1.1 2.0 1.6 1.1 1.0 1.0 .89 .80 .80 .85 11 7 8 9 14 19 12 19 30 23 4 3 11 4 3 8 6 6 6 5 5 5 5 5 5 4 4 4 4 2.4 5.1 2.3 2.6 11 11 7.4 14 44 16 .01 .20 2.2 .01 .00 11 .02 .02 .02 .02 .03 .02 .02 .01 .01 .01 .01 .01 .01 ___ ___ .82 .77 .73 1.4 1.2 .80 .73 .73 .65 .60 .60 .60 .60 .69 .82 .64 .51 89 2.0 1.6 1.4 1.3 1.2 1.0 .84 .77 .67 .60 .60 .53 .49 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 4 3 3 3 3 3 2 2 2 2 2 2 1 1 1 ! 1 13 2] 12 12 11 11 10 10 9 9 8 8 8 8 8 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 L .07 .05 .04 .04 .03 .03 .02 .02 .02 .01 .01 .01 .01 TOTAL 4348.42 1015.05 841.86 129.43 114.89 21.41 148 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM SEDIMENT DISCHARGE, SUSPENDED {TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (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 .49 .51 .70 1.0 .98 .90 .85 .85 .82 .67 .66 1.0 1.2 1.0 1.1 1.1 1.1 1.1 1.1 1.0 .97 .97 1.2 1.1 1.1 .97 .97 .99 1.0 1.1 .01 .01 .01 .02 .02 .02 .02 .02 .02 .01 .01 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 1.0 1.0 1.0 1.0 1.0 .96 1.4 .84 .80 .74 .60 .60 .60 .58 .48 .45 .45 .45 .50 .60 .60 .64 .66 .51 .45 .46 1.2 .89 .71 .66 .72 .02 .02 .01 .01 .01 .01 .02 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .01 .65 .51 .47 .64 .76 .77 3.5 5.1 3.7 3.0 1.8 1.9 1.6 2.2 2.2 115 377 119 258 84 1.5 1.2 .91 .82 .80 .73 .73 .74 .62 .57 4 4 4 3 3 3 3 3 3 3 3 3 3 3 3 13 48 11 30 12 6 5 5 5 4 4 4 4 3 3 .01 <.01 <.01 .01 .01 .01 .03 .05 .03 .03 .02 .02 .01 .02 .02 36 142 24 102 19 .02 .02 .01 .01 .01 .01 .01 .01 .01 <.01 TOTAL 28.50 0.55 22.55 0.28 990.42 323.38 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM 149 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 DISCHARGE (CPS) .52 .45 .45 .40 .45 .57 170 786 43 4.8 4.5 4.4 4.0 362 1780 462 111 258 2.1 1.6 1.0 .98 .99 .99 42 16 .86 .71 .68 .61 .77 TOTAL 4061.83 YEAR e 267363.23 Estimated MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 1543.98 2884582.95 MEAN DISCHARGE (CPS) 3 3 3 2 2 2 20 91 17 7 6 6 5 41 174 94 22 18 6 5 4 4 3 3 9 10 7 6 6 5 5 .01 .01 .01 .01 .01 <.01 61 249 3.1 .09 .07 .07 .06 119 921 118 17 50 .03 .02 .01 .01 .01 .01 4.6 .84 .02 .01 .01 .01 .01 .85 .67 .66 .47 .51 .41 .57 .59 10 1.8 1.2 1.1 1.2 1.3 1720 1200 332 156 29 1.7 98 3.5 168 117 2.0 2.1 1.6 47 98 2.3 1.9 4001.43 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 1516.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 4 4 4 3 3 3 2 2 4 5 4 3 3 2 109 138 61 37 14 5 14 7 30 29 6 5 3 9 29 10 8 .01 .01 .01 <.01 <.01 <.01 <.01 <.01 .57 .03 .01 .01 .01 .01 605 731 57 18 1.8 .02 28 .07 38 19 .03 .03 .01 7.0 11 .06 .04 1.6 1.3 1.1 229 201 7.0 5.9 741 1170 6141000 697700 66210 e32 e!7 e25 621 e22 e!8 e!3 elO e4.8 e!5 e7.0 e!3 e!6 e7.9 e!2 ell e3.6 e4.5 ___ 6 5 4 25 5: 34 4< 8 7 79 214 159 85< 4390 1810001 4110 1030001 1470 e3770( 302 e54 121 el 49 e: 20 e] 12 11 10 10 9 9 8 8 7 7 6 6 5 5 .03 .02 .01 ) .15 .11 I ) ) ) I 3.1 2.7 L.2 .67 .59 .43 .30 .17 .21 .23 .20 .27 .21 .16 .18 .10 .06 —— 247520.7 —— 2878939.10 150 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT SEP 1996 10... 10... TIME 0600 1800 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 117000 164000 SEDI- MENT, SUS- PENDED (MG/L) (80154) 3730 5390 SEDI- MENT, DIS- CHARGE, SUS- PRNPED (T/DAY) (80155) 1180000 2390000 SED. SUSP. FALL DIAM. * FINER THAN .002 MM (70326) 50 40 SED. SUSP. FALL DIAM. * FINER THAN .004 MM (70327) 75 48 SED. SUSP. FALL DIAM. * FINER THAN .008 MM (70328) 82 66 DATE SEP 1996 10... 10... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 88 78 SED. SUSP. FALL DIAM. * FINER THAN .031 MM (70330) 91 89 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 99 97 SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM (70332) 100 100 SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM (70333) 100 100 SED. SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) 100 100 SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 100 100 151 RIO DE LA PLATA BASIN 50045010 RIO DE LA PLATA BELOW LA PLATA DAM, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 23... 24... JUN 1996 18... SEP 10... TIME 1325 1310 1345 1245 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 130 1010 171 195000 SEDI- MENT, SUS- PENDED (H6/L) (80154) 48 58 193 5780 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 17 158 89 3040000 SED. SUSP. SIEVE DIAM. «S FINER THAN .062 MM (70331) 50 78 86 99 152 RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HIGHWAY 2 NEAR TOA ALTA, PR 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 2 (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 km2 ). WATER-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 Acjueduct 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, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC APR MAY JUN 1 314 84 2 139 163 3 159 259 4 94 236 5 83 84 6 65 505 7 37 309 8 154 90 9 150 244 10 65 618 11 286 207 12 241 115 13 138 133 14 119 72 15 81 337 16 44 346 17 70 136 18 110 140 19 91 118 20 45 116 21 391 52 22 221 55 23 154 56 24 355 85 25 197 77 26 606 55 27 337 78 28 268 48 29 536 57 30 234 35 31 68 —— TOTAL 5852 4910 MEAN 189 164 MAX 606 618 MIN 37 35 AC-FT 11610 9740 CFSM .94 .82 IN. 1.09 .91 STATISTICS OF MONTHLY MEAN MEAN 467 425 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 ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 24 34 32 74 33 25 47 36 55 40 69 73 71 33 27 28 95 257 478 178 157 120 278 133 59 47 71 208 101 58 38 2979 96.1 478 24 5910 .48 .55 DATA 319 1352 1971 14.8 1995 FOR 35 32 45 62 50 50 37 39 44 152 53 83 40 89 1060 394 115 84 150 323 467 241 170 147 59 135 217 580 442 240 127 5762 186 1060 32 11430 .93 1.07 120 46 84 50 55 181 103 281 287 330 76 53 68 49 40 40 90 37 33 59 73 47 34 30 29 27 26 23 21 ___ --- 2392 82.5 330 21 4740 .41 .45 FOR WATER YEARS 1960 184 929 1992 16.9 1984 126 409 1989 16.0 1983 1995 CALENDAR YEAR 50908.4 139 13500 7.2 9.1 101000 .70 9.48 249 28 10 Sep 16 Feb 18 Feb 13 25 24 25 25 35 33 26 24 23 24 25 24 22 26 40 33 29 85 57 28 23 20 29 25 21 27 46 23 24 20 17 908 29.3 85 17 1800 .15 .17 - 1996, 99.8 468 1969 8.31 1986 14 20 24 47 39 27 21 18 18 20 16 47 38 26 26 21 24 19 18 21 22 21 19 28 18 15 15 17 22 27 708 23.6 47 14 1400 .12 .13 20 e!7 e!7 16 16 20 92 117 107 43 28 24 23 15 13 13 13 26 44 30 23 13 36 14 13 38 68 97 33 26 26 1081 34.9 117 13 2140 .17 .20 25 24 25 47 57 42 34 29 30 45 46 36 42 39 e78 77 459 418 302 161 e94 42 30 26 27 23 28 39 24 26 2375 79.2 459 23 4710 .40 .44 24 26 28 27 30 32 36 1010 224 65 49 56 39 162 2190 745 294 248 125 47 41 39 35 38 84 168 51 56 60 38 72 6139 198 2190 24 12180 .99 1.14 88 81 58 51 67 46 35 30 e27 39 41 42 42 72 495 1200 548 299 126 85 165 78 290 528 116 66 52 e65 e!75 e61 e40 5108 165 1200 27 10130 .82 .95 36 33 32 35 400 e50 e32 265 e!060 68100 14500 2770 1170 506 e764 e647 673 551 409 352 141 453 205 374 471 220 362 e341 e!02 e!35 95189 3173 68100 32 188800 15.9 17.72 BY WATER YEAR (WY) 186 722 1987 5.07 1984 348 1939 1985 7.63 1984 164 847 1970 11.4 1977 FOR 1996 WATER YEAR Not 133403 364 68100 13 18 determined 27.33 264600 1.82 24.84 357 52 22 Sep 10 May 15 May 12 Sep 10 Sep 10 149 690 1961 13.2 1994 WATER 258 824 31 68100 2 2 247 1677 1979 16.5 1976 YEARS 1960 .5 Sep .7 Apr .9 Apr Not determined Sep 27 187000 1 17 485 85 17 .33 Sep .29 .56 409 3173 1996 19.2 1991 - 1996 1971 1994 10 1996 17 1984 15 1984 10 1996 10 1996 e Estimated 753 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 ml (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* (539 km"), exclude 8.2 mi 2 (21.2 km") upstream from Lago Carite, flow from which is diverted to Rio Guamani. PERIOD OP RECORD.—Water years 1958 to current year WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 10... DEC 11... FEB 1996 07... APR 02... •TUN 11... AUG 14... DATE OCT 1995 10... DEC 11... FEB 1996 07... APR 02... JUN 11... AUG 14... DATE OCT 1995 10... DEC 11... FEB 1996 07... APR 02... JUN 11... AUG 14... TIME 1115 1350 1100 1155 1530 1325 HARD- NESS TOTAL (HG/L AS CACO3 ) (00900) 170 -- -- 180 -- 200 SILICA, DIS- SOLVED (HG/L AS SIO2) (00955) 18 — -- 17 -- 18 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 55 35 94 21 37 51 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 49 -- -- 54 -- 61 SOLIDS, RESIDUE AT 180 DEG. C DIS- SOLVED (MG/L) (70300) 253 — — -- — -- SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 432 432 370 465 460 455 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 11 -- -- 12 -- 11 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 238 -- -- 247 — 273 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.4 7.9 7.9 7.5 7.4 7.2 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 19 -- -- 17 -- 22 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 37.3 -- -- 14.2 -- 37.7 TEMPER- ATURE WATER (DEG C) (00010) 28.0 27.0 25.0 28.0 29.0 29.5 SODIUM AD- SORP- TION RATIO (00931) 0.6 -- -- 0.5 -- 0.7 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) -- 4 13 11 17 13 TUR- BID- ITY (NTU) (00076) 7.1 3.2 7.3 3.4 3.5 4.7 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.1 -- -- 3.9 -- 3.2 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.500 0.780 0.510 0.550 0.740 0.740 OXYGEN, DIS- SOLVED (MG/L) (00300) 5.8 6.0 6.3 6.6 5.4 3.9 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 180 150 190 190 190 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.060 0.040 0.050 0.040 0.070 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 73 74 76 84 70 51 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 — -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.540 0.840 0.550 0.600 0.780 0.810 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 12 15 16 13 17 14 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 29 -- -- 34 -- 30 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.130 0.190 0.090 0.080 0.080 0.150 COLI- FORM, FECAL, 0.45 UM-MF (COLS . / 100 ML) (31616) 6000 4200 K17000 K610 3300 2600 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 18 -- -- 15 -- 14 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.28 0.45 0.41 0.45 0.50 0.39 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) K740 270 4500 K110 K470 K1200 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) 0.41 0.64 0.50 0.53 0.58 0.54 K * non- ideal count 154 DATE OCT 1995 10... DEC 11... FEB 1996 07... APR 02. .. JUN 11... AU6 14... RIO DE LA PLATA BASIN 50046000 RIO DE LA PLATA AT HWY 2 NR TOA ALTA, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 BARIUM, BORON, CADMIUM NITRO- NITRO- PHOS- BARIUM, TOTAL TOTAL TOTAL GEN, GEN, PRORUS ARSENIC DIS- RECOV- RECOV- RECOV- TOTAL TOTAL TOTAL TOTAL SOLVED ERABLE ERABLE ERABLE (MG/L (MG/L (MG/L (UG/L (UG/L (UG/L (UG/L (UG/L AS N) AS NO3) AS P) AS AS) AS BA) AS BA) AS B) 0.95 1.5 1.0 1.1 1.4 1.3 4.2 6.6 4.6 5.0 6.0 6.0 0.040 0.120 0.080 0.100 0.080 0.080 65 <100 50 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CD) AS CR) (00600) (71887) (00665) (01002) (01005) (01007) (01022) (01027) (01034) COBALT, DIS- SOLVED (UG/L AS CO) (01035) <3 <1 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) OCT 1995 10... DEC 11. .. FEB 1996 07. .. APR 02... JUN 11. . . AUG 14. .. 260 IRON, DIS- SOLVED (UG/L AS FE) LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) MANGA- MOLYB- NESE, DIS- SOLVED (UG/L AS MN) DENUM, DIS- SOLVED (UG/L AS MO) NICKEL, DIS- SOLVED (UG/L AS NI) SILVER, DIS- SOLVED (UG/L AS AG) SILVER, STRON- VANA- TOTAL RECOV- ERABLE (UG/L AS AG) TIUM, DIS- SOLVED (UG/L AS SR) 37 <10 <1.0 200 240 DIUM, DIS- SOLVED (UG/L AS V) (01045) (01046) (01051) (01055) (01056) (01060) (01065) (01075) (01077) (01080) (01085) DATE OCT 1995 10... DEC 11. .. FEB 1996 07... APR 02... JUN 11... AUG 14... ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) ALUM- INUM, DIS- SOLVED (UG/L AS AL) (01106) LITHIUM DIS- SOLVED (UG/L AS LI) (01130) SELE- NIUM, DIS- SOLVED (UG/L AS SE) (01145) SELE- NIUM, TOTAL (UG/L AS SE) (01147) MERCURY DIS- SOLVED (UG/L AS HG) (71890) MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) CYANIDE TOTAL (MG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 10 <4 <0.10 <1 <0.10 <0.010 <0.02 Drainage boundaries tnd*t*r m limestone terron* __LifTf s?onc_ Ijjneous and tedim*n*ary rocks TSUJiLLO ALTO \ ))}**»•«« < \ i f f & V~ -*«™™. / ^>o 0r«|ndf d$ Lotxo IsQSi 155 EXPLANATION A 047560 SURFACE-WATER STATION AND NUMBER T 0476 QUALITY-OF- WATER STATION AND NUMBER DAILY SEDIMENT STATION AND NUMBER WELL AND WELL NUMBER 219 ' »*j*wo» •'•,c**u*s J^ ___| !~" 047550 LAKE-ELEVATION STATION AND NUMBER 01 23456 KILOMETERS I __j_ ._! , ^__ 1 01234 MILES Figure 19.--FUO Hondo to Rfo Puerto Nuevo basins. 156 RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CAT AND, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°26'13 H , long 66°09'36", 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 1995 TO SEPTEMBER 1996 DATE NOV 1995 09... JAN 1996 18... FEB 27... APR 24... JUN 28... AUG 27... DATE NOV 1995 09... JAN 1996 18... FEB 27... APR 24. .. JUN 28. .. AUG 27. .. TIME 0745 0830 0850 0930 1015 0930 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 1300 -- -- 1100 -- 1300 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 9000 46500 26500 22500 32000 48000 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 140 -- -- 100 -- 130 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.2 7.3 8.0 7.3 7.5 7.1 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 220 — -- 210 _- 230 TEMPER- ATURE WATER (DEG C) (00010) 26.0 24.5 26.0 26.0 32.0 29.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 1600 -- -- 1700 -- 1900 TUR- BID- ITY (NTU) (00076) 4.2 5.4 6.0 33 25 21 SODIUM AD- SORP- TION RATIO (00931) 20 -- -- 22 -- 23 OXYGEN, DIS- SOLVED (MG/L) (00300) 3.5 3.8 5.3 4.8 6.5 4.5 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 62 -- -- 69 -- 72 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 42 54 60 62 98 57 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 170 150 120 130 180 140 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 91 230 130 220 360 160 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- — COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 41000 5300 5400 K16000 2700 8500 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 360 -- -- 450 -- 480 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 540 2400 2200 K1500 2000 3200 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 2700 -- -- 3400 -- 3500 K = non-ideal count RIO HONDO BASIN 50047530 RIO HONDO AT FLOOD CHANNEL NEAR CATANO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 157 SOLIDS, RESIDUE NITRO- NOV 1995 09... JAN 1996 18.. . FEE 27... APR 24... JUN 26... AU6 27... FLUO- RIDE, DIS- SOLVED (MG/L AS F) SILICA, DIS- SOLVED (MG/L AS SIO2) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) NITRO- GEN, NITRATE TOTAL (MG/L AS N) NITRO- GEN, NITRITE TOTAL (MG/L AS N) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00950) (00955) (70301) (00530) (00620) (00615) (00630) (00610) (00605) (00625) 0.30 15 0.30 12 0.30 12 5200 6030 6410 8 25 39 68 65 14 0 0 0 0 0 0 .150 .190 .390 .080 .050 .250 0 0 0 0 0 0 .010 .010 .110 .070 .050 .010 0. 0. 0. 0. 0. 0. 160 200 500 150 100 260 0. 0. 0. 1. 0. 0. 020 020 480 00 450 030 0. 0. 0. 1. 2. 0. 18 20 72 0 1 20 0.20 0.22 1.2 2.0 2.6 0.23 NITRO- NITRO- PHOS- GEN, GEN, PHORUS ARSENIC TOTAL TOTAL TOTAL TOTAL (MG/L (MG/L (MG/L (UG/L AS N) AS NO3) AS P) AS AS) (00600) (71887) (00665) (01002) (01007) 100 100 NOV 1995 09. . . JAN 1996 18. .. FEB 27... APR 24... JUN 26.. . AUG 27.. . 0, 0. 1, 2, 2. 0, .36 .42 .2 .2 .7 .26 1, 1, 7, 9. 12 1, .6 .9 ,5 .5 ,2 0. 0. 0. 0. 0. 0. 020 020 140 280 320 030 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 700 830 20 360 1700 NOV 1995 09. .. JAN 1996 18. .. FEB 27... APR 24. .. JUN 28... AUG 27... 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) <1 440 <0.10 <0.10 <1 <1 30 <0.010 <0.010 <1 0.10 0.20 158 RIO DB BAYAMON BASIN 50047535 RIO DB BAYAMON AT ARENAS, PR LOCATION.—Lat 18°10'11", long 66°07'18", Hydrologic Unit 21010005, at left bank, 2.61 mi (4.20 km) southeast of plaza de Cidra, 0.56 mi (0.90 km) southwest from Bscuela Segunda Unidad de Bayamon, and 2.70 mi (4.34 km) northeast from Central Cayey. DRAINAGE AREA.--0.45 mi 3 (1.16 km*). PERIOD OF RECORD.--July 1992 to September 1993, October 1995 to September 1996. GAGE.—Water-stage recorder. Elevation of gage is 1,378 ft (420 m), from topographic map. REMARKS.—Records poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC MAY JUN AUG SEP 1 .24 .34 2 .22 .25 3 .21 .20 4 .20 .19 5 .19 1.7 6 .18 2.0 7 .17 1.0 8 .18 .62 9 .17 .41 10 .20 .26 11 e.19 .18 12 e.16 .15 13 .18 .15 14 .30 .14 15 .18 .13 16 .14 6.9 17 .14 1.6 18 .15 .81 19 .36 .52 20 .23 .30 21 .16 .21 22 .15 .18 23 .15 .14 24 1.0 .25 25 .44 .18 26 .26 .15 27 .19 .12 28 2.3 .12 29 1.1 .11 30 .54 .11 31 .32 —— TOTAL 10.60 19.42 MEAN .34 .65 MAX 2.3 6.9 MIN .14 .11 AC-FT 21 39 CFSM .76 1.44 IN. .88 1.61 STATISTICS OF MONTHLY MEAN MEAN .32 .97 MAX .34 1.30 (WY) 1996 1993 MIN .30 .65 (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 INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS .11 .10 .10 .10 .10 .09 .09 .09 .09 .09 .09 .09 .26 .32 .10 .10 .14 .44 .46 .65 .21 .11 .10 .10 .11 .14 .15 .17 .08 .08 .07 4.93 .16 .65 .07 9.8 .35 .41 DATA .39 .63 1993 .16 1996 .07 .07 .07 .07 .07 .07 .07 .18 .17 .08 1.3 .57 .15 3.8 3.8 .44 .23 .19 .37 .87 .47 .23 .15 .08 .14 .12 .64 4.1 .54 .26 .15 19.52 .63 4.1 .07 39 1.40 1.61 FOR WATER .63 .63 1996 .62 1993 .07 .13 .08 .10 2.3 1.3 .48 .29 .36 .26 .14 .12 .12 .13 .15 .12 .09 .09 .08 .08 .08 .08 .08 .08 .08 .08 .08 .08 .08 —— —— 7.21 .25 2.3 .07 14 .55 .60 YEARS 1992 - .20 .25 1996 .16 1993 FOR 1996 426. 1. 141 . . 885 7. . 845 2. 35. 1. , . .08 .08 .08 .08 .09 .09 .13 .08 .09 .09 .14 .09 .09 .09 1.3 .52 .15 .11 .12 .09 .08 .07 .06 .06 .06 .08 .08 .08 .08 .07 .10 4.41 .14 1.3 .06 8.7 .32 .36 1996 .12 .14 1996 .097 1993 WATE 01 16 03 04 34 03 59 22 7 18 08 .07 .06 .32 .19 .26 .10 .07 .06 .07 .06 .06 .13 .10 .23 .38 .25 .09 .08 .07 .27 .15 .08 .06 .08 .08 .06 .08 .05 .04 .06 —— 3.66 .12 .38 .04 7.3 .27 .30 , BY WATER .29 .45 1993 .12 1996 R YEAR Sep 10 May 2 Apr 28 Sep 10 Sep 10 May 4 .04 .03 .03 .03 .05 .06 .12 .20 .35 .27 .20 .18 .23 .21 .22 .31 .19 .16 .15 .14 .12 .11 .18 .12 .11 .12 .13 .11 .09 .09 .09 4.44 .14 .35 .03 8.8 .32 .37 YEAR (WY) 1.08 2.02 1993 .14 1996 .10 .09 .08 1.4 1.7 2.2 6.2 4.3 .86 .17 .06 1.3 1.2 .26 8.9 5.2 2.7 2.3 1.8 1.1 3.2 3.7 2.0 .95 .38 .35 .67 .24 .15 .13 —— 53.69 1.79 8.9 .06 106 3.98 4.44 1.39 1.79 1996 .99 1993 .11 .11 .11 .11 .10 .10 .11 2.6 1.9 .59 .32 4.7 3.1 21 8.3 1.3 .82 .62 .37 .31 .24 .21 .20 .19 .20 .20 .18 .23 .21 .20 .20 48.94 1.58 21 .10 97 3.51 4.05 1.85 2.12 1993 1.58 1996 WATER 1. 1. . 141 . . 885 7. . 729 2. 30. 1. , . .19 .19 2.6 1.7 .57 .27 .21 .18 .17 .17 .17 .17 .31 16 6.1 17 2.1 1.0 .84 .82 .55 .44 1.6 .90 .46 .39 .38 1.1 .55 .36 .35 57.84 1.87 17 .17 115 4.15 4.78 1.03 1.87 1996 .46 1992 YEARS 1992 01 16 85 Sep 03 May 04 Apr Sep 34 Sep 03 May 24 38 5 18 08 .36 .31 .33 .31 .30 .30 .31 .89 18 141 12 1.7 .96 .75 1.4 1.8 .75 .66 .65 1.6 3.1 .74 .59 .48 .39 .41 .35 .34 .30 .27 —— 191.35 6.38 141 .27 380 14.2 15.82 2.86 6.38 1996 .67 1993 - 1996 1996 1993 10 1996 2 1996 28 1996 10 1996 10 1996 4 1996 e Estimated 759 RIO DE BAYAMON BASIN 50047540 RIO SABANA AT VISTA MONTE, PR LOCATION.—Lat 18°10'28", long 66°08'38", Hydrologic Unit 21010005, at left bank, 1.2 ml (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 September 1996. GAGE.—Water-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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY NOV DEC JAN MAR APR MAY JUN JUL AUG SEP 1 1.1 2 .97 3 .92 4 .90 5 .84 6 .82 7 .79 8 .83 9 .78 10 .88 11 .86 12 a. 74 13 a. 72 14 a. 70 15 a. 70 16 a. 65 el 17 a. 64 18 a. 62 19 e2.3 20 a. 68 21 a. 66 22 a. 62 23 a. 62 24 a. 60 25 a. 56 26 a. 58 27 a. 56 28 a. 58 29 a. 54 30 a. 54 .49 .50 .48 .51 .48 .49 .47 .60 .52 .52 .48 .47 .54 .48 .48 .78 .74 .56 .53 .50 .48 .45 .50 .45 .43 .42 .43 .43 .43 31 a. 52 —— .44 .45 .46 .44 .44 .46 .41 .43 .42 .46 .44 .60 .51 .45 .45 .46 .54 .66 .59 .56 .49 .47 .48 .48 .48 .47 .54 .46 .46 .46 .46 TOTAL 23.82 31.64 14.92 MEAN .77 1.05 .48 MAX 2.3 17 .66 MIN .52 .42 .41 AC -FT 47 63 30 CFSM .96 1.32 .60 IN. 1.11 1.47 .69 STATISTICS OF MONTHLY MEAN DATA MEAN .81 1.31 .79 MAX .86 1.56 1.11 (WY) 1993 1993 1993 MIN .77 1.05 .48 (WY) 1996 1996 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 a. 46 a. 46 a. 46 a. 48 a. 46 a. 54 a. 47 a. 72 a. 46 el. 6 a. 60 a. 45 el. 5 e3.4 el. 3 el.O a. 68 .55 .69 1.1 .86 .62 .54 .52 .59 .67 1.2 1.8 .95 .71 .61 26.45 .85 3.4 .45 52 1.07 1.23 FOR WATER .79 .85 1996 .72 1993 .55 .62 .60 .58 2.2 .95 .72 .64 3.0 .87 .63 .53 .48 .45 .43 .43 .41 .41 .40 .40 .39 .39 .39 .39 .38 .38 .38 .40 .39 —— —— 18.79 .65 3.0 .38 37 .81 .87 .38 .38 .39 .37 .41 .41 .38 .37 .38 .37 .43 .34 .33 .31 1.3 .40 .32 .32 .32 .32 .32 .34 .33 .33 .34 .35 .32 .32 .33 .36 .47 12.04 .39 1.3 .31 24 .49 .56 YEARS 1992 - 1996 .49 .65 1996 .33 1993 .27 .39 1996 .15 1993 .45 .52 1.5 .73 .66 .48 .41 .38 .33 .32 .24 .32 .27 .35 .34 .25 .24 .24 .24 .24 .25 .23 .24 .25 .26 .28 .27 .35 .34 .33 —— 11.31 .38 1.5 .23 22 .47 .53 , BY WATER .80 1.23 1993 .38 1996 .31 .33 .35 .35 .35 .34 .42 .46 2.4 .63 .44 .39 .44 .38 .40 .42 .41 .42 .46 .39 .41 .40 .40 .42 .38 .40 .41 .41 .43 .38 .37 14.50 .47 2.4 .31 29 .58 .67 YEAR (WY) 1.36 2.26 1993 .47 1996 .37 .38 .41 1.4 2.1 .92 1.9 1.0 .46 .40 .42 .95 .69 .50 8.6 4.0 1.7 1.0 .80 .65 1.2 1.0 .73 .67 .66 .96 1.0 .69 .61 .61 —— 36.78 1.23 8.6 .37 73 1.53 1.71 1.05 1.23 1996 .87 1993 FOR 1996 WATER YEAR 826.50 2.26 401 .23 .24 2370 12.02 .21 1640 2.82 38.43 1.6 .57 .34 Sap 10 Apr 22 Apr 17 Sap 10 Sep 10 Apr 21 .63 .62 .63 .66 .65 .67 .69 2.8 1.3 .87 .93 1.6 1.7 29 11 1.8 1.4 1.2 .94 .89 .84 .81 .77 .76 .77 .74 .75 .77 .72 .71 .71 68.33 2.20 29 .62 136 2.76 3.18 2.61 3.02 1993 2.20 1996 .71 .71 1.8 1.4 .78 .74 .71 .71 .71 .72 .71 .71 .89 13 6.0 17 3.9 1.6 1.2 1.0 .98 .93 2.4 1.3 1.0 .93 .91 1.4 .90 .90 .87 67.52 2.18 17 .71 134 2.72 3.14 1.56 2.18 1996 .93 1993 WATER YEARS 1992 1.72 2.26 1.18 401 .11 .12 2370 12.02 .11 1240 2.15 29.18 1.6 .48 .17 Sep Mar Jun Sep Sep Mar 1.7 1.1 1.1 1.2 1.1 1.1 1.1 2.7 12 401 43 3.6 3.0 2.6 2.3 2.0 1.7 1.6 1.5 1.6 1.8 1.4 1.3 1.3 1.3 1.4 1.4 1.5 1.0 1.0 —— 500.4 16.7 401 1.0 993 20.8 23.27 6.31 16.7 1996 1.01 1993 - 1996 1996 1993 10 1996 25 1993 6 1993 10 1996 10 1996 23 1993 e Estimated 160 RIO DE BAYAMON BASIN 50047550 LAGO CIDRA AT DAMSITE NEAR CIDRA, PR LOCATION.--Lat 18°11'57", long 66°08'29", Hydrologic Unit 21010005, at Lago de Cidra Dam on Rio de Bayam6n, 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 hmj ) 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; 1,295.86 ft (394.98 m), April 22,1995. minimum elevation EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 1,328.09 ft (404.80 m), Sept. 10; minimum elevation, 1,316.54 ft (401.12 m), June 6. 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 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES NOV DEC JAN FEE APR 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 1321.25 1321.38 1321.46 1321.53 1321.57 1321.59 1321.63 1321.65 1321.69 1321.73 1321.78 1321.82 1321.88 1321.94 1321.97 1322.00 1322.03 1322.05 1322.14 1322.22 1322.26 1322.29 1322.33 1322.37 1322.38 1322.36 1322.40 1322.44 1322.43 1322.41 1322.38 1322.44 1321.25 1322.38 1322.39 1322.38 1322.37 1322.38 1322.42 1322.42 1322.40 1322.39 1322.37 1322.36 1322.36 1322.33 1322.24 1322.16 1322.15 1322.15 1322.08 1322.03 1321.95 1321.87 1321.80 1321.71 1321.65 1321.59 1321.52 1321.44 1321.44 1321.43 1321.44 ... 1322.42 1321.43 1321.40 1321.37 1321.33 1321.30 1321.29 1321.30 1321.28 1321.24 1321.20 1321.17 1321.17 1321.19 1321.22 1321.24 1321.23 1321.22 1321.21 1321.31 1321.41 1321.54 1321.58 1321.56 1321.56 1321.56 1321.64 1321.65 1321.67 1321.69 1321.68 1321.68 1321.67 1321.69 1321.17 1321.66 1321.64 1321.63 1321.61 1321.59 1321.59 1321.59 1321.64 1321.66 1321.67 1321.79 1321.84 1321.84 1322.08 1322.38 1322.37 1322.37 1322.37 1322.42 1322.47 1322.45 1322.41 1322.40 1322.39 1322.41 1322.41 1322.47 1322.52 1322.46 1322.42 1322.39 1322.52 1321.59 1322.38 1322.39 1322.39 1322.39 1322.47 1322.47 1322.43 1322.43 1322.46 1322.43 1322.39 1322.38 1322.37 1322.36 1322.37 1322.36 1322.36 1322.36 1322.36 1322.36 1322.36 1322.36 1322.35 1322.34 1322.34 1322.33 1322.32 1322.29 1322.28 ... 1322.47 1322.28 1322.27 1322.25 1322.24 1322.23 1322.22 1322.20 1322.19 1322.17 1322.16 1322.14 1322.17 1322.16 1322.14 1322.12 1322.25 1322.32 1322.32 1322.29 1322.28 1322.27 1322.25 1322.24 1322.22 1322.20 1322.17 1322.14 1322.09 1321.94 1321.86 1321.78 1321.71 1322.32 1321.71 1321.62 1321.53 1321.57 1321.48 1321.39 1321.25 1321.10 1320.97 1320.85 1320.71 1320.60 1320.50 1320.44 1320.42 1320.41 1320.37 1320.28 1320.18 1320.09 1319.98 1319.88 1319.72 1319.56 1319.40 1319.27 1319.21 1319.11 1319.00 1318.89 1318.82 ... 1321.62 1318.82 1318.73 1318.65 1318.57 1318.48 1318.38 1318.29 1318.22 1318.17 1318.35 1318.42 1318.40 1318.40 1318.38 1318.30 1318.18 1318.11 1318.04 1317.97 1317.92 1317.83 1317.74 1317.64 1317.58 1317.53 1317.45 1317.39 1317.31 1317.21 1317.08 1317.01 1316.91 1318.73 1316.91 1316.78 1316.66 1316.56 1316.73 1317.01 1317.25 1317.58 1317.81 1317.85 1317.89 1317.94 1318.21 1318.34 1318.42 1318.97 1319.43 1319.76 1319.94 1320.07 1320.14 1320.29 1320.49 1320.57 1320.56 1320.47 1320.49 1320.58 1320.61 1320.63 1320.64 —— 1320.64 1316.56 1320.66 1320.62 1320.53 1320.43 1320.32 1320.24 1320.14 1320.39 1320.59 1320.63 1320.65 1320.81 1320.91 1321.35 1321.81 1322.11 1322.33 1322.49 1322.61 1322.70 1322.68 1322.54 1322.40 1322.37 1322.35 1322.30 1322.16 1322.05 1321.97 1321.91 1321.83 1322.70 1320.14 1321.77 1321.70 1321.77 1321.85 1321.83 1321.79 1321.76 1321.76 1321.74 1321.65 1321.55 1321.48 1321.44 1321.74 1322.05 1322.39 A A 1322.39 1322.37 1322.36 1322.29 1322.36 1322.38 1322.26 1322.15 1322.07 1322.09 1322.06 1321.97 1321.88 —— —— 1321.88 1321.85 1321.78 1321.71 1321.65 1321.57 1321.48 1321.59 1321.73 1324.49 A 1322.59 1322.50 1322.47 1322.46 1322.48 1322.44 1322.43 1322.42 1322.43 1322.48 1322.43 1322.42 1322.40 1322.37 1322.31 1322.23 1322.16 1322.12 1322.06 —— —— A No gage-height record 161 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR LOCATION.—Lat 18°12'04", long 66°08'26", Hydrologic Unit 21010005, 0.2 mi (0.3 km) downstream of Lago Cidra Dam on right bank, 2.1 mi (3.4 km) northwest of Plaza de Cidra. DRAINAGE AREA.--8.31 mi> (21.5 km»). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--November 1990 to current year. GAGE.—Water-stage recorder. Elevation of gage is 1,279 ft (390 m), from topographic map. 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. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT DEC JAN FEB MAR APR MAY JTTN SEP 1 9.2 e!4 2 9.1 e!2 3 9.0 ell 4 8.7 e!4 5 8.5 el2 6 8.3 e43 7 8.5 34 8 7.5 24 9 7.6 19 10 8.6 15 11 7.5 14 12 7.0 14 13 6.7 12 14 7.4 12 15 7.0 12 16 7.2 12 17 7.4 11 18 7.5 11 19 8.0 11 20 7.4 11 21 7.9 11 22 7.6 11 23 8.5 11 24 21 11 25 19 11 26 18 12 27 16 11 28 62 15 29 66 15 30 e49 14 31 e!4 —— TOTAL 447.1 440 MEAN 14.4 14.7 MAX 66 43 MIN 6.7 11 AC-FT 887 873 CFSM 1.73 1.76 IN. 2.00 1.97 14 14 14 14 15 15 14 14 13 14 14 14 14 14 14 14 13 10 3.9 3.8 14 17 14 14 13 13 13 13 14 13 14 407.7 13.2 17 3.8 809 1.58 1.82 14 14 14 13 13 13 13 13 13 13 14 14 15 17 23 23 19 17 23 48 37 22 17 16 19 53 40 28 20 17 16 631 20.4 53 13 1250 2.45 2.82 17 19 23 65 45 35 25 35 48 24 17 15 15 14 13 13 13 13 13 14 14 13 13 13 13 14 14 13 13 —— 596 20.6 65 13 1180 2.47 2.66 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1991 MEAN 13.0 22.2 MAX 20.5 41.2 (WY) 1992 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 14.1 30.4 1992 4.36 1994 FOR 19.5 59.6 1992 5.45 1995 17.8 36.5 1991 7.24 1994 13 14 14 14 14 15 15 15 15 14 15 15 15 15 16 16 16 16 16 17 17 17 17 17 17 18 43 28 30 30 30 564 18.2 43 13 1120 2.19 2.52 - 1996 16.5 23.7 1992 11.4 1994 1995 CALENDAR YEAR 3262.32 8.94 66 .68 .80 6470 1.07 14.59 15 7.4 1.0 Oct 29 May 9 May 1 29 25 26 26 27 26 27 27 28 27 26 26 20 18 19 19 19 20 20 20 29 38 39 39 23 11 24 24 20 14 —— 736 24.5 39 11 1460 2.95 3.29 15 17 18 18 19 19 20 14 9.3 9.6 9.2 9.5 9.6 18 21 19 19 19 19 20 20 19 20 20 20 20 20 19 16 14 16 526.2 17.0 21 9.2 1040 2.04 2.35 21 21 16 15 17 16 9.3 3.6 3.5 3.9 4.1 5.4 4.2 4.1 7.5 4.9 4.5 6.0 5.3 4.8 5.0 5.9 5.3 33 46 20 8.9 7.5 7.3 11—— 327.0 10.9 46 3.5 649 1.31 1.46 14 45 62 30 29 27 27 14 3.5 4.0 4.1 16 16 15 15 21 17 14 13 25 37 37 34 3.4 3.8 13 36 35 18 11 18 657.8 21.2 62 3.4 1300 2.55 2.94 19 24 34 32 28 27 16 10 17 25 24 12 20 14 8.8 184 102 32 17 10 8.9 16 44 42 30 22 18 18 17 18 17 906.7 29.2 184 8.8 1800 3.52 4.05 17 16 17 17 17 16 16 11 11 5420 985 123 37 23 20 24 17 14 13 13 28 16 13 12 15 16 16 16 13 14 —— 6986 233 5420 11 13860 28.0 31.24 , BY WATER YEAR (WY) 14.4 24.5 1996 7.37 1995 FOR 1996 13225 36 5420 3 4 15000 27 26230 4 59 32 15 7 10.3 17.0 1996 4.13 1993 WATER YEAR .5 .1 Sep 10 .4 Jul 24 .1 Jun 8 Sep 10 .34 Sep 10 .34 .13 .6 10.8 17.8 1992 3.47 1994 16.0 39.6 1993 1.56 1994 WATER 17 36 5 5420 15000 27 12970 2 29 28 11 2 14.4 29.2 1996 1.18 1995 YEARS 1991 .9 .1 .93 Sep . 60 Aug .80 May Sep .34 Sep .15 .23 .1 47.4 233 1996 1.64 1994 - 1996 1996 1994 10 1996 6 1992 1 1995 10 1996 10 1996 e Estimated 162 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAOO 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-49 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. 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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 2,400 mg/L September 10, 1996; Minimum daily mean, 7 mg/L May 14, 1996. SEDIMENT LOADS: Maximum daily mean, 27,700 tons (25,100 tonnes) September 10, 1996; Minimum daily mean, 0.30 ton (0.27 tonne) June 09, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 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 9.2 9.1 9.0 8.7 8.5 8.3 8.5 7.5 7.6 8.6 7.5 7.0 6.7 7.4 7.0 7.2 7.4 7.5 8.0 7.4 7.9 7.6 8.5 21 19 18 16 62 66 e49 e!4 100 101 102 101 102 102 102 103 103 102 101 100 95 89 83 80 78 76 74 72 69 72 76 85 93 88 79 73 58 54 53 2.5 2.5 2.5 2.4 2.3 2.3 2.3 2.1 2.1 2.4 2.0 1.9 1.7 1.8 1.6 1.6 1.6 1.5 1.6 1.4 1.5 1.5 1.8 4.7 4.8 4.4 3.4 12 10 e5.4 e2.8 e!4 e!2 ell e!4 e!2 e43 34 24 19 15 14 14 12 12 12 12 11 11 11 11 11 11 11 11 11 12 11 15 15 14 62 75 87 88 88 83 57 50 54 69 81 94 100 100 100 99 99 101 129 176 231 209 170 138 111 89 72 58 47 38 e2.2 e2.3 e2.9 e3.1 e2.6 e6.8 5.2 3.2 2.7 2.8 3.1 3.6 3.3 3.2 3.2 3.2 3.0 3.0 3.8 5.2 6.8 6.4 5.0 4.2 3.3 2.8 2.2 2.3 1.9 1.5 TOTAL 447.1 92.4 440 104.8 14 14 14 14 15 15 14 14 13 14 14 14 14 14 14 14 13 10 3.9 3.8 14 17 14 14 13 13 13 13 14 13 14 407.7 DECEMBER 41 58 76 82 85 89 94 100 105 108 111 113 115 118 121 123 126 129 131 134 138 145 156 166 159 146 135 125 115 106 98 1.6 2.1 2.8 3.1 3.5 3.5 3.6 3.6 3.8 4.1 4.0 4.2 4.4 4.4 4.5 4.6 4.6 3.5 1.4 1.4 5.2 6.7 5.7 6.4 5.4 5.1 4.9 4.4 4.3 3.8 3.8 124.4 e Estimated 163 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DAY (CPS) (MG/L) (TONS/DAY) (CPS) (MG/L) (TONS/DAY) (CPS) (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 14 14 14 13 13 13 13 13 13 13 14 14 15 17 23 23 19 17 23 48 37 22 17 16 19 53 40 28 20 17 16 90 83 77 71 66 60 56 51 47 48 65 69 66 66 96 158 241 197 134 93 76 65 56 57 61 62 45 29 18 20 23 3.3 3.1 2.8 2.5 2.3 2.1 1.9 1.8 1.7 1.7 2.4 2.7 2.6 3.0 6.2 9.4 12 9.0 7.9 12 7.8 3.9 2.5 2.4 3.1 8.8 4.9 2.3 1.0 .96 1.1 FEBRUARY 17 19 23 65 45 35 25 35 48 24 17 15 15 14 13 13 13 13 13 14 14 13 13 13 13 14 14 13 13 25 26 32 55 53 50 42 49 55 40 32 31 34 29 28 28 30 38 48 50 50 49 49 49 49 48 48 49 55 ___ 1.2 1.3 2.3 9.9 6.5 4.8 2.9 4.7 7.2 2.6 1.5 1.3 1.4 1.1 .99 1.0 1.1 1.4 1.7 1.9 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.8 1.9 MARCH 13 14 14 14 14 15 15 15 15 14 15 15 15 15 16 16 16 16 16 17 17 17 17 17 17 18 43 28 30 30 30 63 70 63 54 47 42 38 36 46 64 87 74 57 45 44 43 43 47 55 63 63 63 62 61 61 60 60 59 58 58 57 2.3 2.6 2.3 2.1 1.8 1.6 1.5 1.4 1.8 2.5 3.6 3.0 2.4 1.8 1.9 1.9 1.9 2.1 2.4 2.8 2.8 2.9 2.9 2.8 2.8 2.8 6.9 8.4 4.7 4.6 4.6 TOTAL 631 129.16 596 73.09 564 89.9 164 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 29 25 26 26 27 26 27 27 28 27 26 26 20 18 19 19 19 20 20 20 29 38 39 39 23 11 24 24 20 14 ___ APRIL 57 56 56 55 51 48 45 42 39 36 34 32 30 29 25 19 15 19 16 17 30 35 27 22 18 18 34 26 20 24 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY 4.4 3.8 3.9 3.9 3.7 3.4 3.2 3.1 3.0 2.7 2.4 2.2 1.7 1.4 1.3 1.0 .80 1.1 .92 1.0 2.7 3.6 2.8 2.3 1.2 .61 2.3 1.7 1.1 .96 —— 15 17 18 18 19 19 20 14 9.3 9.6 9.2 9.5 9.6 18 21 19 19 19 19 20 20 19 20 20 20 20 20 19 16 14 16 28 33 39 48 52 32 20 11 15 20 26 18 13 7 8 11 13 13 13 14 12 10 11 10 13 15 15 12 11 11 21 1.2 1.6 1.9 2.3 2.6 1.6 1.1 .46 .44 .54 .65 .49 .37 .41 .46 .58 .71 .72 .72 .83 .65 .53 .67 .57 .75 .84 .84 .65 .50 .44 1.0 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 21 21 16 15 17 16 9.3 3.6 3.5 3.9 4.1 5.4 4.2 4.1 7.5 4.9 4.5 6.0 5.3 4.8 5.0 5.9 5.3 33 46 20 8.9 7.5 7.3 11 29 28 28 30 32 32 32 31 31 32 57 118 219 158 88 51 47 50 52 44 34 28 22 37 35 31 31 32 31 29 1.7 1.6 1.2 1.2 1.6 1.5 .82 .31 .30 .34 .63 1.7 2.5 1.7 1.8 .66 .56 .81 .75 .57 .47 .47 .34 4.1 4.4 1.7 .77 .64 .61 .87 —— 736 68.19 526.2 27.12 327.0 36.62 165 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 14 45 62 30 29 27 27 14 3.5 4.0 4.1 16 16 15 15 21 17 14 13 25 37 37 34 3.4 3.8 13 36 35 18 11 18 657.8 13225.5 JULY 33 44 40 29 26 24 25 36 45 59 52 65 91 932 85 89 92 95 97 87 76 66 57 50 43 40 41 37 32 31 26 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) AUGUST i 1.3 6.4 6.9 2.4 2.1 1.8 1.9 1.2 .43 .63 .57 3.0 3.7 261 3.4 5.0 4.2 3.5 3.4 5.8 7.5 6.6 5.2 .46 .44 1.6 3.9 3.5 1.5 1.0 1.3 351.63 37693.37 19 24 34 32 28 27 16 10 17 25 24 12 20 14 8.8 184 102 32 17 10 8.9 16 44 42 30 22 18 18 17 18 17 906.7 21 28 42 38 34 32 29 28 25 28 33 36 38 38 37 2530 521 50 33 30 31 35 47 53 48 44 41 39 37 37 33 —— 1.1 2.0 3.8 3.3 2.6 2.4 1.3 .80 1.2 1.9 2.2 1.1 2.1 1.5 .88 1800 200 4.4 1.5 .84 .74 1.6 6.3 6.1 3.9 2.6 2.0 1.9 1.8 1.8 1.5 2065.16 17 16 17 17 17 16 16 11 11 5420 985 123 37 23 20 24 17 14 13 13 28 16 13 12 15 16 16 16 13 14 —— 6986 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 17 16 17 17 17 16 16 11 11 5420 985 123 37 23 20 24 17 14 13 13 28 16 13 12 15 16 16 16 13 14 31 28 29 33 33 37 43 50 373 2400 2120 873 358 174 169 175 181 187 193 200 207 214 219 209 196 200 208 216 222 227 1.4 1.2 1.4 1.5 1.5 1.7 1.9 1.5 79 27700 6230 323 37 11 9.3 11 8.2 7.0 6.6 7.0 15 9.0 7.6 7.0 7.7 8.5 9.0 9.2 7.8 8.9 34530.9 166 RIO DE BAYAHON BASIN 50047560 RIO DE BAYAHON BELOW LAGO CIDRA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. SEDI- CUBIC MENT, FEET SUS- DATE JUL 1996 14... SEP 10... TIME PER 1230 74 0435 8430 SEDI- MENT, DIS- CHARGE, SUS- PENDED FENDED SED. SED. SUSP. SUSP. FALL FALL DIAM. DIAM. SED. SUSP. FALL DIAM. FINER % FINER % FINER THAN THAN THAN SECOND (MG/L) (T/DAY) .002 MM .004 MM .008 MM 7810 1560 1150 26200 41 61 55 75 69 83 DATE JUL 1996 14... SEP 10... SED. SUSP. FALL DIAM. % FINER THAN .016 MM SED. SUSP. FALL DIAM. % FINER THAN .031 MM SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM 81 88 87 89 99 97 100 98 100 99 100 100 100 100 167 RIO DE BAYAMON BASIN 50047560 RIO DE BAYAMON BELOW LAGO CIDRA, PR—Continued ITER QUALITY DATE OCT 1995 09... NOV 06... 24... DEC 06... 24... JAN 1996 17... FEB 07... MAR 20... JUN 04... SEP 10... 10... DATA, W TIME 1702 1518 1407 1412 1710 1518 1401 1306 1306 0135 1105 ATER YEAR DIS- CHARGE, INST. CUBIC FEET PER SECOND 6.7 41 11 15 14 21 23 17 22 2410 14200 OCTOBER J SEDI- MENT, SUS- PENDED (MO/L) 103 88 136 89 169 272 281 64 1030 2540 1910 L995 TO HJS SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 1.9 9.7 3.9 3.6 6.4 15 17 2.9 61 16500 73300 PTEMBER : SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM 98 91 88 74 90 86 58 90 65 100 99 168 RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AGUAS BUENAS, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°14'39 H , 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 1 (47.9 km1 ). PERIOD OF RECORD.--Water years 1958-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 05 DEC 08 FEE 14 APR 10 JUN 12 AU6 26 DATE 1995 . . . . . . 1996 . . . . . . . . . DATE OCT 1995 05... DEC 08... FEB 1996 14.. . APR 10. . . JUN 12. .. AUG 26. .. 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) 1410 18 1125 17 0730 22 1220 34 1445 63 1210 37 HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 100 -- -- 110 -- 98 262 262 283 265 235 252 MAGNE- CALCIUM SIUM, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS CA) AS MG) (00915) (00925) 25 10 -- -- 26 10 -_ 23 9.9 8.1 26.5 28 7.7 22.5 21 7.9 21.5 4.1 8.0 24.0 9.2 7.4 24.0 120 7.5 24.5 18 SODIUM POTAS- SODIUM, AD- SIUM, DIS- SORP- DIS- SOLVED TION SOLVED (MG/L RATIO (MG/L AS NA) AS K) (00930) (00931) (00935) 13 0.6 3.3 ._ ._ 18 0.8 2.9 _. 14 0.6 3.1 7.8 96 7.9 92 7.8 91 8.3 101 7.4 89 7.7 94 ALKA- LINITY WAT WH TOT FET SULFIDE FIELD TOTAL MG/L AS (MG/L CACO3 AS S) (00410) (00745) 94 <0.5 100 110 100 <0.5 87 100 13 14 10 11 2000 590 220 250 2700 510 420 320 45 32000 25000 12 SULFATE DIS- 3200. K1700 CHLO- RIDE, DIS- SOLVED SOLVED (MG/L AS SO4) (00945) 13 -- -- 5.1 -- 6.9 (MG/L AS CL) (00940) 18 _- -- 18 -- 18 K - non-ideal count RIO DE BAYAMON BASIN 50047600 RIO DE BAYAMON NEAR AQUAS BUENAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 169 OCT 1995 05... DEC 08... FEB 1996 14... APR 10... JUN 12... AUG 26... OCT 1995 05... DEC 08. .. FEB 1996 14... APR 10. .. JUN 12... AUG 26... OCT 1995 05... DEC 08... FEB 1996 14... APR 10... JUN 12... AUG 26... 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) 0.38 0.34 0.26 0.45 1.3 0.23 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 23 -- — 23 — 22 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.4 0.88 0.87 2.0 0.63 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 162 — -- 163 -- 157 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 4.8 6.4 3.9 3.9 8.7 2.8 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 7.90 -- — 15.1 -- 15.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.060 0.040 0.050 0.170 0.060 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 14 4 4 6 162 21 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- -- <1 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.690 1.09 0.620 0.420 0.640 0.390 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 <0.010 <0.010 0.020 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- -- 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.700 1.10 0.620 0.420 0.660 0.400 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.020 0.020 0.020 0.050 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- — <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.36 0.32 0.24 0.43 1.2 0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 970 1400 40 60 <0.10 2.6 •C0.010 <0.010 <0.02 0.03 170 RIO DE 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 czuarry near Highway 174, 1.3 mi (2.1 km) south of colonia Santa Rosa and 4.7 mi (7.6 km) south of Bayamon. DRAINAGE AREA.--41.8 mi 2 (108.3 km2 ). PERIOD OF RECORD.--September 1964 to October 1970, June 1988 to current year. GAGE.--Water-stage recorder and crest-stage gage. Elevation of gage is 98 ft (30 m), from topografic map. REMARKS.--Records fair. Diversion to the Guaynabo water treatment plant, for municipal supply, made upstream from station (at Represa de San Juan). Flow is regulated by storage and release of water at Lago de Cidra (capacity 5,220 acre-ft), 10.5 mi (16.9 km) upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN APR MAY JUN JUL SEP 1 11 9.8 2 9.7 12 3 9.1 19 4 8.6 22 5 8.3 24 6 8.6 63 7 16 33 8 13 14 9 11 11 10 11 10 11 13 9.8 12 10 9.7 13 9.3 9.5 14 9.2 9.2 15 9.0 9.1 16 8.8 9.1 17 13 9.4 18 15 9.4 19 28 9.4 20 12 9.2 21 10 9.0 22 9.8 8.9 23 11 8.8 24 21 9.7 25 15 9.5 26 12 9.3 27 28 9.0 28 20 9.0 29 16 8.9 30 11 9.4 31 9.5 TOTAL 396.9 403.1 MEAN 12.8 13.4 MAX 28 63 MIN 8.3 8.8 AC-FT 787 800 CFSM .31 .32 IN. .35 .36 STATISTICS OF MONTHLY MEAN MEAN 30.5 43.1 MAX 129 174 (WY) 1991 1970 MIN 4.30 7.91 (WY) 1969 1965 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 8.8 9.1 9.0 8.9 8.8 8.8 8.8 8.6 9.0 9.7 10 10 11 9.5 9.2 9.5 17 85 63 20 15 13 82 26 48 43 15 17 14 13 13 632.7 20.4 85 8.6 1250 .49 .56 DATA 41.7 263 1966 5.19 1968 FOR 13 12 12 12 12 25 15 19 44 27 22 34 19 90 160 30 21 19 27 108 46 22 19 19 20 19 28 95 51 24 19 1083 34.9 160 12 2150 .84 .96 18 17 17 17 18 19 19 105 132 40 19 16 14 14 14 14 14 14 13 15 14 13 13 13 13 12 13 12 12 ___ --- 664 22.9 132 12 1320 .55 .59 FOR WATER YEARS 1964 34.6 159 1969 5.30 1968 21.7 75.3 1989 4.75 1965 12 12 12 12 14 13 12 12 12 12 13 12 11 11 15 19 11 11 11 10 9.9 9.4 9.3 8.9 9.0 9.3 10 9.0 9.1 8.6 8.4 347.9 11.2 19 8.4 690 .27 .31 - 1996 17.9 52.9 1990 3.58 1965 1995 CALENDAR YEAR 9091.9 24.9 823 2.6 3.2 18030 .60 8.09 44 10 5.0 Sep 6 May 1 Apr 29 8.1 7.8 112 61 26 18 16 14 14 14 14 20 17 14 14 16 15 14 13 13 14 16 23 18 14 13 13 13 13 13 --- 590.9 19.7 112 7.8 1170 .47 .53 13 13 12 12 12 12 14 14 15 14 14 12 12 12 12 13 13 13 14 14 13 13 23 14 14 16 30 21 13 13 13 443 14.3 30 12 879 .34 .39 13 13 13 16 18 16 17 15 15 16 15 21 18 14 e50 e40 34 e21 e!7 e!4 13 17 14 13 13 13 12 13 12 12 --- 528 17.6 50 12 1050 .42 .47 12 12 12 12 11 11 11 49 75 16 14 14 14 139 100 24 17 17 15 14 14 14 14 15 15 14 14 20 17 15 28 769 24.8 139 11 1530 .59 .68 19 24 19 17 17 16 15 15 15 15 15 14 14 44 35 287 56 28 20 20 20 19 74 52 27 24 23 43 26 23 22 1058 34.1 287 14 2100 .82 .94 23 23 25 43 29 25 23 34 73 8640 622 257 138 113 80 e66 e49 83 46 33 48 e36 e29 e27 29 29 44 e33 e34 e55 --- 10789 360 8640 23 21400 8.60 9.60 , BY WATER YEAR (WY) 21.7 72.7 1971 5.36 1965 FOR 1996 17705 48 8640 7 8 65000 29 35120 1 15 46 14 9 41.7 131 1966 4.85 1994 WATER YEAR .5 .4 Sep 10 .8 Apr 2 .7 Mar 27 Sep 10 .07 Sep 10 .16 .76 .3 19.7 60.8 1970 3.68 1994 22.4 46.6 1970 4.01 1994 WATER 33. 59. 10. 8640 2. 2. 65000 29. 24210 . 10. 56 13 4. 42.2 137 1970 7.47 1994 YEARS 1964 - 4 7 9 Sep 10 2 Apr 19 4 Apr 14 Sep 10 07 Sep 10 80 86 8 63.0 360 1996 6.02 1967 1996 1966 1994 1996 1965 1965 1996 1996 e Estimated 777 RIO DE BAYAMON BASIN 50047990 RIO GUAYNABO NEAR BAYAMON, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°22'32", long 66°07'59", at bridge on Highway 833, 0.2 mi (0.3 km) upstream from Rio de Bayamon, and 2.3 mi (3.7 km) southeast of Bayamon plaza. DRAINAGE AREA.--73.2 mi 2 (189.6 km 2 ). PERIOD OF RECORD.--Water years 1958, 1964, 1971-73, 1976, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 06... DEC 11... FEB 1996 07... APR 10... JUN 03.. . AUG 05... DATE OCT 1995 06. .. DEC 11. . . FEB 1996 07. .. APR 10. . . JUN 03. .. AUG 05. . . TIME 0840 0845 0830 1000 0915 0820 HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 170 -- -- 170 -- 94 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 438 370 395 444 490 456 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 47 -- -- 46 -- 26 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.4 7.0 6.9 7.2 7.1 7.2 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- -- 13 -- 7.0 TEMPER- ATURE WATER (DEG C) (00010) 26.0 24.5 23.0 25.5 27.0 26.5 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 28 -- -- 26 -- 17 TUR- BID- ITY (NTU) (00076) 4.5 13 28 2.5 3.5 84 SODIUM AD- SORP- TION RATIO (00931) 0.9 -- -- 0.9 -- 0.8 OXYGEN, DIS- SOLVED (MG/L) (00300) 6.4 4.2 4.6 4.2 4.3 4.1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.4 -- -- 4.0 -- 2.9 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 78 50 53 50 54 51 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 160 170 170 160 200 110 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 12 19 14 12 33 24 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 21000 43000 K660000 260 K8300 3000 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 13 -- -- 15 -- 8.4 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 6600 23000 38000 K170 650 520 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 31 -- -- 35 -- 20 K = non-ideal count. Discharge measurement values not available due to ponded conditions. 172 RIO DE BAYAMON BASIN 50047990 RIO GUAYNABO NEAR BAYAMON, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE NITRO- FLUO- RIDE, DIS- SOLVED (MG/L AS F) SILICA, DIS- SOLVED (MG/L AS SI02) SUM OF CONSTI- TUENTS , DIS- SOLVED (MG/L) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) NITRO- GEN, NITRATE TOTAL (MG/L AS N) NITRO- GEN, NITRITE TOTAL (MG/L AS N) NITRO- GEN, N02+N03 TOTAL (MG/L AS N) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00950) (00955) (70301) (00530) (00620) (00615) (00630) (00610) (00605) (00625) OCT 1995 06... <0.10 26 257 4 0.620 0.040 0.660 0.100 0.39 0.49 DEC 11... -- -- -- 26 0.910 0.060 0.970 0.190 0.39 0.58 FEB 1996 07... -- -- -- 58 0.730 0.070 0.800 0.120 0.44 0.56 APR 10... 0.20 0.60 236 10 0.580 0.040 0.620 0.180 0.48 0.66 JUN 03... -- -- -- 15 0.460 0.030 0.490 0.050 1.5 1.6 AUG 05... 0.10 17 164 118 0.740 0.020 0.760 0.050 0.47 0.52 NITRO- GEN, TOTAL (MG/L NITRO- GEN, TOTAL (MG/L PHOS- PHORUS TOTAL (MG/L ARSENIC TOTAL (UG/L BARIUM, TOTAL RECOV- ERABLE (UG/L BORON, TOTAL RECOV- ERABLE (UG/L CADMIUM TOTAL RECOV- ERABLE (UG/L CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L COPPER, TOTAL RECOV- ERABLE (UG/L IRON, TOTAL RECOV- ERABLE (UG/L AS N) AS N03) AS P) AS AS) AS BA) AS B) AS CD) AS CR) AS CU) AS FE) (00600) (71887) (00665) (01002) (01007) (01022) (01027) (01034) (01042) (01045) OCT 1995 06... 1.2 5.1 0.160 7 100 40 <1 <1 <10 320 DEC 11... 1.6 6.9 0.240 FEB 1996 07... 1.4 6.0 0.240 APR 10... 1.3 5.7 0.150 <1 100 30 <1 <1 10 390 JUN 03... 2.1 9.3 0.120 AUG 05... 1.3 5.7 0.110 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) OCT 1995 06... 5 170 <0.10 <1 <1 20 <0.010 1 0.04 DEC 11... FEB 1996 07... APR 10... <1 210 <0.10 <1 <1 <10 <0.010 <1 0,05 JUN AUG 05... 773 RIO DE BAYAMON BASIN 50048510 RIO DE BAYAMON AT FLOOD CHANNEL AT BAYAMON, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°24'29", long 66°09'04", at bridge on Highway 890, 1.0 mi (1.6 km) downstream from bridge on Highway 2, and 3.2 mi (5.1 km) above mouth. DRAINAGE AREA.--71.9 mi 2 (186.2 km 2 ). PERIOD OF RECORD.--Water years 1974 to current year. REMARKS.--Prior to 1979 sampling site was 0.8 mile (1.3 km) downstream but was changed because of flood channel construction. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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) OCT 1995 06.. . DEC 11... FEB 1996 07.. . APR 10.. . JUN 03. .. AUG 05.. . 1005 1035 1025 1125 1045 1140 13 21 61 37 16 127 465 422 372 425 460 294 7.4 7.1 7.2 7.5 7.3 7.5 27.5 25.0 24.0 28.0 27.5 27.5 5.2 11 29 4.6 4.4 160 6.8 5.0 6.9 7.0 7.7 5.7 86 60 81 87 97 71 10 12 14 10 <10 31 37000 58000 K60000 41000 40000 45000 7400 4300 23000 660 59000 44000 ALKA- HARD- MAGNE- SODIUM POTAS- LINITY CHLO- NESS CALCIUM SIUM, SODIUM, AD- SIUM, WAT WH SULFATE RIDE, TOTAL DIS- DIS- DIS- SORP- DIS- TOT FET SULFIDE DIS- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED FIELD TOTAL SOLVED SOLVED DATE AS (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS (MG/L (MG/L (MG/L CACO3) AS CA) AS MG) AS NA) AS K) CACO3 AS S) AS SO4) AS CD (00900) (00915) (00925) (00930) (00931) (00935) (00410) (00745) (00945) (00940) OCT 1995 06... 180 48 14 25 0.8 3.0 170 <0.5 16 32 DEC 11... -- -- -- -- -- -- 170 FEB 1996 07... -- -- -- -- -- -- 140 APR 10... 170 45 14 24 0.8 3.2 170 <0.5 15 32 JUN 03... -- -- -- -- -- -- 180 AUG 05... 110 28 8.6 18 0.8 3.5 120 -- 9.9 20 DATE OCT 1995 06... DEC 11... FEB 1996 07... APR 10... JUN 03... AUG 05... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- -- 0.20 -- 0.10 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 26 -- -- 27 -- 19 SOLIDS, SUM OF CONSTI- TUENTS , DIS- SOLVED (MG/L) (70301) 266 -- -- 262 -- 179 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 9.33 — -- 26.3 -- 61.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 5 15 32 10 13 180 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.410 0.460 0.630 0.460 0.280 0.460 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.050 0.050 0.030 0.030 0.040 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.450 0.510 0.680 0.490 0.310 0.500 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.290 0.470 0.250 0.100 0.040 0.110 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.37 0.32 0.37 0.39 0.49 0.58 K « non-ideal count 174 RIO DE BAYAMON BASIN 50048510 RIO DE BAYAMON AT FLOOD CHANNEL AT BAYAMON, PR—Continued HATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCX 1995 06... DEC 11. .. FEB 1996 07... APR 10.. . •TON 03. .. AUG 05... DATE OCT 1995 06. . . DEC 11. . . FEB 1996 07. .. APR 10. . . JUN 03. .. AUG 05.. . NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.66 0.79 0.62 0.49 0.53 0.69 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.3 1.3 0.98 0.84 1.2 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 4.9 5.8 5.8 4.3 3.7 5.3 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.120 0.180 0.130 0.090 0.060 0.240 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- — <1 -- — SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- — <100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 — — 30 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- — <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — — <1 — — PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- 10 -- — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 420 350 180 <0.10 <0.10 10 <0.010 <0.010 <1 PESTICIDE ANALYSES 0.04 CHLOR- DANE, P,P'- P,P'- ENDO- TECH- DDD DDT DI- 01- SULFAN, PCB, ALDRIN, NICAL UNFILT DDE, UNFILT AZINON, ELDRIN I DATE TIME TOTAL TOTAL TOTAL RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) JUN 1996 03... 1045 <0 ENDRIN WATER UNFLTRD DATE REC (UG/L) (39390) JUN 1996 03... <0.010 PARA- THION, DATE TOTAL (U6/L) (39540) JUN 1996 03... <0.010 .100 <0. ETHION, TOTAL (UG/L) (39398) <0.010 PCNS UNFILT RECOVER (U6/L) (39250) •eO.100 .010 <0, HEPTA- CHLOR, TOTAL (UG/L) (39410) <0.010 PER- THANE TOTAL (UG/L) (39034) •eO.100 .100 <0 HEPTA- CHLOR EPOXIDE TOTAL (UG/L) (39420) •eO.010 TOX- APHENE, TOTAL (UG/L) (39400) <1.00 .010 <0 LINDANE TOTAL (UG/L) (39340) <0.010 TOTAL TRI- THION (UG/L) (39786) <0.010 .010 <0 HALA- THION, TOTAL (UG/L) (39530) •eO.010 2,4-D, TOTAL (UG/L) (39730) 0.020 .010 0. METH- OXY- CHLOR, TOTAL (UG/L) (39480) <0.010 2,4,5-T TOTAL (UG/L) (39740) <0.010 .010 <0, METHYL PARA- THION, TOTAL (UG/L) (39600) <0.010 2, 4 -DP TOTAL (UG/L) (82183) <0.010 .010 <0.010 MIREX, TOTAL (UG/L) (39755) <0.010 SILVEX, TOTAL (UG/L) (39760) •eO.010 775 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR LOCATION.—Lat 18°21'51", long 66°03'56", Hydrologic Unit 21010005, on right bank, in the Riberas of Senorial Housing area, 0.6 mi (1.0 km) west of Highway 176 and 2.7 mi (4.3 km) southwest of Rio Piedras Plaza. DRAINAGE AREA.--7.49 mi 2 (19.40 km2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORDS.—March 1988 to current year. GAGE.—water-stage recorder. Elevation of gage is 98.4 ft (30.0 m), from topographic map. REMARKS.--Records poor. Low flow is affected by wastes water discharge from water treatment plant of PRASA and others dispersed pollution points directly to the river. 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 1.8 4.5 2 1.7 9.2 3 9.8 15 4 2.6 3.8 5 2.2 15 6 1.5 69 7 1.7 6.3 8 3.1 3.0 9 2.9 2.3 10 5.4 2.2 11 2.6 2.1 12 2.0 2.1 13 1.8 1.9 14 166 1.7 15 4.2 1.6 16 2.7 1.8 17 12 1.9 18 5.0 1.7 19 67 2.3 20 5.2 1.6 21 20 1.5 22 16 1.4 23 4.4 1.4 24 61 3.1 25 16 2.8 26 84 12 27 11 1.5 28 4.2 2.0 29 3.3 1.7 30 3.0 1.5 31 3.0 —— TOTAL 527.1 177.9 MEAN 17.0 5.93 MAX 166 69 MIN 1.5 1.4 AC-FT 1050 353 CFSM 2.27 .79 IN. 2.62 .88 STATISTICS OF MONTHLY MEAN MEAN 23.3 20.8 MAX 57.3 59.8 (WY) 1991 1993 MIN 8.48 5.93 (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 DEC 1.3 1.7 1.7 1.3 1.3 1.6 1.3 1.3 1.3 3.9 1.6 3.7 3.1 2.2 1.4 2.2 19 36 5.8 2.2 1.9 1.9 14 2.0 1.6 1.6 10 2.6 1.5 1.5 1.5 134.0 4.32 36 1.3 266 .58 .67 DATA 14.1 40.5 1993 4.32 1996 FOR JAN 1.4 1.4 1.3 1.3 1.5 7.5 1.8 23 26 74 8.4 12 2.4 106 23 2.9 2.3 2.5 6.0 5.4 2.3 1.9 1.7 2.4 8.2 1.8 9.3 18 3.9 2.0 1.6 363.2 11.7 106 1.3 720 1.56 1.80 FOR WATER 14.1 24.4 1992 6.95 1995 FEB 1.5 1.5 1.6 1.5 1.4 2.7 1.2 1.3 9.6 1.6 1.5 1.4 1.4 1.4 1.3 1.4 1.3 1.3 1.6 2.9 8.6 9.8 4.7 8.3 2.3 1.4 1.3 1.2 1.2 ___ --- 78.2 2.70 9.8 1.2 155 .36 .39 YEARS 1988 12.1 23.6 1991 2.70 1996 MAR 1.2 1.1 1.2 1.3 3.0 1.3 1.2 1.3 1.4 1.2 2.4 1.1 1.1 1.1 14 1.3 1.2 1.3 1.6 1.2 1.2 1.3 1.2 1.3 1.3 1.5 2.7 1.7 1.5 1.5 1.6 57.3 1.85 14 1.1 114 .25 .28 - 1996 10.7 19.5 1990 1.85 1996 1995 CALENDAR YEAR 4166. 11. 321 . 1. 8270 1. 20. 25 2. 1. 91 4 Sep 6 84 Aug 13 1 Aug 7 52 70 7 5 APR 1.6 1.6 102 9.5 6.9 9.9 3.0 2.5 2.4 2.3 2.3 6.1 2.7 2.4 2.8 2.6 45 3.0 1.7 1.7 3.8 3.1 3.5 2.1 1.9 2.1 1.7 2.9 1.9 4.8 --- 239.8 7.99 102 1.6 476 1.07 1.19 MAY 1.6 1.5 1.7 1.7 1.8 1.7 11 5.4 11 2.5 53 3.5 3.0 2.1 3.2 2.6 2.8 2.5 30 3.6 2.4 2.5 2.8 2.1 2.0 3.7 1.6 1.6 1.6 1.5 1.5 169.5 5.47 53 1.5 336 .73 .84 JUN 1.5 1.4 1.3 1.6 2.6 1.4 1.3 1.3 1.1 3.1 2.9 3.5 1.5 1.5 28 16 1.5 153 5.2 1.9 1.5 1.3 1.2 1.1 1.0 1.1 3.0 1.0 1.1 1.1 —— 245.0 8.17 153 1.0 486 1.09 1.22 JUL 1.0 .97 .94 .92 .94 .95 1.4 27 2.6 1.7 2.0 2.6 2.2 8.2 5.8 2.0 1.8 1.6 1.6 1.5 1.5 1.6 1.5 2.1 2.1 1.7 1.6 66 4.8 2.4 3.3 156.32 5.04 66 .92 310 .67 .78 AUG 2.5 58 4.6 2.3 5.1 1.6 1.8 1.8 1.7 17 11 9.1 8.5 13 8.4 73 4.8 4.6 4.4 62 4.2 2.4 75 33 5.4 3.5 3.0 3.2 3.3 3.0 2.5 433.7 14.0 75 1.6 860 1.87 2.15 SEP 2.2 2.1 4.7 9.4 7.4 3.1 2.7 3.8 39 1650 110 14 8.2 7.3 12 9.9 76 42 12 11 10 9.4 8.8 9.9 15 14 15 15 13 17—— 2153.9 71.8 1650 2.1 4270 9.59 10.70 , BY WATER YEAR (WY) 12.4 23.9 1993 2.83 1995 FOR 1996 4735 12 1650 5390 15 9390 1 23 16 2 1 15.3 47.2 1992 3.38 1994 WATER YEAR .92 .9 Sep 10 .92 Jul 4 .97 Jun 30 Sep 10 .46 Sep 10 .73 .52 .3 .3 12.1 24.8 1989 2.66 1994 15.1 38.0 1993 4.22 1994 WATER 16 24 7 1650 5390 15 11930 2 29 35 7 2 21.5 66.9 1992 6.60 1990 YEARS 1988 .5 .1 .76 Sep . 84 Aug .97 Jun Sep .46 Sep .20 .86 .1 .2 28.9 71.8 1996 6.90 1991 - 1996 1993 1994 10 1996 13 1995 30 1996 10 1996 10 1996 176 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1988 to current year. PERIOD OF DAILY RECORD. — SUSPENDED-SEDIMENT DISCHARGE: April 1988 to currant year. INSTRUMENTATION.-- Automatic sediment sampler since 1988. REMARKS. — During high flow sadiment samples war* collacted by automatic sadimant sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATION: Maximum daily mean, 24,600 mg/L Sap. 18, 1989; Minimum daily mean, 2 mg/L November 18, 1988. SEDIMENT LOADS: Maximum daily mean, a!14,000tons (al03,000tonnas) Sep. 18, 1989; Minimum daily mean, 0.02 ton (0.02 tonne) June 9, 1994. EXTREMES FOR CURRENT YEAR 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 6,940 mg/L September 10, 1996; Minimum daily mean, 7 mg/1 December 01, 1995. 1996; Minimum daily mean, SEDIMENT DISCHARGE, SUSPENDED ( TONS / DAY ), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SEDIMENT LOADS: Maximum daily mean, 34,800 tons (31,600 tonnes) September 10 0.03 ton (0.02 tonne) several days. (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) 1.8 1.7 9.8 2.6 2.2 1.5 1.7 3.1 2.9 5.4 2.6 2.0 1.8 166 4.2 2.7 12 5.0 67 5.2 20 16 4.4 61 16 84 11 4.2 3.3 3.0 3.0 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 18 20 113 31 28 18 17 36 34 68 35 25 22 884 50 61 142 60 610 61 181 120 51 712 178 761 123 52 40 37 37 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN DISCHARGE (CFS) MEAN ___ CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) .08 .09 11 .23 .22 .07 .08 .57 .99 3.8 .36 .14 .11 2190 .61 .61 18 1.4 542 1.3 67 21 .66 233 15 782 5.1 .60 .36 .30 .31 4.5 9.2 15 3.8 15 69 6.3 3.0 2.3 2.2 2.1 2.1 1.9 1.7 1.6 1.8 1.9 1.7 2.3 1.6 1.5 1.4 1.4 3.1 2.8 12 1.5 2.0 1.7 1.5 57 109 164 46 173 697 56 21 15 14 14 14 13 13 12 20 19 18 27 20 19 17 16 38 35 110 26 25 20 11 1.9 7.2 9.7 .49 26 460 1.1 .17 .10 .09 .08 .08 .07 .06 .05 .10 .10 .08 .19 .08 .08 .07 .06 .48 .36 43 .11 .14 .09 .05 1.3 1.7 1.7 1.3 1.3 1.6 1.3 1.3 1.3 3.9 1.6 3.7 3.1 2.2 1.4 2.2 19 36 5.8 2.2 1.9 1.9 14 2.0 1.6 1.6 10 2.6 1.5 1.5 1.5 7 20 23 19 17 25 23 20 18 44 21 42 37 27 18 30 171 360 68 27 23 21 132 25 20 19 117 30 19 19 18 .02 .09 .12 .06 .06 .12 .08 .07 .07 .94 .09 1.3 .38 .24 .07 .20 54 139 1.5 .16 .12 .11 28 .14 .08 .08 20 .35 .08 .07 .07 TOTAL 527.1 3896.99 177.9 552.08 134.0 247.67 777 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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) 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 1.4 1.4 1.3 1.3 1.5 7.5 1.8 23 26 74 8.4 12 2.4 106 23 2.9 2.3 2.5 6.0 5.4 2.3 1.9 1.7 2.4 8.2 1.8 9.3 18 3.9 2.0 1.6 17 16 15 14 17 87 24 225 239 664 97 138 29 1030 236 13 7 18 62 64 28 24 20 29 93 24 109 217 43 23 19 .06 .06 .05 .05 .07 3.3 .12 46 153 1090 5.0 10 .19 1160 43 .10 .04 .17 6.8 2.2 .18 .12 .10 .21 6.2 .12 5.9 18 .72 .12 .08 FEBRUARY 1.5 1.5 1.6 1.5 1.4 2.7 1.2 1.3 9.6 1.6 1.5 1.4 1.4 1.4 1.3 1.4 1.3 1.3 1.6 2.9 8.6 9.8 4.7 8.3 2.3 1.4 1.3 1.2 1.2 ___ —— 19 18 18 18 17 35 14 10 87 21 20 19 18 18 17 17 16 16 20 31 73 94 53 93 28 19 18 17 16 ... —— .08 .08 .08 .07 .07 .44 .05 .04 18 .09 .08 .07 .07 .07 .06 .06 .05 .05 .11 .85 15 18 2.7 5.2 .19 .07 .06 .06 .05 —— 1.2 1.1 1.2 1.3 3.0 1.3 1.2 1.3 1.4 1.2 2.4 1.1 1.1 1.1 14 1.3 1.2 1.3 1.6 1.2 1.2 1.3 1.2 1.3 1.3 1.5 2.7 1.7 1.5 1.5 1.6 MEAN CONCEN- S TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 16 15 14 13 35 17 16 15 14 14 27 14 13 14 163 19 18 18 17 12 10 9 9 9 8 16 70 42 34 28 23 .05 .05 .05 .05 .62 .06 .05 .05 .05 .05 .41 .04 .04 .04 41 .06 .06 .06 .08 .04 .03 .03 .03 .03 .03 .07 .90 .20 .13 .11 .09 TOTAL 363.2 2551.96 78.2 61.80 57.3 44.56 178 RIO PUERTO NOEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MQ/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 1.6 1.6 102 9.5 6.9 9.9 3.0 2.5 2.4 2.3 2.3 6.1 2.7 2.4 2.8 2.6 45 3.0 1.7 1.7 3.8 3.1 3.5 2.1 1.9 2.1 1.7 2.9 1.9 4.8 —— APRIL 18 15 1150 110 79 115 32 21 14 10 9 67 35 32 34 31 480 23 11 10 42 37 41 26 23 25 21 34 25 53 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY .08 .07 2500 8.9 4.1 26 .26 .14 .09 .06 .05 1.5 .25 .21 .26 .22 405 .21 .05 .05 .69 .36 .43 .14 .12 .15 .10 .43 .13 3.0 —— 1.6 1.5 1.7 1.7 1.8 1.7 11 5.4 11 2.5 53 3.5 3.0 2.1 3.2 2.6 2.8 2.5 30 3.6 2.4 2.5 2.8 2.1 2.0 3.7 1.6 1.6 1.6 1.5 1.5 16 12 10 9 9 8 113 65 122 31 524 42 38 23 37 32 34 32 495 42 27 22 35 30 27 44 18 14 12 11 10 .07 .05 .05 .04 .04 .04 12 2.9 9.7 .21 434 .42 .40 .13 .47 .23 .34 .21 187 .44 .18 .15 .29 .18 .14 1.7 .08 .06 .05 .05 .04 1.5 1.4 1.3 1.6 2.6 1.4 1.3 1.3 1.1 3.1 2.9 3.5 1.5 1.5 28 16 1.5 153 5.2 1.9 1.5 1.3 1.2 1.1 1.0 1.1 3.0 1.0 1.1 1.1 —— JUNE 10 9 9 15 30 18 17 16 15 37 37 40 19 18 834 178 19 1050 61 21 18 15 12 10 9 11 32 13 12 11 —— .04 .03 .03 .10 .40 .07 .06 .05 .05 1.3 .96 .57 .08 .15 488 34 .09 1740 1.2 .11 .07 .05 .04 .03 .02 .04 1.9 .04 .03 .03 —— TOTAL 239.8 2953.05 169.5 651.66 245.0 2269.54 179 RIO PUERTO NUEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN 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) 1.0 .97 .94 .92 .94 .95 1.4 27 2.6 1.7 2.0 2.6 2.2 8.2 5.8 2.0 1.8 1.6 1.6 1.5 1.5 1.6 1.5 2.1 2.1 1.7 1.6 66 4.8 2.4 3.3 156.32 4735.92 MEAN CONCEN- TRATION (MG/L) JULY 11 11 11 11 10 10 19 267 102 49 37 33 27 92 67 27 26 24 23 22 21 20 19 25 28 22 20 1000 89 50 43 —— SEDIMENT DISCHARGE (TONS/DAY) .03 .03 .03 .03 .03 .03 .12 50 .79 .22 .20 .47 .20 3.4 3.7 .14 .13 .11 .10 .09 .08 .08 .08 .18 .22 .10 .08 889 1.3 .32 .48 951.77 53484.04 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST MEAN 2.5 58 4.6 2.3 5.1 1.6 1.8 1.8 1.7 17 11 9.1 8.5 13 8.4 73 4.8 4.6 4.4 62 4.2 2.4 75 33 5.4 3.5 3.0 3.2 3.3 3.0 2.5 30 851 53 28 55 15 15 22 20 242 122 105 103 142 97 686 55 53 55 814 51 33 980 345 61 40 37 35 34 32 30 .20 600 .79 .19 2.9 .06 .10 .11 .09 72 6.4 14 14 18 3.1 424 .76 .82 .78 759 .63 .34 634 101 .94 .38 .30 .31 .30 .24 .21 MEAN SCHARGE ICFS) CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) SEPTEMBER 2.2 2.1 4.7 9.4 7.4 3.1 2.7 3.8 39 1650 110 14 8.2 7.3 12 9.9 76 42 12 11 10 9.4 8.8 9.9 15 14 15 15 13 17 29 27 52 110 85 35 33 45 396 6940 1190 160 109 108 134 103 644 460 145 136 130 124 119 114 174 157 156 163 144 179 .17 .16 1.5 12 2.8 .30 .26 .52 233 34800 605 6.6 2.4 2.1 6.4 2.9 753 155 4.8 3.9 3.5 3.2 2.8 3.0 8.4 5.9 6.3 6.6 5.2 9.3 433.7 2655.95 2153.9 36647.01 180 RIO PUERTO NDEVO BASIN 50048770 RIO PIEDRAS AT EL SENORIAL, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT APR 1996 03... JUN 15... 18... AUG 02... 20... DATE APR 1996 03... JUN 15... 18... AUG 02... 20... TIME 1545 1640 1430 1615 1515 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 56 66 48 62 51 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1600 286 1040 356 970 SED. SUSP. FALL DIAM. Ss FINER THAN .031 MM (70330) 66 76 62 75 60 SEDI- MENT, SUS- PENDED (MG/L) (80154) 14800 6320 8210 9660 9890 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 80 95 76 91 77 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 63900 4880 23100 9290 25900 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 88 98 87 97 87 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 28 29 20 26 28 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 94 99 94 99 94 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 34 42 28 38 34 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 100 100 100 98 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 42 48 36 44 43 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 99 181 RIO PUERTO NOEVO BASIN 50048770 RZO PIEDRAS AT EL SENORIAL, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 14... 24... APR 1996 03... JUN 15... 18... AUG 02... 23... TIME 1615 1030 1830 1730 1815 1832 1830 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 2600 92 SEDI- MENT, SUS- PENDED (MG/L) (80154) 5110 1400 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 35900 348 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 74 98 170 168 211 174 192 1230 8030 1110 3120 3060 565 3640 632 1470 1590 82 97 88 95 91 182 RIO PUERTO NUEVO BASIN 50048800 RIO PIEDRAS NEAR RIO PIEDRAS, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°22'15 H , long 66°03'40", at bridge on Winston Churchill Avenue in the El Senorial Housing area, 0.5 mi (0.8 km) west of Highway 176, and 2.5 mi (4.0 km) southwest of Rio Piedras plaza. DRAINAGE AREA.--8.17 mi 2 (20.9 km2 ). PERIOD OF RECORD.--Water years 1972 to current year. WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 1995 20... 0845 17 363 7.1 24. 4.0 6.8 81 95 340000 52000 JAN 1996 12... 0745 E12 218 7.0 23.0 710 7.6 87 78 310000 66000 FEB 22... 0825 6.8 455 7.3 21.5 1.0 5.5 61 31 K740000 K93000 APR 15... 0835 5.6 452 6.9 22.5 1.0 4.2 48 24 K17000 4400 JUN 03... 0800 4.4 485 7.0 25.0 0.60 2.4 29 24 63000 7100 AUG 19... 1030 9.8 421 7.2 26.0 16 4.3 53 31 290000 K140000 ALKA- DATE OCT 1995 20.. . JAN 1996 12. .. FEB 22. .. APR 15. .. JUN 03. .. AUG 19. .. DATE OCT 1995 20... JAN 1996 12... FEB 22... APR 15... JUN 03... AUG 19... HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 140 -- -- 160 __ 140 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- -- 0.20 -_ 0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 35 -- -- 42 -- 36 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 26 -- -- 32 -- 29 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 12 -- -- 13 -- 12 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 222 -- -- 264 -_ 253 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 24 -- -- 28 -- 27 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 10.4 — _- 3.98 _- 6.71 SODIUM AD- SORP- TION RATIO (00931) 0.9 -- __ 1 __ 1 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 1370 20 2 7 19 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.0 _- -- 3.3 -- 3.6 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.850 0.720 0.750 0.480 0.080 0.370 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 120 80 160 160 160 160 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.050 0.070 0.060 0.030 0.040 0.010 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- ~~ NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.900 0.790 0.810 0.510 0.120 0.380 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 18 — -- 16 __ 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 2.20 0.570 4.40 2.20 2.80 0.040 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 30 -- -- 34 -- 31 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.80 2.9 0.70 0.40 0.90 0.22 E » estimated K » non-ideal count DATE OCT 1995 20.. . JAN 1996 12... FEB 22... APR 15... JUN 03... AUG 19... OCT 1995 20. .. JAN 1996 12.. . FEB 22.. . APR 15... JUN 03.. . AUG 19... JUN 1996 03.. . 183 RIO PUERTO NUEVO BASIN 50048800 RIO PIEDRAS NEAR RIO PIEDRAS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 3.0 3.5 5.1 2.6 3.7 0.26 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 3.9 4.3 5.9 3.1 3.8 0.64 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 17 19 26 14 17 2.8 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.300 0.280 0.520 0.280 0.500 0.100 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- -- 2 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 -- -- 30 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 540 300 300 <0.10 <0.10 <0.010 <1 <1 <1 <1 PCB, (UG/L) PESTICIDE ANALYSES CHLOR- DANE, P,P'- TECH- ODD ALDRIN, NICAL UNFILT TOTAL TOTAL (UG/L) (UG/L) RECOVER (UG/L) DDE, TOTAL P,P'- DDT UNFILT RECOVER (UG/L) (UG/L) DI- AZINON, TOTAL (UG/L) TOTAL (UG/L) 0.16 ENDO- DI- SULFAN, ELDRIN I TOTAL (UG/L) (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) 0800 <0.100 <0.010 <0.100 <0.010 <0.010 0.030 <0.010 <0.010 DATE JUN 1996 03... ENDRIN WATER UNFLTRD REC (UG/L) (39390) <0.010 ETHION, TOTAL (UG/L) (39398) <0.010 HEPTA- CHLOR, TOTAL (UG/L) (39410) <0.010 HEPTA- CHLOR EPOXIDE TOTAL (UG/L) (39420) <0.010 LINDANE TOTAL (UG/L) (39340) <0.010 MALA- THION, TOTAL (UG/L) (39530) <0.010 METH- OXY- CHLOR, TOTAL (UG/L) (39480) <0.010 METHYL PARA- THION, TOTAL (UG/L) (39600) <0.010 MI REX, TOTAL (UG/L) (39755) <0.010 DATE JUN 1996 03... PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (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) 0.020 <0.010 <0.010 <0.010 184 RIO PUERTO NUEVO BASIN 50049100 RIO PZEDRAS AT HATO REY, PR LOCATION.—Lat 18°24'34 H , long 66°04'10 H , Hydrologic Unit 21010005, at bridge on Avenida Pineiro near Expreso Las Americas (Luis A. Ferre), and 0.8 mi (1.3 km) southwest of Hato Rey. DRAINAGE AREA.--15.4 mi" (39.9 km*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—June 1970 to December 1987 (discharge measurements only), 1972 to December 1982 (maximum discharge only), January 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 16 ft (5 m), from topographic map. REMARKS.—Records fair except those for estimated daily discharges, which are poor. Mean daily discharge affected by sewage discharges (approximately 2.0 ftVs (0.06 mVs)), 20 ft (6 m) upstream from gaging station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC APR AUG SEP 1 57 54 2 67 90 3 76 122 4 102 26 5 71 128 6 40 324 7 36 61 8 41 30 9 42 26 10 84 21 11 40 21 12 31 18 13 27 15 14 513 15 15 93 13 16 64 15 17 116 23 18 34 14 19 209 17 20 30 13 21 51 13 22 67 13 23 26 12 24 173 95 25 85 17 26 369 159 27 284 33 28 49 34 29 24 23 30 19 37 31 20 - — TOTAL 2940 1482 MEAN 94.8 49.4 MAX 513 324 MIN 19 12 AC -FT 5830 2940 CFSM 6.24 3.25 IN. 7.20 3.63 STATISTICS OF MONTHLY MEAN MEAN 67.4 74.1 MAX 134 235 (WY) 1991 1993 MIN 16.6 23.9 (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 ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 16 15 19 14 14 18 14 13 33 26 15 51 39 26 16 32 90 189 77 33 32 25 58 25 17 14 39 46 14 13 12 1045 33.7 189 12 2070 2.22 2.56 DATA 48.7 168 1993 18.8 1992 FOR 11 10 10 10 17 60 16 87 194 432 137 70 37 238 142 71 32 31 88 53 35 27 23 40 86 36 138 e270 e80 e37 e27 2545 82.1 432 10 5050 5.40 6.23 e24 e23 e25 e25 e20 e30 e!9 e21 e42 21 17 15 13 13 13 13 33 15 33 22 37 47 43 52 e20 e!4 e!3 e!2 ell —— —— 686 23.7 52 11 1360 1.56 1.68 FOR WATER YEARS 1972 45.3 97.4 1993 12.9 1973 39.9 86.9 1995 10.8 1992 ell elO ell e!3 e27 e!2 ell e!2 e!3 ell e22 elO elO elO e!26 e20 e!2 e!4 e21 e23 e!2 ell e9.7 e!2 e!2 e34 e40 e!7 e!4 e!4 e!4 588.7 19.0 126 9.7 1170 1.25 1.44 - 1996 38.2 78.5 1972 11.5 1994 1995 CALENDAR YEAR 23854 65 1170 4 6 47310 4 58 133 23 7 .3 .4 Sep 6 .7 May 11 .7 Apr 28 .30 .38 .6 e!2 e9.5 0550 e248 el!7 e!27 e34 e25 el 6 e!4 el 6 e!07 e!9 e!2 e!3 11 153 59 12 10 25 25 36 27 12 13 11 18 21 59—— 1811.5 60.4 550 9.5 3590 3.97 4.43 , BY WATER 60.3 150 1972 13.6 1995 13 12 17 13 17 25 90 148 165 51 305 99 152 58 47 42 61 30 111 56 30 30 51 26 22 28 20 20 16 14 13 1782 57.5 305 12 3530 3.78 4.36 YEAR (WY) 46.3 97.5 1992 4.12 1972 14 17 12 17 30 27 14 13 9.9 29 87 41 16 33 121 135 25 300 64 27 21 18 18 17 15 22 196 21 29 16 --- 1404.9 46.8 300 9.9 2790 3.08 3.44 44.1 81.9 1995 20.0 1994 FOR 1996 WATER YEAR 26065.1 71.2 4550 9.5 11 10500 22.11 51700 4.69 63.79 137 27 12 Sep 10 Apr 2 Dec 29 Sep 10 Sep 10 15 14 12 12 12 12 23 215 37 19 12 15 19 164 41 13 17 32 31 13 12 12 13 24 186 59 14 507 91 38 40 1724 55.6 507 12 3420 3.66 4.22 47.8 97.4 1993 12.8 1994 WATER 54 84 28 4550 1 1 10500 22 39180 3 48 121 22 9 41 124 59 24 54 16 21 18 15 83 51 130 66 84 81 222 57 23 53 285 65 34 314 136 43 31 20 e21 622 620 e!8 2231 72.0 314 15 4430 4.73 5.46 54.9 84.2 1988 20.2 1993 YEARS 1972 .1 .0 .7 Sep .2 Jun .2 Jul Sep . 11 Sep .56 .34 .4 14 13 150 99 35 17 16 39 e!28 64550 6623 e226 e52 e47 e76 e64 e470 e250 e76 670 664 660 656 662 694 690 696 696 682 ellO —— 7825 261 4550 13 15520 17.2 19.15 92.2 261 1996 26.3 1972 - 1996 1993 1994 10 1996 28 1972 5 1972 10 1996 10 1996 e Estimated 185 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO KEY, PR WATER-QUALITY RECORDS LOCATION.—Lat 18°24'34", long 66°04'10", at bridge on Avenida Piniero at Expreso Las Americas, and 0.8 mi (1.3 km) southwest of Hato Rey. DRAINAGE AREA.—15.4 mi 2 (39.9 km») . PERIOD OF RECORD.—Water years 1971 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 27... JAN 1996 12... FEB 22... APR 15... JUN 13... AU6 19... OCT 27 JAN 12 FEB 22 APR 15 JUN 13 AUG 19 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) (DEG C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1410 24 408 7.3 28.0 230 6.8 83 24 580000 40000 1045 55 275 6.8 24.0 370 6.8 79 39 390000 42000 0950 14 426 7.4 23.5 4.8 5.3 61 18 K150000 56000 1030 12 480 7.1 25.0 1.3 5.4 64 23 43000 20000 1110 12 414 7.0 30.0 1.8 4.2 55 28 86000 35000 1240 23 341 7.5 29.5 19 5.4 70 30 440000 270000 ALKA- HARD- NESS TOTAL (MG/L DATE AS CACO3 ) (00900) 1995 130 1996 . . . 160 120 non-ideal count CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 -- -- 47 -- 35 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 8.8 -- -- 11 -- 8.4 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 21 -- -- 30 -- 21 SODIUM AD- SORP- TION RATIO (00931) 0.8 -- -- 1 0.8 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.8 -- -- 3.7 -- 3.5 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 140 100 150 180 150 120 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- 1.0 -- -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 16 -- -- 15 -- 12 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 23 -- -- 37 23 186 RIO PUERTO NUEVO BASIN 50049100 RIO PIEDRAS AT HATO KEY, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE OCT 1995 27.. . JAN 1996 12.. . FEB 22... APR 15... JUN 13.. . AU6 19... OCT 1995 27 ... JAN 1996 12. .. FEB 22. .. APR 15. .. JUN 13... AUG 19.. . OCT 1995 27... JAN 1996 12.. . FEB 22... APR 15.. . JUN 13... AU6 19... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 -- — 0.10 -- 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 2.6 2.1 1.4 1.7 2.1 1.7 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 18 -- -- 30 -- 21 NITRO- GEN, TOTAL (MG/L AS N) (00600) 3.6 2.9 2.5 2.6 3.0 2.5 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 201 -- -- 282 -- 196 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 16 13 11 11 13 11 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 13.3 -- -- 9.20 -- 12.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.520 0.230 0.240 0.220 0.330 0.280 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 320 468 19 3 9 26 ARSENIC TOTAL (UG/L AS AS) (01002) 2 -- -- 2 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.910 0.690 0.910 0.610 0.680 0.690 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 200 -- -- <100 — -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.090 0.090 0.190 0.260 0.180 0.130 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- -- 50 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.00 0.780 1.10 0.870 0.860 0.820 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.780 0.560 0.980 1.30 1.60 0.930 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 10 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.8 1.5 0.42 0.40 0.50 0.77 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 70 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 16000 320 46 <1 850 240 <0.10 <0.10 200 <1 <0.010 <0.010 <1 0.04 0.20 187 RIO PUERTO NUEVO BASIN 50049820 LACUNA SAN JOSE NO. 2 AT SAN JUAN, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°25'46 M , long 66°02'10 M , 0.2 mi (0.3 km) east of Cafio de Martin Pefia, and 650 ft (200 m) south of Isla Guachinango. DRAINAGE AREA.--Indeterminate. PERIOD OF RECORD.--Water years 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE FEB 1996 01... MAR 04... APR 26... JUN "2.1 ... AUG 30.. . TIME 0920 1000 1120 0945 1000 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 18700 27400 24200 21500 16500 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.1 7.4 8.1 7.4 8.3 TEMPER- ATURE WATER (DEC C) (00010) 24.5 26.5 28.0 29.5 31.0 TRANS- PAR- ENCY (SECCHI DISK) (IN) (00077) 36.0 36.0 21.0 35.0 18.0 OXYGEN, DIS- SOLVED (MG/L) (00300) 3.4 2.3 8.2 5.1 6.9 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 43 31 112 66 97 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 2800 K7400 K7300 5800 3500 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) K130000 300 410 2400 K20 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 72 130 130 86 67 RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) 8 4 27 14 11 DATE FEB 1996 01. . . MAR 04. .. APR 26.. . JUN 27. .. AUG 30. . . NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.030 <0.010 <0.010 <0.010 0.010 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.030 0.010 0.010 <0.010 0.090 NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.060 <0.020 <0.020 <0.020 0.100 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.960 0.830 0.320 1.20 0.82 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.84 0.77 2.5 1.5 1.1 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 1.8 1.6 2.8 2.7 1.9 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 1.6 2.8 2.7 2.0 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 8.2 7.1 12 12 8.9 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.100 0.210 0.360 0.310 0.180 CARBON, ORGANIC TOTAL (MG/L AS C) (00680) 6.5 7.4 12 8.9 8.3 non-ideal count 188 RIO PUERTO NUEVO BASIN 50049920 BAHIA DE SAN JUAN NO. 5 AT SAN JUAN, PR WATER-QUALITY RECORDS LOCATION—Lat 18°26'37", long 66°05'11", 0.4 mi (0.6 km) west of Puente de la Constitucion, and 0.5 mi (0.8 km) south from U.S. Naval Reservation. DRAINAGE—Indeterminate. PERIOD OF RECORD—Water years 1974 to present. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PH OXYGEN, COLI- ALKA- RESIDUE SPE- WATER TRANS- DIS- FORM, STREP- LINITY TOTAL CIFIC WHOLE PAR- SOLVED FECAL, TOCOCCI WAT WH AT 105 CON- FIELD TEMPER- ENCY OXYGEN, (PER- 0.45 FECAL, TOT FET DEG. C, DUCT- (STAND- ATURE (SECCHI DIS- CENT UM-MF (COLS. FIELD SUS- DATE TIME ANCE ARD WATER DISK) SOLVED SATUR- (COLS./ PER MG/L AS FENDED (US/CM) UNITS) (DEG C) (IN) (MG/L) ATION) 100 ML) 100 ML) CACO3 (MG/L) (00095) (00400) (00010) (00077) (00300) (00301) (31616) (31679) (00410) (00530) NOV 1995 09... 0855 48000 7.1 28.0 32.0 4.7 59 K630000 19000 150 37 JAN 1996 18... 0950 39500 7.8 27.0 44.0 6.8 83 600000 380000 150 32 FEB 27... 1015 44500 7.8 26.5 39.0 7.5 92 36000 28000 140 9 APR 24... 1045 36500 7.8 27.0 32.0 4.8 67 39000 K1400 140 23 JUN 26... 1120 32000 7.1 29.0 14.4 2.4 31 530000 310000 150 29 AUG 27... 1045 50000 7.4 29.5 24.0 5.2 68 280000 2600 140 9 NITRO- DATE NOV 1995 09... JAN 1996 18... FEB 27... APR 24... JUN 26... AUG 27... NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.300 <0.010 <0.010 0.100 0.040 0.060 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.100 0.010 0.040 0.070 0.060 0.040 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.400 <0.020 0.040 0.170 0.100 0.100 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 1.40 3.00 1.90 1.30 0.99 1.1 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.3 1.4 0.70 0.70 0.80 0.30 GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 2.7 4.4 2.6 2.0 0.50 1.4 NITRO- GEN, TOTAL (MG/L AS N) (00600) 3.1 4.4 2.6 2.2 0.60 1.5 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 14 20 12 9.6 2.7 6.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.370 0.410 0.330 0.920 0.300 0.340 CARBON, ORGANIC TOTAL (MG/L AS C) (00680) 4.6 8.6 7.3 5.9 8.4 7.2 k-non-ideal count ATLANTIC trj^g uuu*t 05539£L2lf s ^ LAS v . >-.---', O^ P!EDRAS-|\^ ^/Vl.0 AMon *u.| - - J- y- - v "•" SURFACE-WATER STATION 0509 AND NUMBER QUALITY-OF-WATER STATION NUMBER vy QUALITY-OF-WATER PARTIAL V 0575 RECORD STATION AND NUMBER 0564 DAILY SEDIMENT STATION AND NUMBER » ——"~ MINU INUIVlDCn 01 23456 KILOMETERS ^ 222 WELL AND WELL NUMBER I———Li I i _u • , f ^ j ^ LAKE-ELEVATION STATION 01234 • AND NUMBER 189 Figure 20.--R(o Grande de Loiza basin. 190 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 km*). PERIOD OF RECORD.--Water years 1973 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 11 JAN 24 FEB 21 APR 24 JUN 17 AUG 21 DATE 1995 . . . 1996 . . . DATE OCT 1995 11. . . JAN 1996 24. .. FEB 21. . . APR 24 ... JUN 17 ... AUG 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) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) 1215 7.3 482 6.6 27.0 1.7 0930 8.3 410 7.2 23.0 2.4 1115 6.1 460 7.4 24.5 1.8 1305 15 416 7.2 25.5 2.7 1130 5.6 433 7.0 23.5 1.7 1145 10 374 7.0 27.0 4.7 HARD- MAGNE- SODIUM POTAS- NESS CALCIUM SIUM, SODIUM, AD- SIUM, TOTAL DIS- DIS- DIS- SORP- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED AS (MG/L (MG/L (MG/L RATIO (MG/L CACO3) AS CA) AS MG) AS NA) AS K) (00900) (00915) (00925) (00930) (00931) (00935) 160 51 8.9 26 0.9 3.5 _- __ 150 46 7.9 26 0.9 3.1 __ 150 49 7.1 19 0.7 3.4 3.2 5.0 4.9 4.3 3.7 6.2 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 170 140 190 150 170 140 40 14 45000 8800 57 15 37000 39000 58 12 2900 3700 52 40 310000 47000 43 26 28000 6200 77 21 38000 24000 CHLO- SULFATE RIDE, SULFIDE DIS- DIS- TOTAL SOLVED SOLVED (MG/L (MG/L (MG/L AS S) AS SO4) AS CL) (00745) (00945) (00940) <0.5 9.8 32 _ _ __ <0.5 14 32 __ 12 30 RIO GRANDE DE LOIZA BASIN 50050300 QUEBRADA BLASINA NEAR CAROLINA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 191 SOLIDS, RESIDUE DATE OCT 1995 11. . . JAN 1996 24... FEB 21. . . APR 24... JUN 17... AUG 21... DATE OCT 1995 11. . . JAN 1996 24.. . FEB 21. . . APR 24.. . JUN 17... AUG 21. . . DATE OCT 1995 11. . . JAN 1996 24... FEB 21... APR 24... JUN 17... AUG 21... 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 1.9 0.87 1.5 2.7 0.61 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 23 -- — 22 -- 18 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.3 3.3 2.0 2.4 3.5 1.8 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 256 — — 241 -- 222 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 10 15 8.7 11 16 8.0 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.03 — — 9.76 -- 6.11 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.170 0.150 0.190 0.300 0.240 0.100 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 11 11 15 18 2 15 ARSENIC TOTAL (UG/L AS AS) (01002) 5 -- -- <1 -- — SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.03 1.20 0.930 0.720 0.690 1.09 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.170 0.200 0.170 0.160 0.160 0.110 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- -- 60 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, N02+NO3 TOTAL (MG/L AS N) (00630) 1.20 1.40 1.10 0.880 0.850 1.20 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.600 0.670 0.560 0.960 1.00 0.380 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- — <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.50 1.2 0.31 0.54 1.7 0.23 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 390 660 180 <0.10 <0.10 <1 <1 10 20 <0.010 <0.010 <1 0.08 0.24 192 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR JUL SEP 1 28 13 2 25 13 3 24 13 4 24 14 5 26 17 6 24 24 7 47 17 8 27 14 9 21 14 10 68 13 11 77 13 12 32 13 13 26 12 14 24 13 15 21 13 16 20 20 17 18 15 18 17 14 19 17 13 20 16 13 21 163 14 22 38 14 23 23 14 24 21 17 25 19 17 26 18 20 27 16 16 28 22 16 29 17 16 30 15 15 31 14 —— TOTAL 948 450 MEAN 30.6 15.0 MAX 163 24 MIN 14 12 AC -FT 1880 893 CFSM 5.10 2.50 IN. 5.88 2.79 STATISTICS OF MONTHLY MEAN MEAN 40.3 44.6 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 14 16 16 16 15 14 13 13 13 13 17 46 69 44 21 17 32 53 45 475 44 29 24 21 19 18 18 16 16 15 14 1196 38.6 475 13 2370 6.43 7.42 DATA 25.4 55.2 1988 6.65 1990 14 14 13 13 13 14 15 108 21 14 24 17 50 366 90 31 24 55 61 126 47 31 25 21 23 21 23 25 20 17 16 1352 43.6 366 13 2680 7.27 8.38 16 16 30 28 36 21 19 16 38 21 16 14 23 16 14 15 14 12 15 48 17 14 12 99 16 12 12 12 12 —— —— 634 21.9 99 12 1260 3.64 3.93 FOR WATER YEARS 1978 19.5 56.1 1992 8.16 1990 18.4 38.0 1982 6.36 1979 13 14 16 17 19 19 20 22 87 32 154 44 30 26 91 94 47 36 29 26 24 23 21 20 19 21 21 21 19 19 21 1065 34.4 154 13 2110 5.73 6.60 - 1996 13.9 34.4 1996 5.07 1979 FOR 1995 CALENDAR YEAR 11052.4 30.3 510 4.6 4.9 21920 5.05 68.52 52 16 7.4 Aug 19 JUl 2 Jun 27 Not 17 16 16 21 17 16 15 60 22 17 16 17 16 37 24 17 15 15 15 13 36 18 99 35 22 21 19 18 18 29 —— 717 23.9 99 13 1420 3.98 4.45 18 16 15 14 13 13 16 20 19 15 15 14 99 33 18 15 15 14 13 12 12 11 20 18 12 11 11 10 10 10 10 542 17.5 99 10 1080 2.91 3.36 24 12 11 72 49 96 157 65 32 24 62 214 108 49 320 186 77 100 61 42 104 228 75 54 46 42 55 53 44 36 —— 2498 83.3 320 11 4950 13.9 15.49 33 30 29 26 25 24 23 86 85 49 38 104 122 469 234 98 75 67 60 102 53 45 41 39 37 40 34 99 49 34 32 2282 73.6 469 23 4530 12.3 14.15 31 47 216 122 52 42 42 66 41 38 35 32 36 279 158 369 71 45 39 33 32 32 32 29 25 24 22 e22 e20 e!9 18 2069 66.7 369 18 4100 11.1 12.83 30 21 33 31 26 19 17 17 266 3740 386 97 60 49 107 100 45 46 61 235 211 57 52 42 38 37 122 e41 634 32 —— 6052 202 3740 17 12000 33.6 37.52 , BY WATER YEAR (WY) 13.4 27.1 1985 4.64 1979 31.2 77.5 1985 9.56 1988 39.9 122 1979 11.3 1985 FOR 1996 WATER YEAR 19805 54.1 3740 10 11 determined 25.93 9.4 39280 9.02 122.79 98 23 13 Sep 10 May 28 May 25 Sep 10 Sep 10 May 28 38.1 92.3 1993 12.5 1986 WATER 30 54 14 3740 3 3 33.3 90.0 1979 9.30 1991 YEARS 1978 .5 .1 .5 Sep .1 May .6 May Not determined Sep 25 2 22100 5 69 51 15 7 . 93 Sep .8 May .08 .09 .0 47.7 202 1996 11.8 1981 - 1996 1996 1990 10 1996 7 1979 1 1979 10 1996 10 1996 5 1979 e Estimated 193 RIO GRANDE DE LOZZA 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 2 (8.42 km*). WATER-DISCHARGE RECORDS PERIOD OP 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN APR MAY JUN JUL AUG SEP 1 3.9 4.7 2 3.3 6.0 3 5.3 4.9 4 3.2 4.0 5 3.5 11 6 2.7 8.1 7 2.8 5.7 8 2.5 4.5 9 2.3 3.9 10 9.2 3.5 11 5.6 3.0 12 3.7 2.8 13 3.0 2.6 14 7.6 2.5 15 3.1 2.3 16 2.5 3.2 17 2.4 4.3 18 2.0 3.0 19 2.0 2.2 20 1.8 2.1 21 31 2.4 22 15 2.7 23 9.5 1.9 24 14 3.7 25 8.1 7.3 26 6.1 12 27 4.9 4.1 28 25 3.1 29 13 2.6 30 7.6 2.3 31 5.6 TOTAL 212.2 126.4 MEAN 6.85 4.21 MAX 31 12 MIN 1.8 1.9 AC-FT 421 251 CFSM 2.11 1.30 IN. 2.43 1.45 2.1 2.6 2.3 2.1 2.1 2.1 2.2 2.4 2.4 2.4 3.2 2.9 6.4 6.9 4.2 3.3 5.2 16 14 e42 17 10 6.6 4.4 2.8 2.5 2.6 2.5 2.5 2.4 2.2 182.3 5.88 42 2.1 362 1.81 2.09 2.2 2.2 2.2 2.1 2.0 2.3 2.6 15 3.6 2.9 2.9 3.3 3.2 656 32 11 8.3 10 21 25 14 8.9 6.0 4.3 8.7 5.7 11 9.5 6.3 4.3 3.7 292.2 9.43 56 2.0 580 2.90 3.34 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 10.1 15.1 MAX 47.8 36.9 (WY) 1986 1985 MIN 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 6.82 30.1 1988 1.49 1990 FOR 4.81 9.94 1992 1.74 1995 3.3 3.3 3.6 4.1 31 9.9 8.7 4.6 3.7 3.0 2.5 2.4 4.5 2.3 1.9 2.2 2.0 1.8 2.2 4.5 2.3 2.0 1.9 2.0 2.2 1.8 1.6 1.6 1.5 ___ --- 118.4 4.08 31 1.5 235 1.26 1.36 YEARS 1984 3.94 8.21 1989 1.32 1985 1.5 1.6 2.2 2.2 1.9 1.7 2.0 3.8 11 4.2 23 10 5.1 3.5 16 8.8 4.5 3.3 2.8 2.3 1.9 1.9 1.7 1.7 1.5 1.7 1.6 1.6 1.7 1.5 1.5 129.7 4.18 23 1.5 257 1.29 1.48 - 1996 4.01 20.7 1989 1.64 1993 1995 CALENDAR YEAR 1826. 5. 84 . . 3620 1. 20. 10 2. . 76 00 Sep 6 41 Jun 14 61 Jun 8 54 91 4 80 1.4 1.3 2.6 16 6.2 2.7 2.1 13 5.7 2.7 2.4 2.4 2.4 2.2 2.2 1.8 1.6 1.6 1.6 1.5 1.4 1.4 2.6 3.1 2.0 2.3 2.1 1.6 1.6 2.5 —— 94.0 3.13 16 1.3 186 .96 1.08 1.9 1.7 1.5 1.5 1.4 1.4 1.6 2.5 2.3 3.1 2.4 2.1 8.7 4.3 2.5 2.2 1.9 1.8 1.7 1.7 1.5 1.4 10 3.6 2.4 2.1 2.0 1.8 1.7 1.6 1.6 77.9 2.51 10 1.4 155 .77 .89 2.2 1.9 1.8 5.0 12 16 17 5.5 2.5 2.1 5.8 72 31 8.1 53 53 25 39 23 12 12 17 11 12 9.8 9.1 8.5 12 8.5 7.4 --- 495.2 16.5 72 1.8 982 5.08 5.67 6.8 6.4 6.2 6.4 6.0 5.2 5.1 26 18 11 6.3 41 21 61 50 28 18 14 11 11 8.3 7.2 6.0 5.7 5.7 5.5 4.3 17 6.2 3.9 3.5 431.7 13.9 61 3.5 856 4.28 4.94 3.3 3.4 32 21 11 7.4 5.9 4.8 4.4 5.2 4.5 4.4 7.2 664 53 e79 27 15 8.2 7.7 5.3 4.8 8.4 6.0 4.9 4.7 4.8 5.8 5.2 5.1 5.2 428.6 13.8 79 3.3 850 4.25 4.91 6.2 4.9 10 22 8.2 7.0 5.7 4.9 19 6326 90 42 25 618 e22 624 12 15 15 16 37 19 14 9.9 8.8 8.2 9.1 9.5 13 9.3 830.7 27.7 326 4.9 1650 8.52 9.51 , BY WATER YEAR (WY) 2.24 4.88 1989 .75 1994 FOR 1996 3419 9 326 1 1 7610 14 1 6780 2 39 20 4 1 7.04 31.5 1985 .62 1994 WATER YEAR .3 .34 Sep 10 .3 Apr 2 .5 Mar 27 Sep 10 .64 Sep 10 .2 Apr 2 .87 .14 .3 .7 6.53 21.3 1987 2.12 1994 6.47 15.0 1993 2.02 1986 WATER 7 12 2 457 7610 14 5070 2 29 12 2 1 6.93 20.2 1988 1.95 1994 YEARS 1984 .00 .3 .50 .33 .37 .64 .30 .15 .25 .5 .0 Dec Hay Apr Sep Sep May 9.86 27.7 1996 1.36 1990 - 1996 1988 1990 7 1987 20 1994 26 1994 10 1996 10 1996 21 1994 e Estimated 194 RIO GRANDE DE LOZZA 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.— SUSPENDED-SEDIMENT DISCHARGE: October 1984 to September 1986 and from October 1989 to current year. INSTRUMENTATION.-- USDH-49 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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,360 mg/L September 10, 1996; Minimum daily mean, <1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 4,840 tons (4,390 tonnes) September 10, 1996; Minimum daily mean, <0.01 ton (<0.01 tonnes) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 3.9 3.3 5.3 3.2 3.5 2.7 2.8 2.5 2.3 9.2 5.6 3.7 3.0 7.6 3.1 2.5 2.4 2.0 2.0 1.8 31 15 9.5 14 8.1 6.1 4.9 25 13 7.6 5.6 15 14 13 8 10 5 4 4 3 35 19 8 6 21 8 7 7 7 7 5 205 55 15 46 17 8 4 131 48 12 6 .15 .12 .25 .07 .09 .04 .03 .02 .02 1.8 .31 .08 .05 .88 .06 .05 .05 .04 .04 .03 104 2.5 .40 1.9 .38 .13 .06 38 1.8 .27 .09 TOTAL 212.2 153.71 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 4.7 6.0 4.9 4.0 11 8.1 5.7 4.5 3.9 3.5 3.0 2.8 2.6 2.5 2.3 3.2 4.3 3.0 2.2 2.1 2.4 2.7 1.9 3.7 7.3 12 4.1 3.1 2.6 2.3 126.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 3 13 8 6 34 21 16 11 7 5 3 4 5 8 12 17 11 9 7 5 6 8 4 15 26 47 18 14 10 6 .04 .31 .11 .07 3.1 .50 .24 .14 .08 .04 .03 .03 .04 .05 .07 .15 .18 .08 .04 .03 .05 .06 .02 .19 1.1 2.5 .21 .11 .07 .04 2.1 2.6 2.3 2.1 2.1 2.1 2.2 2.4 2.4 2.4 3.2 2.9 6.4 6.9 4.2 3.3 5.2 16 14 e42 17 10 6.6 4.4 2.8 2.5 2.6 2.5 2.5 2.4 2.2 4 2 2 1 1 1 2 3 2 1 1 1 15 16 2 3 14 64 55 210 48 12 8 6 5 5 8 12 12 12 12 .02 .02 .01 .01 .01 .01 .01 .02 .01 .01 .01 .01 .37 .33 .02 .02 .33 6.2 2.7 e38 2.4 .33 .14 .07 .04 .03 .05 .08 .08 .08 .07 9.68 182.3 51.49 e Estimated 195 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 2.2 2.2 2.2 2.1 2.0 2.3 2.6 15 3.6 2.9 2.9 3.3 3.2 e56 32 11 8.3 10 21 25 14 8.9 6.0 4.3 8.7 5.7 11 9.5 6.3 4.3 3.7 12 12 12 11 11 11 11 63 11 11 12 14 14 424 141 27 20 34 87 113 38 14 9 6 70 57 36 30 6 4 4 .07 .07 .07 .06 .06 .07 .08 7.2 .11 .08 .09 .12 .12 e!95 17 .79 .45 1.0 7.5 12 1.5 .33 .14 .07 2.3 .87 1.6 .82 .11 .05 .04 FEBRUARY 3.3 3.3 3.6 4.1 31 9.9 8.7 4.6 3.7 3.0 2.5 2.4 4.5 2.3 1.9 2.2 2.0 1.8 2.2 4.5 2.3 2.0 1.9 2.0 2.2 1.8 1.6 1.6 1.5 —— —— 7 10 10 12 159 33 54 11 10 8 7 6 17 15 8 5 5 6 6 14 11 5 2 3 4 6 8 10 9 —— —— .06 .09 .10 .16 28 1.2 2.0 .13 .10 .07 .05 .04 .48 .09 .04 .03 .03 .03 .03 .25 .07 .03 .01 .02 .02 .03 .03 .04 .04 —— MARCH 1.5 1.6 2.2 2.2 1.9 1.7 2.0 3.8 11 4.2 23 10 5.1 3.5 16 8.8 4.5 3.3 2.8 2.3 1.9 1.9 1.7 1.7 1.5 1.7 1.6 1.6 1.7 1.5 1.5 8 9 9 7 8 9 14 22 40 15 51 25 11 6 69 26 17 9 <1 <1 <1 5 6 4 3 3 3 3 3 3 2 .03 .04 .05 .04 .04 .04 .07 .74 1.7 .18 6.3 .71 .16 .05 8.1 .69 .21 .09 <.01 <.01 <.01 .03 .03 .02 .01 .01 .01 .01 .01 .01 .01 TOTAL 292.2 —— 249.77 118.4 —— 33.27 129.7 —— 19.39 e Estimated 196 RIO GRANDE DE LOXZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 1.4 1.3 2.6 16 6.2 2.7 2.1 13 5.7 2.7 2.4 2.4 2.4 2.2 2.2 1.8 1.6 1.6 1.6 1.5 1.4 1.4 2.6 3.1 2.0 2.3 2.1 1.6 1.6 2.5 APRIL 2 3 9 84 18 5 4 52 17 8 7 15 17 21 22 10 5 7 13 17 8 3 6 7 4 5 5 4 4 7 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MAY .01 .01 .11 11 .36 .04 .02 5.0 .30 .06 .05 .10 .11 .13 .13 .05 .02 .03 .05 .07 .03 .01 .07 .06 .02 .04 .03 .02 .02 .05 —— 1.9 1.7 1.5 1.5 1.4 1.4 1.6 2.5 2.3 3.1 2.4 2.1 8.7 4.3 2.5 2.2 1.9 1.8 1.7 1.7 1.5 1.4 10 3.6 2.4 2.1 2.0 1.8 1.7 1.6 1.6 12 6 3 4 5 6 11 15 5 8 7 6 32 12 9 6 3 2 3 4 4 4 34 4 2 1 1 1 1 1 1 .06 .03 .01 .02 .02 .02 .05 .09 .03 .08 .04 .03 1.4 .15 .06 .03 .02 .01 .01 .02 .02 .02 1.3 .04 .01 .01 .01 .00 .00 .01 .01 2.2 1.9 1.8 5.0 12 16 17 5.5 2.5 2.1 5.8 72 31 8.1 53 53 25 39 23 12 12 17 11 12 9.8 9.1 8.5 12 8.5 7.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 2.2 1.9 1.8 5.0 12 16 17 5.5 2.5 2.1 5.8 72 31 8.1 53 53 25 39 23 12 12 17 11 12 9.8 9.1 8.5 12 8.5 7.4 1 1 1 14 108 64 75 16 6 6 29 546 135 19 349 286 165 200 39 26 39 68 22 13 11 11 11 40 29 26 .01 .00 .00 .24 5.5 4.5 4.4 .28 .04 .03 2.2 174 24 .44 86 51 11 31 2.6 .87 1.5 4.6 .64 .41 .30 .27 .25 1.5 .67 .53 TOTAL 94.0 18.00 77.9 3.61 495.2 408.78 197 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 6.8 6.4 6.2 6.4 6.0 5.2 5.1 26 18 11 6.3 41 21 61 50 28 18 14 11 11 8.3 7.2 6.0 5.7 5.7 5.5 4.3 17 6.2 3.9 3.5 431.7 3419.3 JULY 19 10 6 3 2 2 2 116 68 31 19 211 89 365 99 16 9 9 10 32 7 1 3 6 10 10 6 79 33 11 7 —— .35 .17 .10 .06 .03 .03 .03 15 4.1 1.1 .35 35 5.6 94 16 1.3 .44 .35 .30 .98 .15 .03 .05 .10 .17 .17 .07 9.9 .62 .12 .07 186.74 6887.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 3.3 3.4 32 21 11 7.4 5.9 4.8 4.4 5.2 4.5 4.4 7.2 864 53 879 27 15 8.2 7.7 5.3 4.8 8.4 6.0 4.9 4.7 4.8 5.8 5.2 5.1 5.2 6 6 174 89 53 49 47 40 32 18 10 6 26 434 323 474 38 16 7 15 3 4 25 17 13 11 9 7 6 5 5 .06 .05 24 5.1 1.6 .99 .75 .52 .38 .25 .13 .07 2.1 e!78 68 e228 2.9 .65 .17 .34 .05 .05 1.3 .28 .18 .14 .11 .11 .09 .07 .07 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 6.2 4.9 10 22 8.2 7.0 5.7 4.9 19 e326 90 42 25 e!8 e22 e24 12 15 15 16 37 19 14 9.9 8.8 8.2 9.1 9.5 13 9.3 18 5 32 97 14 3 5 10 120 3360 985 122 26 21 81 101 35 54 59 100 176 21 4 4 4 4 4 19 48 6 .44 .07 2.5 13 .31 .05 .07 .12 31 84840 278 15 1.8 el.O e5.4 e8.6 1.2 2.6 3.0 6.3 22 1.1 .14 .09 .09 .09 .09 .57 2.0 .15 428.6 516.51 830.7 5236.78 e Estimated 198 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DEC 1995 20... JAN 1996 14... SEP 10... 10... TIME 0702 1602 0245 1430 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. «8 FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. «8 FINER THAN .008 MM (70328) 87 391 369 310 9830 5590 3550 7060 2310 5910 3540 5910 21 25 32 17 26 30 38 23 31 35 42 31 DEC 1995 20... JAN 1996 14... SEP 10... 10... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 43 46 54 41 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 57 56 63 51 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 78 74 81 64 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 94 89 91 76 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 98 97 96 84 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 99 99 99 90 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 96 RIO GRANDE DE LOIZA BASIN 50051150 QUEBRADA BLANCA AT EL JAGUAL--Continued WATER QUALITY DATA, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT 799 DATE OCT 1995 14... DEC 20... JAN 1996 14... 26... JUN 07... 12... AUG 16... SEP 10... 10... 20... TIME 1000 1040 1552 0910 1030 1340 0420 0045 0530 1115 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 7.6 59 262 7.0 21 61 239 310 326 24 SEDI- MENT, SUS- PENDED (MG/L) (80154) 127 238 3390 102 212 265 4810 3570 2720 517 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2.6 38 2400 1.9 12 44 3100 2990 2390 34 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 92 97 85 88 97 85 76 80 77 97 200 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* (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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY DEC JAN APR MAY JUN JUL AUG 1 3.5 4.8 2 3.4 4.3 3 3.3 4.1 4 3.1 3.8 5 3.0 4.0 6 2.7 4.8 7 2.5 3.8 8 2.4 3.5 9 2.3 3.3 10 3.8 3.1 11 3.3 3.0 12 2.6 2.9 13 2.4 3.0 14 2.6 2.9 15 2.2 2.9 16 2.3 5.4 17 2.7 4.6 18 2.4 3.4 19 2.8 2.7 20 2.4 2.6 21 46 2.5 22 8.7 2.5 23 5.5 2.4 24 8.2 2.6 25 e5.2 3.2 26 eS.O 4.8 27 e4.5 2.7 28 e22 2.3 29 elO 2.3 30 e6.6 2.1 31 e5.3 --- TOTAL 182.7 100.3 MEAN 5.89 3.34 MAX 46 5.4 MIN 2.2 2.1 AC-FT 362 199 CFSM 1.58 .89 IN. 1.82 1.00 STATISTICS OF MONTHLY MEAN MEAN 9.01 12.6 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 2.1 2.1 2.0 2.0 1.9 1.9 1.9 1.9 1.8 1.8 2.4 2.4 2.9 3.5 2.5 2.1 2.5 4.9 4.7 8.7 3.1 2.5 2.3 2.1 1.9 1.9 1.9 1.9 1.8 1.8 1.7 78.9 2.55 8.7 1.7 156 .68 .78 1.7 1.7 1.7 1.7 1.7 1.8 1.9 11 2.8 2.2 2.2 2.4 2.5 87 29 8.5 5.2 4.3 9.5 16 9.2 5.5 4.1 3.7 4.4 3.5 6.4 9.1 5.8 4.0 3.3 253.8 8.19 87 1.7 503 2.19 2.52 3.0 3.8 3.0 3.2 22 11 7.5 4.5 3.7 3.2 3.0 2.7 2.5 2.4 2.3 2.5 2.3 2.3 2.1 2.6 2.2 2.0 1.9 1.9 1.9 1.8 1.7 1.7 1.7 —— 106.4 3.67 22 1.7 211 .98 1.06 DATA FOR WATER YEARS 1984 5.09 22.8 1988 1.17 1990 FOR 4.93 23.4 1992 1.16 1990 3.20 10.3 1984 1.23 1990 1.6 1.6 1.7 1.7 1.5 1.4 1.4 1.7 2.9 1.8 4.6 2.4 1.7 1.5 5.4 3.5 2.0 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.2 1.2 1.1 1.3 1.2 1.7 57.0 1.84 5.4 1.1 113 .49 .57 - 1996 3.09 17.4 1989 1.15 1992 1995 CALENDAR YEAR 1583.63 4.34 175 .30 .43 3140 1.16 15.75 6.8 1.8 .54 Sep 6 Jun 14 Apr 29 1.5 1.2 4.9 16 4.5 2.3 1.8 6.3 2.9 1.8 1.7 2.1 1.9 1.5 1.5 1.4 1.3 1.3 1.2 1.2 1.1 1.1 1.1 1.4 1.2 1.2 1.4 1.1 1.1 1.3 —— 70.3 2.34 16 1.1 139 .63 .70 , BY WATER 2.39 6.60 1985 .66 1995 FOR 1996 4525 12 1750 15000 20 8980 1.1 1.0 .98 .96 .93 .95 1.0 1.4 1.6 1.5 1.4 1.3 1.8 1.7 1.2 1.2 1.2 1.2 1.1 1.1 1.1 .98 2.0 1.4 1.1 1.1 1.1 1.0 1.0 .96 .99 37.35 1.20 2.0 .93 74 .32 .37 YEAR (WY) 6.58 35.8 1985 .86 1995 1.2 1.1 1.0 2.9 9.2 18 18 3.9 2.3 2.0 2.5 88 49 8.5 61 99 29 47 19 8.8 8.5 13 6.3 4.7 3.8 3.2 3.1 4.9 3.3 2.7 —— 524.9 17.5 99 1.0 1040 4.68 5.22 6.96 17.5 1996 1.63 1994 WATER YEAR .75 .4 .93 .99 .86 .90 Sep 10 May 5 May 1 Sep 10 Sep 10 May 4 3.31 45 13 2 1 .02 .7 .2 2.5 2.3 2.2 2.1 2.0 2.0 1.9 12 7.9 5.3 6.1 51 23 113 52 14 7.9 5.7 4.6 4.6 3.8 3.4 3.1 3.0 3.0 3.1 2.8 13 5.6 3.4 3.1 369.4 11.9 113 1.9 733 3.19 3.67 6.00 20.5 1993 1.45 1994 WATER 6 12 3 1750 15000 20 4990 1 25 10 2 3.0 2.9 14 19 7.2 4.4 3.5 3.3 3.1 3.1 2.9 2.5 2.4 61 59 198 13 6.3 4.5 4.1 3.3 3.0 5.6 3.6 2.9 2.7 2.6 2.6 2.4 2.5 2.4 450.8 14.5 198 2.4 894 3.89 4.48 6.03 14.5 1996 1.51 1994 YEARS 1984 .89 .4 .19 Sep .29 Sep .41 May Sep .86 Sep .26 May .84 .02 .0 .93 2.4 2.3 16 7.4 3.0 2.6 2.5 3.6 59 1750 191 41 22 16 19 31 11 13 10 11 19 8.4 7.8 6.8 6.7 6.4 6.7 6.8 6.0 5.5 —— 2293.9 76.5 1750 2.3 4550 20.4 22.82 16.7 76.5 1996 1.88 1990 - 1996 1996 1990 10 1996 12 1990 19 1990 10 1996 10 1996 30 1990 e Estimated 201 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR—Continued WATER-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-49 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 days. SEDIMENT LOADS: Maximum daily mean, 33,000 tons (29,900 tonnes) Sep. 10, 1996; Minimum daily mean, 0.0 ton (0.0 tonne) several days. EXTREMES FOR CURRENT YEAR 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 5,090 mg/L Sep. 10, 1996; Minimum daily mean, 1.0 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 33,000 tons (29,900 tonnes) Sep. 10, 1996; Minimum daily mean, 0.01 ton (0.01 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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) 3.5 3.4 3.3 3.1 3.0 2.7 2.5 2.4 2.3 3.8 3.3 2.6 2.4 2.6 2.2 2.3 2.7 2.4 2.8 2.4 46 8.7 5.5 8.2 e5.2 eS.O e4.5 e22 elO e6.6 e5.3 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 10 10 10 10 8 6 5 4 3 12 14 10 8 9 7 7 6 5 9 7 360 31 12 28 11 7 5 74 242 25 11 .09 .09 .09 .08 .06 .04 .03 .02 .02 .16 .12 .07 .05 .06 .04 .05 .05 .03 .08 .05 333 .79 .18 .65 e.15 .09 .07 .0 182.7 e. e3. e30 e3.3 e.16 372.67 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 4.8 4.3 4.1 3.8 4.0 4.8 3.8 3.5 3.3 3.1 3.0 2.9 3.0 2.9 2.9 5.4 4.6 3.4 2.7 2.6 2.5 2.5 2.4 2.6 3.2 4.8 2.7 2.3 2.3 2.1 100.3 8 8 9 9 12 18 6 2 3 5 6 4 7 9 7 18 19 16 8 6 5 4 3 3 6 17 6 6 7 5 .10 .09 .10 .10 .13 .25 .06 .02 .03 .04 .05 .03 .06 .07 .06 .46 .25 .16 .06 .05 .03 .03 .02 .02 .06 .25 .04 .04 .04 .03 2.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 2.1 2.1 2.0 2.0 1.9 1.9 1.9 1.9 1.8 1.8 2.4 2.4 2.9 3.5 2.5 2.1 2.5 4.9 4.7 8.7 3.1 2.5 2.3 2.1 1.9 1.9 1.9 1.9 1.8 1.8 1.7 78.9 3 3 3 4 11 24 15 9 11 15 23 9 47 27 15 10 22 60 22 91 10 8 7 6 5 4 5 5 5 6 6 .02 .02 .02 .02 .06 .12 .07 .05 .05 .07 .16 .06 .38 .26 .10 .06 .22 .89 .32 6.0 .09 .05 .04 .03 .02 .02 .02 .03 .03 .03 .03 9.34 e Estimated 202 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 TOTAL 1.7 1.7 1.7 1.7 1.7 1.8 1.9 11 2.8 2.2 2.2 2.4 2.5 87 29 8.5 5.2 4.3 9.5 16 9.2 5.5 4.1 3.7 4.4 3.5 6.4 9.1 5.8 4.0 3.3 253.8 6 6 5 5 5 5 6 51 10 6 7 9 9 477 109 33 19 15 45 61 33 15 10 10 18 20 23 41 16 15 15 —— .03 .03 .02 .02 .02 .02 .03 2.6 .07 .03 .04 .06 .06 390 14 .79 .27 .17 1.7 3.4 .86 .22 .11 .10 .22 .19 .49 1.2 .26 .16 .13 417.30 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 3.0 3.8 3.0 3.2 22 11 7.5 4.5 3.7 3.2 3.0 2.7 2.5 2.4 2.3 2.5 2.3 2.3 2.1 2.6 2.2 2.0 1.9 1.9 1.9 1.8 1.7 1.7 1.7 FEBRUARY 10 13 10 12 133 41 33 14 8 7 6 6 10 16 14 11 11 11 11 10 9 5 3 4 5 6 4 3 3 106.4 .08 .14 .09 .10 14 1.6 .71 .17 .08 .06 .05 .04 .07 .11 .08 .08 .07 .07 .06 .07 .05 .03 .02 .02 .02 .03 .02 .01 .01 17.94 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 1.6 1.6 1.7 1.7 1.5 1.4 1.4 1.7 2.9 1.8 4.6 2.4 1.7 1.5 5.4 3.5 2.0 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.1 1.2 1.2 1.1 1.3 1.2 1.7 57.0 3 3 4 4 3 3 6 11 13 5 17 8 5 4 27 20 13 7 6 10 14 11 6 3 2 4 6 7 7 7 6 .01 .01 .02 .02 .01 .01 .02 .06 .12 .03 .35 .05 .02 .02 .83 .20 .07 .03 .03 .04 .05 .04 .02 .01 .01 .01 .02 .02 .02 .02 .03 2.20 203 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 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 1.5 1.2 4.9 16 4.5 2.3 1.8 6.3 2.9 1.8 1.7 2.1 1.9 1.5 1.5 1.4 1.3 1.3 1.2 1.2 1.1 1.1 1.1 1.4 1.2 1.2 1.4 1.1 1.1 1.3 APRIL 6 7 22 199 43 9 6 19 20 20 10 7 7 12 17 10 6 7 10 12 8 5 5 5 6 6 6 5 5 4 33 .02 .02 .87 I .66 .05 .03 .62 .15 .10 .05 .04 .04 .05 .07 .04 .02 .02 .03 .04 .02 .02 .02 .02 .02 .02 .02 .02 .02 .02 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY 1.1 1.0 .98 .96 .93 .95 1.0 1.4 1.6 1.5 1.4 1.3 1.8 1.7 1.2 1.2 1.2 1.2 1.1 1.1 1.1 .98 2.0 1.4 1.1 1.1 1.1 1.0 1.0 .96 .99 4 4 4 6 10 13 10 8 6 4 5 5 7 6 4 5 6 7 8 9 6 4 7 4 4 5 5 6 6 5 6 .01 .01 .01 .02 .02 .03 .03 .03 .02 .02 .02 .02 .04 .03 .02 .02 .02 .02 .03 .03 .02 .01 .04 .02 .01 .01 .02 .02 .02 .01 .02 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) JUNE 1.2 1.1 1.0 2.9 9.2 18 18 3.9 2.3 2.0 2.5 88 49 8.5 61 99 29 47 19 8.8 8.5 13 6.3 4.7 3.8 3.2 3.1 4.9 3.3 2.7 8 9 10 14 111 86 93 20 18 16 10 709 214 18 275 385 50 166 28 17 18 48 17 6 8 11 11 27 11 8 .02 .03 .03 .13 4.4 6.3 5.4 .21 .12 .08 .07 269 97 .43 115 216 4.5 54 1.6 .41 .42 2.0 .30 .08 .08 .10 .10 .46 .10 .06 TOTAL 70.3 36.12 37.35 0.65 524.9 778.43 204 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 •OTAI •EAR MEAN DISCHARGE (CPS) 2.5 2.3 2.2 2.1 2.0 2.0 1.9 12 7.9 5.3 6.1 51 23 113 52 14 7.9 5.7 4.6 4.6 3.8 3.4 3.1 3.0 3.0 3.1 2.8 13 5.6 3.4 3.1 369.4 4525.75 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO, PR-Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 8 7 6 3 2 3 4 48 32 12 19 265 112 411 194 24 9 6 5 5 5 5 4 3 3 3 4 55 19 9 7 .05 .04 .03 .02 .01 .02 .02 3.5 .87 .18 .38 81 8.1 317 57 .96 .19 .10 .06 .06 .05 .04 .03 .02 .02 .03 .03 4.7 .32 .09 .06 474.98 37714.22 MEAN DISCHARGE (CPS) 3.0 2.9 14 19 7.2 4.4 3.5 3.3 3.1 3.1 2.9 2.5 2.4 61 59 198 13 6.3 4.5 4.1 3.3 3.0 5.6 3.6 2.9 2.7 2.6 2.6 2.4 2.5 2.4 MEAN CONCEN- TRATION (MG/L) AUGUST 4 3 63 74 12 13 17 8 4 5 5 7 11 285 246 744 50 18 16 17 4 2 16 14 9 6 3 1 1 2 2 SEDIMENT DISCHARGE (TONS /DAY) .04 .02 4.1 4.0 .27 .15 .16 .08 .04 .04 .04 .05 .07 133 113 1340 1.9 .32 .19 .19 .04 .02 .58 .14 .07 .04 .02 .01 .01 .01 .02 MEAN DISCHARGE (CPS) 2.4 2.3 16 7.4 3.0 2.6 2.5 3.6 59 1750 191 41 22 16 19 31 11 13 10 11 19 8.4 7.8 6.8 6.7 6.4 6.7 6.8 6.0 5.5 —— MEAN CONCEN- TRATION (MG/L) SEPTEMBER 3 4 224 39 7 3 5 13 308 5090 724 105 15 10 70 126 15 33 32 50 84 17 4 1 1 1 1 2 2 2 —— SEDIMENT DISCHARGE (TONS/DAY) .02 .02 77 1.4 .06 .02 .03 .14 382 33000 495 13 .91 .42 4.9 17 .48 1.5 .90 1.8 6.0 .39 .08 .02 .02 .02 .03 .03 .03 .02 —— 450.8 1598.62 2293.9 34003.24 205 RIO GRANDE DE LOIZA BASIN 50051180 QUEBRADA SALVATIERRA NEAR SAN LORENZO—Continued MATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1995 21... 21... JUN 1996 12... SEP 03... 10... TIME 1617 1647 0201 1720 0415 DIS- CHARGE, INST. CUBIC FEET PER SECOND 204 694 284 236 1740 SEDI- MENT, SUS- PENDED (MG/L) 7380 5020 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 4070 9400 SED. SUSP. FALL DIAM. SED. SED. SUSP. SUSP. FALL FALL DIAM. DIAM. % FINER % FINER H FINER THAN THAN THAN .002 MM .004 MM .008 MM 5210 4000 5480 3490 9150 43000 30 31 28 26 21 34 37 36 34 28 39 42 44 41 36 DATE OCT 1995 21... 21... JUN 1996 12... SEP 03... 10... SED. SUSP. FALL DIAM. * FINER THAN .016 MM SED. SUSP. PALL DIAM. * FINER THAN .031 MM SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM SED. SUSP. SIEVE DIAM. * FINER THAN .125 MM SED. SUSP. SIEVE DIAM. * FINER THAN .250 MM SED. SUSP. SIEVE DIAM. * FINER THAN .500 MM SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM 52 53 58 50 44 64 64 69 63 54 85 78 84 81 72 95 89 96 91 88 99 95 99 95 94 100 98 99 98 98 100 100 100 99 99 206 RIO GRANDE DE LOZZA BASIN 50051180 QUEBRADA SALVATZERRA NEAR SAN LORENZO--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 21... DEC 20... JAN 1996 14... FEB 05... JUN 12... 16... JUL 12... AUG 14... SEP 10... TZME 1737 1020 1807 0935 1144 0658 0645 1725 0045 DIS- CHARGE, ZNST. CUBIC FEET PER SECOND 382 15 306 16 281 489 161 48 1760 SEDI- MENT, SUS- PENDED (MG/L) 1710 444 3460 288 728 3690 935 271 4250 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 1760 18 2860 12 552 4870 406 35 20200 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM 87 98 87 95 88 89 91 98 81 207 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 2 (26.4 km2 ). PERIOD OP 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES JAN FEB APR JUN JUL 1 34 24 2 33 24 3 41 24 4 31 23 5 41 25 6 31 30 7 36 30 8 35 24 9 30 23 10 47 22 11 51 21 12 36 21 13 30 21 14 32 20 15 27 23 16 28 23 17 26 26 18 29 23 19 29 20 20 25 19 21 64 21 22 57 21 23 35 21 24 32 23 25 27 29 26 26 34 27 25 22 28 47 20 29 32 19 30 26 19 31 25 —— TOTAL 1068 695 MEAN 34.5 23.2 MAX 64 34 MIN 25 19 AC -FT 2120 1380 CFSM 3.38 2.27 IN. 3.90 2.53 STATISTICS OF MONTHLY MEAN MEAN 59.6 68.6 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 INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 18 21 20 20 21 19 18 18 18 19 28 34 93 46 30 26 30 36 50 506 645 638 635 632 629 629 629 627 624 623 622 1404 45.3 506 18 2780 4.44 5.12 621 622 621 620 e!9 621 621 680 635 629 627 626 640 6250 elOO 654 640 670 668 86 47 36 30 629 630 628 627 630 627 624 626 1384 44.6 250 19 2750 4.38 5.05 DATA FOR WATER 45.3 163 1988 12.5 1992 FOR 30.2 50.0 1993 14.6 1990 626 623 625 634 648 632 629 626 628 631 622 622 623 622 621 23 23 22 23 32 28 24 22 29 29 23 22 21 21 ___ —— 754 26.0 48 21 1500 2.55 2.75 YEARS 1977 27.0 67.5 1984 11.0 1992 21 21 21 23 23 23 23 29 51 19 47 22 18 18 31 39 29 20 20 19 19 18 18 18 18 19 19 19 18 18 17 718 23.2 51 17 1420 2.27 2.62 - 1996 21.9 45.4 1989 11.3 1992 1995 CALENDAR YEAR 10122. 27. 506 9. 9. 20080 2. 36. 46 20 11 8 7 Dec 20 0 May 5 4 Apr 30 72 92 17 16 16 35 22 17 15 37 21 16 17 18 17 24 23 17 16 16 16 15 17 16 26 23 18 18 18 17 17 19 —— 580 19.3 37 15 1150 1.90 2.12 18 16 15 15 15 14 18 26 25 19 17 21 24 24 19 18 18 17 17 17 16 16 19 16 15 14 14 14 13 13 13 536 17.3 26 13 1060 1.70 1.95 25 21 17 21 24 36 106 92 32 28 35 244 125 56 222 214 68 94 47 33 39 58 45 35 32 31 35 58 44 32 —— 1949 65.0 244 17 3870 6.37 7.11 29 27 27 25 23 23 22 50 63 39 31 137 57 287 221 91 76 66 63 63 55 50 46 45 45 46 41 76 63 48 51 1986 64.1 287 22 3940 6.28 7.24 51 65 190 84 52 41 36 47 37 641 641 639 46 196 187 641 elOl 668 652 46 49 43 43 42 37 35 35 34 33 31 29 2472 79.7 641 29 4900 7.82 9.02 48 47 32 118 46 42 44 50 199 65120 6500 6250 6200 6170 6160 6210 6140 6120 6140 6120 6330 6120 ellO 692 686 694 6120 688 678 670 8944 298 5120 32 17740 29.2 32.62 , BY WATER YEAR (WY) 19.9 46.0 1985 10.7 1980 FOR 1996 22490 61, 5120 13 14 12600 23. 12 44610 6. 82. 92 29 17 44.6 155 1985 9.68 1990 WATER YEAR .4 Sep 10 May 29 May 25 Sep 10 .26 Sep 10 May 31 .02 .02 47.0 140 1979 10.9 1994 43.9 118 1979 15.4 1994 WATER 43 89 18 5120 7 8 13200 9 31600 4 58 67 24 12 46.5 202 1979 14.5 1991 YEARS 1977 .6 .7 .6 Sep .1 Feb .5 Jun Aug .44 Aug .28 .10 68.4 298 1996 16.9 1980 - 1996 1979 1990 10 1996 4 1981 19 1994 31 1979 31 1979 e Estimated 208 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 Col6n Garcia and 2.0 mi (3.2 km) northwest from Escuela Segunda Unidad de Carlos Zayas. DRAINAGE AREA.--25.0 mi 1 (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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DEC JAN FEB APR JUN JUL AUG SEP 1 113 82 2 105 79 3 116 82 4 96 78 5 115 96 6 105 114 7 119 100 8 114 79 9 94 73 10 151 67 11 183 62 12 131 62 13 107 60 14 114 58 15 91 62 16 89 69 17 83 78 18 84 61 19 86 53 20 81 52 21 368 54 22 194 57 23 118 52 24 130 60 25 105 72 26 92 104 27 84 60 28 183 e54 29 140 e50 30 98 e46 31 90 - — TOTAL 3779 2076 MEAN 122 69.2 MAX 368 114 MIN 81 46 AC-FT 7500 4120 CFSM 4.88 2.77 IN. 5.62 3.09 STATISTICS OF MONTHLY MEAN MEAN 118 123 MAX 266 222 (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 e48 646 652 646 649 45 40 40 39 38 53 57 160 108 71 53 64 91 155 858 161 100 82 74 67 67 68 62 56 54 51 2955 95.3 858 38 5860 3.81 4.40 DATA 89.6 110 1993 69.7 1994 49 50 49 46 44 50 50 211 82 62 67 71 84 906 e329 170 127 196 195 291 195 141 115 102 113 102 113 120 105 89 86 4410 142 906 44 8750 5.69 6.56 FOR WATER 105 192 1992 50.1 1995 82 84 93 126 204 141 127 96 95 104 81 74 81 81 70 74 71 68 71 104 87 67 62 116 83 57 55 53 51 --- 2558 88.2 204 51 5070 3.53 3.81 YEARS 1990 67.4 102 1994 21.0 1992 50 49 53 52 52 50 50 48 190 79 198 111 76 63 123 147 107 71 63 57 53 51 47 46 43 49 49 48 50 46 47 2218 71.5 198 43 4400 2.86 3.30 - 1996 49.4 76.5 1995 17.4 1992 FOR 1995 CALENDAR YEAR 30944 84. 903 12 13 61380 3. 46. 174 55 20 8 Sep 6 May 4 Apr 29 39 04 45 40 43 137 80 53 43 135 71 48 46 50 50 54 69 45 40 39 38 35 76 56 95 85 51 45 54 42 41 50 1756 58.5 137 35 3480 2.34 2.61 44 36 34 32 30 30 33 61 70 52 42 44 103 74 42 36 36 34 31 29 27 26 57 41 31 28 26 25 25 22 26 1227 39.6 103 22 2430 1.58 1.83 46 38 33 105 92 206 437 203 87 68 90 448 313 177 449 394 261 290 226 150 196 280 172 123 103 94 107 141 111 85 --- 5525 184 449 33 10960 7.37 8.22 76 71 70 73 65 64 63 135 195 125 97 307 222 761 462 233 177 146 137 162 123 109 103 98 95 109 92 175 149 99 93 4886 158 761 63 9690 6.30 7.27 96 122 277 243 151 123 108 135 107 101 96 95 90 445 378 1330 268 204 175 159 150 139 153 145 125 118 115 110 107 102 97 6064 196 1330 90 12030 7.82 9.02 117 145 133 195 115 101 93 93 625 elOOOO ellOO e580 e450 e400 e380 e490 e310 e290 e310 e280 e780 e270 e240 e210 e200 e220 e280 e200 el 80 e!50 --- 18937 631 10000 93 37560 25.2 28.18 , BY WATER YEAR (WY) 32.6 58.5 1996 16.8 1992 FOR 1996 56391 154 10000 22 26 56800 35 111900 6 83 248 89 43 65.3 186 1992 25.2 1995 WATER YEAR Sep 10 May 30 May 25 Sep 10 .62 Sep 10 .16 .91 126 290 1992 42.3 1994 106 208 1993 42.3 1994 WATER 104 154 67 10000 6 7 56800 35 75560 4 56 177 59 23 106 196 1996 39.3 1994 YEARS 1990 .8 Sep .3 Apr .4 Apr Sep .62 Sep .17 .69 214 631 1996 59.7 1990 - 1996 1996 1994 10 1996 29 1992 25 1992 10 1996 10 1996 • E»timat«d 209 RIO ORANDE DB LOIZA BASIN 50051800 RIO GRANDE DB LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued WATER-QUALITY RECORDS PERIOD OP RECORDS.— Water years 1990 to current year. PERIOD OP DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: February 1990 to current year. INSTRUMENTATION.— USDH-49 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 POR PERIOD OP 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 POR CURRENT YEAR 1996— SEDIMENT CONCENTRATION: Maximum daily mean, 2,530 mg/L September 10, 1996; Minimum daily mean, 7 mg/L November 20, 1995. SEDIMENT LOADS: Maximum daily mean, 80,600 tons (73,100 tonnes) September 10, 1996; Minimum daily mean, 0.97 ton (0.88 tonne) November 20, 1995. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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) 113 105 116 96 115 105 119 114 94 151 183 131 107 114 91 89 83 84 86 81 368 194 118 130 105 92 84 183 140 98 90 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) DECEMBER 113 105 116 96 115 105 119 114 94 151 183 131 107 114 91 89 83 84 86 81 368 194 118 130 105 92 84 183 140 98 90 80 53 63 46 101 126 127 41 21 177 224 155 110 88 58 53 52 51 46 30 402 257 78 32 19 15 13 245 196 58 55 25 15 21 12 32 36 42 13 5. 102 126 57 32 28 14 13 12 11 11 6. 1770 149 25 11 5. 3. 3. 302 80 15 13 5 6 4 8 0 82 79 82 78 96 114 100 79 73 67 62 62 60 58 62 69 78 61 53 52 54 57 52 60 72 104 60 e54 e50 e46 58 45 33 26 73 96 65 50 43 37 35 44 52 36 23 37 68 22 11 7 10 14 14 25 64 113 44 22 15 31 13 9.6 7.4 5.4 27 29 18 11 8.5 6.7 5.9 7.4 8.4 5.6 3.8 8.8 15 3.7 1.6 .97 1.4 2.1 2.0 4.9 13 34 7.3 e3.2 e2.0 e4.1 e48 e46 e52 e46 e49 45 40 40 39 38 53 57 160 108 71 53 64 91 155 858 161 100 82 74 67 67 68 62 56 54 51 62 65 65 59 38 25 22 20 21 21 157 194 152 263 231 56 63 90 194 1210 211 133 96 69 50 42 52 19 15 14 14 67.8 e8.3 e8.5 e7.8 e4.9 3.1 2.4 2.2 2.2 2.2 29 33 86 84 47 8.1 13 29 104 6790 97 36 21 14 9.0 7.7 9.7 3.1 2.3 2.0 1.9 TOTAL 3779 2991.3 2076 270.77 2955 7476.2 e Estimated 210 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 1995 TO SEPTEMBER 1996 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 49 50 49 46 44 50 50 211 82 62 67 71 84 906 e329 170 127 196 195 291 195 141 115 102 113 102 113 120 105 89 86 13 13 12 12 12 11 12 318 96 76 77 72 90 777 423 231 155 257 264 435 248 102 60 37 80 93 104 125 42 31 34 1.7 1.7 1.6 1.5 1.4 1.6 1.7 228 22 13 15 14 39 5050 e415 107 54 144 150 344 135 39 19 10 27 26 32 43 12 7.4 7.8 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 82 84 93 126 204 141 127 96 95 104 81 74 81 81 70 74 71 68 71 104 87 67 62 116 83 57 55 53 51 57 94 121 140 393 217 196 123 97 103 46 21 37 70 43 31 30 30 51 117 71 40 32 116 87 30 39 53 57 13 21 31 49 241 87 67 32 27 30 10 4.1 11 16 8.0 6.2 5.8 5.5 10 41 18 7.2 5.3 61 21 4.6 5.7 7.5 7.7 50 49 53 52 52 50 50 48 190 79 198 111 76 63 123 147 107 71 63 57 53 51 47 46 43 49 49 48 50 46 47 54 33 20 14 22 31 20 32 250 79 312 112 52 45 141 178 120 73 66 58 52 67 67 65 64 62 60 57 55 57 58 7.2 4.4 2.8 2.0 3.1 4.1 2.6 4.3 146 17 223 35 11 7.7 89 84 40 14 11 8.9 7.4 9.2 8.6 8.2 7.5 8.2 7.9 7.4 7.4 7.1 7.5 TOTAL 4410 6964.4 2558 853.6 2218 803.5 e Estimated 211 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 1995 TO SEPTEMBER 1996 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 45 40 43 137 80 53 43 135 71 48 46 50 50 54 69 45 40 39 38 35 76 56 95 85 51 45 54 42 41 50 —— APRIL 60 58 59 199 77 42 32 355 83 60 54 49 44 54 75 67 60 40 53 65 103 119 103 78 70 66 52 39 31 44 MAY 7.2 6.3 7.2 135 18 6.1 3.8 257 16 7.8 6.7 6.6 6.0 10 15 8.2 6.4 4.1 5.4 6.0 46 20 39 20 9.5 7.9 7.6 4.4 3.4 6.4 —— 44 36 34 32 30 30 33 61 70 52 42 44 103 74 42 36 36 34 31 29 27 26 57 41 31 28 26 25 25 22 26 60 93 75 59 47 35 28 145 121 99 120 151 212 94 72 71 72 73 70 67 72 79 89 91 65 45 31 21 22 25 25 7.3 9.1 6.8 5.1 3.8 2.8 2.9 24 23 14 13 18 73 19 8.2 6.8 7.1 6.7 5.9 5.3 5.2 5.5 14 10 5.5 3.3 2.2 1.4 1.5 1.5 1.8 46 38 33 105 92 206 437 203 87 68 90 448 313 177 449 394 261 290 226 150 196 280 172 123 103 94 107 141 111 85 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 31 40 33 115 100 272 1240 260 55 14 72 780 1460 853 1220 681 221 511 194 140 255 414 130 30 28 30 72 305 112 72 4.5 4.0 2.9 49 40 172 1730 164 14 2.6 32 1080 1260 434 2820 947 158 540 124 57 148 406 64 10 7.7 7.6 23 134 34 17 TOTAL 1756 703.0 1227 313.7 5525 10486.3 212 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 1995 TO SEPTEMBER 1996 DAY MEAN 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 TOTAL YEAR MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY 76 71 70 73 65 64 63 135 195 125 97 307 222 761 462 233 177 146 137 162 123 109 103 98 95 109 92 175 149 99 93 4886 •6391 39 19 10 121 121 99 95 164 210 44 24 469 304 1050 683 78 18 20 24 18 13 12 20 32 33 32 31 254 98 47 32 —— 7.9 3.7 1.9 27 21 17 16 85 122 15 6.3 599 188 4190 1450 52 8.8 8.0 8.9 8.0 4.5 3.4 5.4 8.5 8.4 9.3 7.6 142 44 13 7.9 7089.5 151471.27 MEAN DISCHARGE (CFS) 96 122 277 243 151 123 108 135 107 101 96 95 90 445 378 1330 268 204 175 159 150 139 153 145 125 118 115 110 107 102 97 MEAN CONCEN- TRATION (MG/L) AUGUST 28 106 425 94 48 44 40 124 47 42 41 41 40 755 542 1240 30 22 29 33 32 29 87 108 28 18 17 16 14 13 13 SEDIMENT DISCHARGE (TONS/DAY) 7.4 37 385 63 20 15 12 48 14 11 11 10 9.9 1640 753 13100 23 12 14 14 13 11 45 43 9.6 5.7 5.2 4.7 4.1 3.6 3.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 117 145 133 195 115 101 93 93 625 elOOOO ellOO e580 e450 e400 e380 e490 e310 e290 e310 e280 e780 e270 e240 e210 e200 e220 e280 e200 e!80 elSO 72 176 155 413 106 54 31 18 388 2530 1180 316 104 150 250 374 354 318 295 400 309 176 100 63 71 68 61 47 36 30 33 81 71 295 33 15 7.8 4.6 4870 S80600 S7300 e739 el43 el71 e262 e440 e376 e258 e239 e316 e392 e237 e69 e38 e39 e39 e41 e30 e!8 e!4 6064 16347.6 18937 97171.4 e Estimated 213 RIO GRANDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE DEC 1995 20... 20... 28... JAN 1996 14... AUG 16... SEP 10... TIME 0815 1250 1310 1645 0500 0515 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 4490 365 61 4310 11400 11100 SEDI- MENT, SUS- FENDED (MG/L) (80154) 3570 1110 1080 4720 7060 3840 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 43300 1090 177 54900 217000 115000 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 31 49 45 31 21 38 SED. SUSP. FALL DIAM. «6 FINER THAN .004 MM (70327) 36 58 58 37 27 51 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 49 73 73 44 33 64 DATE DEC 1995 20... 20... 28... JAN 1996 14... AUG 16... SEP 10... SED. SUSP. FALL DIAM. «6 FINER THAN .016 MM (70329) 62 83 83 55 46 78 SED. SUSP. FALL DIAM. «6 FINER THAN .031 MM (70330) 78 86 88 70 54 82 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 93 97 97 88 71 97 SED. SUSP. SIEVE DIAM. «6 FINER THAN .125 MM (70332) 98 99 99 94 88 98 SED. SUSP. SIEVE DIAM. «6 FINER THAN .250 MM (70333) 99 100 100 97 95 99 SED. SUSP. SIEVE DIAM. «6 FINER THAN .500 MM (70334) 100 100 100 99 98 100 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 99 100 214 RIO GRAMDE DE LOIZA BASIN 50051800 RIO GRANDE DE LOIZA AT HWY 183 NEAR SAN LORENZO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE DEC 1995 12... JAN 1996 14... FEE 05... MAR 11... JUN 07... JUL 15... SEP 09... 10... TIME 0945 1905 0915 1000 1000 1000 2230 0230 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 61 2350 249 341 445 295 3780 43000 SEDI- MENT, SUS- PEHDED (MG/L) (80154) 255 1470 497 1130 2000 448 3490 1080 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 42 9330 334 1040 2400 357 35600 125000 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 97 82 96 99 88 99 85 100 215 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 km'). 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC JAN JUL AUG 1 32 19 2 26 20 3 24 19 4 21 19 5 20 25 6 20 46 7 22 24 8 19 19 9 18 17 10 32 16 11 40 15 12 23 14 13 20 14 14 24 13 15 17 13 16 17 32 17 15 22 18 15 18 19 17 17 20 15 16 21 129 15 22 40 15 23 26 14 24 40 17 25 25 18 26 21 21 27 18 16 28 126 15 29 35 e!4 30 22 e!4 31 21 TOTAL 940 557 MEAN 30.3 18.6 MAX 129 46 MIN 15 13 MED 22 17 AC-FT 1860 1100 CFSM 4.25 2.60 IN. 4.90 2.90 STATISTICS OF MONTHLY MEAN MEAN 24.0 22.5 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 13 14 14 13 13 13 12 12 11 11 13 12 29 23 15 13 41 72 47 130 30 20 17 15 14 14 14 13 12 12 11 693 22.4 130 11 14 1370 3.13 3.61 11 11 10 9.9 9.7 11 12 68 16 14 16 15 55 300 158 42 29 47 67 139 55 34 28 24 28 26 60 54 33 25 22 1429.6 46.1 300 9.7 28 2840 6.46 7.45 DATA FOR WATER 16.7 23.1 1991 10.6 1994 FOR 22.0 47.5 1992 7.85 1990 20 20 23 28 93 28 25 20 19 19 18 18 17 17 16 17 16 15 15 17 14 13 13 15 13 12 12 11 11 ___ --- 575 19.8 93 11 17 1140 2.78 3.00 YEARS 1990 16.0 24.9 1995 8.93 1990 11 11 12 12 12 11 11 12 59 13 110 22 14 13 74 25 15 13 14 11 11 10 9.7 9.6 10 10 9.8 10 9.7 9.1 9.4 583.3 18.8 110 9.1 11 1160 2.64 3.04 - 1996 11.6 18.8 1996 7.35 1993 1995 CALENDAR YEAR 8743. 24. 730 4. 5. 17340 3. 45. 39 11 5. 1 0 Sep 6 2 Jul 14 1 Jul 9 35 55 7 9.2 9.3 20 27 12 11 10 17 11 9.1 8.4 11 9.9 12 11 9.6 8.8 8.2 7.8 9.1 7.5 7.7 9.5 11 8.8 9.9 11 9.0 7.9 11 --- 324.7 10.8 27 7.5 9.7 644 1.52 1.69 8.6 9.0 8.5 7.3 7.8 7.6 8.6 11 11 11 9.1 8.7 46 14 10 9.2 9.7 8.5 8.6 7.9 8.0 8.0 34 11 8.7 8.2 8.2 7.8 7.5 7.4 7.2 338.1 10.9 46 7.2 8.6 671 1.53 1.76 7.7 7.8 7.6 33 81 105 265 96 26 19 41 223 60 24 286 174 58 114 43 24 57 134 39 23 19 15 17 15 13 11 --- 2038.1 67.9 286 7.6 36 4040 9.51 10.62 11 11 12 13 17 17 18 71 50 29 25 118 84 440 233 49 31 23 20 21 16 14 13 12 12 12 11 54 18 12 11 1478 47.7 440 11 18 2930 6.68 7.70 9.9 11 140 36 18 13 11 11 9.7 9.2 8.8 8.5 14 208 116 370 52 29 21 19 19 19 20 18 16 15 15 14 12 11 9.8 1283.9 41.4 370 8.5 15 2550 5.80 6.69 57 23 13 13 11 9.1 10 19 185 e!940 254 118 86 73 69 90 57 53 57 50 144 51 46 39 36 38 50 36 33 30 --- 3690.1 123 1940 9.1 50 7320 17.2 19.23 , BY WATER YEAR (WY) 8.24 10.8 1996 6.18 1990 FOR 1996 13930 38 1940 7 7 15200 22 27630 5 72 70 16 9 15.2 31.9 1993 6.11 1994 WATER YEAR .8 .1 Sep 10 .2 May 31 .6 May 28 Sep 10 .60 Sep 10 .33 .58 .1 29.2 67.9 1996 9.59 1991 25.0 54.6 1993 8.42 1995 WATER 22 38 12 1940 3 3 15200 22 3 16450 3 43 36 11 5 21.6 41.4 1996 6.98 1994 47.8 123 1996 14.1 1990 YEARS 1990 - 1996 .7 .1 .1 Sep .3 Aug .8 Aug Sep . 60 Sep .3 Aug .18 .22 .7 1996 1994 10 1996 17 1994 11 1994 10 1996 10 1996 17 1994 e Estimated 216 RIO GRANDE DE LOZZA BASIN 50053025 RIO TURABO 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-49 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 days. 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 1996. SEDIMENT CONCENTRATION: Maximum daily mean, 9,230 mg/L September 10, 1996; Minimum daily mean, 2 mg/L September 3, 1996. SEDIMENT LOADS: Maximum daily mean, 80,900 tons (73,400 tonnes) September 10, 1996; Minimum daily mean, 0.09 ton (0.08 tonne) September 02, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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) 32 26 24 21 20 20 22 19 18 32 40 23 20 24 17 17 15 15 17 15 129 40 26 40 25 21 18 126 35 22 21 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 32 26 24 21 20 20 22 19 18 32 40 23 20 24 17 17 15 15 17 15 129 40 26 40 25 21 18 126 35 22 21 10 10 11 21 18 12 16 25 35 40 54 25 20 35 42 52 43 32 23 17 392 57 24 34 7 7 8 608 41 25 22 .86 .70 .67 1.2 .99 .68 .94 1.3 1.6 4.5 11 1.6 1.1 2.4 1.9 2.3 1.8 1.3 1.1 .68 650 7.3 1.7 4.5 .49 .42 .38 1080 4.1 1.5 1.3 TOTAL 940 1790.31 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 19 20 19 19 25 46 24 19 17 16 15 14 14 13 13 32 22 18 17 16 15 15 14 17 18 21 16 15 el 4 e!4 557 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 20 19 17 17 28 77 23 15 11 10 9 9 9 8 8 51 23 18 13 10 8 7 8 8 8 19 10 6 6 7 1.0 1.0 .90 .84 3.1 18 1.5 .79 .51 .41 .37 .35 .32 .29 .29 14 1.4 .90 .57 .41 .31 .29 .29 .37 .39 1.1 .44 .23 e.23 e.28 13 14 14 13 13 13 12 12 11 11 13 12 29 23 15 13 41 72 47 130 30 20 17 15 14 14 14 13 12 12 11 9 11 12 9 7 5 5 5 5 6 7 9 34 22 10 8 79 112 77 239 36 33 33 32 32 32 32 31 31 31 28 .32 .42 .44 .33 .25 .18 .16 .16 .16 .18 .25 .31 4.3 1.4 .42 .28 22 66 16 144 2.9 1.8 1.5 1.3 1.2 1.2 1.2 1.1 1.0 .98 .86 50.88 693 272.60 e Estimated 277 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (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 11 11 10 9.9 9.7 11 12 68 16 14 16 15 55 300 158 42 29 47 67 139 55 34 28 24 28 26 60 54 33 25 22 25 23 21 18 17 15 15 141 19 16 19 14 135 1090 280 51 25 61 91 224 47 34 25 22 32 28 83 79 24 16 19 .74 .65 .56 .49 .43 .44 .53 50 .85 .60 .87 .57 124 2340 215 5.9 2.0 8.7 35 125 7.1 3.2 1.9 1.4 2.6 2.0 21 15 2.3 1.1 1.1 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 20 20 23 28 93 28 25 20 19 19 18 18 17 17 16 17 16 15 15 17 14 13 13 15 13 12 12 11 11 21 15 19 34 163 28 16 9 9 9 9 10 10 9 9 8 9 11 14 14 15 15 16 17 17 18 18 18 13 1.1 .79 1.3 3.0 81 2.1 1.1 .50 .47 .45 .45 .47 .46 .43 .38 .37 .39 .45 .56 .67 .58 .56 .58 .69 .59 .57 .58 .56 .39 MARCH 11 11 12 12 12 11 11 12 59 13 110 22 14 13 74 25 15 13 14 11 11 10 9.7 9.6 10 10 9.8 10 9.7 9.1 9.4 9 7 8 10 12 12 12 11 320 13 214 23 11 7 126 28 13 11 11 10 10 10 10 10 9 9 9 9 8 8 7 .27 .19 .25 .31 .40 .35 .36 .34 177 .46 102 1.5 .44 .23 89 2.0 .53 .38 .39 .32 .31 .28 .25 .25 .25 .25 .24 .24 .21 .19 .18 TOTAL 1429.6 2971.03 575 101.54 583.3 379.37 218 RIO GRANDE DB LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 9.2 9.3 20 27 12 11 10 17 11 9.1 8.4 11 9.9 12 11 9.6 8.8 8.2 7.8 9.1 7.5 7.7 9.5 11 8.8 9.9 11 9.0 7.9 11—— APRIL 7 6 20 34 11 9 7 20 8 7 10 13 17 11 15 23 32 26 18 13 13 13 14 12 10 10 10 8 6 8 —— .17 .16 2.3 4.9 .36 .25 .21 1.3 .24 .18 .22 .40 .45 .37 .44 .59 .76 .59 .38 .32 .25 .27 .35 .36 .24 .31 .32 .19 .14 .22 —— MEAN DISCHARGE (CPS) 8.6 9.0 8.5 7.3 7.8 7.6 8.6 11 11 11 9.1 8.7 46 14 10 9.2 9.7 8.5 8.6 7.9 8.0 8.0 34 11 8.7 8.2 8.2 7.8 7.5 7.4 7.2 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 10 12 10 9 8 9 9 10 10 12 11 9 71 19 17 17 16 15 14 13 11 9 70 52 30 17 15 13 11 8 6 .22 .28 .24 .18 .17 .18 .22 .29 .29 .34 .26 .22 27 .73 .48 .41 .41 .34 .32 .28 .24 .19 7.1 1.5 .71 .39 .32 .28 .23 .15 .12 MEAN DISCHARGE (CPS) 7.7 7.8 7.6 33 81 105 265 96 26 19 41 223 60 24 286 174 58 114 43 24 57 134 39 23 19 15 17 15 13 11 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 12 13 12 69 329 174 633 159 28 18 62 441 79 24 626 212 45 206 54 30 56 230 42 24 20 18 16 14 13 13 .25 .27 .24 9.7 253 180 1620 76 2.0 .92 36 360 19 1.5 792 144 6.9 157 6.8 2.0 10 217 4.5 1.5 1.0 .74 .71 .58 .47 .39 TOTAL 324.7 17.24 338.1 44.09 2038.1 3904.47 219 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 DISCHARGE (CPS) 11 11 12 13 17 17 18 71 50 29 25 118 84 440 233 49 31 23 20 21 16 14 13 12 12 12 11 54 18 12 11 MEAN CONCEN- TRATION (MG/L) JULY 12 11 11 10 10 10 10 75 62 34 27 274 102 1150 475 65 35 24 20 15 9 6 5 5 5 5 5 55 32 19 8 TOTAL 1478 —— YEAR e 13930.8 Estimated SEDIMENT DISCHARGE (TONS/DAY) .36 .33 .34 .36 .45 .46 .49 24 8.8 2.7 2.1 116 52 2900 499 8.7 3.0 1.5 1.1 .85 .38 .21 .17 .16 .16 .17 .15 22 1.6 .64 .25 3648.43 145204.68 MEAN DISCHARGE (CFS) 9.9 11 140 36 18 13 11 11 9.7 9.2 8.8 8.5 14 208 116 370 52 29 21 19 19 19 20 18 16 15 15 14 12 11 9.8 1283.9 MEAN CONCEN- TRATION (MG/L) AUGUST 6 6 251 44 18 11 10 9 8 9 11 11 13 499 264 9870 78 26 13 8 5 4 15 9 5 6 6 6 6 6 6 —— SEDIMENT DISCHARGE (TONS/DAY) .16 .17 221 5.0 .90 .40 .29 .26 .21 .23 .26 .26 1.2 1040 168 47600 12 2.1 .81 .42 .24 .21 1.0 .46 .23 .23 .23 .23 .20 .18 .16 49057.04 MEAN MEAN CONCEN- DISCHARGE TRATION (CPS) 57 23 13 13 11 9 10 19 185 e!940 254 118 86 73 69 90 57 53 57 50 144 51 46 39 36 38 50 36 33 30 - 3690 (MG/L) SEPTEMBER 98 21 2 3 4 .1 6 8 51 240 9230 517 207 140 112 99 160 72 60 57 60 314 70 68 43 33 48 63 30 27 29 —— .1 —— SEDIMENT DISCHARGE (TONS/DAY) 116 2.3 .09 .12 .12 .14 .21 3.1 973 e80900 392 67 33 22 20 57 11 8.6 8.9 8.1 297 9.7 8.6 4.6 3.2 5.0 9.4 2.9 2.3 2.3 —— 82967.68 220 RIO GRANDE DE LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN,PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OD SUSPENDED-SEDIMENT OCT 1995 21... 28... JAN 1996 14... SEP 10... 10... DATE OCT 1995 21... 28... JAN 1996 14... SEP 10... 10... TIME 1757 1612 1642 0315 1130 SED. SUSP. FALL DIAM. ; FINER THAN 016 MM 51 72 44 39 45 DIS- CHARGE, INST. CUBIC FEET PER SECOND 857 774 1300 2330 2320 SED. SUSP. FALL DIAM. % FINER THAN .031 MM 67 83 63 49 56 SEDI- MENT, SUS- PENDED (MG/L) 6980 7900 10200 23300 17800 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM 85 98 88 63 70 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 16200 16500 36100 147000 112000 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM 98 99 97 74 82 SJ2D» SUSP. FALL DIAM. % FINER THAN .002 MM 18 29 19 16 25 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM 99 100 99 84 90 SED. SUSP. FALL DIAM. % FINER THAN .004 MM 26 48 22 23 31 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM 100 100 100 93 96 SED. SUSP. FALL DIAM. % FINER THAN .008 MM 36 57 29 29 35 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM 100 100 100 98 99 221 RIO GRANDE DB LOIZA BASIN 50053025 RIO TURABO ABOVE BORINQUEN,PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 21... JAN 1996 13... 14... MAY 23... JUN 28... AU6 15... SEP 10... TIME 1812 2142 1812 1736 1448 2130 0600 DIS- CHARGE, INST. CUBIC FEET PER SECOND 674 557 663 15 15 702 984 SEDI- MENT, SUS- PENDED (MG/L) 5780 1060 835 306 478 684 2570 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 10500 1590 1490 12 19 1300 6830 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM 93 98 70 81 100 97 90 222 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 1 (232.6 km1 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—1959 (low-flow measurement only), February to November 1959 (monthly measurements only). December 1959 to current year. GAGE.--Water-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, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV FEB 1 155 132 2 140 129 3 146 130 4 123 127 5 163 134 6 165 215 7 140 180 8 165 122 9 124 109 10 173 102 11 256 94 12 192 92 13 125 93 14 150 85 15 109 97 16 101 185 17 94 167 18 91 108 19 119 87 20 104 83 21 777 83 22 407 90 23 168 80 24 225 81 25 168 115 26 150 182 27 124 95 28 804 77 29 325 70 30 162 67 31 143 --- TOTAL 6288 3411 MEAN 203 114 MAX 804 215 MIN 91 67 AC-FT 12470 6770 CFSM 2.26 1.27 IN. 2.60 1.41 STATISTICS OF MONTHLY MEAN MEAN 356 314 MAX 1910 1131 (WY) 1971 1988 MIN 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 68 66 76 67 69 69 71 62 62 61 99 108 258 172 124 86 85 185 362 1900 285 158 121 102 147 113 95 84 76 67 67 5365 173 1900 61 10640 1.93 2.22 DATA 225 714 1988 33.6 1968 64 66 63 62 57 61 64 472 177 107 84 135 87 2110 1520 329 210 279 408 775 416 236 188 160 175 169 198 322 218 155 131 9498 306 2110 57 18840 3.41 3.93 FOR WATER 147 559 1992 45.3 1968 123 121 125 183 514 256 221 152 126 164 117 108 88 102 94 98 101 101 89 123 141 89 79 136 124 75 69 65 61 ___ --- 3845 133 514 61 7630 1.48 1.59 YEARS 1960 109 291 1984 35.6 1968 60 60 66 68 71 68 62 62 287 118 407 172 96 75 231 248 173 88 79 68 66 66 61 59 55 58 63 58 64 56 59 3224 104 407 55 6390 1.16 1.34 - 1996 91.6 306 1989 23.2 1968 FOR 1995 CALENDAR YEAR 58308 160 3800 19 19 115700 1. 24. 280 76 28 Sep 16 Apr 29 Apr 29 78 15 59 49 148 373 161 79 62 201 104 67 61 69 70 58 101 65 51 48 46 44 57 97 83 120 68 53 67 51 48 54 --- 2614 87.1 373 44 5180 .97 1.08 59 44 42 40 38 36 41 61 97 66 61 55 117 131 60 53 49 48 42 40 36 33 92 63 46 36 34 33 32 31 30 1646 53.1 131 30 3260 .59 .68 42 50 37 137 136 489 877 904 149 95 116 1860 925 318 1800 1740 699 829 510 223 292 876 308 180 146 129 140 212 153 111 --- 14483 483 1860 37 28730 5.38 6.00 95 87 84 85 74 73 73 251 449 213 146 878 595 2240 2370 467 277 205 194 223 176 143 134 121 115 126 114 282 280 127 111 10808 349 2370 73 21440 3.88 4.48 116 138 903 589 259 171 141 165 131 116 109 104 96 1780 1620 4850 665 335 234 199 176 156 217 226 155 133 133 133 128 118 117 14413 465 4850 96 28590 5.18 5.97 128 277 219 412 160 124 108 203 281 e20000 e2100 e!200 e860 e770 e740 e960 e600 e590 e620 e540 61520 e460 6410 e400 e392 e460 6540 e390 e350 e330 36144 1205 20000 108 71690 13.4 14.97 , BY WATER YEAR (WY) 89.0 355 1978 30.6 1995 FOR 1996 111739 305 20000 30 34 83000 32 29 221600 3 46 555 123 57 235 863 1985 33.7 1974 WATER YEAR Sep 10 May 31 May 26 Sep 10 .32 Sep 10 May 31 .40 .29 251 1283 1979 34.1 1975 229 660 1961 21.8 1974 WATER 217 526 82 20000 11 11 83000 32 17 157100 2 32 360 106 39 258 949 1979 51.4 1994 YEARS 1960 .3 Sep Apr Apr Sep .32 Sep Aug .41 .81 291 1205 1996 37.4 1967 - 1996 1979 1967 10 1996 8 1968 8 1968 10 1996 10 1996 18 1994 e Estimated 223 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGDAS, 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 mg/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 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 5,230 mg/L September 10, 1996 ; minimum daily mean, 14 mg/L July 3, 1996. SEDIMENT LOADS: Maximum daily mean, 396,000 tons (359,000 tonnes) September 10, 1996; minimum daily 2.5 ton (2.3 tonnes) May 30-31,1996. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE TIME 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) OCT 1995 10... JAN 1996 11... FEE 15... APR 18... JUN 24... AUG 12... 1005 0900 0840 0855 0905 0850 107 73 81 51 162 98 255 232 237 254 205 244 6.2 6.6 6.8 7.0 7.3 7.2 27.0 25.5 24.5 26.5 28.0 28.5 16 170 74 31 8.1 22 5.8 6.6 7.2 6.7 6.4 5.4 71 79 84 83 81 69 <10 23000 <10 27000 16 31000 19 2500 19 K19000 <10 22000 460 37000 K18000 K1600 2000 420 DATE OCT 1995 10... JAN 1996 11... FEB 15... APR 18... JUN 24... AUG 12... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 76 _„ __ 74 -- 70 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 19 -- -- 19 -- 18 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 6.9 -- -- 6.4 — 6.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 19 -- — 21 -- 20 SODIUM AD- SORP- TION RATIO (00931) 0.9 -- -- 1 — 1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.1 -- -- 2.1 -- 1.8 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 72 84 75 74 61 82 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- 0.6 __ — SULFATE DIS- SOLVED (MG/L AS S04) (00945) 11 -- -- 13 -- 11 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 18 -- -- 21 -- 18 non-ideal count 224 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 10... JAN 1996 11... FEB 15... APR 18... JUN 24... AUG 12... OCT 1995 10... JAN 1996 11... FEB 15... APR 18... JUN 24... AUG 12... DATE FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) <0.10 — — 0.10 — <0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (HG/L AS N) (00625) 0.37 0.56 0.36 0.43 0.38 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 34 -- -- 31 -- 37 NITRO- GEN, TOTAL (HG/L AS N) (00600) 0.88 1.3 0.94 0.91 0.90 0.50 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (HG/L) (70301) 153 -- — 158 — 161 NITRO- GEN, TOTAL (HG/L AS NO3) (71887) 3.9 5.6 4.2 4.0 4.0 2.2 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS UN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 44.3 -- -- 21.5 -- 42.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.080 0.140 0.180 0.080 0.070 0.080 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (HG/L) (00530) 16 184 87 42 25 31 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (HG/L AS N) (00620) 0.480 0.660 0.540 0.470 0.500 0.350 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (HG/L AS N) (00615) 0.030 0.040 0.040 0.010 0.020 0.020 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — — 30 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (HG/L AS N) (00630) 0.510 0.700 0.580 0.480 0.520 0.370 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — -- <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.070 0.120 0.050 0.140 0.040 0.050 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — — <1 — — PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.30 0.44 0.31 0.29 0.34 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- — <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) OCT 1995 10... JAN 1996 11... FEB 15... APR 18... JUN 24... AUG 12... 1100 1800 <1 180 220 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <0.02 <0.02 225 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE 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 MEAN CONCEN- SEDIMENT TRATXON DISCHARGE (MG/L) (TONS/DAY) OCTOBER 155 140 146 123 163 165 140 165 124 173 256 192 125 150 109 101 94 91 119 104 777 407 168 225 168 150 124 804 325 162 143 68 37 99 111 125 137 121 130 57 82 206 175 103 116 75 44 39 40 56 57 318 187 42 138 138 118 98 377 189 63 91 29 14 40 37 57 63 46 58 20 58 151 92 35 48 22 12 10 9, 19 16 2880 300 19 85 64 49 33 2160 194 27 35 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 132 129 130 127 134 215 180 122 109 102 94 92 93 85 97 185 167 108 87 83 83 90 80 81 115 182 95 77 70 67 95 98 99 105 106 108 145 96 66 74 93 117 144 125 93 117 128 78 54 37 27 33 48 72 95 130 53 43 39 37 34 34 35 37 40 67 72 32 20 20 24 29 36 29 24 98 59 23 13 8 5 8 10 16 30 67 14 8 7 6 .3 .9 .0 .9 .3 .6 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 68 66 76 67 69 69 71 62 62 61 99 108 258 172 124 86 85 185 362 1900 285 158 121 102 147 113 95 84 76 67 67 50 74 110 159 176 182 182 130 82 52 60 90 173 115 103 77 73 87 218 725 206 126 104 86 111 98 78 73 67 63 62 9.2 13 22 29 33 34 35 22 14 8.6 21 27 148 54 35 18 18 48 262 7880 167 54 34 24 71 31 20 17 14 11 11 6288 6682.7 3411 908.0 5365 9184.8 226 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE HE LOIZA AT CAQUAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) FEBRUARY MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 64 66 63 62 57 61 64 472 177 107 84 135 87 2110 1520 329 210 279 408 775 416 236 188 160 175 169 198 322 218 155 131 60 57 55 53 51 56 62 288 181 180 80 115 107 763 548 176 153 230 288 430 222 66 48 45 43 42 75 228 120 70 53 10 10 9 8 7 9 11 556 93 54 18 43 25 12100 3710 156 87 184 451 957 271 43 24 20 20 19 45 225 74 29 19 .5 .8 .9 .2 123 121 125 183 514 256 221 152 126 164 117 108 88 102 94 98 101 101 89 123 141 89 79 136 124 75 69 65 61 40 37 39 130 1030 182 168 80 60 125 95 68 66 92 65 61 65 69 77 103 142 98 79 110 109 78 104 146 200 13 12 13 65 2550 133 105 34 20 57 30 20 16 26 16 16 18 19 19 35 55 24 17 56 38 16 19 26 33 60 60 66 68 71 68 62 62 287 118 407 172 96 75 231 248 173 88 79 68 66 66 61 59 55 58 63 58 64 56 59 208 203 198 195 198 201 192 102 279 209 391 647 562 262 185 181 92 82 125 144 124 141 161 183 207 215 218 219 206 191 177 34 33 35 36 38 37 32 17 239 70 662 300 148 53 195 149 51 19 26 27 22 25 26 29 31 34 37 34 36 29 28 9498 19289.4 3845 3501 3224 2532 227 RIO GRANDE DE LOZZA BASIN 50055000 RIO GRANDE DE LOZZA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) (CFS) 59 49 148 373 161 79 62 201 104 67 61 69 70 58 101 65 51 48 46 44 57 97 83 120 68 53 67 51 48 54 APRIL 169 193 222 272 283 61 41 147 143 155 176 137 97 68 60 98 211 206 163 100 64 117 69 210 259 322 301 249 128 68 MAY 27 26 118 492 147 13 6.8 133 41 28 29 26 18 11 17 17 29 27 20 12 13 36 20 69 47 46 55 35 17 9.9 —— 59 44 42 40 38 36 41 61 97 66 61 55 117 131 60 53 49 48 42 40 36 33 92 63 46 36 34 33 32 31 30 63 57 71 91 112 118 120 108 164 172 194 218 251 124 94 109 129 119 104 93 83 72 86 76 63 52 43 36 30 30 31 9.9 6.9 8.0 9.7 11 12 13 18 43 31 32 32 85 49 15 15 17 16 12 10 8.1 6.4 23 13 7.8 5.1 4.0 3.2 2.6 2.5 2.5 42 50 37 137 136 489 877 904 149 95 116 1860 925 318 1800 1740 699 829 510 223 292 876 308 180 146 129 140 212 153 111 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 42 50 37 137 136 489 877 904 149 95 116 1860 925 318 1800 1740 699 829 510 223 292 876 308 180 146 129 140 212 153 111 42 56 44 101 108 299 465 452 118 73 47 815 390 172 772 610 148 335 130 83 196 392 228 186 177 165 108 62 41 29 5 7 4 48 43 464 1500 2070 49 19 15 4870 1370 148 5480 2850 334 1280 215 58 199 1080 192 90 70 58 40 35 17 8 .0 .7 .4 .7 2614 1585.7 1646 523.7 14483 22619.8 228 RIO GRANDB DB LOIZA BASIN 50055000 RIO GRANDB DB LOIZA AT CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 DISCHARGE (CFS) 95 87 84 85 74 73 73 251 449 213 146 878 595 2240 2370 467 277 205 194 223 176 143 134 121 115 126 114 282 280 127 111 MEAN CONCEN- TRATION (MG/L) JULY 20 17 14 59 187 132 96 107 167 140 112 430 255 894 1000 56 22 21 20 130 107 52 40 35 29 26 40 170 195 82 78 TOTAL 10808 —— YEAR e 111739 Estimated SEDIMENT DISCHARGE (TONS/ DAY) 5.2 3.9 3.3 15 38 26 19 89 197 81 44 1600 493 10800 10900 82 17 12 11 84 54 21 15 12 9.2 8.9 12 232 173 28 23 25108.5 545634.6 MEAN DISCHARGE (CFS) 116 138 903 589 259 171 141 165 131 116 109 104 96 1780 1620 4850 665 335 234 199 176 156 217 226 155 133 133 133 128 118 117 14413 MEAN CONCEN- TRATION (MG/L) AUGUST 90 95 381 336 96 60 53 111 55 40 41 43 65 804 701 1120 215 123 81 158 350 387 350 156 68 47 38 42 50 60 72 —— SEDIMENT DISCHARGE (TONS/ DAY) MEAN DISCHARGE (CPS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) SEPTEMBER 28 36 1320 547 72 28 20 52 20 13 12 12 17 6510 4410 22600 397 113 51 85 165 163 206 106 29 17 14 15 18 19 23 37118 128 277 219 412 160 124 108 203 281 e20000 e2100 e!200 e860 e770 e740 e960 e600 e590 e620 e540 e!520 e460 e410 e400 e392 e460 e540 e390 e350 e330 —— 36144 99 189 154 261 134 97 97 146 189 5230 1230 715 525 235 225 372 388 351 239 184 491 465 187 79 65 66 66 66 66 65 —— —— 40 166 129 370 60 32 28 83 883 e396000 67000 e3150 e!450 e522 e459 e856 e806 e563 e389 e286 e!350 e!210 e222 e86 e69 e76 e89 e82 e65 e60 —— 416581 229 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT JUL 1996 14... AUG 16... 16... SEP 10... 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. «6 FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 1430 8010 0730 14700 0750 12600 1131 49100 2160 2510 2400 46700 99600 81600 8390 1110000 30 39 44 24 53 49 53 28 61 58 62 33 DATE JUL 1996 14... AUG 16... 16... SEP 10... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. «6 FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. «6 FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. «6 FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. «6 FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 72 71 74 43 85 77 80 54 98 96 97 71 100 99 99 89 100 100 100 98 100 100 100 100 100 100 100 100 230 RIO GRANDE DE LOIZA BASIN 50055000 RIO GRANDE DE LOIZA AT CAGUAS--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 12... FEB 1996 05... APR 05... JUN 15... 16.. . 22.. . JUL 14... AUG 01... 16... 16... TIME 1529 1155 0940 1445 1128 1210 1400 1822 0630 0710 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 166 601 146 1860 2570 1910 5520 118 20000 17300 SEDI- MENT, SUS- PENDED (MG/L) (80154) 236 2040 351 622 989 837 2010 94 2500 2340 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 106 3310 138 3120 6860 4320 30000 30 135000 109000 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 95 100 95 99 98 99 98 98 97 98 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR A6UAS 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. 231 DRAINAGE AREA.—5.30 mi* (13.72 km*). 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 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 NOV DEC JAN JUL AUG 1 2.9 2.4 2 2.6 2.4 3 2.5 3.9 4 2.5 29 5 2.6 8.4 6 2.7 8.3 7 2.5 4.7 8 2.4 3.7 9 2.3 2.9 10 2.4 2.6 11 2.2 2.5 12 2.2 2.4 13 2.1 2.3 14 1.9 2.3 15 1.7 2.2 16 1.7 7.4 17 2.1 2.8 18 1.8 2.4 19 2.4 2.2 20 1.8 2.1 21 2.1 2.0 22 1.9 2.0 23 1.8 1.9 24 3.9 2.0 25 2.2 2.2 26 2.0 2.3 27 27 1.8 28 4.8 2.1 29 2.6 2.8 30 2.4 2.1 31 2.3 —— TOTAL 98.3 118.1 MEAN 3.17 3.94 MAX 27 29 MIN 1.7 1.8 AC-PT 195 234 CFSM .60 .74 IN. .69 .83 STATISTICS OF MONTHLY MEAN MEAN 8.05 7.23 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 1.9 1.9 1.9 1.9 1.9 2.7 2.0 1.8 1.7 1.9 1.9 1.8 2.0 1.6 1.5 1.6 1.5 17 6.6 2.4 2.0 1.7 4.5 2.0 18 3.8 2.5 2.4 1.9 1.8 1.7 99.8 3.22 18 1.5 198 .61 .70 1.6 1.6 1.5 1.4 1.4 1.6 1.5 10 5.4 2.4 2.1 3.9 2.3 37 28 7.4 7.3 5.7 27 41 13 7.8 6.6 5.8 6.7 6.1 8.0 15 9.2 6.8 5.6 280.7 9.05 41 1.4 557 1.71 1.97 DATA FOR WATER 6.60 13.4 1993 2.34 1995 FOR 8.41 16.7 1992 2.48 1995 4.9 4.4 4.2 3.8 3.9 4.6 3.6 4.5 6.4 5.6 3.7 3.3 3.1 3.0 2.9 2.8 2.8 2.8 2.9 2.7 3.2 2.6 2.5 3.4 2.4 2.3 2.1 2.0 1.9 ___ ___ 98.3 3.39 6.4 1.9 195 .64 .69 YEARS 1990 4.78 8.00 1991 2.96 1995 1.8 1.8 1.8 1.8 2.0 1.8 1.8 1.8 1.9 1.6 2.4 1.8 1.6 1.6 12 2.7 2.0 1.8 1.8 1.7 1.7 1.7 1.6 1.5 1.4 1.4 1.7 1.7 1.6 1.5 1.5 64.8 2.09 12 1.4 129 .39 .45 - 1996 4.78 8.87 1990 2.09 1996 1995 CALENDAR YEAR 1659. 4. 143 1. 1. 3290 . 11. 6. 2. 1. 5 55 Sep 6 3 Apr 30 5 Apr 25 86 65 5 6 8 1.4 1.4 13 2.6 1.9 2.8 1.9 1.7 1.7 1.6 1.5 1.8 1.6 1.7 1.9 2.0 1.5 1.5 1.4 1.3 1.6 3.0 2.6 2.2 1.6 1.4 1.4 1.3 1.4 1.3 —— 64.0 2.13 13 1.3 127 .40 .45 1.2 1.2 1.2 1.2 1.2 1.2 3.5 2.3 2.7 3.8 2.4 2.0 1.9 1.8 1.7 1.7 1.8 1.7 2.7 1.9 1.6 1.6 12 2.6 2.4 2.3 2.3 2.1 2.0 2.0 2.0 72.0 2.32 12 1.2 143 .44 .51 2.0 1.9 1.9 5.0 3.5 3.6 9.9 2.9 2.6 2.4 2.7 23 5.6 2.9 27 31 8.8 14 5.5 2.9 2.8 8.3 2.8 2.5 2.4 2.8 2.5 e2.0 el. 9 el. 8 188.9 6.30 31 1.8 375 1.19 1.33 el. 8 1.7 1.7 1.6 1.6 1.6 1.7 16 5.6 2.8 2.4 3.5 6.8 57 29 6.6 3.9 3.2 3.0 3.0 2.8 2.7 2.6 2.6 2.6 2.5 2.5 5.9 3.6 2.8 2.6 187.7 6.05 57 1.6 372 1.14 1.32 3.7 2.8 7.8 6.9 3.1 2.7 2.6 2.4 2.4 2.4 2.3 2.2 2.1 18 49 46 8.9 4.6 3.1 2.9 2.8 2.6 12 3.2 2.5 2.5 2.4 2.4 2.4 2.3 2.3 213.3 6.88 49 2.1 423 1.30 1.50 14 3.1 3.1 3.6 2.6 2.4 2.5 3.4 13 1260 71 28 17 12 15 11 10 12 9.5 9.0 9.9 8.1 7.5 7.5 7.4 7.4 7.3 11 9.9 9.8 --- 1588.0 52.9 1260 2.4 3150 9.99 11.15 , BY WATER YEAR (WY) 4.94 13.1 1993 1.84 1995 FOR 1996 3073 8 1260 1 1 4990 21 1 6100 1 21 10 2 1 5.83 18.0 1993 2.32 1996 WATER YEAR .9 .40 Sep 10 .2 May 1 .2 Apr 30 Sep 10 .22 Sep 10 .1 May 4 .58 .58 .4 .6 4.57 8.05 1993 2.32 1994 6.41 18.6 1993 1.86 1994 WATER 7 11 4 1260 1 1 4990 21 1 5130 1 18 9 4 2 6.42 11.2 1993 1.85 1994 YEARS 1990 .08 .1 .41 Sep .2 May .2 Apr Sep .22 Sep .1 May .34 .14 .6 .3 .0 14.4 52.9 1996 3.32 1994 - 1996 1993 1995 10 1996 1 1996 30 1996 10 1996 10 1996 4 1996 e Estimated 232 RIO ORANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AQUAS 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.-- USHD-49 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, 2 mg/L several days. SEDIMENT LOADS: Maximum daily mean, 24,500 tons (22,200 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.02 tonne) several days. EXTREMES FOR CURRENT YEAR 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 5,300 mg/L September 10, 1996; Minimum daily mean, 3 mg/L May 26, 1996. SEDIMENT LOADS: Maximum daily mean, 24,500 tons (22,200 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.02 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) NOVEMBER 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) 2.9 2.6 2.5 2.5 2.6 2.7 2.5 2.4 2.3 2.4 2.2 2.2 2.1 1.9 1.7 1.7 2.1 1.8 2.4 1.8 2.1 1.9 1.8 3.9 2.2 2.0 27 4.8 2.6 2.4 2.3 MEAN CONCEN- TRATION (MG/L) OCTOBER 33 32 32 41 32 31 30 23 22 20 19 21 21 17 15 14 23 16 73 17 19 26 21 36 25 18 1320 167 145 126 107 SEDIMENT DISCHARGE (TONS/DAY) .26 .23 .22 .28 .23 .23 .20 .15 .13 .13 .12 .13 .12 .08 .07 .06 .19 .08 .68 .08 .11 .14 .10 .40 .15 .10 427 2.2 1.0 .81 .67 MEAN DISCHARGE (CFS) 2.4 2.4 3.9 29 8.4 8.3 4.7 3.7 2.9 2.6 2.5 2.4 2.3 2.3 2.2 7.4 2.8 2.4 2.2 2.1 2.0 2.0 1.9 2.0 2.2 2.3 1.8 2.1 2.8 2.1 2.4 2.4 3.9 29 8.4 8.3 4.7 3.7 2.9 2.6 2.5 2.4 2.3 2.3 2.2 7.4 2.8 2.4 2.2 2.1 2.0 2.0 1.9 2.0 2.2 2.3 1.8 2.1 2.8 2.1 69 40 86 470 81 96 156 97 59 42 31 23 21 21 20 191 468 559 512 443 387 395 423 448 426 395 349 114 51 61 .45 .26 1.1 140 2.3 4.3 2.0 .99 .46 .30 .21 .15 .13 .13 .12 7.8 3.5 3.6 3.1 2.5 2.1 2.1 2.1 2.4 2.5 2.5 1.7 .60 .50 .36 MEAN DISCHARGE (CFS) 1.9 1.9 1.9 1.9 1.9 2.7 2.0 1.8 1.7 1.9 1.9 1.8 2.0 1.6 1.5 1.6 1.5 17 6.6 2.4 2.0 1.7 4.5 2.0 18 3.8 2.5 2.4 1.9 1.8 1.7 MEAN CONCEN- TRATION (MG/L) DECEMBER 16 13 12 17 24 49 40 38 34 24 16 11 19 13 12 12 11 613 96 25 20 20 68 20 688 51 29 25 18 17 17 SEDIMENT DISCHARGE (TONS/DAY) .08 .07 .06 .09 .12 .58 .22 .19 .16 .12 .08 .05 .11 .05 .05 .05 .05 51 2.6 .17 .11 .09 2.8 .11 196 .65 .21 .17 .09 .08 .08 TOTAL 98.3 436.35 118.1 190.26 99.8 256.29 233 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS , PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 DISCHARGE (CPS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 1.6 1.6 1.5 1.4 1.4 1.6 1.5 10 5.4 2.4 2.1 3.9 2.3 37 28 7.4 7.3 5.7 27 41 13 7.8 6.6 5.8 6.7 6.1 8.0 15 9.2 6.8 5.6 16 16 15 15 14 14 14 306 118 47 19 49 25 871 632 111 119 81 624 926 222 118 98 71 50 36 86 255 42 9 9 .07 .06 .06 .05 .05 .06 .06 20 7.7 .32 .11 .70 .16 488 123 2.3 3.4 1.3 213 241 8.2 2.5 1.7 1.1 .89 .59 2.1 12 1.2 .17 .13 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) FEBRUARY 4.9 4.4 4.2 3.8 3.9 4.6 3.6 4.5 6.4 5.6 3.7 3.3 3.1 3.0 2.9 2.8 2.8 2.8 2.9 2.7 3.2 2.6 2.5 3.4 2.4 2.3 2.1 2.0 1.9 8 11 15 21 21 50 24 47 98 65 45 30 23 23 26 29 32 36 39 34 40 9 4 32 9 6 5 5 6 .11 .13 .17 .21 .22 .75 .24 1.0 2.0 1.4 .45 .27 .19 .19 .20 .22 .25 .27 .30 .25 .43 .07 .03 .95 .06 .03 .03 .03 .03 MEAN DISCHARGE (CPS) 1.8 1.8 1.8 1.8 2.0 1.8 1.8 1.8 1.9 1.6 2.4 1.8 1.6 1.6 12 2.7 2.0 1.8 1.8 1.7 1.7 1.7 1.6 1.5 1.4 1.4 1.7 1.7 1.6 1.5 1.5 MEAN CONCEN- TRATION (MG/L) MARCH 8 10 10 10 10 7 4 8 13 13 34 18 21 23 447 46 13 8 6 6 8 7 5 5 4 4 6 8 10 11 11 SEDIMENT DISCHARGE (TONS/DAY) .04 .05 .05 .05 .05 .03 .02 .04 .07 .06 .25 .09 .09 .10 48 .36 .07 .04 .03 .03 .04 .03 .02 .02 .02 .02 .02 .03 .05 .04 .04 TOTAL 280.7 1131.98 98.3 10.48 64.8 49.85 234 RIO GRANDE DE LOZZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BDENAS , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE 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 1.4 1.4 13 2.6 1.9 2.8 1.9 1.7 1.7 1.6 1.5 1.8 1.6 1.7 1.9 2.0 1.5 1.5 1.4 1.3 1.6 3.0 2.6 2.2 1.6 1.4 1.4 1.3 1.4 1.3 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 10 10 1010 381 68 34 24 20 17 17 47 47 34 30 26 23 20 20 20 20 15 80 152 165 145 122 71 37 21 20 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MAY .04 .04 159 2.8 .35 .50 .12 .09 .08 .07 .19 .22 .15 .14 .14 .12 .08 .08 .08 .07 .06 1.1 1.1 .98 .63 .47 .27 .13 .08 .07 —— 1.2 1.2 1.2 1.2 1.2 1.2 3.5 2.3 2.7 3.8 2.4 2.0 1.9 1.8 1.7 1.7 1.8 1.7 2.7 1.9 1.6 1.6 12 2.6 2.4 2.3 2.3 2.1 2.0 2.0 2.0 20 21 25 30 35 32 80 46 32 56 51 36 28 22 19 17 16 14 33 14 9 10 624 8 5 3 6 11 13 10 10 .06 .07 .08 .09 .11 .10 2.1 .28 .25 .68 .34 .20 .14 .11 .09 .08 .08 .07 .39 .08 .04 .04 52 .05 .03 .02 .03 .06 .07 .06 .05 2.0 1.9 1.9 5.0 3.5 3.6 9.9 2.9 2.6 2.4 2.7 23 5.6 2.9 27 31 8.8 14 5.5 2.9 2.8 8.3 2.8 2.5 2.4 2.8 2.5 e2.0 el. 9 el. 8 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 2.0 1.9 1.9 5.0 3.5 3.6 9.9 2.9 2.6 2.4 2.7 23 5.6 2.9 27 31 8.8 14 5.5 2.9 2.8 8.3 2.8 2.5 2.4 2.8 2.5 e2.0 el. 9 el. 8 9 9 8 59 46 45 133 31 32 33 32 1140 60 30 539 551 152 481 75 30 28 200 29 22 17 26 24 19 15 12 .05 .05 .04 1.2 .58 .59 5.4 .26 .22 .22 .24 100 1.0 .24 61 70 5.6 46 1.4 .24 .21 11 .22 .15 .11 .25 .16 e.ll e.08 e.06 TOTAL 64.0 169.25 72.0 57.85 188.9 306.68 e Estimated 235 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS , PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY el. 8 1.7 1.7 1.6 1.6 1.6 1.7 16 5.6 2.8 2.4 3.5 6.8 57 29 6.6 3.9 3.2 3.0 3.0 2.8 2.7 2.6 2.6 2.6 2.5 2.5 5.9 3.6 2.8 2.6 L87.7 )73.9 9 8 8 7 6 6 5 333 55 13 24 46 105 1440 619 92 63 57 51 41 33 26 30 36 42 38 32 105 63 50 40 —— e.05 .04 .03 .03 .03 .03 .02 39 1.8 .10 .16 1.0 3.1 580 85 1.8 .66 .50 .41 .33 .25 .19 .21 .25 .29 .26 .22 3.0 .60 .38 .28 720.02 29889.90 MEAN DISCHARGE (CPS) 3.7 2.8 7.8 6.9 3.1 2.7 2.6 2.4 2.4 2.4 2.3 2.2 2.1 18 49 46 8.9 4.6 3.1 2.9 2.8 2.6 12 3.2 2.5 2.5 2.4 2.4 2.4 2.3 2.3 MEAN CONCEN- TRATION (MG/L) AUGUST 50 23 91 103 38 27 19 13 10 13 20 27 25 536 1000 1110 140 42 17 10 13 12 741 29 14 14 15 16 17 19 20 SEDIMENT DISCHARGE (TONS /DAY) .62 .18 4.1 2.9 .32 .19 .13 .09 .06 .09 .12 .16 .14 59 900 204 3.7 .55 .15 .08 .10 .08 70 .29 .09 .09 .10 .10 .11 .12 .12 MEAN DISCHARGE (CPS) I 14 3.1 3.1 3.6 2.6 2.4 2.5 3.4 13 1260 71 28 17 12 15 11 10 12 9.5 9.0 9.9 8.1 7.5 7.5 7.4 7.4 7.3 11 9.9 9.8 ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 14 3.1 3.1 3.6 2.6 2.4 2.5 3.4 13 1260 71 28 17 12 15 11 10 12 9.5 9.0 9.9 8.1 7.5 7.5 7.4 7.4 7.3 11 9.9 9.8 719 17 25 52 94 34 33 59 397 5300 1730 585 293 125 254 179 158 391 153 147 165 123 119 114 110 109 110 174 156 151 123 .17 .63 .89 .67 .22 .22 .61 132 24500 406 45 14 4.1 14 5.5 4.3 21 3.9 3.6 4.7 2.7 2.4 2.3 2.2 2.2 2.2 6.4 4.2 4.0 213.3 1247.78 1588.0 25313.11 236 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS, PR—Continued HATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DIS- CHARGE, INST. CUBIC DATE OCT 1995 27... DEC 18... 25... JAN 1996 08... MAY 23... SEP 10... TIME 1607 1857 1717 0832 0615 0915 PER SECOND 485 33 138 36 33 3450 SEDI- SEDI- MENT, SUS- PENDED DIS- CHARGE, SUS- PENDED SED. SUSP. FALL DIAM. SED. SED. SUSP. SUSP. FALL FALL DIAM. DIAM. FINER % FINER % FINER THAN THAN THAN (MG/L) (T/DAY) .002 MM .004 MM .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 10100 13300 13200 9920 1180 3700 2200 213 5510 490 21700 202000 34 49 39 71 48 20 40 64 53 82 58 26 48 77 70 87 67 30 DATE OCT 1995 27... DEC 18... 25... JAN 1996 08... MAY 23... SEP 10... 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) 63 83 86 90 75 35 78 84 90 91 85 41 87 99 97 99 98 52 92 99 99 99 99 61 95 100 99 99 100 71 99 100 100 100 100 82 100 100 100 100 100 91 237 RIO GRANDE DE LOIZA BASIN 50055100 RIO CAGUITAS NEAR AGUAS BUENAS, PR—Continued WATER QUALITY DATA, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OP SUSPENDED SEDIMENT DATE OCT 1995 27... NOV 16... APR 1996 03... JUN 18... JUL 14... AU6 14... 23... TIME 1807 1532 1520 1730 1500 1345 1745 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 75 37 49 62 198 53 27 SEDI- MENT, SUS- PENDED (MG/L) (80154) 6590 585 28400 3880 4420 2670 14500 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1330 58 3760 649 2360 382 1060 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 99 92 98 100 96 99 79 238 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR LOCATION.--Lat 18°13'59", long 66°02'53 M , Hydrologic Unit 21010005, on left bank, 0.9 mi (1.4 km) southwest from Plaza de 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 km'). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--Hay 1992 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 216 ft (66 m), from topographic map. REMARKS.--Records poor. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES APR AUG SEP 1 3.7 e5.2 2 3.9 e5.4 3 4.3 e!2 4 5.8 e30 5 e6.2 e60 6 e6.2 el9 7 e6.0 e!2 8 e5.6 e8.4 9 e5.4 e6.6 10 e5.4 e6.0 11 eS.O e5.6 12 eS.O e5.4 13 e4.8 e5.4 14 e4.5 e5.2 15 e4.0 eS.O 16 e4.0 el7 17 e4.6 eS.O 18 e5.6 e6.0 19 e5.2 eS.O 20 e4.1 e4.6 21 e4.7 e4.5 22 e4.4 e4.4 23 e4.2 e4.4 24 e8.8 e4.3 25 eS.O e4.5 26 e4.7 e4.8 27 e!7 eS.O 28 e56 e4.2 29 e!3 e5.2 30 e5.6 e6.0 31 e5.2 - — TOTAL 227.9 279.1 MEAN 7.35 9.30 MAX 56 60 MIN 3.7 4.2 AC-FT 452 554 CFSH .89 1.12 IN. 1.03 1.26 e4.5 e4.2 e4.2 e4.2 e4.2 e4.8 e5.8 e4.6 e3.5 e4.0 eS.O e4.8 e6.2 e4.7 e3.5 e3.8 e3.5 e37 e5.2 e4.8 e7.0 e5.4 13 32 33 51 e5.6 e5.4 e4.5 e4.2 e4.2 287.8 9.28 51 3.5 571 1.12 1.29 e4.2 e4.1 e4.0 e4.0 e4.5 e4.0 e4.5 42 49 18 e5.2 e7.6 e5.4 71 70 e!6 e!6 e!3 e22 e84 e22 e!6 e!4 el2 el4 el3 e22 e34 e!6 e!5 ell 637.5 20.6 84 4.0 1260 2.49 2.87 STATISTICS OF MONTHLY MEAN DATA FOR WATER MEAN 11.3 19.3 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 14.6 37.0 1993 4.17 1995 FOR 12.6 20.6 1996 1.90 1995 8.7 8.6 8.2 8.3 9.5 9.5 8.9 7.1 11 12 7.8 6.6 6.2 6.0 5.5 5.8 7.7 8.3 8.5 8.9 8.7 7.7 6.0 6.8 7.3 7.3 5.6 5.4 5.4 ___ --- 223.3 7.70 12 5.4 443 .93 1.00 YEARS 1992 6.55 9.20 1993 2.45 1995 .8 .6 .6 .3 .4 .8 .3 6.3 9.9 6.4 10 8.4 7.6 7.6 45 18 10 8.9 8.2 8.0 7.5 6.5 7.2 5.9 6.5 6.0 5.6 5.6 7.1 4.5 4.8 254.3 8.20 45 4.3 504 .99 1.14 - 1996 5.39 8.20 1996 1.75 1995 1995 CALENDAR YEAR 3300. 9. 508 . . 6550 1. 14. 10 2. . 37 04 Sep 6 72 Apr 30 77 Apr 27 09 85 7 89 4.6 3.8 74 16 7.0 6.8 5.5 4.9 4.2 3.4 3.5 4.2 4.2 4.1 5.2 5.4 3.6 3.4 3.3 2.8 3.8 8.4 8.0 7.0 4.4 3.9 3.4 4.0 4.8 4.4 --- 222.0 7.40 74 2.8 440 .89 1.00 3.3 2.9 3.2 2.7 2.4 2.5 5.2 6.5 5.7 7.0 5.1 3.3 4.5 4.1 3.7 3.9 3.8 3.6 4.5 5.2 3.0 2.7 23 8.5 5.9 5.1 5.1 4.3 4.0 3.7 3.9 152.3 4.91 23 2.4 302 .59 .69 3.8 3.8 3.7 11 8.1 9.9 31 7.2 5.3 4.5 6.5 47 18 9.7 48 65 33 26 23 12 13 21 11 8.8 7.6 8.2 7.4 8.1 6.4 6.1 474.1 15.8 65 3.7 940 1.91 2.13 5.4 5.3 5.1 5.1 4.8 4.6 4.7 25 24 10 7.3 11 28 130 95 32 22 18 15 15 12 11 10 10 10 10 9.6 21 15 8.5 8.1 592.5 19.1 130 4.6 1180 2.31 2.67 13 11 26 25 14 11 9.1 8.3 8.1 7.6 7.2 6.4 5.3 37 95 150 22 12 8.4 6.9 5.9 5.2 26 12 7.2 6.3 5.5 5.3 5.3 5.1 4.9 572.0 18.5 150 4.9 1130 2.23 2.57 21 9.6 13 7.2 6.4 5.4 5.3 12 8.9 e!320 e!70 e84 e48 e30 e37 e27 e25 e30 e24 e23 e24 e20 e!9 e!8 e!8 e!8 e!8 e27 e24 e24 2116.8 70.6 1320 5.3 4200 8.53 9.52 , BY WATER YEAR (WY) 10.1 27.8 1993 1.16 1995 FOR 1996 6039 16 1320 2 3 9040 31 11980 2 27 26 6 4 13.1 41.2 1993 2.31 1994 WATER YEAR .6 .5 Sep 10 . 4 May 5 .1 Apr 30 Sep 10 .60 Sep 10 .00 .17 .5 .0 8.48 15.8 1996 1.71 1994 15.6 45.5 1993 2.65 1995 WATER 14 24 8 1320 9040 31 10450 1 23 23 6 1 11.9 20.2 1993 4.63 1995 37.6 70.6 1996 12.3 1994 YEARS 1992 - 1996 .4 .5 .33 Sep .72 Apr .77 Apr Sep .60 Sep .74 .71 .6 .9 1993 1994 10 1996 30 1995 27 1995 10 1996 10 1996 e Estimated 239 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR- -Continued WATER- QUALITY RECORDS PERIOD OF RECORDS.-- Water years 1992 to current year. PERIOD OF DAILY RECORD. -- SUSPENDED- SEDIMENT DISCHARGE: June 1992 to current year. INSTRUMENTATION.-- US D-49 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 rog/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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 3,820 mg/L September 10, 1996; Minimum daily mean, 5 mg/L April 16-17, 1996. SEDIMENT LOADS: M«yftiBnm daily mean, 19,100 tons (17,300 tonnes) September 10, 1996; Minimum daily mean, 0.05 ton (0.04 tonne) April 17, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 HAY 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) 3.7 3.9 4.3 5.8 e6.2 e6.2 66.0 e5.6 65.4 65.4 65.0 65.0 e4.8 e4.5 64.0 64.0 e4.6 65.6 65.2 64.1 64.7 e4.4 64.2 68.8 65.0 e4.7 617 656 e!3 e5.6 65.2 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) OCTOBER 11 12 13 15 15 12 28 29 29 30 30 30 30 31 31 31 32 32 32 33 31 27 31 25 30 35 34 107 85 29 21 TOTAL 227.9 .11 .13 .15 .25 6.33 .20 .47 .46 .44 .43 .40 .41 .40 .39 .36 .34 .37 .44 .47 .41 .40 .33 .36 .42 .54 6.46 el.O ell 68.4 e.70 6.31 30.88 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 65.2 e5.4 612 630 660 619 e!2 68.4 e6.6 e6.0 65.6 65.4 65.4 65.2 e5.0 617 68.0 e6.0 e5.0 e4.6 e4.5 64.4 e4.4 64.3 64.5 e4.8 e5.0 64.2 65.2 66.0 50 e.71 59 e.84 64 el. 4 92 65.3 123 615 120 e!2 72 63.0 55 el. 5 41 .83 31 .50 27 .42 26 .38 25 .36 24 .35 23 .32 69 e2.1 89 e2.9 41 19 21 25 30 36 43 51 63 33 26 22 22 .78 .29 .27 .30 .36 .42 .50 .61 .78 .44 .32 .28 .36 MEAN DISCHARGE (CFS) e4.5 e4.2 e4.2 64.2 64.2 64.8 65.8 64.6 63.5 64.0 65.0 e4.8 e6.2 e4.7 e3.5 63.8 63.5 e37 65.2 e4.8 67.0 65.4 13 32 33 51 65.6 65.4 64.5 64.2 64.2 MEAN CONCEN- TRATION (MG/L) DECEMBER 25 27 25 22 19 17 15 14 15 16 15 16 16 17 17 18 19 204 68 23 22 21 90 71 88 238 59 24 20 19 16 SEDIMENT DISCHARGE (TONS/DAY) 6.35 6.32 e.29 6.25 6.22 6.21 6.21 6.19 6.16 6.18 6.19 6.21 6.24 6.25 6.19 6.18 6.18 68.6 e3.8 e.29 6.34 e.35 7.5 12 47 48 e2.4 6.36 e.27 e.22 6.18 279.1 53.62 287.8 135.13 e Estimated 240 RIO QRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 e4.2 e4.1 e4.0 e4.0 e4.5 e4.0 e4.5 42 49 18 e5.2 e7.6 e5.4 71 70 e!6 e!6 e!3 e22 e84 e22 e!6 e!4 e!2 e!4 e!3 e22 e34 e!6 e!5 ell 20 21 20 20 17 26 30 159 197 77 32 29 29 277 269 49 70 64 75 195 193 86 69 58 55 57 74 117 103 68 57 e.22 e.23 e.22 e.21 e.19 e.29 e.35 22 51 4.2 e.63 e.50 e.51 226 157 el. 5 e3.0 e2.5 e3.5 e28 e27 e4.4 e2.8 e2.0 el. 9 e2.1 e3.5 e8.8 e6.9 e2.8 e2.0 8.7 8.6 8.2 8.3 9.5 9.5 8.9 7.1 11 12 7.8 6.6 6.2 6.0 5.5 5.8 7.7 8.3 8.5 8.9 8.7 7.7 6.0 6.8 7.3 7.3 5.6 5.4 5.4 —— MEAN CONCEN- SEDIMENT TRATZON DISCHARGE (MG/L) (TONS/DAY) FEBRUARY MEAN DISCHARGE (CFS) 44 36 29 24 19 16 13 11 53 63 40 30 28 28 28 24 34 44 27 44 41 32 21 27 35 35 38 42 45 1.1 .84 .65 .53 .50 .40 .31 .21 1.9 2.2 .88 .53 .46 .45 .43 .37 .83 1.0 .64 1.1 .96 .67 .34 .55 .70 .67 .60 .61 .65 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH .8 .6 .6 .3 .4 .8 .3 6.3 9.9 6.4 10 8.4 7.6 7.6 45 18 10 8.9 8.2 8.0 7.5 6.5 7.2 5.9 6.5 6.0 5.6 5.6 7.1 4.5 4.8 49 54 49 22 10 10 10 21 40 12 37 56 52 45 177 102 46 30 21 20 20 20 19 15 12 11 13 16 20 23 32 .64 .66 .61 .26 .15 .13 .12 .90 1.1 .21 1.1 1.2 1.1 .93 43 5.4 1.3 .73 .47 .44 .40 .36 .36 .26 .21 .17 .19 .24 .35 .27 .47 TOTAL 637.5 566.25 223.3 21.08 254.3 63.73 e Estimated 241 RIO GRANDE DB LOIZA BASIN 50055170 RIO CAGOlTAS NEAR CAGTJAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 4.6 3.8 74 16 7.0 6.8 5.5 4.9 4.2 3.4 3.5 4.2 4.2 4.1 5.2 5.4 3.6 3.4 3.3 2.8 3.8 8.4 8.0 7.0 4.4 3.9 3.4 4.0 4.8 4.4 ___ APRIL 23 35 291 80 39 36 29 27 26 41 20 7 6 6 7 5 5 11 21 24 26 47 39 33 15 7 7 8 12 18 ___ MEAN MEAN MEAN CONCEN- SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) (MG/L) (TONS/DAY) MAY .28 .36 246 3.8 .74 .65 .44 .36 .30 .39 .19 .08 .07 .07 .09 .07 .05 .10 .19 .18 .27 1.7 .88 .64 .18 .07 .06 .08 .16 .22 3.3 2.9 3.2 2.7 2.4 2.5 5.2 6.5 5.7 7.0 5.1 3.3 4.5 4.1 3.7 3.9 3.8 3.6 4.5 5.2 3.0 2.7 23 8.5 5.9 5.1 5.1 4.3 4.0 3.7 3.9 14 8 10 16 21 15 24 36 33 29 21 10 29 20 20 20 19 19 26 64 30 19 96 37 26 22 18 11 8 11 15 .12 .06 .09 .12 .14 .10 .50 .67 .52 .57 .31 .09 .53 .22 .19 .21 .20 .19 .43 .94 .25 .14 7.9 .83 .42 .31 .25 .13 .08 .11 .16 JUNE 3.8 3.8 3.7 11 8.1 9.9 31 7.2 5.3 4.5 6.5 47 18 9.7 48 65 33 26 23 12 13 21 11 8.8 7.6 8.2 7.4 8.1 6.4 6.1 —— 20 22 21 35 33 44 82 37 26 21 173 483 377 43 504 257 97 76 117 41 51 89 19 15 14 14 14 43 15 13 .21 .23 .21 1.2 .79 1.2 5.4 .77 .37 .25 4.1 74 21 1.1 142 49 10 8.6 7.7 1.4 1.9 5.9 .61 .35 .29 .31 .28 1.1 .25 .22 TOTAL 222.0 258.67 152.3 16.78 474.1 340.74 242 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 5.4 5.3 5.1 5.1 4.8 4.6 4.7 25 24 10 7.3 11 28 130 95 32 22 18 15 15 12 11 10 10 10 10 9.6 21 15 8.5 8.1 592.5 6039.6 JULY 14 16 19 21 22 21 20 126 268 37 19 55 313 896 436 282 242 92 24 19 23 29 34 18 13 12 11 74 72 37 36 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .21 .24 .26 .29 .28 .26 .26 20 23 1.0 .38 2.0 23 701 127 24 14 4.4 .98 .75 .73 .85 .96 .51 .36 .32 .29 7.0 2.8 .86 .77 958.76 23935.21 13 11 26 25 14 11 9.1 8.3 8.1 7.6 7.2 6.4 5.3 37 95 150 22 12 8.4 6.9 5.9 5.2 26 12 7.2 6.3 5.5 5.3 5.3 5.1 4.9 572.0 213 403 252 97 51 26 15 13 13 13 12 11 11 209 545 473 26 12 10 9 9 10 107 58 32 27 26 25 24 23 22 —— 10 12 18 6.8 2.1 .75 .37 .29 .28 .26 .23 .19 .15 26 638 303 1.7 .38 .24 .17 .15 .14 17 2.2 .62 .47 .39 .36 .34 .32 .29 1043.19 MEAN DISCHARGE (CFS) MEAN CONCEN- TRATION (MG/L) SEDIMENT DISCHARGE (TONS/DAY) SEPTEMBER 21 9.6 13 7.2 6.4 5.4 5.3 12 8.9 e!320 e!70 e84 e48 e30 e37 e27 e25 e30 e24 e23 e24 e20 el9 e!8 e!8 e!8 e!8 e27 e24 e24—— 2116.8 98 46 69 34 28 25 24 60 60 3820 1130 489 271 166 143 143 119 118 116 104 104 102 97 93 89 85 81 97 113 107 —— —— 15 1.3 6.1 .68 .50 .36 .34 2.3 9.9 e!9100 e966 e!67 e48 e!7 e!4 e!2 e8.3 e8.8 e7.5 e6.6 e6.6 e6.0 eS.l e4.6 e4.3 e4.1 e3.9 e5.9 e7.3 e6.9 —— 20446.38 243 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NR CAGUAS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE JUN 1996 11... 15... SEP 10... 1525 1800 0930 3210 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 7.0 169 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1310 6490 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 25 2960 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 68 32 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 79 46 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 82 58 9360 81100 26 36 43 JUN 1996 11... 15... SEP 10... SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 86 75 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 89 88 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 100 96 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 100 98 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 100 99 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 57 73 82 95 97 98 100 244 RIO GRANDE DE LOIZA BASIN 50055170 RIO CAGUITAS NEAR CAGUAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT NOV 1995 04... 05... DEC 07... FEB 1996 21... MAR 19... JUN 11... 15... JUL 14... AUG 16... SEP 10... 10... TIME 1405 1635 1645 1605 0745 1525 1800 1630 0700 0245 0930 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 30 60 5.8 8.2 8.2 7.0 169 364 431 1780 3210 SEDI- MENT, SUS- PENDED (MG/L) (80154) 70 107 169 48 21 1310 6490 2900 1110 2380 9360 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 5.7 17 2.6 1.1 0.46 25 2960 2850 1290 11400 81100 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 72 90 88 72 58 100 96 99 98 95 82 245 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGDAS, PR LOCATION.—Lat 18°14'55", long 66°01'40", Hydrologic 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 2 ). 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DEC JAN JUL AUG SEP 1 e!4 e!9 2 e!2 e20 3 e!2 e24 4 ell e71 5 e!6 645 6 618 651 7 e!2 637 8 e!9 630 9 e!4 625 10 618 623 11 e!4 622 12 e!7 620 13 e!4 e!8 14 e!3 618 15 613 e!6 16 e!2 634 17 e!3 626 18 613 618 19 639 618 20 618 616 21 618 615 22 616 614 23 621 613 24 632 613 25 620 e!7 26 618 627 27 646 614 28 637 ell 29 622 617 30 e!9 615 31 620 TOTAL 581 707 MEAN 18.7 23.6 MAX 46 71 MIN 11 11 MED 17 18 AC-FT 1150 1400 CFSM 1.60 2.01 IN. 1.85 2.25 STATISTICS OF MONTHLY MEAN MEAN 23.4 33.7 MAX 27.6 56.8 (WY) 1993 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 612 613 613 ell e!3 619 616 612 614 616 630 620 623 617 e!2 613 612 643 631 620 615 612 613 ell 627 620 615 613 e!2 ell elO 519 16.7 43 10 13 1030 1.43 1.65 ell e!2 ell elO elO ell elO e38 e82 e!7 ell e28 613 elOl 6147 625 619 618 656 689 638 624 619 e!9 624 622 635 642 e30 621 619 1012 32.6 147 10 21 2010 2.79 3.21 616 616 615 615 618 e!9 616 e!4 619 620 616 e!5 614 614 614 615 620 e!4 e!8 617 615 615 613 614 615 613 613 612 ell —— — 446 15.4 20 11 15 885 1.31 1.42 DATA FOR WATER YEARS 1991 22.6 58.4 1993 8.87 1995 FOR 38.6 120 1992 14.2 1995 17.6 23.8 1991 10.8 1992 613 613 e!2 612 616 e!3 613 622 626 e!8 630 622 620 620 e77 636 625 623 624 623 621 620 620 619 e!9 620 618 617 619 618 621 670 21.6 77 12 20 1330 1.85 2.13 - 1996 12.6 21.6 1996 7.54 1994 1995 CALENDAR YEAR 11181.1 30.6 1450 4.6 5.0 22180 2.62 35.52 46 17 5.6 Sep 6 Apr 6 Mar 31 Not 617 e!6 6165 639 618 e!4 626 e!7 616 e!6 614 e!7 614 614 616 619 e!4 614 615 613 614 618 620 617 e!2 ell elO e!2 614 614 — 636 21.2 165 10 15 1260 1.81 2.02 , BY WATER 15.8 39.8 1993 5.49 1994 612 ell elO elO elO ell 619 e20 625 626 618 615 622 614 612 615 e!2 ell 612 614 elO 69.3 632 613 elO elO 69.5 69.1 68.1 e7.9 67.5 425.4 13.7 32 7.5 12 844 1.17 1.35 YEAR (WY) 25.7 59.8 1993 3.35 1994 e8.4 68.4 69.0 627 623 625 e70 632 620 617 619 6160 656 621 6190 6220 664 elOO 650 622 620 660 629 620 e!7 620 618 616 e!4 613—— 1368.8 45.6 220 8.4 21 2720 3.90 4.35 23.4 45.6 1996 2.86 1994 FOR 1996 WATER YEAR 20219.2 55.2 8600 7.5 8.3 determined 23.89 40100 4.72 64.23 65 18 11 Sep 10 Hay 31 May 28 Sep 10 Sep 10 Not 613 612 612 ell ell ell e!2 ellO 650 e25 e!8 e20 645 6400 6220 650 631 624 622 622 621 620 619 e!9 619 e!8 618 643 627 621 619 1363 44.0 400 11 20 2700 3.75 4.33 31.6 74.6 1993 4.13 1994 627 621 656 650 628 620 619 e!8 618 e!8 617 616 615 6130 6350 6330 666 638 623 622 621 620 688 626 e!9 619 618 618 618 e!7 e!7 1563 50.4 350 15 20 3100 4.31 4.97 32.7 58.0 1995 3.82 1994 WATER YEARS 1991 33.4 55.2 11.9 8600 1.3 1.4 determined 23.89 24200 2.85 38.76 42 14 5.6 Sep Jun Jun Sep Sep elOO e23 e23 626 619 617 e!8 624 6120 68600 6450 6200 6120 688 ellO 680 672 686 670 664 672 658 654 654 652 652 652 680 674 670 —— 10928 364 8600 17 70 21680 31.1 34.72 95.7 364 1996 8.82 1994 - 1996 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 e Estimated 246 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1991 to current year. PERIOD OF DAILY RECORD.— SUSPENDED-SEDIMENT DISCHARGE: December 1990 to current year. INSTRUMENTATION.— USDH-49 sediment sampler 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, 5 mg/L Several days. 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 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,570 mg/L September 10, 1996; Minimum daily mean, 11 mg/L several days. SEDIMENT LOADS: Maximum daily mean, e34,700 tons (e31,500 tonnes) September 10, 1996; Minimum daily mean, eO.35 ton (eO.32 tonne) May 03, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 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!4 e!2 e!2 ell e!6 e!8 e!2 e!9 e!4 e!8 e!4 e!7 e!4 e!3 e!3 e!2 e!3 e!3 e39 e!8 e!8 e!6 e21 e32 e20 e!8 e46 e37 e22 e!9 e20 33 39 45 29 47 51 37 54 46 53 43 57 67 65 62 55 48 42 163 22 36 46 56 160 106 54 125 148 65 54 118 el. 3 el. 3 el. 4 e.85 e2.5 63.1 el. 2 e3.4 el. 7 e2.8 el. 6 e2.8 e2.6 e2.3 62.1 el. 8 el. 7 el. 5 e67 el.O 62.1 e2.0 63.9 e!4 e5.6 e2.7 633 e!5 e3.9 e2.8 e7.5 e!9 e20 e24 671 e45 651 637 630 625 623 622 620 e!8 e!8 e!6 634 e26 e!8 e!8 e!6 e!5 e!4 e!3 e!3 e!7 e27 e!4 ell e!7 e!5 238 217 193 352 82 85 112 58 30 23 34 30 30 43 60 90 76 64 60 63 64 54 41 53 51 106 90 76 49 34 e!2 e!2 e!2 e!88 ell e!5 ell e4.7 e2.0 el. 4 62.1 el. 7 el. 5 62.1 e2.6 e!2 e5.4 63.1 e2.8 62.7 62.6 62.0 el. 4 62.1 e2.7 e9.4 63.3 62.2 62.4 el. 5 MEAN DISCHARGE (CFS) e!2 e!3 e!3 ell e!3 e!9 e!6 e!2 e!4 e!6 e30 e20 e23 e!7 e!2 e!3 e!2 e43 e31 e20 e!5 e!2 e!3 ell e27 e20 e!5 e!3 e!2 ell elO MEAN CONCEN- TRATION (MG/L) DECEMBER 36 78 130 86 51 55 54 43 37 36 92 128 66 71 61 51 45 98 84 52 44 33 40 33 65 58 41 40 39 39 38 SEDIMENT DISCHARGE (TONS/DAY) el. 2 e2.7 e4.6 e2.5 el. 8 e4.0 e2.5 el. 4 el. 4 el. 5 ell e6.8 e4.4 e3.3 el. 9 el. 7 el. 5 e!5 e7.7 e2.8 el. 8 el.l e2.7 el. 2 e!5 e3.7 el. 7 el. 4 el. 3 el.l el.O 581 196.45 707 334.7 519 111.7 e Estimated 247 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGUAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 TOTAL 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) JANUARY ell e!2 ell elO elO ell elO e38 e82 e!7 ell e28 e!3 elOl e!47 e25 e!9 e!8 e56 e89 e38 e24 e!9 e!9 e24 e22 e35 e42 e30 e21 e!9 37 36 35 35 34 33 32 304 371 251 323 85 47 865 417 215 158 62 135 219 229 202 173 91 113 105 93 110 86 63 42 el.l el. 2 el.O e.93 e.91 e.98 e.87 e51 e565 e!2 e9.4 e7.3 el. 7 e805 e413 elS eS.l e3.1 e56 e69 e23 e!3 e9.1 e4.8 e8.6 e6.7 e9.1 e!3 e7.0 e3.6 e2.1 FEBRUARY e!6 e!6 elS elS elS e!9 e!6 e!4 e!9 e20 e!6 elS e!4 e!4 e!4 e!5 e20 e!4 elS e!7 elS elS e!3 e!4 elS e!3 e!3 e!2 ell ___ ___ 24 24 28 40 54 57 40 38 56 57 59 54 49 51 55 58 57 46 52 91 86 85 111 155 191 148 109 83 92 ___ ___ el.O el.O el.l el. 8 e2.7 e3.1 el. 8 el. 5 e3.1 e3.3 e2.6 e2.1 el. 9 el. 9 e2.1 e2.3 e3.5 el. 8 e2.6 e4.2 e3.4 e3.4 e3.8 e5.8 e7.7 e5.4 e3.7 e2.6 e2.8 ___ ___ MARCH e!3 e!3 e!2 e!2 e!6 e!3 e!3 e22 e26 elS e30 e22 e20 e20 e77 e36 e25 e23 e24 e23 e21 e20 e20 e!9 e!9 e20 elS e!7 e!9 e!8 e21 109 118 66 31 16 15 16 36 74 53 53 26 36 48 640 110 62 47 39 32 28 25 23 20 18 16 16 15 32 21 44 e3.8 e4.0 e2.2 el.O e.67 e.54 e.56 e6.5 e5.6 e2.6 eS.l el. 5 e2.0 e2.6 eS81 ell e4.2 e3.0 e2.5 e2.0 el. 6 el. 4 el. 2 el.l e.91 e.86 e.78 e.71 el. 7 el.l e2.8 1012 2122.59 446 84.0 670 656.53 e Estimated 248 RIO GRANDE DE LOZZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGOAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE (CPS) 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 CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL e!7 e!6 e!65 e39 e!8 e!4 e26 e!7 e!6 e!6 e!4 e!7 e!4 e!4 e!6 e!9 e!4 e!4 el5 e!3 e!4 e!8 e20 e!7 e!2 ell elO e!2 el4 e!4 636 45 42 260 71 43 35 28 23 19 15 15 30 21 34 47 42 17 14 15 15 15 31 51 63 57 50 39 30 23 21 e2.1 el. 8 e496 e7.4 e2.1 el. 3 el. 8 el.l e.81 e.67 e.57 el. 4 e.76 el. 4 e2.2 e2.2 e.64 e.55 e.57 e.50 e.57 e2.2 e3.1 e2.9 el. 8 el. 5 el.l e.94 e.85 e.79 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY el2 ell elO elO elO ell e!9 e20 e25 e26 e!8 e!5 e22 e!4 e!2 e!5 e!2 ell e!2 e!4 elO e9.3 e32 e!3 elO elO e9.5 e9.1 e8.1 e7.9 e7.5 19 17 12 14 18 17 48 44 72 63 56 43 62 24 17 32 39 35 41 38 28 28 57 24 24 29 30 27 25 23 27 .62 .51 .35 .41 .52 e.52 e3.8 e2.5 e5.2 e4.6 e2.8 el. 7 eS.l e.92 e.54 el. 7 el. 2 el.O el. 5 el. 5 .79 .70 e .8 .86 .66 .86 .76 .67 .54 .48 .54 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE e8.4 e8.4 e9.0 e27 e23 e25 e70 e32 e20 el7 el9 e!60 e56 e21 e!90 e220 e64 elOO e50 e22 e20 e60 e29 e20 e!7 e20 el8 e!6 e!4 e!3 59 50 35 73 72 71 96 73 76 79 64 214 110 42 387 182 119 170 125 61 58 102 75 67 60 60 66 73 81 90 el. 3 el.l e.86 e7.3 e4.9 e5.2 e!2 e9.5 e5.2 e3.9 e3.1 e42 e32 e4.3 e81 e99 e38 e36 e24 e5.6 e3.3 elO e8.6 e4.4 e3.0 e3.0 e3.4 e3.4 e3.3 e3.3 541.62 425.4 49.65 1368.8 461.96 e Estimated 249 DAY RIO GRANDE OE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGOAS, PR — Continued SEDIMENT DISCHARGE, SUSPENDED ( TONS / DAY ), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JULY e!3 e!2 e!2 ell ell ell e!2 ellO eSO e25 e!8 e20 e45 e400 e220 eSO e31 e24 e22 e22 e21 e20 e!9 e!9 e!9 e!8 e!8 e43 e27 e21 e!9 1363 119.2 95 56 59 137 243 400 421 145 108 80 59 43 33 396 248 37 11 11 11 11 12 12 12 13 13 13 14 14 14 15 15 —— e3.3 el. 9 el. 9 e4.2 e7.2 e!2 e!3 e!9 e22 e7.9 e3.4 e2.2 e2.7 e211 e213 elS el. 2 .81 .68 .67 .67 .66 .64 .64 .66 .66 .66 el.l el. 3 e.94 e.81 551.80 42771.67 MEAN DISCHARGE (CFS) e27 e21 e56 eSO e28 e20 e!9 e!8 e!8 e!8 el7 e!6 elS e!30 e350 e330 e66 e38 e23 e22 e21 e20 e88 e26 e!9 el9 el8 e!8 el8 e!7 e!7 MEAN CONCEN- TRATION (MG/L) AUGUST 16 17 18 22 26 31 27 23 19 17 16 14 13 25 55 329 115 58 30 19 81 108 98 90 109 139 174 169 151 131 73 SEDIMENT DISCHARGE (TONS/DAY) e.98 el.l el. 8 e3.1 e2.6 e2.0 el. 4 el. 2 .95 .84 .74 .63 .53 e4.5 e33 e303 e55 e8.2 e2.5 el.l e4.7 e6.0 e!2 e!2 e6.5 e7.1 e8.7 e8.2 e7.3 e6.2 e3.4 MEAN DISCHARGE (CFS) S! elOO e23 e23 e26 e!9 e!7 e!8 e24 e!20 e8600 e450 e200 e!20 e88 ellO e80 e72 e86 e70 e64 e72 e58 e54 e54 e52 e52 e52 e80 e74 e70 MEAN CONCEN- TRATION (MG/L) EPTEMBER 34 16 19 32 49 57 61 72 155 1570 600 318 193 118 76 64 56 49 43 38 33 29 25 22 20 21 23 25 27 29 ___ SEDIMENT DISCHARGE (TONS/DAY) e3.8 e2.4 el. 2 e2.1 e2.9 e2.7 e2.9 e4.1 e28 e34700 e!900 e272 e83 e33 e20 el6 ell elO e9.0 e6.8 e6.0 eS.O e3.8 e3.2 e2.8 e2.9 e3.2 e4.4 e5.6 e5.6 1563 507.27 10928 37153.4 250 RIO ORANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CAGOAS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBOTION OF SUSPENDED SEDIMENT OCT 1995 27... JAN 1996 05... 14... JOL 14... 28... DATE OCT 1995 27... JAN 1996 05... 14... JUL 14... 28... TIME 1832 1523 2032 1730 1615 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 72 81 66 75 61 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 318 7.2 439 e400 e43 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 81 82 76 78 70 SEDI- MENT, SUS- PENDED (MG/L) (80154) 6370 991 5270 3280 2390 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 92 98 90 96 90 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 5470 19 6240 e3540 e277 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 98 99 95 98 98 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 32 62 31 51 36 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 100 98 99 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 49 69 42 58 43 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 100 100 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 60 76 53 66 49 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 100 e » estimate 251 RIO GRANDE DE LOIZA BASIN 50055225 RIO CAGUITAS AT VILLA BLANCA AT CA6UAS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 31... NOV 04... 07... JAN 1996 09... 11... 14... FEE 25... JUL 12... 28... AUQ 15... TIME 1637 1757 1500 1817 1548 2132 0943 1630 1516 1116 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 19 364 34 531 15 517 13 e400 e43 e350 SEDI- MENT, SUS- PENDED (MG/L) (80154) 256 3320 435 2490 436 2250 207 3690 494 2580 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 13 3260 40 3570 18 3140 7.3 63985 e57 62438 SED. SUSP. SIEVE DIAM. 96 FINER THAN .062 MM (70331) 94 94 96 94 98 94 98 98 70 74 252 RIO GRANDB DB 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 DRAINAGE AREA.—14.1 mi' (36.5 km'). PERIOD OF RECORD.—Water years 1972 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 Caguas plaza. 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) (DEC C) (NTU) (MG/L) ATION) (MG/L) 100 ML) 100 ML) (00061) (00095) (00400) (00010) (00076) (00300) (00301) (00340) (31616) (31679) OCT 1995 10... 1210 37 550 6.3 28.0 6.5 3.0 38 80 450000 61000 JAN 1996 11... 1010 29 560 7.1 26.0 3.5 3.3 40 60 K75000 K14000 FEB 14... 0910 25 535 7.2 24.5 3.7 1.7 20 76 K60000 K13000 APR 08... 0810 9.0 550 7.0 25.0 2.5 4.0 47 12 30000 3700 JUN 05... 0900 14 461 6.9 27.0 1.6 2.9 36 23 240000 30000 AUG 20... 0820 21 490 7.3 26.0 3.7 4.6 56 13 K62000 7100 ALKA- DATE OCT 1995 10... JAN 1996 11... FEB 14... APR 08... JUN 05... AUG 20... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 120 — -- 190 -- 180 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 32 -- -- 53 -- 46 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 10 -- -- 15 — 15 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 37 -- -- 34 — 29 SODIUM AD- SORP- TION RATIO (00931) 1 -- — 1 -- 0.9 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 6.1 -- — 3.8 -- 3.5 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 140 170 150 170 150 160 SULFIDE TOTAL (MG/L AS S) (00745) 0.6 -- -- <0.5 -- — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 27 -- -- 52 -- 42 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 50 — — 38 — 32 non-ideal count RIO GRANDE DE LOIZA BASIN 50055250 RIO CAGUITAS AT HIGHWAY 30 AT CAGUAS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 253 SOLIDS, RESIDUE DATE OCT 1995 10... JAN 1996 11... FEB 14... APR 08... JUN 05... AU6 20... DATE OCT 1995 10... JAN 1996 11... FEB 14... APR 08... JUN 05... AU6 20... OCT 1995 10... JAN 1996 11... FEB 14... APR 08... JUN 05... AUG 20. .. FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 — — 0.20 — 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 12 10 10 1.6 2.1 <0.79 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 -- -- 32 — 34 NITRO- GEN, TOTAL (MG/L AS N) (00600) 13 11 11 2.2 2.6 1.8 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 270 -- -- 330 -- 298 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 56 47 47 9.7 12 7.9 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 26.8 -- — 8.02 — 16.6 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 1.70 1.40 1.40 0.310 0.390 0.230 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 24 33 28 11 12 31 ARSENIC TOTAL (UG/L AS AS) (01002) 2 -- -- 1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.340 0.480 0.400 0.490 0.430 0.890 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- 100 -- — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.200 0.100 0.150 0.100 0.110 0.110 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 80 -- -- 50 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.540 0.580 0.550 0.590 0.540 1.00 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — -- <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 11.0 8.10 8.00 1.20 1.20 0.690 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 4 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 1.0 1.9 2.0 0.40 0.90 <0.10 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 30 — — 20 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 910 750 250 350 <0.10 <0.10 <1 <1 40 <1 0.020 <0.010 1.1 0.13 254 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAZROA AT BAZROA, PR LOCATION.—Lat 18°15"32", long 66°02'24", Hydrologic Unit 21010005, on left bank, in the Bairoa Housing Area, 1.6 mi (2.6 km) northwest of Plaza de Caguas, 4.1 mi (6.6 km) 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 ). WATER-DISCHARGE RECORDS PERZOD 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 fair except those for estimated daily discharges, which are poor. Gage-height and precipitation satellite telemetry at station. Mean daily discharge affected by domestic discharges. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAZLY MEAN VALUES DAY OCT DEC APR SEP 1 6.7 7.2 2 5.9 3.7 3 5.7 22 4 5.4 31 5 7.6 16 6 8.9 48 7 5.7 18 8 7.2 9.5 9 9.5 7.7 10 5.7 5.9 11 7.4 5.1 12 4.3 4.7 13 4.0 4.1 14 4.7 3.7 15 4.2 3.6 16 3.7 7.0 17 13 5.7 18 6.7 4.2 19 11 4.5 20 4.7 3.6 21 4.4 3.3 22 3.4 3.0 23 7.6 2.7 24 25 3.9 25 10 3.3 26 3.4 8.0 27 45 2.8 28 17 6.4 29 5.6 21 30 3.3 7.0 31 3.7 —— TOTAL 260.4 276.6 MEAN 8.40 9.22 MAX 45 48 MZN 3.3 2.7 AC-FT 517 549 CFSM 1.65 1.81 ZN. 1.91 2.03 STATZSTZCS OF MONTHLY MEAN MEAN 9.79 9.94 MAX 25.3 22.2 (WY) 1991 1993 MZN 4.30 5.71 (WY) 1992 1995 SUMMARY STATZSTZCS ANNUAL TOTAL ANNUAL MEAN HIGHEST ANNUAL MEAN LOWEST ANNUAL MEAN HIGHEST DAZLY MEAN LOWEST DAZLY 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 3.3 2.9 2.7 2.3 2.2 2.2 2.5 2.2 2.2 2.2 2.3 1.8 2.8 2.5 2.0 3.2 2.0 63 18 4.4 4.9 5.4 26 17 27 13 7.6 7.9 7.2 6.5 6.1 255.3 8.24 63 1.8 506 1.62 1.87 6.4 6.1 6.6 5.9 5.6 10 5.8 23 16 6.4 4.9 20 7.1 66 69 16 8.6 7.6 14 33 11 6.9 5.9 5.9 8.6 6.7 15 38 10 5.9 4.6 456.5 14.7 69 4.6 905 2.90 3.34 DATA FOR WATER 8.95 19.7 1993 4.63 1992 FOR 9.02 14.7 1996 4.12 1995 .3 .2 .1 .2 .5 .5 .3 5.4 32 10 5.5 .9 .7 .6 .5 .4 .6 .7 .6 .3 .7 .2 .1 .2 .4 4.0 3.9 3.9 3.8 —— 162.5 5.60 32 3.8 322 1.10 1.19 YEARS 1991 5.11 8.60 1991 3.42 1994 3.8 3.8 3.8 3.9 5.3 4.0 4.0 6.4 4.7 3.9 V.5 4.1 4.0 3.8 40 6.7 4.6 4.3 4.2 3.8 3.9 3.9 3.8 3.6 3.6 3.7 4.4 4.3 4.5 4.1 5.0 171.4 5.53 40 3.6 340 1.09 1.26 - 1996 4.18 5.53 1996 2.87 1994 1995 CALENDAR YEAR 2769. 7. 232 1. 1. 5490 1. 20. 14 3. 2. 1 59 Sep 6 3 Jul 2 6 Jun 30 49 28 4 1 3.9 3.8 e86 9.7 12 8.8 4.5 3.6 3.6 3.4 3.3 4.5 3.6 4.1 6.7 12 3.4 3.1 3.1 3.0 3.5 28 12 7.7 6.1 6.3 6.3 7.9 6.5 6.5 —— 276.9 9.23 86 3.0 549 1.82 2.03 5.7 5.2 5.0 4.3 4.2 4.2 7.5 9.2 5.2 5.5 4.9 4.5 7.5 4.2 3.9 6.0 4.0 4.2 17 4.4 3.4 3.4 19 4.3 3.8 5.8 3.6 3.8 3.7 3.5 3.4 174.3 5.62 19 3.4 346 1.11 1.28 3.4 3.4 3.2 4.8 5.0 4.0 7.4 3.4 6.4 3.9 5.6 13 3.9 3.1 27 23 5.1 8.3 4.3 3.6 4.3 11 4.4 3.5 3.2 5.4 3.3 3.4 3.3 3.2 —— 186.8 6.23 27 3.1 371 1.23 1.37 3.1 3.1 3.1 3.1 3.1 2.9 3.1 40 4.5 2.9 3.1 3.8 5.0 48 20 3.5 15 3.7 3.4 4.0 3.7 3.6 3.4 3.3 3.1 3.1 3.1 18 3.4 3.3 3.6 230.0 7.42 48 2.9 456 1.46 1.68 49 9.1 8.6 4.9 3.9 3.6 4.3 4.1 4.3 5.1 4.3 4.4 4.2 19 86 147 13 8.8 7.6 7.5 7.0 7.2 19 31 15 15 14 15 8.8 8.6 8.0 547.3 17.7 147 3.6 1090 3.48 4.01 8.0 7.1 17 7.0 6.6 6.2 6.1 7.9 24 1700 e80 e41 e32 e28 e29 e34 e22 e20 e22 e!9 e54 e!9 el7 e!5 el4 e!5 el9 el4 e!3 ell—— 2307.9 76.9 1700 6.1 4580 15.1 16.90 , BY WATER YEAR (WY) 4.77 9.23 1996 2.61 1992 FOR 1996 5305 14 1700 1 2 7200 18 10520 2 38 21 5 3 6.15 12.5 1993 2.91 1994 WATER YEAR .9 .5 Sep 10 .8 Dec 12 . 2 Dec 6 Sep 10 .16 Sep 10 .85 .85 .0 .2 5.16 8.64 1993 2.72 1995 8.39 16.5 1991 4.35 1994 WATER 8 14 4 1700 1 1 7200 18 6190 1 22 13 4 2 8.25 17.7 1996 4.09 1991 YEARS 1991 .55 .5 .52 Sep .3 Jul .6 Jun Sep . 16 Sep .68 .86 .4 .7 22.8 76.9 1996 4.50 1991 - 1996 1996 1994 10 1996 2 1995 30 1995 10 1996 10 1996 e Estimated 255 RIO QRANDE 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-49 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 days. SEDIMENT LOADS: Maximum daily mean, 37,900 tons (34,300 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.01 tonne) several days. EXTREME FOR CURRENT YEAR 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 7,040 mg/L September 10, 1996; Minimum daily mean, 4 mg/L Several days. SEDIMENT LOADS: Maximum daily mean, 37,900 tons (34,300 tonnes) September 10, 1996; Minimum daily mean, 0.04 ton (0.03 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 6.7 5.9 5.7 5.4 7.6 8.9 5.7 7.2 9.5 5.7 7.4 4.3 4.0 4.7 4.2 3.7 13 6.7 11 4.7 4.4 3.4 7.6 25 10 3.4 45 17 5.6 3.3 3.7 28 13 10 10 30 65 33 39 54 35 40 15 10 12 14 16 79 36 165 24 21 20 43 228 130 19 637 109 31 13 17 .51 .21 .16 .14 .82 1.9 .51 .92 2.0 .57 1.1 .17 .11 .15 .16 .16 4.9 .80 10 .34 .30 .19 1.2 27 11 .18 288 7.3 .50 .11 .22 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 7.2 3.7 22 31 16 48 18 9.5 7.7 5.9 5.1 4.7 4.1 3.7 3.6 7.0 5.7 4.2 4.5 3.6 3.3 3.0 2.7 3.9 3.3 8.0 2.8 6.4 21 7.0 36 17 129 195 95 304 120 36 12 8 7 7 7 6 6 31 25 10 10 9 9 9 8 19 23 50 15 35 130 75 .95 .18 9.1 44 4.4 70 6.4 .96 .25 .12 .09 .08 .07 .06 .06 1.1 .40 .11 .12 .09 .08 .07 .06 .25 .21 2.1 .11 1.4 22 1.6 3.3 2.9 2.7 2.3 2.2 2.2 2.5 2.2 2.2 2.2 2.3 1.8 2.8 2.5 2.0 3.2 2.0 63 18 4.4 4.9 5.4 26 17 27 13 7.6 7.9 7.2 6.5 6.1 40 24 14 9 9 11 13 12 9 7 9 12 14 18 12 17 12 562 108 22 27 31 180 120 192 85 50 41 39 38 37 .36 .19 .10 .06 .05 .07 .09 .07 .05 .04 .06 .06 .13 .13 .08 .18 .09 184 7.7 .27 .57 .47 55 5.9 52 3.4 1.0 .87 .76 .66 .61 260.4 361.63 276.6 166.42 255.3 315.02 256 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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) (MQ/L) (TONS/DAY) JANUARY 6.4 6.1 6.6 5.9 5.6 10 5.8 23 16 6.4 4.9 20 7.1 66 69 16 8.6 7.6 14 33 11 6.9 5.9 5.9 8.6 6.7 15 38 10 5.9 4.6 35 34 33 32 32 63 34 148 105 67 44 130 33 536 487 101 48 42 89 215 70 28 20 33 113 47 88 250 58 47 55 .61 .56 .59 .51 .48 2.2 .57 15 12 1.2 .58 12 .64 348 315 7.0 1.1 .98 7.8 34 2.3 .53 .32 .57 3.2 .87 4.7 36 1.7 .73 .69 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MQ/L) (TONS/DAY) FEBRUARY .3 .2 .1 .2 .5 .5 .3 5.4 2 0 5.5 .9 .7 .6 .5 .4 .6 .7 .6 .3 .7 .2 .1 .2 .4 4.0 3.9 3.9 3.8 63 42 22 12 7 6 5 12 601 62 30 19 14 10 7 7 7 6 24 21 14 10 9 8 15 12 9 7 5 .73 .47 .25 .13 .08 .07 .06 .47 178 3.3 .44 .26 .18 .12 .09 .08 .08 .08 .43 .25 .18 .11 .10 .09 .20 .13 .09 .07 .05 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MQ/L) (TONS/DAY) MARCH 3.8 3.8 3.8 3.9 5.3 4.0 4.0 6.4 4.7 3.9 7.5 4.1 4.0 3.8 40 6.7 4.6 4.3 4.2 3.8 3.9 3.9 3.8 3.6 3.6 3.7 4.4 4.3 4.5 4.1 5.0 6 8 11 14 28 16 10 36 159 78 56 18 10 9 263 42 19 14 10 9 6 6 6 6 6 8 38 31 27 26 66 .06 .08 .11 .15 .49 .17 .10 3.5 2.1 .81 1.7 .20 .11 .09 86 .84 .23 .16 .12 .09 .06 .06 .06 .06 .06 .09 .46 .35 .33 .28 .98 TOTAL 456.5 812.43 162.5 186.59 171.4 99.90 257 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 ^ 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 3.9 3.8 e86 9.7 12 8.8 4.5 3.6 3.6 3.4 3.3 4.5 3.6 4.1 6.7 12 3.4 3.1 3.1 3.0 3.5 28 12 7.7 6.1 6.3 6.3 7.9 6.5 6.5 ___ APRIL 68 36 705 60 70 49 28 20 15 14 13 23 19 20 27 77 13 15 21 16 9 170 74 108 37 15 11 27 29 11 MAY .71 .37 e831 1.9 8.0 1.8 .35 .19 .15 .13 .12 .32 .19 .23 2.4 8.8 .12 .12 .18 .13 .09 72 3.5 2.5 .60 .25 .19 .77 .52 .19 5.7 5.2 5.0 4.3 4.2 4.2 7.5 9.2 5.2 5.5 4.9 4.5 7.5 4.2 3.9 6.0 4.0 4.2 17 4.4 3.4 3.4 19 4.3 3.8 5.8 3.6 3.8 3.7 3.5 3.4 13 19 20 22 23 21 46 94 51 33 26 25 85 16 11 27 15 13 182 71 18 17 382 63 17 35 10 9 10 8 7 .21 .26 .28 .25 .26 .25 1.7 6.4 .73 .50 .34 .30 4.9 .18 .11 1.9 .16 .15 30 .91 .17 .15 37 .74 .18 2.9 .10 .10 .10 .08 .06 JUNE 3.4 3.4 3.2 4.8 5.0 4.0 7.4 3.4 6.4 3.9 5.6 13 3.9 3.1 27 23 5.1 8.3 4.3 3.6 4.3 11 4.4 3.5 3.2 5.4 3.3 3.4 3.3 3.2 ___ 15 36 32 26 36 38 44 27 40 22 73 82 19 14 300 171 65 51 29 24 61 76 18 12 11 43 16 11 10 10 .13 .33 .28 .37 .72 .41 1.6 .25 5.0 .23 1.8 4.6 .20 .12 61 29 .92 2.3 .34 .23 .82 7.4 .21 .12 .10 3.0 .14 .10 .09 .09 TOTAL 276.9 937.82 174.3 91.37 186.8 121.90 e Estimated 258 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER 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) 3.1 3.1 3.1 3.1 3.1 2.9 3.1 40 4.5 2.9 3.1 3.8 5.0 48 20 3.5 15 3.7 3.4 4.0 3.7 3.6 3.4 3.3 3.1 3.1 3.1 18 3.4 3.3 3.6 JULY 10 9 7 6 5 5 4 280 127 40 19 15 65 354 186 63 122 20 14 11 9 7 6 5 4 6 9 195 22 9 9 TOTAL 230.0 —— YEAR e 5305.9 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .08 .07 .06 .05 .04 .04 .04 80 2.3 .30 .16 .26 1.0 113 18 .60 30 .20 .13 .12 .09 .07 .05 .05 .04 .05 .08 35 .24 .08 .08 282.28 45446.31 49 9.1 8.6 4.9 3.9 3.6 .3 .1 .3 .1 .3 .4 .2 19 86 147 13 8.8 7.6 7.5 7.0 7.2 19 31 15 15 14 15 8.8 8.6 8.0 547.3 109 55 49 28 23 20 24 20 18 26 20 14 12 260 518 732 18 8 8 9 9 23 58 117 11 13 17 46 60 50 45 —— 46 2.6 2.4 .37 .24 .19 .28 .23 .21 .56 .24 .16 .13 19 926 566 .71 .19 .17 .17 .17 .54 3.4 16 .46 .51 .64 2.4 1.4 1.1 .98 1593.45 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 8.0 7.1 17 7.0 6.6 6.2 6.1 7.9 24 1700 e80 e41 e32 e28 e29 e34 e22 e20 e22 e!9 e54 e!9 el7 e!5 e!4 e!5 e!9 e!4 e!3 ell—— 2307.9 42 39 106 47 42 38 34 50 589 7400 1660 763 672 542 384 381 378 346 109 23 12 10 8 6 4 2 6 16 18 18 —— —— .90 .74 14 .87 .74 .63 .56 1.2 306 37900 e!430 e231 e!70 e!31 e90 e86 e71 e30 e6.5 el. 3 el.l .90 .38 .26 .14 .09 .27 .69 .65 .58 —— 40477.50 259 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1995 27... DEC 18... FEB 1996 09... 09... APR 03... JUL 14... AUG 15... SEP 09... DATE OCT 1995 27... DEC 18... FEB 1996 09... 09... APR 03... JUL 14... AUG 15... SEP 09... TIME 1740 1655 1415 1740 1645 1620 2330 2315 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 71 76 54 63 69 85 76 70 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 253 233 14 190 520 139 964 224 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 84 81 66 73 79 88 81 80 SEDI- MENT, SUS- PENDED (MG/L) (80154) 9180 2310 8330 7280 8830 1760 5090 8530 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 92 94 75 86 88 97 93 90 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 6270 1450 315 3730 12400 660 13200 5160 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 97 98 83 96 96 99 98 97 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 28 49 26 34 29 47 36 32 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 85 99 99 99 99 99 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 39 56 29 36 41 63 48 42 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 86 99 100 100 100 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 51 63 42 51 54 79 64 56 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 91 100 100 100 100 100 260 RIO GRANDE DE LOIZA BASIN 50055390 RIO BAIROA AT BAIROA, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 19... 24... DEC 18... 18... FEE 1996 09... 09... APR 03... JTJN 15... JX7L 14... SEP 10... TIME 1640 0425 1323 1345 1430 1900 1535 1915 1605 0230 DIS- CHARGEE, INST. CUBIC FEET PER SECOND (00061) 26 75 85 78 109 98 126 122 164 1170 SEDI- MENT, SUS- PENDED (MG/L) (80154) 700 1990 1430 1630 2360 3240 1630 3140 1340 11700 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 49 403 328 343 694 857 554 1030 593 37000 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 99 99 100 99 97 98 85 99 99 98 261 RIO GRANDE DE LOIZA BASIN 50055400 RIO BAIROA NEAR CAGUAS, PR WATER-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 Grande de Loiza, and 1.4 mi (2.3 km) north of Caguas plaza. DRAINAGE AREA.--5.4 mi 2 (14.0 km2 ). PERIOD OF RECORD.--Water years 1958, 1962-66, 1973-74, 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE OCT 1995 13... JAN 1996 09... FEE 14... APR 08... JUN 05. .. AUG 20.. . TIME 0725 1120 1040 0945 1015 1000 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 3.8 4.9 5.0 3.9 2.9 7.4 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 418 355 425 394 500 495 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.4 6.9 7.6 7.2 7.1 7.3 TEMPER- ATURE WATER (DEC C) (00010) 25.0 23.5 22.5 24.5 27.0 26.5 TUR- BID- ITY (NTU) (00076) 3.6 14 0.90 3.3 1.1 1.0 OXYGEN, DIS- SOLVED (MG/L) (00300) 5.5 7.0 3.2 5.7 1.4 0.85 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 65 80 36 67 17 10 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 12 <10 <10 <10 48 58 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 31000 K610000 K14000 K73000 K680000 K620000 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 440000 470000 3600 4200 57000 560000 DATE OCT 1995 13. .. JAN 1996 09. .. FEE 14. .. APR 08. .. JUN 05. .. AUG 20. . . HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 150 -- -- 160 -- 160 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 36 -- -- 40 -- 38 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 14 -- -- 14 -- 15 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 23 -- -- 22 -- 29 SODIUM AD- SORP- TION RATIO (00931) 0.8 -- _- 0.8 -- 1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.6 -- -- 4.8 -- 6.3 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 120 120 150 130 160 180 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 16 -- -- 15 -- 19 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 35 -- -- 29 39 non-ideal count 262 RIO GRANDE DE LOIZA BASIN 50055400 RIO BAIROA NEAR CAGUAS, PR- -Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE OCT 1995 13... JAN 1996 09... FEE 14.. . APR 08.. . JUN 05.. . AUG 20.. . OCT 1995 13. .. JAN 1996 09. .. FEE 14. .. APR 08. . . JUN 05. . . AUG 20. . . OCT 1995 13. .. JAN 1996 09. .. FEB 14... APR 08. .. JUN 05... AUG 20... FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- -- 0.20 -- 0.10 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.69 0.45 0.37 0.39 9.1 4.6 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 30 -- — 28 — 29 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.2 2.2 2.4 1.6 9.8 5.7 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 231 -- -- 231 -- 283 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 9 .7 9.5 10 7.0 43 25 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 2.37 -- -- 2.46 -- 5.67 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.390 0.330 0.290 0.250 1.10 1.10 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 10 60 7 6 5 4 ARSENIC TOTAL (UG/L AS AS) (01002) 3 -- -- 2 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.40 1.65 1.89 1.16 0.660 0.820 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- -- 100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.100 0.050 0.110 0.040 0.020 0.280 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 -- -- 40 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.50 1.70 2.00 1.20 0.680 1.10 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.150 0.090 0.150 0.090 7.70 4.00 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.54 0.36 0.22 0.30 1.4 0.60 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- 20 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 500 340 <1 120 60 <0.10 <0.10 <1 <1 10 <0.010 <0.010 <1 0.04 0.03 263 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR LOCATION.--Lat 18°14'02", long 65°53'07", Hydrologic Unit 21010005, on left bank, 2.43 mi (3.91 km) northeast of Plaza de Juncos, 1.3 mi (2.1 km) southeast of Escuela La Placita and 0.35 mi (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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY NOV JAN MAR MAY JUN JUL AUG SEP 1 16 11 2 32 9.6 3 28 15 4 16 17 5 84 15 6 58 90 7 22 31 8 24 15 9 18 14 10 26 11 11 20 10 12 14 9.0 13 24 8.7 14 18 8.6 15 12 22 16 16 11 17 14 8.8 18 14 7.7 19 11 7.3 20 35 7.3 21 17 10 22 109 8.5 23 30 7.1 24 104 9.0 25 95 9.3 26 41 7.6 27 17 7.1 28 15 6.5 29 13 6.4 30 10 6.5 31 10 —— TOTAL 963 407.0 MEAN 31.1 13.6 MAX 109 90 MIN 10 6.4 AC-FT 1910 807 CFSM 1.39 .61 IN. 1.61 .68 6.6 6.4 5.7 5.8 6.1 6.6 6.0 5.3 5.3 5.4 6.5 7.0 18 25 9.5 6.7 6.0 19 103 59 13 13 7.4 6.3 5.7 42 14 6.5 5.8 5.3 5.0 442.9 14.3 103 5.0 878 .64 .74 STATISTICS OF MONTHLY MEAN DATA MEAN 47.4 65.5 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 31.4 59.0 1991 12.0 1994 FOR 4.9 5.1 4.9 4.9 4.9 4.7 6.3 39 43 21 28 113 67 1410 415 58 35 32 66 400 74 33 27 26 29 30 54 78 35 25 e22 3195.7 103 1410 4.7 6340 4.62 5.33 FOR WATER 42.5 103 1996 6.34 1995 e21 623 622 620 642 45 86 25 18 16 16 15 14 14 14 14 15 17 14 15 13 12 11 91 30 15 12 11 11 ___ —— 672 23.2 91 11 1330 1.04 1.12 YEARS 1990 30.7 66.7 1995 10.4 1993 9.8 8.9 8.7 8.5 11 12 9.5 8.9 9.1 8.1 17 11 8.0 7.0 40 17 9.3 8.1 28 613 11 10 10 9.6 8.9 9.0 9.2 9.0 9.8 9.4 9.4 358.2 11.6 40 7.0 710 .52 .60 - 1996 12.2 18.1 1991 5.63 1993 1995 CALENDAR YEAR 13697. 37. 1570 1. 2. 27170 1. 22. 57 9. 3. 2 5 Sep 16 9 May 15 3 Apr 28 68 85 2 2 9.0 8.2 8.0 8.5 9.0 7.9 8.1 7.5 7.0 6.8 8.5 8.2 14 9.2 7.7 13 8.9 7.2 6.9 6.2 5.8 5.7 6.0 8.9 7.7 6.6 6.2 5.7 5.9 9.3 —— 237.6 7.92 14 5.7 471 .36 .40 8.2 6.1 5.3 4.9 4.7 4.5 5.5 11 19 13 11 7.4 106 31 9.8 7.3 6.6 6.2 5.6 5.3 4.9 4.8 5.5 5.8 5.4 5.2 4.9 4.6 4.8 4.7 7.4 336.4 10.9 106 4.5 667 .49 .56 13 9.5 9.0 7.6 10 24 61 15 9.2 7.3 22 242 39 15 elOO e400 6200 6250 e!30 e42 e!2 e28 e!4 e7.2 5.8 5.2 6.0 44 15 9.7 —— 1752.5 58.4 400 5.2 3480 2.62 2.92 8.0 6.8 6.0 6.3 5.3 5.2 4.3 944 188 79 55 195 395 388 598 68 35 23 17 627 e!3 elO 68.1 e7.6 e7.6 e7.2 e6.4 6130 e!40 e6.9 5.8 3396.5 110 944 4.3 6740 4.91 5.67 5.1 6.2 38 48 13 7.6 5.6 5.3 4.6 7.7 17 5.3 4.1 173 279 504 266 69 25 15 14 9.1 43 46 12 6.6 5.3 6.1 6.6 5.3 4.2 1656.7 53.4 504 4.1 3290 2.40 2.76 59 17 5.8 142 35 8.4 5.7 9.0 401 4040 191 19 7.2 4.8 115 67 10 81 112 60 45 33 38 28 24 28 24 22 22 21—— 5674.9 189 4040 4.8 11260 8.48 9.47 , BY WATER YEAR (WY) 8.59 11.0 1993 5.29 1995 FOR 1996 19093 52 4040 4 4 19100 24 37870 2 31 85 11 5 29.4 123 1992 4.83 1990 WATER YEAR .4 .2 Sep 10 .1 Aug 13 .9 Dec 31 Sep 10 .12 Sep 10 .34 .85 .4 51.7 117 1992 14.7 1991 52.5 147 1993 6.74 1994 WATER 42 52 22 4040 1 1 19100 24 30760 1 25 74 10 4 33.1 54.0 1995 10.2 1993 YEARS 1990 .5 .3 .0 Sep .1 Oct .4 Oct Sep . 12 Sep .90 .87 .2 85.1 189 1996 34.9 1990 - 1996 1992 1994 10 1996 27 1992 22 1992 10 1996 10 1996 e Estimated 264 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-49 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, 4 mg/L April 7,1991. 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 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 1,490 mg/L September 10, 1996; Minimum daily mean, 6 mg/L July 6-7, 1996. SEDIMENT LOADS: Maximum daily mean, 17,900 tons (16,200 tonnes) September 10, 1996; Minimum daily mean, 0.07 ton (0.06 tonne) July 7, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 16 32 28 16 84 58 22 24 18 26 20 14 24 18 12 16 14 14 11 35 17 109 30 104 95 41 17 15 13 10 10 46 63 74 48 132 109 59 63 66 87 56 44 62 52 40 40 44 42 73 60 160 76 143 197 124 85 52 44 41 39 38 1.9 9.7 6.3 2.3 35 21 3.6 4.4 3.2 7.7 3.1 1.7 4.8 2.6 1.3 1.7 1.7 1.3 9.2 2.9 148 7.0 131 100 62 11 2.5 1.7 1.4 1.1 1.0 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER 11 9.6 15 17 15 90 31 15 14 11 10 9.0 8.7 8.6 22 11 8.8 7.7 7.3 7.3 10 8.5 7.1 9.0 9.3 7.6 7.1 6.5 6.4 6.5 —— 37 36 45 50 46 159 119 17 14 14 14 13 13 13 51 37 36 34 32 30 36 37 32 31 35 31 30 29 28 27 —— 1.1 .93 2.0 2.4 2.0 55 12 .70 .51 .41 .37 .33 .31 .31 4.5 1.1 1.1 .81 .66 .58 1.1 .84 .62 .81 .91 .66 .58 .51 .48 .48 —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 6.6 6.4 5.7 5.8 6.1 6.6 6.0 5.3 5.3 5.4 6.5 7.0 18 25 9.5 6.7 6.0 19 103 59 13 13 7.4 6.3 5.7 42 14 6.5 5.8 5.3 5.0 26 25 23 17 12 10 12 14 22 38 49 52 51 198 228 226 170 45 140 119 99 43 62 20 10 44 112 42 22 16 12 .46 .43 .36 .27 .20 .17 .20 .20 .31 .56 .86 .99 2.8 16 5.9 4.1 2.7 2.4 49 26 3.4 1.5 1.3 .35 .16 16 4.6 .74 .35 .23 .16 TOTAL 963 592.1 407.0 94.11 442.9 142.70 265 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continuad SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), HATER YEAR OCTOBER 1995 TO 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 TOTAL MEAN MEAN CONCEN- SEDIMENT MEAN DISCHARGE TRATION DISCHARGE DISCHARGE (CFS) (MG/L) (TONS/DAY) (CFS) JANUARY 4.9 5.1 4.9 4.9 4.9 4.7 6.3 39 43 21 28 113 67 1410 415 58 35 32 66 400 74 33 27 26 29 30 54 78 35 25 •22 11 11 11 10 10 10 10 90 83 117 67 177 108 800 343 102 136 203 133 326 122 77 70 70 71 71 102 127 112 112 84 .14 .15 .14 .14 .13 .14 .17 13 17 7.8 8.1 99.6 28 5220 625 16 13 18 29 682 26 6.9 5.1 4.9 5.5 5.7 16 31 11 7.6 5.2 621 623 622 620 642 45 86 25 18 16 16 15 14 14 14 14 15 17 14 15 13 12 11 91 30 15 12 11 11 ___ MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) FEBRUARY 621 623 622 620 642 45 86 25 18 16 16 15 14 14 14 14 15 17 14 15 13 12 11 91 30 15 12 11 11 58 89 151 120 86 92 122 78 80 81 83 87 92 90 65 66 77 81 85 90 86 16 9 122 115 68 76 30 18 3.3 5.3 9.2 6.8 5.3 14 43 5.3 3.9 3.6 3.6 3.5 3.5 3.4 2.4 2.5 3.1 3.7 3.3 3.7 3.0 .52 .27 89 9.9 2.7 2.5 .91 .51 3195.7 6902.41 672 241.71 MEAN DISCHARGE (CFS) 9.8 8.9 8.7 8.5 11 12 9.5 8.9 9.1 8.1 17 11 8.0 7.0 40 17 9.3 8.1 28 613 11 10 10 9.6 8.9 9.0 9.2 9.0 9.8 9.4 9.4 358.2 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MARCH 15 14 13 17 25 30 31 31 30 30 43 39 32 29 67 55 41 33 66 36 24 34 34 29 40 65 80 86 56 31 36 .41 .33 .30 .39 .80 .93 .81 .75 .74 .65 2.6 1.2 .68 .55 16 2.8 1.0 .74 6.2 61.3 .72 .95 .91 .75 .96 1.6 2.0 2.1 1.5 .78 .93 52.38 a Estimated 266 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 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) 9.0 8.2 8.0 8.5 9.0 7.9 8.1 7.5 7.0 6.8 8.5 8.2 14 9.2 7.7 13 8.9 7.2 6.9 6.2 5.8 5.7 6.0 8.9 7.7 6.6 6.2 5.7 5.9 9.3 ___ APRIL 58 91 87 70 62 58 54 51 71 108 53 16 21 45 45 35 55 104 86 53 47 48 44 39 40 45 46 46 45 49 ___ 1.4 2.0 1.9 1.6 1.5 1.2 1.2 1.0 1.4 2.0 1.2 .37 .79 1.1 .94 1.2 1.3 2.0 1.6 .88 .74 .75 .71 .93 .83 .79 .77 .70 .72 1.2 MEAN DISCHARGE (CPS) 8.2 6.1 5.3 4.9 4.7 4.5 5.5 11 19 13 11 7.4 106 31 9.8 7.3 6.6 6.2 5.6 5.3 4.9 4.8 5.5 5.8 5.4 5.2 4.9 4.6 4.8 4.7 7.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 74 114 111 89 55 32 43 73 67 49 37 30 578 1180 326 103 55 38 34 33 29 25 26 30 31 32 32 32 35 39 37 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 1.6 1.9 1.6 1.2 .70 .39 .65 2.4 3.6 1.7 1.1 .60 590 124 8.9 2.1 .98 .63 .50 .47 .38 .33 .39 .47 .46 .44 .42 .40 .45 .50 .67 13 9.5 9.0 7.6 10 24 61 15 9.2 7.3 22 242 39 15 elOO e400 e200 6250 6130 642 e!2 e28 614 67.2 5.8 5.2 6.0 44 15 9.7 57 51 43 36 30 58 94 53 36 31 49 279 106 26 457 303 53 39 50 47 42 35 29 30 35 40 37 52 22 24 2.2 1.3 1.0 .74 .81 4.3 18 2.5 .89 .62 4.7 298 13 1.1 61040 6517 645 624 625 elO el. 4 el. 8 el. 6 e.67 .55 .57 .60 9.6 .84 .62 237.6 34.72 336.4 749.93 1752.5 2028.41 e Estimated 267 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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) 8.0 6.8 6.0 6.3 5.3 5.2 4.3 944 188 79 55 195 395 388 598 68 35 23 17 627 e!3 elO 68. 1 67.6 67.6 67.2 66.4 6130 6140 66.9 5.8 JULY 26 27 27 16 7 6 6 335 226 63 76 167 343 304 438 120 77 62 55 48 35 25 18 13 13 15 49 80 22 36 37 TOTAL 3396.5 —— YEAR e 19093.4 Estimated MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST .57 .50 .44 .26 .11 .08 .07 2050 166 15 14 105 598 616 1160 23 7.4 3.9 2.5 63.4 el. 2 6.78 el. 6 6.27 6.27 6.31 6.88 65.0 68.1 62.2 .57 4787.41 37859.81 5.1 6.2 38 48 13 7.6 5.6 5.3 4.6 7.7 17 5.3 4.1 173 279 504 266 69 25 15 14 9.1 43 46 12 6.6 5.3 6.1 6.6 5.3 4.2 1656.7 30 7 70 96 44 27 19 19 22 32 49 22 13 196 356 419 188 106 61 47 39 32 66 89 42 28 25 27 28 23 21 —— .42 .11 11 13 1.6 .56 .29 .27 .27 .94 2.7 .32 .15 147 559 805 126 21 4.3 1.9 1.5 .79 21 13 1.4 .50 .36 .46 .52 .33 .24 1735.93 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 59 17 5.8 142 35 8.4 5.7 9.0 401 4040 191 19 7.2 4.8 115 67 10 81 112 60 45 33 38 28 24 28 24 22 22 21—— 5674.9 73 50 26 147 76 32 26 32 259 1490 224 51 35 42 120 93 41 120 127 39 38 37 37 36 36 56 65 64 61 58 —— —— 28 2.9 .41 122 9.5 .74 .39 .86 1940 17900 217 2.9 .65 .55 98 24 1.2 50 56 6.3 4.6 3.3 3.8 2.7 2.3 4.5 4.2 3.8 3.7 3.3 --- 20497.60 268 RIO GRANDE DE LOIZA BASIN 50055750 RIO GURABO BELOW EL MANGO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT OCT 1995 21... SEP 1996 09... 10... TIME 1734 2212 1312 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. H FINER THAN .002 MM (70326) SED. SUSP. FALL DIAM. H FINER THAN .004 MM (70327) SED. SUSP. FALL DIAM. H FINER THAN .008 MM (70328) 514 3330 5610 2090 2900 3490 31400 2350 35600 55 27 39 61 34 47 66 39 54 DATE OCT 1995 21... SEP 1996 09... 10... SED. SUSP. FALL DIAM. H FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. H FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. H FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. H FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. H FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. H FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. H FINER THAN 1.00 MM (70335) 73 48 65 78 54 76 96 64 87 98 73 95 99 83 98 99 93 99 99 99 99 269 RIO GRANDE DE LOIZA BASIN 50055750 RIO GDRABO BELOW EL MANGO--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 10... DEC 17... JAN 1996 14... FEB 24... JUN 15... AUG 14... 17... TIME 1530 1030 0322 1822 1627 0529 2030 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 42 6.0 1340 481 997 64 434 SEDI- MENT, SUS- PENDED (MG/L) (80154) 343 250 794 351 1150 166 95 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 39 3.8 2860 456 3100 26 111 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 96 95 99 99 100 96 98 270 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALBNCIANO NEAR JONCOS, 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 2 (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 mVs), Oct. 9, 1970, 18,200 ftVs (515 mVs). DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV JAN FEB MAR JUN JUL AUG SEP 1 25 15 2 24 13 3 22 13 4 27 14 5 68 13 6 61 23 7 32 21 8 55 13 9 32 12 10 46 11 11 42 10 12 27 10 13 27 10 14 24 10 15 21 76 16 19 19 17 17 15 18 23 13 19 24 13 20 20 13 21 154 21 22 55 16 23 42 13 24 57 20 25 51 22 26 32 19 27 21 15 28 51 14 29 28 13 30 17 13 31 15 —— TOTAL 1159 503 MEAN 37.4 16.8 MAX 154 76 MIN 15 10 AC-FT 2300 998 CFSM 2.28 1.02 IN. 2.63 1.14 STATISTICS OF MONTHLY MEAN MEAN 73.2 86.7 MAX 293 461 (WY) 1986 1988 HIN 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 INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 13 14 14 14 13 13 12 12 11 10 26 19 39 47 22 15 14 22 52 183 32 20 17 16 14 21 22 14 12 12 12 757 24.4 183 10 1500 1.49 1.72 13 13 13 12 12 16 14 128 69 43 36 45 57 376 277 57 36 49 228 317 89 54 44 38 41 37 33 46 35 30 28 2286 73.7 376 12 4530 4.50 5.19 DATA FOR WATER 54.0 550 1988 11.0 1990 FOR 24.9 77.0 1992 11.4 1976 29 53 36 38 165 48 65 29 24 22 21 18 17 16 12 14 13 12 13 22 16 15 13 30 20 14 13 12 14 ___ —— 814 28.1 165 12 1610 1.71 1.85 YEARS 1971 18.9 47.9 1984 7.21 1974 14 13 13 14 15 13 14 11 19 14 28 17 13 12 20 28 16 14 29 14 12 12 11 11 10 11 11 10 13 10 9.3 451.3 14.6 29 9.3 895 .89 1.02 - 1996 18.9 39.7 1973 7.01 1977 1995 CALENDAR YEAR 13560. 37. 870 1. 2. 26900 2. 30. 60 15 4. 8 2 Sep 16 8 Hay 2 0 Apr 28 27 76 5 9.7 9.1 9.4 37 29 14 12 15 12 8.9 68 35 17 13 13 12 11 21 17 16 13 13 16 21 15 13 29 16 12 20—— 547.1 18.2 68 8.9 1090 1.11 1.24 13 9.1 8.3 7.8 7.7 9.1 8.2 15 26 22 17 13 13 13 7.5 7.0 10 6.7 5.6 6.0 5.0 4.5 10 6.3 5.0 4.2 4.5 4.1 4.7 13 6.8 293.1 9.45 26 4.1 581 .58 .66 53 22 7.4 44 189 e232 273 46 23 16 41 456 189 73 442 322 171 231 118 53 46 240 59 38 29 25 42 76 34 26—— 3616.4 121 456 7.4 7170 7.35 8.20 23 22 22 20 19 18 17 126 112 70 96 284 208 380 412 80 56 49 41 40 33 30 28 27 26 30 25 34 32 23 22 2405 77.6 412 17 4770 4.73 5.46 23 32 120 115 40 28 23 24 21 22 21 18 16 216 497 869 155 66 55 40 48 39 47 62 42 41 39 40 36 34 35 2864 92.4 869 16 5680 5.63 6.50 49 68 52 428 45 33 29 27 264 eSOOO e!90 e86 e70 e66 674 672 684 684 690 660 660 648 641 38 35 34 57 40 56 33 7313 244 5000 27 14510 14.9 16.59 , BY WATER YEAR (WY) 15.0 41.7 1985 5.17 1995 48.6 268 1985 5.02 1990 53.1 188 1979 4.95 1994 FOR 1996 WATER YEAR 23008.9 62.9 5000 4.1 5.5 24900 22.95 45640 3.83 52.19 92 22 11 Sep 10 May 28 May 22 Sep 10 Sep 10 48.1 163 1981 4.61 1994 60.9 231 1979 4.71 1994 WATER YEARS 1971 49.2 121 17.1 9100 1.4 1.7 40000 25.63 1.4 35640 3.00 40.75 72 18 6.9 Dec Jul Jul Dec Dec Apr 85.6 255 1979 10.8 1987 - 1996 1988 1990 8 1987 15 1994 10 1994 8 1987 8 1987 21 1988 e Estimated 277 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1983 to 1986 and water year 1989 to current year. PERIOD OP DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1994 to current year. INSTRUMENTATION.— Automatic sediment sampler since 1984. 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, 8,340 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several days. 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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 8,340 mg/L September 10, 1996; Minimum daily mean, 2 mg/L December 5, 1995. SEDIMENT LOADS: Maximum daily mean, 263,000 tons (238,000 tonnes) September 10, 1996; Minimum daily mean, 0.08 tons (0.07 tonne) several days. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 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 24 22 27 68 61 32 55 32 46 42 27 27 24 21 19 17 23 24 20 154 55 42 57 51 32 21 51 28 17 15 10 10 10 27 119 107 55 93 60 73 76 49 44 39 35 31 28 35 39 35 430 119 103 101 180 58 36 80 56 42 36 .67 .64 .60 3.5 32 20 4.9 21 5.4 11 9.1 3.7 3.3 2.5 2.0 1.6 1.3 2.4 3.0 1.9 735 23 18 21 63 5.4 2.0 25 4.7 2.0 1.5 15 13 13 14 13 23 21 13 12 11 10 10 10 10 76 19 15 13 13 13 21 16 13 20 22 19 15 14 13 13 30 26 22 19 16 26 13 8 8 8 7 7 7 7 144 43 31 25 21 17 31 25 20 28 38 22 13 8 8 8 1.2 .90 .76 .69 .54 2.0 .81 .28 .25 .23 .21 .21 .20 .20 63 2.2 1.2 .93 .72 .58 2.2 1.1 .72 2.0 2.4 1.1 .52 .31 .28 .29 13 14 14 14 13 13 12 12 11 10 26 19 39 47 22 15 14 22 52 183 32 20 17 16 14 21 22 14 12 12 12 8 9 8 4 2 6 6 6 7 7 54 25 62 82 37 13 23 20 80 595 136 32 10 13 18 29 50 28 19 11 8 .28 .32 .29 .15 .09 .20 .21 .20 .21 .21 6.6 1.4 8.1 12 2.3 .53 1.1 1.2 16 683 13 1.7 .45 .56 .69 2.7 3.3 1.1 .62 .37 .25 TOTAL 1159 1031.11 503 88.03 757 759.13 272 RIO GRANDE DE LOZZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 HAY 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 13 13 12 12 16 14 128 69 43 36 45 57 376 277 57 36 49 228 317 89 54 44 38 41 37 33 46 35 30 28 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 13 13 13 12 12 16 14 128 69 43 36 45 57 376 277 57 36 49 228 317 89 54 44 38 41 37 33 46 35 30 28 31 14 12 15 12 10 14 314 123 113 55 113 93 673 495 95 63 82 445 544 58 28 27 32 40 50 61 86 58 27 18 1.1 .49 .41 .49 .38 .43 .55 167 68 16 6.5 16 19 1160 816 15 6.2 11 601 820 16 4.1 3.2 3.3 4.5 5.0 5.5 11 5.7 2.2 1.3 29 53 36 38 165 48 65 29 24 22 21 18 17 16 12 14 13 12 13 22 16 15 13 30 20 14 13 12 14 15 95 61 55 394 95 187 58 15 14 14 14 8 5 6 8 7 5 5 29 24 40 19 43 20 8 6 4 4 1.2 21 5.9 5.7 282 13 40 4.8 .95 .81 .82 .68 .38 .20 .18 .30 .26 .17 .18 1.8 1.1 2.2 .67 6.4 1.3 .29 .18 .14 .16 14 13 13 14 15 13 14 11 19 14 28 17 13 12 20 28 16 14 29 14 12 12 11 11 10 11 11 10 13 10 9.3 5 5 5 6 11 22 21 15 26 18 39 25 9 6 20 44 19 6 48 17 6 5 4 4 4 3 3 5 9 16 19 .17 .18 .19 .23 .45 .75 .75 .48 1.5 .69 3.8 1.2 .33 .20 1.8 3.5 .89 .22 4.2 .67 .19 .15 .13 .12 .10 .10 .09 .13 .32 .42 .48 TOTAL 2286 3787.35 814 392.77 451.3 24.43 273 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE 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 TOTAL 9.7 9.1 9.4 37 29 14 12 15 12 8.9 68 35 17 13 13 12 11 21 17 16 13 13 16 21 15 13 29 16 12 20—— 547.1 APRIL 21 19 16 53 34 19 16 23 26 22 174 61 42 38 33 23 15 26 25 18 16 14 16 44 46 43 45 20 15 26 —— —— MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CPS) MAY .55 .46 .42 10 3.0 .70 .52 1.1 .82 .53 65 6.7 2.0 1.3 1.1 .76 .45 2.3 1.4 .78 .58 .50 .67 2.5 1.8 1.6 4.4 .85 .50 1.5 —— 114.79 13 9.1 8.3 7.8 7.7 9.1 8.2 15 26 22 17 13 13 13 7.5 7.0 10 6.7 5.6 6.0 5.0 4.5 10 6.3 5.0 4.2 4.5 4.1 4.7 13 6.8 293.1 24 21 20 27 37 38 38 37 37 32 44 22 17 13 10 10 9 10 10 8 6 6 7 7 7 8 8 8 8 21 10 ___ .82 .52 .45 .57 .76 .93 .83 1.6 3.3 3.0 2.1 .72 .66 .48 .21 .18 .26 .18 .16 .13 .08 .08 .19 .12 .10 .09 .09 .09 .10 1.8 .18 20.78 53 22 7.4 44 189 e232 273 46 23 16 41 456 189 73 442 322 171 231 118 53 46 240 59 38 29 25 42 76 34 26—— 3616.4 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 54 77 7 63 303 407 509 58 29 21 216 794 336 125 819 559 235 277 207 64 29 457 99 35 19 23 56 125 24 28 13 7.2 .15 15 302 e366 579 7.6 1.8 1.7 28 1530 292 29 1370 651 133 244 78 9.5 3.5 578 16 3.7 1.4 1.5 8.3 31 2.3 2.0 6305.65 e Estimated 274 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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- DISCHARGE TRATION (CFS) (MG/L) 23 22 22 20 19 18 17 126 112 70 96 284 208 380 412 80 56 49 41 40 33 30 28 27 26 30 25 34 32 23 22 JULY 40 71 116 88 56 38 25 486 314 119 169 979 385 722 767 43 36 36 35 35 35 35 23 14 14 13 8 19 50 22 21 TOTAL 2405 —— YEAR e 23008.9 Estimated SEDIMENT DISCHARGE (TONS /DAY) 2.5 4.2 6.9 4.8 2.9 1.8 1.1 425 106 24 73 936 336 1460 1720 9.6 5.4 4.7 3.9 3.8 3.1 2.8 1.8 1.0 .97 1.1 .55 2.5 4.6 1.4 1.3 5152.72 323977.21 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) AUGUST 23 32 120 115 40 28 23 24 21 22 21 18 16 216 497 869 155 66 55 40 48 39 47 62 42 41 39 40 36 34 35 26 52 1070 346 74 62 59 55 52 49 47 54 65 458 1570 2020 325 94 46 23 95 80 75 51 96 72 28 9 9 10 11 1.6 5.0 677 119 8.0 4.6 3.7 3.6 3.0 2.9 2.7 2.7 2.9 419 5850 9020 154 17 6.9 2.5 13 8.4 10 8.3 11 7.9 3.0 .99 .88 .88 1.1 2864 16371.55 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 49 68 52 428 45 33 29 27 264 eSOOO e!90 e86 e70 e66 e74 e72 e84 e84 e90 e60 e60 e48 e41 38 35 34 57 40 56 33 44 121 89 1830 82 59 63 55 1380 8340 2570 381 166 157 271 254 215 182 155 131 111 94 80 69 68 63 95 28 67 25 12 29 13 7810 10 5 4 4 8910 0263000 e9570 e!52 e35 e29 e51 e50 e45 e41 e36 e26 e!8 e!4 e9 7 6 5 17 3 13 2 .2 .9 .0 .1 .1 .4 .9 .0 .3 7313 289928.9 275 RIO GRANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1995 25... DEC 20... JAN 1996 28... JUL 08... AUG 03... 15... SEP 04... 10... 10... OCT 1995 25... DEC 20... JAN 1996 28... JUL 08... AUG 03... 15... SEP 04... 10... 10... TIME 1645 0905 1226 1930 1617 1615 0615 0845 1240 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 50 65 72 60 77 74 43 74 57 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 182 1080 43 273 248 103 557 10700 13400 SED. SUSP. FALL DIAM. H FINER THAN .031 MM (70330) 62 73 80 76 84 81 58 85 68 SEDI- MENT, SUS- PENDED (MG/L) (80154) 21300 2420 2100 3780 3760 2740 9380 7160 3670 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 77 90 98 98 99 99 66 99 90 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 10500 7070 244 2790 2510 762 14100 207000 133000 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 94 96 99 100 100 100 81 100 98 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 25 43 43 36 38 50 22 37 41 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 99 99 100 100 100 100 92 100 100 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 32 52 51 44 60 61 26 50 46 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 100 100 100 100 100 100 98 109 100 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 39 57 57 50 68 67 32 59 48 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 100 100 100 100 99 100 100 276 RIO ORANDE DE LOIZA BASIN 50056400 RIO VALENCIANO NEAR JUNCOS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE DEC 1995 20... JAN 1996 14... FEB 02... APR 11... JUN 18... JUL 12... AUG 03... 15... SEP 10... 10... TIME 0800 0630 1420 0655 1345 1000 2015 1815 1300 1445 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 333 473 113 206 366 662 229 153 14200 8660 SEDI- MENT, SUS- PENDED (MG/L) (80154) 2310 549 329 347 418 1070 2850 3090 7250 4090 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2080 701 100 193 413 1910 1760 1280 278000 95600 SED. SUSP. SIEVE DIAM. * FINER THAN .062 MM (70331) 100 99 98 99 99 99 100 100 98 86 277 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT 6URABO, PR 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 2 (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 except those for estimated daily discharges, which are poor. 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN SEP 1 48 28 2 42 26 3 69 28 4 45 34 5 133 30 6 133 72 7 85 70 8 79 27 9 84 21 10 77 18 11 92 15 12 68 13 13 65 16 14 71 12 15 51 56 16 48 41 17 51 23 18 41 16 19 55 13 20 61 11 21 131 12 22 138 17 23 64 11 24 189 12 25 89 22 26 103 15 27 54 15 28 57 12 29 61 13 30 33 11 31 28 —— TOTAL 2345 710 MEAN 75.6 23.7 MAX 189 72 MIN 28 11 AC-FT 4650 1410 CFSM 1.26 .39 IN. 1.45 ,44 9.8 9.3 9.2 8.4 11 12 12 10 9.6 12 16 21 33 42 26 14 16 35 103 136 42 24 16 12 14 13 57 23 16 14 13 789.3 25.5 136 8.4 1570 .42 .49 STATISTICS OF MONTHLY MEAN DATA MEAN 215 210 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 150 863 1988 10.7 1968 12 12 12 11 10 13 14 106 96 94 25 101 86 1420 817 87 44 39 128 493 143 57 39 32 36 42 57 93 59 32 25 4235 137 1420 10 8400 2.27 2.62 FOR WATER 62.0 204 1992 16.4 1968 23 26 25 22 89 47 96 36 23 49 34 27 24 23 20 21 23 27 22 30 23 25 25 75 96 40 28 24 22 —— --- 1045 36.0 96 20 2070 .60 .65 YEARS 1960 46.4 131 1989 12.6 1968 22 20 19 20 29 30 23 21 25 24 37 52 24 18 48 90 36 23 60 31 19 16 14 13 12 11 12 12 13 14 13 801 25.8 90 11 1590 .43 .49 - 1996 39.1 97.5 1985 11.2 1965 FOR 1995 CALENDAR YEAR 22565. 61. 2580 4. 5. 44760 1. 13. 103 19 8. 9 8 Sep 16 5 May 19 8 Apr 21 03 94 6 12 11 12 26 52 18 13 12 13 9.6 54 47 24 20 13 16 15 12 11 8.0 7.3 6.7 7.5 16 12 7.8 12 9.5 7.1 8.7 —— 493.2 16.4 54 6.7 978 .27 .30 13 8.0 6.6 6.0 5.5 5.8 6.6 9.5 39 21 24 11 22 94 17 35 12 7.5 6.8 6.0 5.1 4.9 6.2 9.3 5.2 5.1 3.7 4.2 4.4 6.3 7.3 418.0 13.5 94 3.7 829 .22 .26 38 32 20 23 69 158 222 80 33 21 34 414 176 82 456 1870 e900 e!200 e680 e!70 55 126 61 34 24 19 18 67 41 21 —— 7144 238 1870 18 14170 3.96 4.41 16 14 12 12 11 9.5 9.0 510 295 106 72 231 e398 e374 e679 125 74 56 44 45 38 28 23 21 21 20 18 50 55 22 16 3404.5 110 679 9.0 6750 1.82 2.10 155 31 82 146 52 26 19 17 14 16 27 15 12 205 260 2090 278 161 70 45 39 26 48 96 33 22 18 16 18 15 13 4065 131 2090 12 8060 2.18 2.51 30 63 38 308 94 26 17 31 40 26200 2190 353 232 190 506 601 260 305 341 224 166 131 121 102 91 94 105 93 104 83 —— 33139 1105 26200 17 65730 18.3 20.48 , BY WATER YEAR (WY) 41.8 108 1978 13.1 1995 FOR 1996 58589 160 26200 3 5 62100 31 116200 2 36 162 26 9 144 746 1985 12.7 1990 WATER YEAR .0 Sep 10 .7 May 27 .2 May 25 Sep 10 .44 Sep 10 .66 .20 .7 133 468 1970 16.8 1972 115 376 1993 20.7 1994 WATER 130 286 42 26200 3 5 62100 31 94540 2 29 205 48 17 164 610 1979 24.8 1967 YEARS 1960 .2 Sep .7 May .2 May Sep .44 Sep .17 .45 240 1225 1960 8.76 1967 - 1996 1979 1967 10 1996 27 1996 25 1996 10 1996 10 1996 e Estimated 278 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO—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-49 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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 4,050 mg/L September 10, 1996; minimum daily mean, 4 mg/L September 26, 1996. SEDIMENT LOADS: Maximum daily mean, 267,000 tons (242,000 tonnes) September 10, 1996; minimum daily 0.09 tons (0.08 tonne) May 29, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 48 42 69 45 133 133 85 79 84 77 92 68 65 71 51 48 51 41 55 61 131 138 64 189 89 103 54 57 61 33 28 46 30 67 49 108 119 85 75 46 44 72 37 42 64 40 35 52 30 24 65 121 140 70 148 102 275 72 56 64 45 30 6. 3. 13 6. 46 45 20 17 11 10 18 6. 7. 12 5. 4. 7. 3. 4. 11 114 71 13 83 32 82 11 10 11 4. 2. 0 5 0 8 8 6 6 2 3 5 1 3 NOVEMBER 28 26 28 34 30 72 70 27 21 18 15 13 16 12 56 41 23 16 13 11 12 17 11 12 22 15 15 12 13 11 ___ 19 14 28 36 28 49 68 31 23 18 15 12 14 17 100 98 28 19 15 12 12 25 19 23 32 19 15 14 16 15 ___ 1 2 3 2 14 14 2 1 21 10 2 1 1 .5 .97 .2 .3 .2 .3 .3 .86 .59 .41 .68 .58 .0 .79 .51 .35 .42 .2 .58 .80 .9 .74 .60 .49 .57 .43 ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 9.8 9.3 9.2 8.4 11 12 12 10 9.6 12 16 21 33 42 26 14 16 35 103 136 42 24 16 12 14 13 57 23 16 14 13 13 12 12 11 11 10 10 10 10 11 11 25 37 38 32 18 20 32 93 102 45 25 20 16 19 18 55 28 22 19 17 .35 .32 .29 .25 .31 .35 .32 .28 .27 .36 .50 1.4 3.7 4.8 2.5 .67 1.2 3.1 29 57 5.6 1.6 .87 .53 .79 .65 9.4 1.7 .96 .71 .61 TOTAL 2345 691.7 710 87.27 789.3 130.39 279 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 12 12 12 11 10 13 14 106 96 94 25 101 86 1420 817 87 44 39 128 493 143 57 39 32 36 42 57 93 59 32 25 17 16 16 15 14 17 19 99 130 145 29 107 152 637 412 84 45 28 153 379 118 53 31 20 13 11 32 81 51 26 17 .55 .54 .49 .45 .40 .59 .72 37 52 51 2.1 34 34 6070 1580 20 5.5 2.8 152 776 49 8.1 3.3 1.7 1.2 1.2 5.7 22 8.7 2.3 1.1 FEBRUARY 23 26 25 22 89 47 96 36 23 49 34 27 24 23 20 21 23 27 22 30 23 25 25 75 96 40 28 24 22 ___ 11 17 29 26 72 51 118 106 53 50 32 17 12 9 6 6 15 31 17 25 22 22 28 64 95 44 32 26 20 .__ .68 1.4 2.0 1.6 24 7.7 33 10 3.5 9.4 3.0 1.2 .75 .53 .34 .31 1.0 2.2 1.0 2.1 1.4 1.7 1.9 25 27 4.9 2.5 1.7 1.2 —— MARCH 22 20 19 20 29 30 23 21 25 24 37 52 24 18 48 90 36 23 60 31 19 16 14 13 12 11 12 12 13 14 13 16 13 10 9 28 25 14 12 19 12 22 50 18 15 43 81 36 28 60 30 18 14 11 8 6 8 11 15 14 13 11 .94 .68 .50 .47 2.3 2.1 .89 .70 1.3 .80 3.6 7.7 1.1 .70 9.7 22 3.6 1.8 11 1.1 .93 .60 .40 .28 .21 .25 .37 .48 .50 .48 .38 TOTAL 4235 8924.44 1045 173.01 801 79.46 280 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO--Continued 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) 12 11 12 26 52 18 13 12 13 9.6 54 47 24 20 13 16 15 12 11 8.0 7.3 6.7 7.5 16 12 7.8 12 9.5 7.1 8.7 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) APRIL 10 11 14 22 40 33 35 33 28 16 31 23 23 30 26 19 15 17 17 9 10 11 11 20 18 15 15 13 10 12 .33 .33 .48 2.2 6.2 1.6 1.2 1.0 .96 .41 5.6 2.9 1.5 1.6 .91 .84 .63 .61 .53 .19 .19 .20 .22 .88 .60 .32 .52 .33 .19 .29 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CPS) (MG/L) (TONS/DAY) MEAN DISCHARGE (CPS) MAY 13 8.0 6.6 6.0 5.5 5.8 6.6 9.5 39 21 24 11 22 94 17 35 12 7.5 6.8 6.0 5.1 4.9 6.2 9.3 5.2 5.1 3.7 4.2 4.4 6.3 7.3 16 10 9 8 8 8 10 13 24 11 25 15 19 159 96 64 89 64 50 35 24 14 8 12 9 8 10 9 7 7 10 .59 .22 .15 .13 .12 .12 .18 .38 2.7 .65 1.6 .47 4.9 41 4.6 10 3.2 1.3 .88 .57 .33 .18 .13 .31 .13 .11 .11 .10 .09 .13 .19 38 32 20 23 69 158 222 80 33 21 34 414 176 82 456 1870 e900 e!200 e680 e!70 55 126 61 34 24 19 18 67 41 21 —— MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 38 32 20 23 69 158 222 80 33 21 34 414 176 82 456 1870 e900 e!200 e680 e!70 55 126 61 34 24 19 18 67 41 21 33 28 15 22 64 196 168 87 49 28 26 294 247 94 366 827 211 100 61 37 25 98 74 55 31 18 19 42 45 28 5.5 2.6 .80 2.0 20 89 110 20 4.6 1.6 2.9 460 124 21 714 4410 e!64 e39 e!7 e7.6 3.7 43 12 5.1 2.0 .90 .89 9.4 5.4 1.6 493.2 33.76 418.0 75.57 7144 6299.59 e Estimated 281 RIO GRANDE DE LOIZA BASIN 50057000 RIO GDRABO AT GURABO--Continued SEDIMENT DISCHARGE, SUSPENDED {TONS/DAY), WATER 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- DISCHARGE TRATION (CFS) (MG/L) 16 14 12 12 11 9.5 9.0 510 295 106 72 231 e398 e374 e679 125 74 56 44 45 38 28 23 21 21 20 18 50 55 22 16 JULY 24 15 9 8 8 9 11 147 140 88 76 189 283 282 458 66 25 16 15 17 18 19 16 12 10 9 10 48 59 17 15 TOTAL 3404.5 —— YEAR e 58589.0 Estimated MEAN SEDIMENT MEAN CONCEN- SEDIMENT DISCHARGE DISCHARGE TRATION DISCHARGE (TONS/DAY) (CFS) (MG/L) (TONS/DAY) AUGUST 1.0 .57 .30 .26 .24 .24 .27 700 145 25 15 140 e351 e481 e!070 24 5.0 2.4 1.8 2.0 1.9 1.4 .98 .66 .56 .51 .51 12 9.8 1.0 .63 2995.03 304427.47 155 31 82 146 52 26 19 17 14 16 27 15 12 205 260 2090 278 161 70 45 39 26 48 96 33 22 18 16 18 15 13 4065 431 34 105 158 132 86 54 29 15 17 30 13 13 134 238 760 206 134 39 35 42 32 46 87 46 26 14 12 13 14 14 —— 576 3.1 31 62 20 6.0 2.8 1.3 .58 .73 2.3 .54 .40 116 1050 5940 158 70 7.5 4.3 4.5 2.2 9.7 25 4.2 1.5 .70 .55 .63 .54 .48 8102.55 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) SEPTEMBER 30 63 38 308 94 26 17 31 40 26200 2190 353 232 190 506 601 260 305 341 224 166 131 121 102 91 94 105 93 104 83 —— 33139 24 61 37 321 87 30 22 59 180 4050 772 284 238 194 345 355 175 212 280 139 51 25 12 6 5 4 6 9 10 10 —— —— 4.7 14 5.2 567 27 2.2 1.0 5.8 214 267000 6240 271 150 99.7 721 757 125 219 276 86 23 8.8 3.9 1.6 1.1 1.1 1.8 2.4 2.8 2.3 —— 276834.4 282 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OP SUSPENDED SEDIMENT DATE JAN 1996 19... JUL 08... AUG 01... 15... SEP 10... DATE JAN 1996 19... JUL 08... AUG 01... 15... SEP 10... TIME 2216 2030 1410 2400 0100 SED. SUSP. PALL DIAM. ; FINER THAN 016 MM 90 82 88 85 DIS- CHARGE, INST. CUBIC FEET PER SECOND 533 2280 383 3680 2640 SED. SUSP. PALL DIAM. % FINER THAN .031 MM 93 85 92 90 SEDI- MENT, SUS- PENDED (MG/L) 1710 1280 2440 3460 5070 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM 98 99 100 97 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) 2460 7860 2520 34400 36100 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM 99 100 100 99 SED. SUSP. PALL DIAM. * FINER THAN .002 MM 63 64 63 42 30 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM 100 100 100 99 SED. SUSP. PALL DIAM. % FINER THAN .004 MM 72 73 74 53 43 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM 100 100 100 100 SED. SUSP. PALL DIAM. % FINER THAN .008 MM 83 76 81 71 56 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM 100 100 100 100 74 84 95 99 100 100 100 283 RIO GRANDE DE LOIZA BASIN 50057000 RIO GURABO AT GURABO, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT OCT 1995 21... 21... 26... JAN 1996 13... 19... MAR 20... JUN 15... JUL 14... AU6 01... 16... 16... SEP 04... 10... 10... DIS- CHARGE, XNST. CUBIC FEET PER SECOND SEDI- MENT, SUS- PENDED (MG/L) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM 2100 2300 1520 1430 2101 1346 1630 1230 1720 0445 0745 0930 0445 1045 625 576 70 55 531 29 952 950 298 4680 3560 1370 9530 37500 310 523 523 813 259 49 142 494 26 21 708 2.0 956 2460 249 639 2570 2070 821 10400 1080 10400 1260 4670 5050 130000 4790 485000 95 98 98 99 88 99 99 98 78 99 98 99 90 99 284 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO HEAR 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 km 2 ). PERIOD OF RECORD.--Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 10 DEC 12 FEE 14 APR 10 JUN 05 AUG 12 OCT 10 DEC 12 FEE 14 APR 10 JUN 05 AUG 12 E = K = DATE TIME 1995 0825 0805 1996 0745 0805 0815 1010 STREP- TOCOCCI FECAL, (COLS. DATE PER 100 ML) (31679) 1995 720 450 1996 K1600 300 860 4000 estimated non- ideal count DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) E77 E21 E23 E10 E69 E15 HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 110 -- -- 120 -- 120 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 315 440 386 385 331 382 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- -- 28 -- 27 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.6 7.0 6.9 6.9 6.8 7.0 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 11 -- -- 12 -- 13 TEMPER- ATURE WATER (DEG C) (00010) 28.0 25.0 25.5 27.5 29.0 30.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 26 -- -- 32 -- 30 TUR- BID- ITY (NTU) (00076) 17 5.5 7.8 3.5 2.5 13 SODIUM AD- SORP- TION RATIO (00931) 1 -- -- 1 -- 1 OXYGEN, DIS- SOLVED (MG/L) (00300) 4.0 4.5 3.0 3.1 3.7 4.0 POTAS - SIUM, DIS- SOLVED (MG/L AS K) (00935) 4.8 -- -- 5.2 -- 4.3 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 50 53 36 38 48 53 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 110 170 130 110 98 140 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 24 14 18 18 48 21 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 3800 K8400 6000 540 K7100 K9000 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 12 -- -- 19 -- 16 RIO GRANDE DE LOIZA BASIN 50057025 RIO GURABO NEAR GURABO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 285 DATE OCT 1995 10. .. DEC 12... FEB 1996 14... APR 10.. . JUN 05... AUG 12. .. DATE OCT 1995 10. .. DEC 12. .. FEB 1996 14. .. APR 10. .. JUN 05. . . AUG 12. . . OCT 1995 10. .. DEC 12.. . FEB 1996 14... APR 10... JUN 05... AUG 12... CHLO- RIDE, DIS- SOLVED (HG/L AS CL) (00940) 30 — -- 40 -- 31 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.89 0.63 0.70 0.34 2.2 0.38 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- -- 0.20 — 0.10 NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.3 2.4 1.5 1.4 3.2 1.1 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 30 — -- 29 -- 35 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 10 11 6.7 6.4 14 4.8 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 206 — -- 231 — 240 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.350 0.330 0.180 0.060 0.500 0.040 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 14 11 16 12 28 28 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- -- 1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.33 1.77 0.770 1.09 0.940 0.690 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.070 0.030 0.040 0.010 0.060 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- -- 30 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.40 1.80 0.810 1.10 1.00 0.700 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.180 0.210 0.250 0.020 0.120 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.71 0.42 0.45 0.32 2.1 0.36 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 1100 380 <1 270 400 <0.10 <0.10 <1 <1 <1 <1 10 <0.010 <0.010 <1 <1 0.03 0.04 286 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR LOCATION.--Lat 18°17'41", long 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» (19.50 km»). 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT DEC JAN MAR MAY JUN JUL 1 7.2 6.6 2 7.2 19 3 7.5 29 4 7.2 14 5 7.2 27 6 7.2 83 7 48 21 8 29 11 9 17 8.3 10 8.4 7.1 11 14 6.6 12 7.3 6.2 13 5.7 6.2 14 5.3 5.8 15 5.3 5.5 16 7.4 7.7 17 67 6.1 18 28 5.6 19 53 7.0 20 10 5.3 21 9.6 4.7 22 9.1 4.7 23 7.4 4.7 24 66 6.1 25 11 5.6 26 15 5.6 27 31 5.3 28 11 5.0 29 8.0 5.6 30 6.7 5.6 31 6.5 TOTAL 530.2 340.9 MEAN 17.1 11.4 MAX 67 83 MIN 5.3 4.7 AC-PT 1050 676 CPSM 2.27 1.51 IN. 2.62 1.68 4.9 5.7 5.8 5.4 5.3 5.0 5.0 5.0 5.1 5.9 14 5.1 6.3 5.0 5.0 5.9 5.2 42 13 5.2 6.3 4.8 57 11 17 8.3 6.5 6.2 5.8 5.4 5.2 293.3 9.46 57 4.8 582 1.26 1.45 STATISTICS OF MONTHLY MEAN DATA MEAN 15.8 13.8 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 5.2 5.3 5.2 5.0 5.0 21 5.2 21 6.9 13 10 35 8.7 74 44 14 6.3 5.3 5.0 41 9.2 5.7 4.5 5.4 9.3 5.8 18 66 15 8.7 7.8 491.5 15.9 74 4.5 975 2.11 2.43 FOR WATER 11.2 24.5 1992 4.48 1994 6.5 6.1 6.4 5.6 6.1 4.6 4.4 4.4 35 15 5.7 4.4 4.4 4.1 4.0 4.0 3.9 3.7 3.8 21 6.6 5.4 5.0 .9 .7 .6 .0 .0 3.9 ___ —— 196.2 6.77 35 3.7 389 .90 .97 YEARS 1990 9.79 18.8 1995 4.29 1994 3.5 3.5 3.8 4.4 7.0 4.3 3.6 3.2 5.2 3.2 5.1 3.3 3.0 3.0 14 5.6 4.0 3.7 4.8 3.6 3.5 3.5 3.3 3.2 3.1 4.8 4.2 3.1 3.3 2.6 3.1 129.5 4.18 14 2.6 257 .55 .64 - 1996 4.81 6.02 1995 2.48 1994 FOR 1995 CALENDAR YEAR 4961. 13. 467 1. 1. 9840 1. 24. 29 5. 1. 8 6 Sep 6 2 Jan 8 5 Jan 2 81 51 0 7 3.5 3.3 46 8.8 32 11 5.1 4.4 3.5 3.3 3.3 5.2 3.9 3.3 3.7 7.2 3.5 3.3 2.1 3.1 8.1 9.2 34 8.8 5.8 .9 .8 .5 .2 .7 --- 248.5 8.28 46 2.1 493 1.10 1.23 .7 .4 .5 .4 .1 4.8 7.4 5.6 5.4 6.5 5.2 4.9 6.7 6.4 7.0 7.8 4.8 4.3 30 8.4 4.7 3.9 11 5.2 5.2 15 5.4 4.6 4.2 4.2 4.4 205.1 6.62 30 3.9 407 .88 1.01 .5 .3 .9 .1 .2 .4 .4 .1 .0 .7 4.8 18 4.7 6.3 38 10 6.1 e66 e4.9 e4.0 e3.9 e6.0 e4.7 e3.3 3.3 3.5 3.5 3.7 3.7 3.7 --- 244.7 8.16 66 3.3 485 1.08 1.21 3.5 3.7 3.7 3.7 4.0 4.2 4.7 24 8.6 5.8 6.0 5.6 5.7 19 20 4.6 3.7 4.9 4.1 4.1 4.0 3.8 4.1 5.6 5.5 4.2 4.0 12 5.8 4.4 13 210.0 6.77 24 3.5 417 .90 1.04 52 297 31 16 15 11 13 10 9.2 9.1 18 9.3 12 52 46 126 24 19 13 11 12 12 36 e!50 e28 el6 el3 el2 e43 el3 ell 1139.6 36.8 297 9.1 2260 4.88 5.63 e!2 e!2 23 18 18 15 14 21 36 e!670 e227 e82 e37 e28 e21 e!6 15 21 15 13 12 11 10 8.4 8.2 7.1 8.9 7.3 6.0 55 --- 2447.9 81.6 1670 6.0 4860 10.8 12.09 , BY WATER YEAR (WY) 5.70 11.1 1993 3.24 1995 FOR 1996 6477 17 1670 2 3 7500 24 2 12850 2 32 29 5 3 9.42 19.5 1992 2.50 1994 WATER YEAR .4 .7 Sep 10 .1 Apr 19 .3 Mar 27 Sep 10 .60 Sep 10 .4 Mar 30 .35 .00 .8 .7 8.22 20.0 1993 1.78 1994 9.36 24.9 1993 3.40 1990 WATER 12 17 5 1670 1 1 7500 24 1 8920 1 22 19 5 2 15.0 36.8 1996 4.36 1990 YEARS 1990 .3 .7 .77 Sep .1 Jun .2 Jun Sep .60 Sep . 0 Jun .64 .23 .0 .4 25.0 81.6 1996 4.74 1994 - 1996 1996 1994 10 1996 8 1994 8 1994 10 1996 10 1996 21 1994 e Estimated 287 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RXO CANAS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORDS.— Water years 1990 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 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, 12,900 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 1996.— SEDIMENT CONCENTRATION: Maximum daily mean, 12,900 mg/L September 10, 1996; Minimum daily mean, 1 mg/L October 1,2,3, 1996. SEDIMENT LOADS: Maximum daily mean, 95,000 tons (86,200 tonnes) September 10, 1996; Minimum daily mean, 0.02 ton (0.02 tonne) October 01-02, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MG/L) (TONS/DAY) OCTOBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) DECEMBER 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 7.2 7.2 7.5 7.2 7.2 7.2 48 29 17 8.4 14 7.3 5.7 5.3 5.3 7.4 67 28 53 10 9.6 9.1 7.4 66 11 15 31 11 8.0 6.7 6.5 1 1 1 2 3 3 1830 871 234 49 331 37 28 25 23 101 1410 742 1310 63 59 60 61 2450 71 351 928 129 64 50 40 .02 .02 .03 .04 .05 .06 677 187 18 1.1 31 .74 .43 .35 .32 3.6 1140 158 757 1.8 2.2 1.8 1.2 860 2.3 24 256 4.7 1.4 .91 .71 6.6 19 29 14 27 83 21 11 8.3 7.1 6.6 6.2 6.2 5.8 5.5 7.7 6.1 5.6 7.0 5.3 4.7 4.7 4.7 6.1 5.6 5.6 5.3 5.0 5.6 5.6 33 471 993 135 716 2020 231 30 17 16 17 18 20 21 23 191 29 25 38 22 17 16 17 26 24 18 14 12 17 16 .58 90 108 6.0 155 753 17 .93 .39 .30 .31 .31 .33 .33 .34 7.9 .48 .37 .88 .31 .22 .21 .21 .48 .37 .27 .20 .16 .30 .25 4.9 5.7 5.8 5.4 5.3 5.0 5.0 5.0 5.1 5.9 14 5.1 6.3 5.0 5.0 5.9 5.2 42 13 5.2 6.3 4.8 57 11 17 8.3 6.5 6.2 5.8 5.4 5.2 9 28 19 15 11 9 7 7 7 22 367 27 20 15 13 12 11 1160 327 24 142 21 1740 170 422 59 31 29 26 25 24 .12 .52 .30 .21 .16 .12 .10 .09 .10 .46 39 .37 .34 .20 .18 .19 .15 326 24 .34 8.4 .28 1720 7.2 58 1.5 .55 .48 .41 .36 .34 TOTAL 530.2 4131.78 340.9 1145.43 293.3 2190.47 288 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 DISCHARGE (CPS) 5.2 5.3 5.2 5.0 5.0 21 5.2 21 6.9 13 10 35 8.7 74 44 14 6.3 5.3 5.0 41 9.2 5.7 4.5 5.4 9.3 5.8 18 66 15 8.7 7.8 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 24 23 23 23 22 494 23 593 28 265 61 941 32 2220 935 87 32 22 21 1070 93 32 21 27 69 24 452 2120 145 45 35 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY .34 .34 .32 .30 .30 103 .33 88 .58 46 2.0 208 .75 1660 316 4.6 .54 .32 .29 369 2.7 .50 .26 .47 2.5 .37 32 532 7.0 1.1 .73 6.5 6.1 6.4 5.6 6.1 4.6 4.4 4.4 35 15 5.7 4.4 4.4 4.1 4.0 4.0 3.9 3.7 3.8 21 6.6 5.4 5.0 .9 .7 .6 .0 .0 3.9 ___ ___ 17 10 8 7 19 18 11 8 973 340 32 15 14 17 19 19 17 16 14 512 27 16 13 12 10 9 10 11 12 ___ ___ .30 .16 .14 .11 .51 .22 .14 .09 420 36 .51 .17 .17 .18 .21 .20 .18 .16 .15 132 .49 .24 .18 .16 .13 .11 .11 .11 .12 ___ ___ MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 3.5 3.5 3.8 4.4 7.0 4.3 3.6 3.2 5.2 3.2 5.1 3.3 3.0 3.0 14 5.6 4.0 3.7 4.8 3.6 3.5 3.5 3.3 3.2 3.1 4.8 4.2 3.1 3.3 2.6 3.1 9 7 5 4 46 15 8 7 19 6 4 4 4 3 100 27 9 5 3 3 5 6 7 8 10 20 23 18 14 10 7 .09 .07 .05 .05 1.0 .18 .08 .06 .35 .05 .06 .04 .03 .03 10 .46 .09 .05 .04 .03 .05 .05 .06 .07 .08 .46 .27 .15 .12 .07 .06 TOTAL 491.5 3380.64 196.2 593.25 129.5 14.25 289 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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) 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 3.5 3.3 46 8.8 32 11 5.1 4.4 3.5 3.3 3.3 5.2 3.9 3.3 3.7 7.2 3.5 3.3 2.1 3.1 8.1 9.2 34 8.8 5.8 4.9 4.8 4.5 4.2 4.7 ___ APRIL 6 9 1950 66 1000 178 32 33 38 38 37 34 31 28 26 127 88 45 21 14 207 269 1140 185 31 17 12 9 8 7 ___ MAY .05 .08 1450 1.9 403 14 .44 .39 .36 .34 .33 .48 .33 .25 .26 3.1 .82 .41 .18 .12 16 24 233 5.9 .49 .23 .16 .11 .10 .09 ___ 4.7 4.4 4.5 4.4 4.1 4.8 7.4 5.6 5.4 6.5 5.2 4.9 6.7 6.4 7.0 7.8 4.8 4.3 30 8.4 4.7 3.9 11 5.2 5.2 15 5.4 4.6 4.2 4.2 4.4 4 4 8 18 35 29 52 39 25 32 23 20 27 42 36 62 105 21 898 109 20 17 351 39 27 341 26 15 11 22 45 .06 .04 .09 .21 .38 .38 1.3 .60 .37 .61 .32 .26 .67 .75 .87 2.1 1.4 .25 223 6.8 .25 .18 19 .54 .37 66 .38 .19 .13 .25 .55 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 4.5 4.3 3.9 4.1 4.2 4.4 4.4 4.1 4.0 4.7 4.8 18 4.7 6.3 38 10 6.1 e66 e4.9 e4.0 e3.9 e6.0 e4.7 e3.3 3.3 3.5 3.5 3.7 3.7 3.7 ___ 24 9 12 18 11 5 6 8 12 18 26 145 20 34 805 64 34 1800 144 23 15 11 9 9 8 7 12 19 15 9 ___ .29 .10 .12 .20 .12 .06 .07 .09 .13 .24 .34 14 .25 .79 265 1.8 .58 e!220 e2.4 e.25 e.16 8.18 e.12 e.08 .07 .07 .11 .19 .15 .09 ___ TOTAL 248.5 2156.92 205.1 328.30 244.7 1508.05 e Estimated 290 RIO QRANDE DE LOIZA BASIN 50058350 RIO CANAS AT RIO CANAS, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE DAY (CFS) (MQ/L) (TONS/DAY) JULY 1996 3.5 3.7 3.7 3.7 4.0 4.2 4.7 24 8.6 5.8 6.0 5.6 5.7 19 20 4.6 3.7 4.9 4.1 4.1 4.0 3.8 4.1 5.6 5.5 4.2 4.0 12 5.8 4.4 13 110.0 i77.4 6 6 7 6 4 4 4 569 51 29 26 14 7 593 612 22 15 13 11 10 8 7 6 12 27 11 18 96 30 10 286 —— .05 .06 .07 .06 .05 .05 .05 85 1.6 .44 .44 .21 .11 61 55 .28 .15 .18 .12 .11 .09 .07 .06 .36 .42 .12 .19 6.6 .51 .12 41 254.57 128325.82 MEAN DISCHARGE (CPS) 52 297 31 16 15 11 13 10 9.2 9.1 18 9.3 12 52 46 126 24 19 13 11 12 12 36 •150 •28 •16 •13 •12 •43 •13 •11 MEAN CONCEN- TRATION (MO/L) AUGUST 1780 2720 890 130 74 49 64 43 11 8 427 30 52 1630 774 3530 382 125 24 9 4 3 712 2400 158 22 14 11 764 22 22 SEDIMENT DISCHARGE (TONS/DAY) 855 6410 81 6.0 3.3 1.4 2.6 1.2 .29 .20 48 .79 4.0 377 584 1840 26 6.1 .79 .24 .11 .09 197 •3820 •12 .87 .45 .35 •28 .72 .62 MEAN DISCHARGE (CFS) CM •12 •12 23 18 18 15 14 21 36 •1670 •227 •82 •37 •28 •21 •16 15 21 15 13 12 11 10 8.4 8.2 7.1 8.9 7.3 6.0 55—— MEAN CONCEN- TRATION (MO/L) 21 21 449 295 128 100 90 160 1110 12900 1380 536 500 467 139 35 30 207 41 12 10 9 9 8 6 4 33 9 6 2030 —— SEDIMENT DISCHARGE (TONS/DAY) • .61 • .61 68 15 6.4 3.8 3.3 8.6 152 •95000 •847 •119 •50 •41 •7.9 •1.5 1.2 18 1.6 .43 .28 .25 .22 .18 .13 .08 1.7 .16 .09 1710—— 1139.6 14563.12 2447.9 98059.04 291 RIO GRANDE DE LOIZA BASIN 50058350 RIO CANAS AT CANAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT DATE OCT 1995 17... DEC 23... JAN 1996 14... FEB 09... APR 03... •TON 15... JUL 14... AUO 24... DATE OCT 1995 17... DEC 23... JAN 1996 14... FEB 09... APR 03... JUN 15... JUL 14... AUO 24... TIME 1237 1707 2317 1630 1630 1050 1740 1530 SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) 54 45 34 46 43 56 80 35 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 725 563 561 256 573 26 40 389 SED. SUSP. FALL DIAM. H FINER THAN .031 MM (70330) 65 59 43 56 53 68 82 43 SEDI- MENT, SUS- PENDED (MO/L) (80154) 14600 19300 13200 13200 21500 8300 1880 9770 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 80 73 58 71 64 84 98 54 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 28600 29300 20000 9100 33300 583 203 10300 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 89 88 75 86 76 93 99 65 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 30 22 16 21 22 -- 47 22 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 94 97 90 96 87 98 100 77 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 33 27 20 26 29 35 60 25 SED. SUSP. SIEVE DIAM. H FINER THAN .500 MM (70334) 98 99 97 99 94 99 100 88 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 43 34 26 33 34 47 70 30 SED. SUSP. SIEVE DIAM. % FINER THAN 1.00 MM (70335) 100 100 99 100 98 100 100 96 292 50058350 RIO CANAS AT CANAS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 26... 27... NOV 16... DEC 23... JAN 1996 20... APR 03... JUL 14... AUG 01... 14... 24... TIME 1600 1732 1625 1737 1517 1745 1500 1745 1645 1330 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 48 23 14 656 261 215 26 175 43 1310 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1410 5160 1850 14900 4500 10200 1050 9080 1340 10100 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 183 320 70 26400 3170 5920 74 4290 156 35600 SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) 97 86 99 79 79 95 100 81 97 66 293 RIO GRANDE DE LOIZA BASIN 50059000 liAGO LOIZA AT DAMSITE NEAR TRDJILLO ALTO, PR LOCATION.—Lat 18°19'49", long 66°01'00", Hydrologic Unit 21010005, at pumpsite at damsite, and 1.9 ml (3.1 km) south of Trujillo Alto plaza. DRANAIGE AREA.—208 ml 2 (539 km1 ). 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 hm3 ). 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), Jan. 14; but could have been highter on Sept. 10-11 during Hurricane Hortense event; minimum elevation, 130.01 ft (39.62 m), June 4. 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 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 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 134.79 134.33 134.61 134.77 134.73 134.49 134.85 134.55 134.23 134.55 134.41 134.76 134.34 134.56 134.68 134.76 134.32 134.44 134.82 134.34 NOV 134.52 134.68 134.46 134.72 134.72 134.56 134.48 134.64 134.70 134.74 134.74 134.72 134.70 134.66 134.76 134.64 134.84 134.40 134.40 134.36 DEC 134.20 134.12 134.04 133.96 133.84 133.74 133.62 133.48 133.36 133.28 133.28 133.32 133.68 133.92 133.98 133.96 133.93 134.77 134.58 134.44 JAN 134.20 134.10 134.02 133.88 133.78 133.84 133.78 134.46 134.50 134.44 134.50 134.70 134.56 134.68 134.46 134.46 134.79 134.58 134.58 134.06 FEB 134.56 134.70 134.50 134.72 134.74 134.68 134.68 134.48 134.39 134.38 134.52 134.58 134.60 134.65 134.66 134.66 134.72 134.76 134.79 134.58 MAR 134.32 134.22 134.14 134.06 134.06 134.00 133.92 133.84 134.20 134.22 134.88 134.84 134.82 134.74 134.66 134.64 134.82 134.80 134.85 134.79 APR 133.36 133.20 133.99 134.60 134.84 134.85 134.73 134.83 134.80 134.68 134.70 134.72 134.65 134.56 134.58 134.56 134.44 134.28 134.16 133.97 MAY 133.08 132.87 132.68 132.46 132.26 132.05 132.02 131.95 132.06 132.08 132.06 131.93 131.98 132.22 132.14 132.14 132.00 131.85 132.46 132.36 JUN 130.36 130.26 130.07 130.16 130.42 131.66 133.72 134.84 134.92 134.92 134.94 134.32 134.74 134.72 134.59 134.09 134.75 134.26 135.02 134.98 JUL 134.93 134.92 134.88 134.85 134.77 134.70 134.62 132.76 134.66 134.60 134.88 134.74 134.88 134.54 134.80 134.86 134.96 134.94 134.72 135.08 AUG 134.54 134.46 134.46 134.86 134.40 134.60 134.74 134.88 134.94 135.00 134.78 134.82 134.88 133.90 133.80 133.68 134.52 134.66 134.34 134.78 SEP A A A A A A 134.61 133.96 A A A A A A A A 134.50 133.98 134.20 133.94 133.84 134.24 134.60 134.10 134.50 134.64 134.52 134.48 134.58 134.74 134.52 134.30 134.28 134.22 134.18 134.24 134.48 134.46 134.38 134.36 134.28 ___ 134.78 134.42 134.62 134.64 134.84 134.36 134.52 134.52 134.46 134.38 134.28 134.56 134.34 134.67 134.44 134.78 134.56 134.66 134.52 134.50 134.76 134.42 134.72 134.72 134.68 134.74 134.68 134.65 134.58 134.50 134.42 ___ ___ 134.68 134.59 134.48 134.34 134.20 134.08 134.00 133.86 133.76 133.62 133.50 133.84 133.86 133.88 134.00 133.90 133.76 133.63 133.48 133.32 133.22 ___ 132.16 131.92 132.00 131.92 131.75 A A A A 130.72 130.50 134.61 134.54 134.60 134.86 134.98 134.94 134.90 134.88 135.06 134.92 ___ 134.68 134.82 134.92 135.04 134.54 134.64 134.68 134.56 134.58 134.68 134.78 134.58 134.84 A A A A A A A A A 133.90 134.70 134.60 134.53 134.86 134.64 134.50 A 134.68 134.26 ___ 134.85 133.84 134.84 134.18 134.84 133.28 134.79 133.78 134.79 134.38 134.88 133.50 134.85 133.20 135.06 130.07 135.08 132.76 A No gage-height record ^ RIO GRANDE DE LOIZA BASIN 50059000 LAGO LOIZA AT DAMSITE, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°19'49", long 66°01'00", at pumphouse at damsite, and 1.9 mi (3.1 km) south of Tru- jillo Alto plaza. DRAINAGE AREA.--208 mi* (539 km 2 ). PERIOD OP RECORD.--Water years 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE JAN 1996 11. .. FEE 15. .. APR 08. .. JUN 05.. . AUG 12... DATE JAN 1996 11... PEB 15.. . APR 08... JUN 05... AUG 12. .. DATE JAN 1996 11... FEB 15.. . APR 08.. . JUN 05.. . AUG 12.. . PH OXYGEN, OXYGEN COLI- ALKA- SPE- WATER DIS- DEMAND, FORM, STREP- LINITY CIFIC WHOLE SOLVED CHEM- FECAL, TOCOCCI WAT 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 SATUR- 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 295 6.9 25.5 2.3 28 11 26 K13 85 1015 283 7.0 24.5 1.2 14 <10 Kll 40 92 1120 331 7.3 26.0 0.2 2 14 K17 K2 120 1110 337 6.4 29.5 2.0 26 22 46 72 110 1130 235 7.0 28.0 0.4 5 <10 200 250 79 RESIDUE NITRO- TOTAL NITRO- NITRO- NITRO- NITRO- NITRO- GEN,AM- AT 105 GEN, GEN, GEN, GEN, GEN, MONIA + NITRO- NITRO- SULFIDE DEG. C, NITRATE NITRITE NO2+NO3 AMMONIA ORGANIC ORGANIC GEN, GEN, TOTAL SUS- TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL TOTAL (MG/L PENDED (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 10 -- 0.010 <0.020 0.420 0.36 0.78 0.78 3.5 19 0.070 0.030 0.100 0.240 0.560 0.80 0.90 4.0 <0.5 9 <0.010 <0.010 <0.020 1.10 <0.20 1.3 1.3 5.8 6 <0.010 0.010 <0.020 0.510 0.69 1.2 1.2 5.4 16 0.060 0.040 0.100 0.310 2.1 2.4 2.5 11 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 CU) AS FE) AS MM) AS ZN) AS CN) (UG/L) (MG/L) (00665) (01022) (01042) (01045) (01055) (01092) (00720) (32730) (38260) 0.100 0.240 0.490 20 <10 3600 930 40 <0.010 <1 0.03 0.160 1.40 K = non-ideal count RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA 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' (541 km2 ). HATER-DISCHARGE RECORDS PERIOD OF RECORD.—December 1986 to current year. GAGE.—Hater-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, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES 295 DAY OCT NOV DEC APR MAY JUN AUG SEP 1 3.2 e68 2 195 e6.6 3 22 e!47 4 4.1 e5.9 5 170 e!36 6 230 e348 7 3.6 e!68 8 204 e4.8 9 182 e4.8 10 4.1 e4.9 11 192 e4.9 12 3.6 eS.O 13 e!6 e4.9 14 e6.2 e4.7 15 e3.1 e4.7 16 e3.3 e!4 17 e227 e4.8 18 7.8 e!40 19 18 e5.2 20 197 e4.5 21 714 e4.4 22 e253 e4.2 23 e5.9 3.8 24 e488 4.5 25 elO 4.6 26 el!6 4.1 27 e!88 4.4 28 e444 4.0 29 e!45 3.9 30 eS.l 4.2 31 e71 TOTAL 4132.0 1128.8 MEAN 133 37.6 MAX 714 348 MEN 3.1 3.8 AC -FT 8200 2240 CFSM .64 .18 IN. .74 .20 .3 .5 .8 .7 .7 .6 .5 .0 .2 3.9 3.9 4.1 4.6 4.2 4.5 4.5 4.4 10 e309 elllO e32 elSS eS.5 e5.7 e5.8 e!74 e5.7 e5.3 eS.5 eS.5 eS.5 1908.9 61.6 1110 3.9 3790 .29 .34 eS.l e4.9 e4.8 e4.8 e4.9 eS.O eS.O e4.9 e4.9 e5.3 5.4 153 124 3060 2110 248 43 191 268 1130 204 197 4.8 130 4.9 158 170 401 169 4.9 140 8965.6 289 3060 4.8 17780 1.38 1.60 STATISTICS OF MONTHLY MEAN DATA FOR HATER MEAN 236 513 MAX 842 2732 (WY) 1991 1988 MEN 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 375 2603 1988 17.2 1994 FOR 166 733 1992 2.49 1995 5.0 5.1 103 5.3 297 150 183 124 66 220 6.0 5.6 5.4 5.6 6.1 5.4 5.0 5.0 5.1 102 5.7 9.8 6.7 20 126 5.2 4.9 4.7 4.6 —— 1497.2 51.6 297 4.6 2970 .25 .27 YEARS 1987 75.5 242 1989 4.52 1990 4.5 4.2 4.5 4.6 5.0 4.5 4.5 4.7 4.5 4.7 4.8 77 4.9 4.8 223 155 5.6 5.6 5.3 5.5 5.6 5.3 5.5 5.5 5.4 5.5 5.6 5.8 5.7 5.2 4.9 597.2 19.3 223 4.2 1180 .09 .11 - 1996 48.9 299 1989 6.45 1990 1995 CALENDAR YEAR 39943. 109 5090 . . 79230 . 7. 208 2. . 80 Sep 6 42 May 13 61 May 9 52 11 2 83 4.9 4.9 5.8 6.3 5.7 13 6.4 5.4 5.4 4.8 4.7 5.5 6.1 6.1 4.9 4.2 5.8 5.5 4.8 4.3 7.8 5.6 .4 .4 .4 .2 .3 16 4.4 5.0 --- 175.0 5.83 16 4.2 347 .03 .03 4.1 4.3 4.4 4.1 3.9 3.4 3.8 e3.7 e4.0 e4.1 e4.0 e3.8 e3.8 e3.5 e3.5 e3.3 e3.3 e3.1 e3.0 e2.9 e2.7 e2.5 e2.3 e2.2 e2.0 el. 8 el. 7 el. 5 el. 4 el. 4 el. 4 94.9 3.06 4.4 1.4 188 .01 .02 , BY HATER YEAR 31.8 112 1987 1.20 1995 FOR 1996 177317 484 110000 1 1 223000 49 351700 2 31 441 5 2 93.3 367 1992 1.03 1995 el. 3 el. 3 el. 3 el. 3 el. 2 el. 2 el. 2 148 1.6 1.5 1.6 1480 327 147 1920 1420 378 923 142 142 247 569 127 5.3 2.4 52 50 122 2.6 62 --- 8279.8 276 1920 1.2 16420 1.32 1.47 (WY) 188 784 1987 1.96 1994 HATER YEAR .2 Sep .2 JUn .3 JUn Sep .31 Sep .32 .56 .4 .5 10 5 1 10 10 2.4 2.3 2.1 2.0 2.0 1.9 1.9 e!260 e2.9 elll e3.1 e434 e671 e2120 e2330 e250 elSS elOS e!27 e2.7 e!52 e2.1 el. 9 el. 9 e!40 1.8 1.6 e389 163 2.1 2.0 8446.7 272 2330 1.6 16750 1.30 1.50 176 672 1993 1.62 1994 HATER 242 652 37 110000 223000 49 175600 1 15 383 8 2 626 624 530 286 295 3.3 3.3 3.3 3.3 3,8 153 4.1 3.8 1590 1210 7010 378 239 275 5.6 157 5.0 398 462 5.0 4.0 3.6 3.3 3.3 2.9 150 14440.6 466 7010 2.9 28640 2.23 2.57 202 718 1988 2.21 1994 2.4 130 199 321 e221 2.6 2.5 313 47 ellOOOO 5950 1120 678 464 780 997 636 e817 e614 e618 ellOO 179 380 268 215 322 440 e!74 e!60 500 127650.5 4255 110000 2.4 253200 20.4 22.72 792 4255 1996 29.7 1990 YEARS 1987 - 1996 .8 Sep .42 May .49 Aug Sep .31 Sep .16 .76 .3 .2 1988 1994 10 1996 13 1995 11 1994 10 1996 10 1996 e Estimated 296 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 days. 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 days. EXTREMES FOR CURRENT YEAR 1995.-- SEDIMENT CONCENTRATION: Maximum daily mean, 4,290 mg/L September 10, 1996; minimum daily mean, 4 mg/L November 22, 1995. SEDIMENT LOADS: Maximum daily mean, 1,500,000 tons (1,360,000 tonnes) September 10, 1996; minimum daily 0.03 tons (0.02 tonne) June 7, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT 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 3.2 195 22 4.1 170 230 3.6 204 182 4.1 192 3.6 e!6 e6.2 e3.1 e3.3 8227 7.8 18 197 714 e253 e5.9 e488 elO e!16 e!88 e444 e!45 eS.l e71 4132.0 OCTOBER 19 31 28 22 33 34 21 36 31 23 31 6 18 24 22 21 32 25 30 35 41 54 25 55 27 36 38 44 43 25 25 NOVEMBER .16 50 3.5 .25 46 59 .20 55 46 .25 52 .05 el. 9 e.42 e.19 e.19 e66 .69 2.2 48 335 e74 e.41 e!72 e.83 e31 e52 e!62 e50 e.34 e22 1331.58 e68 e6.6 e!47 e5.9 e!36 e348 e!68 e4.8 e4.8 e4.9 e4.9 eS.O e4.9 e4.7 e4.7 e!4 e4.8 e!40 e5.2 e4.5 e4.4 e4.2 3.8 .5 .6 .1 .4 .0 3.9 4.2 1128.8 37 28 34 25 39 51 37 19 15 14 13 13 12 11 11 16 21 32 15 10 6 4 5 7 10 14 18 23 24 24 16 .50 e39 e.39 e45 elll e61 e.25 e.20 e.19 e.18 e.17 e.16 e.15 e.13 el. 5 e.28 835 e.21 e.12 e.08 e.05 .06 .09 .12 .15 .22 .25 .25 .27 312.97 10 8309 elllO 832 8155 85.5 85.7 85.8 8174 85.7 85.3 85.5 e5.5 85.5 1908.9 DECEMBER 24 24 24 24 24 24 24 23 23 23 23 23 23 23 23 23 23 26 53 66 29 34 26 25 25 36 23 21 19 17 16 .28 .29 .31 .30 .30 .29 .28 .25 .26 .24 .24 .26 .29 .26 .28 .28 .27 .91 8103 8615 84. 843 .39 .39 .39 .36 .31 .28 .26 .23 823.20 e Estimated 297 RIO GRANDE DE LOZZA BASIN 50059050 RIO GRANDE DE LOZZA BELOW DAM SITE LOZZA, PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 TOTAL eS.l e4.9 e4.8 e4.8 e4.9 eS.O eS.O e4.9 e4.9 e5.3 5.4 153 124 3060 2110 248 43 191 268 1130 204 197 4.8 130 4.9 158 170 401 169 4.9 140 8965.6 14 13 12 11 10 9 8 7 7 6 5 24 30 53 115 34 30 39 42 85 39 39 25 33 23 37 36 52 39 25 34 —— .20 .17 .15 .14 .13 .12 .11 .10 .09 .09 .08 42 36 718 1030 88 7.4 70 105 490 78 69 .32 44 .30 60 66 149 64 .33 48 3166.73 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATZON DISCHARGE (CFS) (MG/L) (TONS/DAY) FEBRUARY 5.0 5.1 103 5.3 297 150 183 124 66 220 6.0 5.6 5.4 5.6 6.1 5.4 5.0 5.0 5.1 102 5.7 9.8 6.7 20 126 5.2 4.9 4.7 4.6 ___ —— 1497.2 23 22 34 25 45 37 39 31 26 44 24 20 16 13 11 12 14 16 20 33 25 27 25 30 35 26 25 25 25 —— —— —— .31 .31 34 .36 112 49 72 42 27 74 .38 .30 .23 .19 .17 .17 .19 .22 .27 28 .39 .92 .46 2.5 33 .36 .34 .32 .31 —— 479.70 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATZON DISCHARGE (CFS) (MG/L) (TONS/DAY) MARCH 4.5 4.2 4.5 4.6 5.0 4.5 4.5 4.7 4.5 4.7 4.8 77 4.9 4.8 223 155 5.6 5.6 5.3 5.5 5.6 5.3 5.5 5.5 5.4 5.5 5.6 5.8 5.7 5.2 4.9 597.2 25 24 24 24 24 23 23 23 23 22 22 33 25 24 37 34 20 16 12 10 8 8 8 7 7 7 7 8 9 10 12 —— .30 .27 .29 .30 .32 .29 .28 .29 .28 .29 .29 23 .33 .31 88 45 .30 .24 .18 .15 .12 .11 .11 .11 .11 .11 .11 .12 .14 .14 .16 162.05 e Estimated 298 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAM SITE LOIZA, PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY 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 4.9 4.9 5.8 6.3 5.7 13 6.4 5.4 5.4 4.8 4.7 5.5 6.1 6.1 4.9 4.2 5.8 5.5 4.8 4.3 7.8 5.6 4.4 4.4 4.4 4.2 4.3 16 4.4 5.0 ___ APRIL 13 15 17 20 23 38 52 46 40 35 35 35 34 34 34 34 33 33 33 32 30 27 26 24 23 22 21 22 26 31 .18 .20 .28 .34 .35 1.6 .90 .67 .58 .46 .44 .51 .56 .56 .44 .38 .52 .50 .43 .38 .70 .42 .31 .29 .27 .25 .24 .26 .31 .42 MEAN DISCHARGE (CFS) 4.1 4.3 4.4 4.1 3.9 3.4 3.8 e3.7 e4.0 e4.1 e4.0 e3.8 e3.8 e3.5 e3.5 e3.3 e3.3 e3.1 e3.0 e2.9 e2.7 e2.5 e2.3 e2.2 e2.0 el. 8 el. 7 el. 5 el. 4 el. 4 el. 4 37 44 41 33 33 32 32 32 32 33 34 35 36 37 38 39 40 41 42 43 44 45 47 48 49 51 52 54 53 45 37 .41 .51 .49 .37 .34 .30 .33 .32 .35 .36 .37 .36 .36 .35 .36 .35 .35 .34 .34 .34 .32 .30 .29 .29 .27 .25 .24 .22 .20 .17 .14 MEAN DISCHARGE (CFS) el. 3 el. 3 el. 3 el. 3 el. 2 el. 2 el. 2 148 1.6 1.5 1.6 1480 327 147 1920 1420 378 923 142 142 247 569 127 5.3 2.4 52 50 122 2.6 62 MEAN CONCEN- TRATION (MG/L) JUNE 31 25 21 17 14 12 9 35 20 16 13 92 56 33 94 93 55 99 36 34 36 61 28 33 26 29 26 26 20 28 SEDIMENT DISCHARGE (TONS/DAY) .11 .09 .07 .06 .05 .04 .03 88 .09 .07 .06 482 107 44 952 630 131 523 44 39 63 211 33 .49 .17 14 8.2 19 .15 15 175.0 13.75 94.9 9.99 8279.8 3404.68 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 1995 TO SEPTEMBER 1996 299 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- DISCHARGE TRATION (CFS) (MG/L) 2.4 2.3 2.1 2.0 2.0 1.9 1.9 e!260 e2.9 elll e3.1 e434 e671 e2120 e2330 6250 6155 6108 6127 62.7 e!52 62.1 el. 9 el. 9 e!40 1.8 1.6 6389 163 2.1 2.0 JULY 21 20 19 18 17 16 15 92 57 32 26 56 66 87 105 43 31 30 34 19 31 23 19 15 31 21 17 40 36 23 20 TOTAL 8446.7 —— YEAR e 177317.2 Estimated SEDIMENT DISCHARGE (TONS/DAY) .14 .12 .11 .10 .09 .08 .08 6501 .47 625 .21 e!41 6246 61020 61540 681 651 625 645 6.14 650 6.13 e.10 e.08 640 .10 .07 170 62 .13 .11 3999.26 1573700.93 MEAN DISCHARGE (CFS) 626 624 530 286 295 3.3 3.3 3.3 3.3 3.8 153 4.1 3.8 1590 1210 7010 378 239 275 5.6 157 5.0 398 462 5.0 4.0 3.6 3.3 3.3 2.9 150 14440.6 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER 626 624 530 286 295 3.3 3.3 3.3 3.3 3.8 153 4.1 3.8 1590 1210 7010 378 239 275 5.6 157 5.0 398 462 5.0 4.0 3.6 3.3 3.3 2.9 150 L4440.6 62 59 51 37 41 36 36 49 57 35 53 68 54 90 53 224 45 42 44 32 45 36 55 53 28 26 24 22 20 19 48 —— 242 234 162 90 94 .33 .31 .43 .50 .36 39 .75 .54 929 895 6290 133 82 92 .48 99 .47 170 171 .38 .28 .23 .20 .18 .15 125 9852.59 2.4 130 199 321 6221 2.6 2.5 313 47 ellOOOO 5950 1120 678 464 780 997 636 6817 6614 6618 ellOO 179 380 268 215 322 440 e!74 e!60 500 --- 127650.5 19 30 29 213 85 24 21 113 40 4290 2070 450 311 248 197 157 124 112 98 89 112 75 80 74 97 88 89 71 69 82 41 61 705 6304 576 97 1500000 43100 1410 536 293 402 428 220 6271 6211 6239 6449 36 125 78 55 106 152 633 e30 186 1550144 .12 .17 .14 .43 RIO GRANDE DE LOIZA BASIN 50059050 RIO GRANDE DE LOIZA BELOW DAMSITE LOIZA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT 300 DATE SEP 1996 10... DATE SEP 1996 10... TIME 0430 SED. SUSP. FALL DIAM. 9« FINER THAN .016 MM (70329) DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 95500 SED. SUSP. FALL DIAM. ?S FINER THAN .031 MM (70330) SEDI- MENT, SUS- PENDED (M6/L) (80154) 4020 SED. SUSP. SIEVE DIAM. 9s FINER THAN .062 MM (70331) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 1040000 SED. SUSP. SIEVE DIAM. 9s FINER THAN .125 MM (70332) SED. SUSP. FALL DIAM. 9s FINER THAN .002 MM (70326) 34 SED. SUSP. SIEVE DIAM. 9s FINER THAN .250 MM (70333) SED. SUSP. FALL DIAM. Ss FINER THAN .004 MM (70327) 40 SED. SUSP. SIEVE DIAM. * FINER THAN .500 MM (70334) SED. SUSP. FALL DIAM. 9s FINER THAN .008 MM (70328) 43 SED. SUSP. SIEVE DIAM. 9s FINER THAN 1.00 MM (70335) 53 63 81 95 97 98 100 301 RIO GRANDE DB LOIZA BASIN 50059050 RIO GRANDE DB LOIZA BELOW DAHSITB LOIZA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE JAN 1996 15... JUN 08... 12... 18... 18... JXJL 21... AOG 23... SEP 03... TIME 0020 0920 1000 1545 1615 1141 1645 2300 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 21 2370 2680 2260 4150 2120 1750 1650 SEDI- MENT, SUS- PENDED (MG/L) (80154) 174 630 160 755 443 150 219 115 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 9.9 4030 1160 4610 4960 859 1030 512 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 94 95 95 97 93 96 98 95 302 RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°21'35", long 66°00'1S U , 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 2 (552 km 2 ). PERIOD OF RECORD.--Water years 1981 to current year. REMARKS: Flow controlled by Lago Loiza reservoir. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 OCT 13 JAN 24 FEB 15 APR 18 JUN 13 AUG 20 DATE 1995 1996 . . . . . . DATE OCT 1995 13. .. JAN 1996 24. .. FEB 15. .. APR 18. .. JUN 13 ... 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- 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) 0850 E16 402 6.4 27.0 1. 1030 E130 255 7.1 23.5 49 1120 E6.1 346 7.5 25.5 1. 1045 5.0 334 7.3 25.5 15 1005 E3.3 300 6.7 28.5 8. 1125 29 267 7.3 29.0 71 HARD- MAGNE- SODIUM NESS CALCIUM SIUM, SODIUM, AD- TOTAL DIS- DIS- DIS- SORP- (MG/L SOLVED SOLVED SOLVED TION AS (MG/L (MG/L (MG/L RATIO CACO3) AS CA) AS MG) AS NA) (00900) (00915) (00925) (00930) (00931) 130 32 13 26 1 -- -. 110 27 11 25 1 -_ 88 22 8.1 17 0.8 ,1 2.5 7.0 ,5 4.6 5.1 .3 4.9 4.3 ALKA- POTAS- LINITY SIUM, WAT WH DIS- TOT FET SOLVED FIELD (MG/L MG/L AS AS K) CACO3 (00935) (00410) 3.1 130 79 110 3.0 110 90 3.2 100 31 12 510 210 81 22 K110000 63000 56 17 4400 620 62 31 30000 25000 63 36 2200 600 56 30 44000 49000 CHLO- SULFATE RIDE, SULFIDE DIS- DIS- TOTAL SOLVED SOLVED (MG/L (MG/L (MG/L AS S) AS SO4) AS CL) (00745) (00945) (00940) <0.5 18 26 __ __ <0.5 14 25 __ 12 16 E = estimate K = non-ideal count RIO GRANDE DE LOIZA BASIN 50059100 RIO GRANDE DE LOIZA BELOW TRUJILLO ALTO, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 303 DATE OCT 1995 13... JAN 1996 24. .. FEB 15. . . APR 18. .. JUN 13... AUG 20.. . OCT 1995 13. .. JAN 1996 24. .. FEB 15. . . APR 18. . . JUN 13. . . AUG 20. . . OCT 1995 13. .. JAN 1996 24.. . FEB 15... APR 18... JUN 13... AUG 20... 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) 0.42 0.74 0.50 <0.23 0.92 0.72 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 30 — — 24 — 20 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.2 2.1 1.2 0.42 1.7 1.8 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 226 -- -- 195 — 158 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.5 9.5 5.5 1.9 7.3 8.1 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) E10 -- -- 2.63 -- 12.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.120 0.190 0.130 <0.020 0.110 0.170 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 5 50 4 20 -- 40 ARSENIC TOTAL (UG/L AS AS) (01002) 1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.810 1.39 0.740 0.320 0.720 1.02 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 <0.010 0.020 0.080 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 50 -- -- 50 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.820 1.40 0.750 0.320 0.740 1.10 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — — CYANIDE TOTAL (MG/L AS CM) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.050 0.080 0.150 0.030 0.280 0.150 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 — -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.37 0.66 0.35 <0.20 0.64 0.57 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 130 810 30 210 <0.10 0.10 10 <0.010 <0.010 0.04 0.03 E - estimated 304 RIO GRANDE DE LOIZA BASIN 50061000 RIO GRANDE DE LOIZA AT CAROLINA, PR LOCATION.—Lat 18°22'39", long 65°57'08", Bydrologic Unit 21010005, on upstream right bank of Highway 3 bridge, at km 11.5, 0.5 mi (0.8 km) southeast of Carolina Plaza, 3.3 mi (5.3 km) west of Canovanas Plaza and 2.5 mi (4.0 km) soughwest of Cerro San Jose, and 8.8 mi (14.2 km) downstream fro Rio Grande de Loiza mouth. DRAINAGE AREA.—243 mi* (629 km* ) . WATER-STAGE RECORDS PERIOD OF RECORD.—January 1991 to current year. GAGE.—Water-stage recorder. Elevation of gage is 32.8 ft (10.0 m), from topographic map. REMARKS.—Flow regulated by Lago Loiza Dam and also by tidal changes. Gage-height and precipitation satellite telemetry at station. EXTREMES FOR PERIOD OF RECORD.—Maximum gage-height, 43.66 ft (13.307 m), Sept. 10, 1996; minimum, 3.91 ft (1.192 m), Aug. 6, 1991. EXTREMES FOR CURRENT YEAR.—Maximum gage-height, 43.66 ft (13.307 m), Sept. 10; minimum 4.20 ft (1.280 m), July 25. GAGE HEIGHT, FEET, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES 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 MAX MIN 4.92 5.72 5.39 5.13 5.56 5.77 5.13 5.75 5.44 5.60 5.76 5.07 5.67 5.31 5.05 5.70 6.53 5.64 6.35 6.40 5.73 7.01 5.95 7.05 5.84 6.00 5.79 6.19 6.45 5.12 5.03 7.05 4.92 5.74 5.16 5.49 5.67 5.98 7.23 6.49 5.13 .90 .86 .88 .97 .97 5.07 4.94 5.39 5.23 5.76 5.05 5.03 5.02 5.00 5.08 5.18 5.08 5.01 5.07 5.12 5.06 5.02 —— 7.23 4.86 5.17 5.04 5.11 5.18 5.20 5.22 5.18 5.16 5.27 5.29 5.13 5.21 5.38 5.52 5.37 5.39 5.44 6.39 7.14 7.39 6.23 5.78 5.24 5.23 5.16 5.69 5.11 5.14 5.04 5.00 4.92 7.39 4.92 4.98 5.03 5.01 4.94 4.92 5.09 5.07 5.80 5.84 6.45 5.71 6.14 5.71 8.00 11.06 6.52 5.90 5.98 5.73 8.13 6.74 ___ —— 4.88 4.90 5.44 4.95 5.97 5.67 5.95 5.72 4.97 6.10 5.10 4.94 4.95 5.04 5.16 5.49 5.83 6.18 6.52 6.74 4.84 4.99 4.89 4.88 5.57 4.93 4.93 5.06 5.27 —— —— 6.74 4.84 5.53 5.78 6.01 6.21 6.00 5.10 5.02 5.14 5.18 5.29 5.47 6.31 6.54 6.72 7.15 6.26 5.01 4.94 4.93 4.85 4.82 4.79 4.89 4.82 4.79 4.85 4.82 4.71 4.77 4.80 4.91 7.15 4.71 5.03 5.04 5.38 5.73 5.22 .95 .94 .84 .82 .88 4.90 5.03 5.31 5.29 5.18 5.12 5.04 5.08 5.29 5.51 5.90 6.30 6.25 4.81 4.81 4.93 4.94 5.07 5.15 5.18 —— 6.30 4.81 5.17 5.30 5.49 5.69 5.86 6.05 6.29 6.32 5.23 5.03 4.85 4.88 4.95 5.02 5.04 5.08 5.17 5.22 5.40 5.56 5.18 5.05 5.09 5.08 5.05 5.17 5.33 5.50 5.62 5.72 5.82 6.32 4.85 5.95 6.08 5.90 4.90 4.80 4.82 4.88 5.58 5.01 4.97 4.95 8.12 7.32 A A A A A A 5.65 5.39 7.04 5.26 5.34 4.82 4.97 4.94 5.25 4.98 5.00 —— ___ —— 4.79 4.81 A A A A A A A A A A A A A A A A A A A A A A 5.31 4.92 4.91 A 5.79 5.11 4.97 —— 6.33 7.13 7.12 6.73 6.19 5.19 5.24 5.16 5.13 5.02 5.62 4.99 4.93 7.82 6.94 14.23 6.51 6.22 A A A A A A A A A A A A —— A A A A A A A A A 36.50 16.19 8.95 8.08 7.73 7.50 8.47 7.49 7.02 7.80 6.54 A A 6.35 5.82 A A 6.72 A A 6.90 —— —— A No gage-height record 305 RIO GRANDE DE LOIZA 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 1 (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 and Dec. 19 to Jan. 3, which are poor. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT JAN FEB MAY JUN SEP 1 13 14 2 15 26 3 19 38 4 12 32 5 32 23 6 19 71 7 16 53 8 15 36 9 15 22 10 16 18 11 14 17 12 13 18 13 16 35 14 17 22 15 12 18 16 13 20 17 53 19 18 19 18 19 22 14 20 17 12 21 24 12 22 19 13 23 75 13 24 121 15 25 54 16 26 36 14 27 21 13 28 21 13 29 19 14 30 15 13 31 14 — - TOTAL 787 662 MEAN 25.4 22.1 MAX 121 71 MIN 12 12 AC-FT 1560 1310 CFSM 2.58 2.24 IN. 2.98 2.50 12 14 11 12 10 10 10 10 10 11 9.9 9.4 11 12 8.7 8.6 45 69 29 615 e!7 616 614 e!3 612 ell 615 619 613 elO 69.8 477.4 15.4 69 8.6 947 1.57 1.80 STATISTICS OF MONTHLY MEAN DATA MEAN 41.2 44.2 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 32.4 116 1971 5.82 1968 FOR 69.8 69.6 69.2 68.8 e!4 e!9 616 622 640 16 13 40 44 712 239 39 28 32 47 79 49 30 623 622 634 41 81 92 50 34 27 1920.4 61.9 712 8.8 3810 6.30 7.26 FOR WATER 24.8 62.4 1969 6.66 1977 25 22 21 22 19 28 34 23 23 18 18 15 15 14 13 e!3 e!4 e!3 e!3 e!3 12 12 11 17 21 13 11 10 10 —— 493 17.0 34 10 978 1.73 1.86 YEARS 1967 19.2 48.4 1988 4.04 1977 10 9.9 9.9 10 15 13 11 10 9.2 8.7 21 13 9.0 7.6 29 18 9.9 7.9 14 8.7 7.3 6.7 6.8 7.2 6.8 6.6 7.3 6.8 6.5 6.1 5.9 318.8 10.3 29 5.9 632 1.05 1.21 - 1996 14.0 36.2 1969 3.54 1977 1995 CALENDAR YEAR 8407. 23. 859 2. 3. 16680 2. 31. 37 11 4. 9 0 Sep 16 9 Jun 26 5 Jun 20 34 79 7 5.7 5.7 5.4 7.0 7.7 6.2 5.9 5.7 5.8 5.7 6.1 8.3 14 7.2 7.3 15 9.0 7.6 7.2 7.0 7.0 7.7 9.9 11 8.0 7.6 7.0 6.9 7.4 8.9 --- 230.9 7.70 15 5.4 458 .78 .87 7.0 6.1 5.9 5.9 6.1 6.4 7.2 8.4 14 11 8.3 6.8 7.1 11 7.5 7.2 6.6 6.3 6.4 6.0 5.8 6.1 7.4 7.7 7.9 7.4 6.9 6.4 6.3 6.2 6.7 226.0 7.29 14 5.8 448 .74 .85 7.4 6.6 6.3 6.6 66.4 68.2 622 e!2 7.0 6.3 67.0 17 11 7.5 56 47 22 9.1 7.4 6.6 7.4 9.4 9.1 7.6 7.0 7.0 7.3 8.0 9.2 8.3 359.7 12.0 56 6.3 713 1.22 1.36 6.8 6.2 6.3 6.5 6.5 6.7 7.0 353 72 25 15 26 28 68 116 21 15 14 13 14 13 11 11 11 14 15 12 44 22 13 12 1004.0 32.4 353 6.2 1990 3.29 3.80 11 11 13 22 14 13 11 9.7 9.3 9.7 12 11 16 86 65 112 30 21 10 9.1 9.1 69.5 640 6110 615 613 612 ell ell elO 69.4 745.8 24.1 112 9.1 1480 2.44 2.82 68.8 68.4 68.4 625 630 641 44 71 230 4230 356 78 54 44 133 695 46 45 41 43 33 29 28 25 23 22 22 27 22 19 --- 5881.6 196 4230 8.4 11670 19.9 22.24 , BY WATER YEAR (WY) 15.1 53.2 1971 4.36 1994 FOR 1996 13106 35 4230 5 6 10100 13 26000 3 49 44 13 6 28.2 93.2 1969 4.28 1974 WATER YEAR .6 .8 Sep 10 . 4 Apr 3 .0 Mar 28 Sep 10 .58 Sep 10 .64 .55 .6 18.4 63.7 1970 2.80 1974 19.3 63.7 1979 3.72 1974 WATER 27 58 10 4230 1 15000 13 19600 2 37 43 12 5 25.4 137 1979 5.69 1991 YEARS 1967 .1 .0 .5 Sep .80 Jul .5 Jul Sep . 10 Sep .80 Jul .75 .36 .1 38.9 196 1996 5.20 1967 - 1996 1971 1994 10 1996 24 1977 18 1977 13 1982 13 1982 24 1977 e Estimated 306 THIS PAGE WAS LEFT BLANK INTENTIONALLY ATLANTIC OCEAN s ^,'V^—^ Oi \ ^/f \ /^^U!LLO •^ «y ^L /j f /^^^ / -I^\ v iNk*i.AJOk / uy\r-4\ NAGUABO^ 1 \ >. ^^-x^. l\ rv_ :A 7 \ /--\V\\ \ > ^~^- \ J ^- COQ. HUMACAO X EXPLANATION SURFACE-WATER STATION AND NUMBER QUALITY-OF-WATER STATION AND NUMBER 0655 DA)LY SEDIMENT STATION AND NUMBER WE|_L NUMBER 01 23456 KILOMETERS 1234 307 Figure 21.--Northeastern river basins the Rio Herrera to Rio Anton Ruiz basins. 306 RIO ESFIRITU SANTO BASIN 50063500 QUEBRADA TORONJA AT EL VERDE, PR LOCATION.—Lat 18°19'43", long 65049'14", Hydrologic Unit 21010005, in Caribbean National Forest, at downstream side of culvert on Highway 186, 0.2 mi (0.3 km) upstream from Rio Espiritu Santo, and about 0.9 mi (1.4 km) south of El Verde. DRAINAGE AREA.—0.064 mi 2 (0.166 km*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—April 1983 to current year. GAGE.—Water-stage recorder, crest-stage gage and concrete broad-V-notch crested weir. Elevation of gage is 876 ft (267 m), from topographic map. REMARKS.—Records poor. Gage-height satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY APR JUN AUG SEP 1 e.10 e.ll 2 e.ll el. 3 3 e.10 el. 3 4 e.08 e.54 5 e.45 e.52 6 e.66 el. 8 7 e.34 e.32 8 e.66 e.30 9 e.32 e.16 10 e.60 e.16 11 6.13 6.13 12 e.10 e.13 13 e.56 e.20 14 e.12 e.14 15 e.06 e.12 16 e.54 e.15 17 e.17 e.14 18 e.25 e.ll 19 e.43 e.12 20 e.09 e.08 21 e.06 e.08 22 e.07 e.07 23 62.0 e.07 24 el. 5 e.26 25 e.20 e.10 26 e.18 e.10 27 e.09 e.06 28 e.07 e.ll 29 e.06 e.21 30 e.05 e.09 31 e.08 —— TOTAL 10.23 8.98 MEAN .33 .30 MAX 2.0 1.8 MZN .05 .06 AC-FT 20 18 CFSM 5.50 4.99 IN. 6.34 5.57 e.08 e.08 e.05 e.05 e.05 e.06 e.04 e.05 e.10 e.10 e.06 e.06 e.50 e.66 e.12 e.15 e2.7 el3 el. 9 e.36 e.32 e.25 a. 21 e.18 e.19 e.17 e.19 e.42 e.20 e.19 e.18 22.67 .73 13 .04 45 12.2 14.06 e.16 e.16 e.16 e.16 e.20 e.45 el. 6 el. 5 e.24 e.14 e.29 el. 5 e.26 e4.9 e2.6 e2.3 e.52 e.80 e2.1 e5.4 el. 5 e.97 e.70 el.O e.51 e.32 e.56 e4.0 e.57 e.31 e.33 36.21 1.17 5.4 .14 72 19.5 22.45 e.25 e.30 e.46 e.38 e.26 e2.9 e.40 6.23 e.17 6.12 e.ll e.10 e.10 e.09 e.08 e.06 e.07 e.07 e.07 e.05 e.05 e.04 e.04 e.27 e.09 e.05 e.05 e.06 e.05 —— 6.97 .24 2.9 .04 14 4.01 4.32 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1983 MEAN .29 .64 MAX 1.35 1.56 (WY) 1986 1993 MIN .059 .15 (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 9 0 PERCENT EXCEEDS .54 1.55 1993 .091 1990 FOR .44 1.39 1993 .14 1986 .33 1.15 1995 .092 1987 e.05 e.04 e.03 e.04 e.15 e.06 e.04 e.06 e.10 e.04 e.07 e.02 e.02 e.03 e.03 e.03 e.02 e.02 e.03 e.03 e.03 e.03 e.04 e.03 e.03 e.05 e.06 e.05 e.05 e.03 e.03 1.34 .043 .15 .02 2.7 .72 .83 - 1996 .21 .63 1990 .016 1994 1995 CALENDAR YEAR 158.80 .44 13 .03 .04 315 7.25 98.46 .65 .16 .05 Dec 18 May 1 Apr 27 e.02 e.03 e.04 e6.0 e.44 e.10 e.07 e.06 e.05 e.04 e.04 e.46 e.19 e.24 e.15 e.22 e.08 e.06 e.04 e.03 e.05 e.08 e2.7 e.57 e.ll e.39 6.14 e.07 e.08 a. 98 —— 13.53 .45 6.0 .02 27 7.52 8.39 , BY WATER .23 .61 1987 .035 1984 FOR 1996 328 28 36 1 652 15 203 2 e.ll e.08 e.08 e.06 e.09 e.57 e5.4 el. 9 e5.6 el. 5 6.41 6.30 e2.6 e.46 e.27 6.21 e.18 e.16 6.14 6.14 6.13 6.12 6.14 e.ll e.06 e.06 e.06 e.04 e.04 e.04 e.07 21.13 .68 5.6 .04 42 11.4 13.10 YEAR (WY) .39 1.17 1993 .080 1994 e.05 e.05 e.04 e.32 e.ll e.78 e.24 e.06 e.03 e.03 e.79 el. 5 e.17 e.79 64.4 64.0 e.42 e.38 e.26 e.15 e.19 6.31 e.19 6.12 6.13 6.13 6.13 e.17 6.13 6.12 —— 16.19 .54 4.4 .03 32 8.99 10.04 .29 .61 1987 .056 1991 WATER YEAR .63 .90 .02 .02 .98 .0 .75 .2 .20 .04 Sep 10 Mar 12 Mar 12 May 7 May 7 e.ll 6.14 6.14 e.15 e.15 e.16 6.21 66.4 el. 3 e.42 e.28 e.88 6.94 e!2 63.8 e.96 e.78 e.73 e.62 e3.3 6.60 e.50 e.49 6.67 el. 7 el. 9 e.62 e2.0 e.68 e.52 e.35 43.50 1.40 12 .11 86 23.4 26.97 .43 1.70 1993 .046 1991 e.88 e.53 e3.4 e2.4 e2.3 el. 6 e.93 e.80 e.44 a. 34 e.35 e.34 e3.5 e!2 e2.3 63.0 6.81 6.59 e.51 6.41 e.38 e.35 e4.9 62.1 6.55 e.44 e.39 e.38 e.29 e.24 e.24 47.69 1.54 12 .24 95 25.6 29.57 .36 1.54 1996 .054 1993 WATER YEARS 1983 .39 .90 .17 28 .00 .00 101 2.61 .00 284 6.52 88.65 .78 .15 .05 Sep Mar Mar Aug Aug Apr 6.21 e.18 e.20 e.20 e.49 e.34 e.29 e3.9 e5.0 e28 el 8 68.1 63.9 62.2 62.7 65.2 el. 3 el. 4 6.92 6.82 6.99 6.84 e.75 e.83 6.65 e.78 el. 8 e7.4 e2.0 e.80 100.19 3.34 28 .18 199 55.7 62.12 .53 3.34 1996 .060 1991 - 1996 1996 1984 10 1996 13 1994 30 1994 13 1990 13 1990 10 1983 e Estimated 309 RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO GRANDE, 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 Grands. DRAINAGE AREA.--8.62 mi* (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. REVISIONS.—The maximum discharge for period of record has been revised to 21,200 ftVs (600 m'/s). Aug. 13, 1990, gage-height, 16.62 ft (5.06 m). DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV DEC JAN MAR MAY JUL AUG 1 23 26 2 21 125 3 22 126 4 27 51 5 62 49 6 85 169 7 52 35 8 78 28 9 74 15 10 86 15 11 44 12 12 35 12 13 60 19 14 45 13 15 32 11 16 63 12 17 53 11 18 65 11 19 69 10 20 34 e8.4 21 27 eB.O 22 27 e7.8 23 134 e7.6 24 173 el2 25 49 e22 26 49 e!8 27 29 ell 28 24 e!2 29 23 19 30 21 16 31 22 —— TOTAL 1608 891.8 MEAN 51.9 29.7 MAX 173 169 MIN 21 7.6 AC-FT 3190 1770 CFSM 6.02 3.45 IN. 6.94 3.85 7.7 10 8.6 8.8 7.4 8.2 7.5 5.9 13 31 13 11 55 74 14 15 162 624 85 25 16 14 12 9.9 9.0 8.2 8.6 15 8.7 7.5 7.1 1302.1 42.0 624 5.9 2580 4.87 5.62 STATISTICS OF MONTHLY MEAN DATA MEAN 60.2 83.0 MAX 202 196 (WY) 1971 1985 MIN 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 72.1 179 1971 16.8 1994 FOR 6.6 6.2 5.9 5.8 5.8 25 12 185 24 12 9.9 e34 e20 e419 elSO e74 e55 e56 e74 el86 e64 38 29 64 92 72 113 340 89 58 55 2380.2 76.8 419 5.8 4720 8.91 10.27 FOR WATER 53.3 119 1969 18.5 1977 58 45 61 96 55 227 102 52 46 36 31 29 27 27 23 23 26 23 23 22 20 19 18 81 36 17 14 12 11 ___ --- 1260 43.4 227 11 2500 5.04 5.44 YEARS 1966 49.9 117 1982 10.8 1983 9.0 8.0 7.4 6.8 37 15 10 10 21 8.6 12 10 7.1 6.5 6.6 8.9 7.8 6.8 6.5 6.1 5.9 5.4 5.1 5.0 5.0 6.3 11 12 18 5.9 4.8 295.5 9.53 37 4.8 586 1.11 1.28 - 1996 38.6 153 1990 9.53 1996 1995 CALENDAR YEAR 14894. 40. 624 4. 6. 29540 4. 64. 85 18 8. 5 8 Dec 18 8 Jun 10 9 Jun 21 73 28 0 4.2 3.6 3.7 890 31 7.1 5.2 4.5 4.4 4.6 4.4 54 43 15 33 82 14 12 13 11 11 14 207 94 32 33 40 30 48 120 --- 1868.7 62.3 890 3.6 3710 7.23 8.06 36 24 21 20 17 52 203 110 167 108 51 48 238 72 37 32 27 25 23 24 25 28 33 37 23 21 18 16 15 15 18 1584 51.1 238 15 3140 5.93 6.84 20 32 30 86 33 105 77 38 20 22 86 158 60 56 423 273 73 63 48 31 40 78 48 31 22 19 25 49 22 18 --- 2086 69.5 423 18 4140 8.07 9.00 17 16 17 e!7 e!5 e!8 e23 e743 6145 645 640 elSO 6160 6350 6190 674 658 650 e47 e!20 e47 e36 e35 e38 e!02 e!62 e45 670 e64 e29 e29 2952 95.2 743 15 5860 11.0 12.74 e40 e52 e90 e!60 e89 e50 e34 e28 e27 e27 e30 623 elOO 6300 e220 6240 e57 640 e39 631 e29 e28 6250 e73 e34 e20 619 e!8 el7 e!6 e!5 2196 70.8 300 15 4360 8.22 9.48 e!3 e!3 e!3 e35 e54 e36 e24 631 elSO e2000 e310 e!20 elOO e80 ellO e92 e70 678 e62 e66 e42 e33 e30 e26 e24 e30 e67 126 76 61 —— 4002 133 2000 13 7940 15.5 17.27 , BY WATER YEAR (WY) 43.8 119 1981 6.27 1984 FOR 1996 22426 61 2000 3 5 13100 12 44480 7 96 125 29 7 66.7 185 1979 14.9 1973 WATER YEAR .3 .3 Sep 10 .6 Apr 2 .5 Mar 20 Sep 10 .66 Sep 10 .11 .78 .7 46.1 120 1970 10.0 1975 52.1 114 1983 11.1 1975 WATER 57. 98. 21. 2600 3. 4. 21200 16. 41380 6. 90. 122 25 10 59.5 123 1988 18.5 1994 YEARS 1966 1 6 6 Dec 6 Apr 4 Jun Aug 62 Aug 63 02 59.0 191 1989 17.7 1971 - 1996 1979 1994 7 1987 2 1996 30 1975 13 1990 13 1990 e Estimated 310 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 1995 TO SEPTEMBER 1996 OCT 11 JAN 24 FEB 21 APR 24 JUN 17 AUG 21 DATE 1995 1996 OCT 11 JAN 24 FEB 21 APR 24 JUN 17 AUG 21 OCT 11 JAN 24 FEB 21 APR 24 JUN 17 AUG 21 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) 0950 38 0755 127 0915 19 1000 69 0925 71 0920 30 HARD- NESS TOTAL (MG/L DATE AS CAC03 ) (00900) 1995 25 1996 ... ... 16 ... 34 FLUO- RIDE, DIS- SOLVED DATE (MG/L AS F) (00950) 1995 <0.10 1996 . . . ... <0.10 . . . <0.10 non- ideal count 80 75 113 61 64 112 MAGNE- CALCIUM SIUM, DIS- DIS- SOLVED SOLVED (MG/L (MG/L AS CA) AS MG) (00915) (00925) 5.6 2.7 -- __ 3.5 1.8 __ 7.3 3.9 SOLIDS, SILICA, SUM OF DIS- CONSTI- SOLVED TUENTS, (MG/L DIS- AS SOLVED SI02) (MG/L) (00955) (70301) 14 52 __ __ 8.8 38 __ 19 83 6.3 25.0 7 6.4 20.5 8 7.0 22.5 1 6.3 22.0 4 6.6 23.0 8 7.1 25.0 0 SODIUM SODIUM, AD- DIS- SORP- SOLVEJ TION (MG/L RATIO AS NA) (00930) (00931) 6.7 0.6 __ __ 5.5 0.6 __ 7.9 0.6 RESIDUE SOLIDS, TOTAL DIS- AT 105 SOLVED DEC. C, (TONS SUS- PER PENDED DAY) (MG/L) (70302) (00530) 5.44 1 20 11 7.11 9 7 6.79 6 .2 .2 .2 .2 .5 .90 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 0.50 -- -- 0.50 -- 0.70 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.090 0.090 0.070 0.070 0.060 0.060 7.7 8.2 8.0 8.4 8.2 8.3 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 21 18 36 13 10 54 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 0.010 0.010 <0.010 91 89 90 95 95 99 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.090 0.090 0.070 0.080 0.070 0.060 10 <10 <10 25 <10 15 SULFATE DIS- 430 2200 K70 3500 K680 210 CHLO- RIDE, DIS- 710 4400 440 5900 470 680 SOLVED SOLVED (MG/L AS SO4) (00945) 1.9 -- -- 2.1 -- 1.6 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.030 0.010 0.030 0.020 0.010 (MG/L AS CL) (00940) 8.5 -- -- 8.4 -_ 10 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.24 <0.19 <0.20 0.37 0.25 <0.20 311 RIO ESPIRITU SANTO BASIN 50063800 RIO ESPIRITU SANTO NEAR RIO GRANDE, PR—Continued WATER-QUALITY RECORDS DATE OCT 1995 11... JAN 1996 24... FEB 21. .. APR 24... JUN 17... AU6 21... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (HG/L AS N) (00625) 0.25 0.22 <0.21 0.40 0.27 <0.20 NITRO- GEN, TOTAL (HG/L AS N) (00600) 0.34 0.31 <0.20 0.48 0.34 <0.20 NITRO- GEN, TOTAL (HG/L AS N03) (71887) 1.5 1.4 0.58 2.1 1.5 0.82 PHOS- PHORUS TOTAL (HG/L AS P) (00665) <0.020 <0.020 0.040 0.040 <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 TOTAL RECOV- ERABLE (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 OCT 1995 11. .. JAN 1996 24. .. FEB 21. .. APR 24. .. JUN 17. .. AUG 21. .. 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 MM) (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) 370 10 20 <0.10 <0.10 <1 <1 10 <1 <0.010 <0.010 <0.02 <0.02 312 RIO ESPIRITO 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 km2 ). PERIOD OF RECORD.—May 1967 to December 1970, January 1972 to September 1982, August 1990 to current year. GAGE.--Water-stage recorder. 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DEC JAN FEB APR MAY JUN AUG SEP 1 12 14 2 11 62 3 12 93 4 13 45 5 34 45 6 33 109 7 16 33 8 19 45 9 33 23 10 38 18 11 21 17 12 17 15 13 21 18 14 17 16 15 11 13 16 17 17 17 23 18 18 21 15 19 31 13 20 16 11 21 18 9.6 22 11 9.2 23 81 8.9 24 112 11 25 54 15 26 32 12 27 17 9.1 28 13 11 29 14 12 30 12 15 31 11 —— TOTAL 791 752.8 MEAN 25.5 25.1 MAX 112 109 MIN 11 8.9 AC-FT 1570 1490 CFSM 3.49 3.43 IN. 4.03 3.83 8.5 7.8 6.9 6.9 6.7 6.5 5.9 5.7 8.4 19 10 10 41 43 14 13 75 173 63 22 15 13 11 10 9.3 9.0 12 13 10 8.3 7.8 664.7 21.4 173 5.7 1320 2.93 3.38 STATISTICS OF MONTHLY MEAN DATA MEAN 57.4 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 47.5 140 1971 13.8 1968 FOR 7.8 7.7 7.3 6.9 8.0 29 24 99 29 18 13 67 21 429 157 49 29 43 90 148 65 41 30 38 49 62 102 134 49 33 32 1917.7 61.9 429 6.9 3800 8.46 9.76 FOR WATER 43.0 151 1969 10.1 1977 28 25 40 27 46 101 30 22 19 18 e!7 e!5 e!5 e!5 e!5 el3 e!3 el 5 e!3 e!3 e!2 ell ell e45 e24 e!8 e!5 e!3 ell ___ —— 660 22.8 101 11 1310 3.11 3.36 YEARS 1967 30.5 76.4 1969 5.80 1977 e9.4 e9.0 e8.4 eS.O e32 e!4 e9.0 e9.0 e!9 eS.O ell e9.0 e6.6 e6.0 e6.0 e8.2 e7.0 e6.2 e6.0 e5.6 e5.4 e4.9 e4.7 e4.6 e4.6 e6.4 elO ell e!6 7.2 7.6 279.8 9.03 32 4.6 555 1.23 1.42 - 1996 20.9 54.4 1969 4.50 1977 1995 CALENDAR YEAR 9159. 25. 439 3. 3. 18170 3. 46. 53 13 4. 2 1 Sep 16 5 Apr 29 6 Apr 28 43 61 6 6.2 5.7 5.6 38 10 7.0 7.2 6.2 6.1 5.9 5.6 23 36 eS.O e!8 e42 e7.4 e6.4 e6.8 e5.8 e5.8 e7.2 50 44 12 6.7 9.1 6.5 29 39—— 466.2 15.5 50 5.6 925 2.13 2.37 13 7.0 5.9 5.4 5.2 9.8 40 47 85 46 18 12 29 27 10 8.1 7.4 6.8 6.2 6.1 6.7 6.5 11 8.4 5.9 5.3 6.1 5.2 4.9 4.6 7.8 467.3 15.1 85 4.6 927 2.06 2.38 7.2 5.3 7.9 14 8.9 40 35 13 7.4 7.8 49 73 31 22 171 132 52 24 19 14 13 39 24 13 10 9.5 13 26 13 9.0 903.0 30.1 171 5.3 1790 4.12 4.60 8.0 7.5 8.1 7.5 6.6 6.1 8.0 362 91 36 21 67 71 155 104 35 27 22 21 53 22 16 15 17 43 73 22 30 26 16 16 1412.8 45.6 362 6.1 2800 6.23 7.19 e23 27 40 72 37 29 19 16 15 15 17 13 52 177 128 137 54 e36 e26 e22 e!9 e!7 e!40 e52 e25 e!8 e!7 el 6 e!5 e!4 e!3 1301 42.0 177 13 2580 5.74 6.62 e!2 e!2 e!2 e!7 e29 e!8 e!3 e!7 elOO ellOO e!70 e64 e58 e45 e58 e50 e39 e42 33 35 23 18 16 14 13 15 19 43 25 17 —— 2127 70.9 1100 12 4220 9.70 10.82 , BY WATER YEAR (WY) 27.8 119 1978 6.29 1995 FOR 1996 11743 32 1100 4 5 6430 14 3 23290 4 59 63 16 6 52.1 203 1969 10.2 1974 WATER YEAR .3 .1 Sep 10 .6 Mar 24 .1 Mar 19 Jan 14 .11 Jan 14 .7 May 30 .39 .76 .5 31.3 86.5 1968 6.22 1975 37.3 109 1969 8.66 1994 WATER 40 87 17 3470 2 2 17400 15 1 29360 5 75 80 17 6 42.3 90.0 1968 7.39 1991 YEARS 1967 .5 .1 .3 May .2 Aug .5 Aug Sep .50 Sep .6 Mar .54 .31 .6 49.3 153 1975 12.4 1967 - 1996 1969 1994 21 1969 15 1991 10 1991 16 1975 16 1975 13 1977 e Estimated 313 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR LOCATION.--Lat 18°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 de la Mina, and 3.2 mi (5.1 km) southeast of Mameyes. DRAINAGE AREA.—6.88 mi* (17.82 km 1 )- 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC JAN MAR MAY JUN JUL AUG SEP 1 29 34 2 56 50 3 35 67 4 36 48 5 52 63 6 e49 149 7 e49 65 8 e61 62 9 e48 44 10 e45 41 11 e34 38 12 e36 38 13 e!04 34 14 46 29 15 39 31 16 55 34 17 46 31 18 41 27 19 76 25 20 40 22 21 35 23 22 33 22 23 80 21 24 90 26 25 72 26 26 82 37 27 44 22 28 40 23 29 36 44 30 34 33 31 35 TOTAL 1558 1209 MEAN 50.3 40.3 MAX 104 149 MIN 29 21 AC-FT 3090 2400 CFSM 7.30 5.86 IN. 8.42 6.54 STATISTICS OF MONTHLY MEAN MEAN 64.7 79.3 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 24 33 28 30 23 28 22 21 27 48 33 29 70 88 33 36 122 277 97 59 40 35 31 28 26 26 25 40 24 22 21 1446 46.6 277 21 2870 6.78 7.82 DATA 59.9 164 1971 16.6 1990 20 19 19 21 20 46 35 94 30 23 36 82 48 e838 elOO ellO e43 e40 e71 ellS e42 e32 e26 e38 e69 e55 e62 el!3 e40 e26 e28 2341 75.5 838 19 4640 11.0 12.66 FOR WATER 54.7 105 1969 25.0 1985 e26 e24 e33 e37 e28 e53 e51 e28 e28 e23 e23 e21 e28 e28 e29 e31 e25 e22 e34 e23 e21 e20 e20 elOO e38 e27 e24 e23 e22 ... —— 890 30.7 100 20 1770 4.46 4.81 YEARS 1967 41.8 68.0 1988 21.7 1968 e20 e!9 e!9 e20 e78 e33 e27 e32 e45 e26 e28 e23 e20 e20 e20 e27 e23 e21 e!9 e!8 e!7 e!7 e!6 e!6 e!5 el6 e!8 e32 e35 e!9 e!7 756 24.4 78 15 1500 3.54 4.09 - 1996 37.6 79.7 1990 18.1 1968 FOR 1995 CALENDAR YEAR 16915 46. 326 11 13 33550 6. 91. 86 35 19 3 Sep 16 May 3 Apr 27 74 46 e!6 e!6 e!7 e357 e71 e30 e24 e23 e21 e!9 e!8 e84 e49 e26 e42 e45 e25 e40 e41 e22 e23 e28 el!4 e60 e30 e37 e31 e40 e35 e67 —— 1451 48.4 357 16 2880 7.03 7.85 e31 e26 e24 e23 e24 e50 elll elOB e86 e79 e45 e47 e613 e66 e36 e27 e23 e!9 e!7 e!7 e!8 e22 e28 e32 e!5 e!6 e!5 e!2 e!2 el8 e20 1680 54.2 613 12 3330 7.88 9.08 e58 e79 e27 e93 e40 e69 e56 e!7 e!3 e!6 e86 el!3 e20 e32 e!34 e!36 e32 e48 e20 e!4 e20 e36 e!5 e!4 el4 e!5 e!9 e47 e20 e!8 --- 1321 44.0 136 13 2620 6.40 7.14 el 6 e!5 e!5 e!7 e!5 e!4 e30 e452 e53 e20 e!4 e46 e34 e762 e69 e40 e23 e20 e23 e33 e!7 e!6 e!5 e!4 e25 e29 e20 e20 e23 e27 e30 1947 62.8 762 14 3860 9.13 10.53 e45 e35 e80 e62 e35 e22 e!8 e!6 e20 e!7 e!8 e!9 e21 e30 e56 e!25 eB9 e43 e43 e35 e30 e27 e!23 e91 e49 e44 e45 e50 e39 e39 e37 1403 45.3 125 16 2780 6.58 7.59 e27 e26 e28 e37 e77 e39 e31 e61 e271 e2140 e276 e92 e61 e61 e!45 e!06 e54 e60 e56 e84 e79 e48 e37 e33 e29 e30 e38 e!56 e41 e53 4276 143 2140 26 8480 20.7 23.12 , BY WATER YEAR (WY) 40.3 83.1 1973 14.5 1984 FOR 1996 20278 55 2140 12 15 12800 11 40220 8 109 87 32 17 65.2 147 1970 18.7 1973 WATER YEAR .4 Sep 10 May 28 May 25 Sep 10 .09 Sep 10 .05 .64 55.5 112 1970 12.4 1985 50.2 93.4 1969 20.3 1994 WATER 55 78 33 2780 6 9 20500 13 5 40410 8 110 100 33 16 52.5 81.4 1988 20.4 1994 YEARS 1967 .8 .0 .1 Sep .9 Apr .4 Jun Sep .91 Sep .1 Apr .11 .15 60.1 166 1989 26.6 1986 - 1996 1971 1994 18 1989 20 1970 12 1985 18 1989 18 1989 8 1970 e Estimated 314 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.— tJSDH-49 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 days. 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 1996.-- SEDIMENT CONCENTRATION: Maximum daily mean, 484 mg/L September 10, 1996; Minimum daily mean, 1 mg/L several days. SEDIMENT LOADS: Maximum daily mean, e4,290 tons (e3,891 tonnes) September 10, 1996; Minimum daily mean, eO.05 tons (eO.04 tonne) March 19, 1996. SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), MATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 29 56 35 36 52 e49 e49 e61 e48 e45 634 636 e!04 46 39 55 46 41 76 40 35 33 80 90 72 82 44 40 36 34 35 17 15 3 2 9 7 9 13 11 25 11 8 18 13 11 17 8 6 41 33 31 30 30 19 16 28 6 4 7 6 3 1.3 3.6 .27 .19 1.5 e.89 el. 4 62.2 el. 4 e3.5 el.O e.73 e7.6 1.6 1.2 3.7 1.0 .71 14 3.6 2.9 2.6 6.6 5.0 10 10 .77 .40 .71 .51 .33 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) NOVEMBER TOTAL 1558 91.21 34 50 67 48 63 149 65 62 44 41 38 38 34 29 31 34 31 27 25 22 23 22 21 26 26 37 22 23 44 33 1209 4 6 15 20 19 48 19 14 11 8 6 4 3 5 8 13 21 19 14 10 7 6 5 4 4 7 4 4 14 9 .33 .94 2.9 2.6 3.2 30 3.5 2.4 1.3 .87 .60 .44 .30 .35 .66 1.2 1.8 1.4 .93 .61 .45 .34 .27 .31 .30 .77 .24 .25 2.8 .83 62.89 MEAN DISCHARGE (CFS) 24 33 28 30 23 28 22 21 27 48 33 29 70 88 33 36 122 277 97 59 40 35 31 28 26 26 25 40 24 22 21 1446 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 6 5 4 3 3 3 3 3 4 9 6 5 15 19 8 6 25 91 12 6 5 6 8 5 4 5 .41 .44 .30 .25 .19 .22 .18 .17 .30 1.2 .54 .37 3.7 5.2 .74 .57 20 108 3.6 1.0 .48 .38 .33 .30 .29 .34 .40 .99 .30 .26 .29 151.74 e Estimated 315 DAY RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA,PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN 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 TOTAL MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JANUARY 20 19 19 21 20 46 35 94 30 23 36 82 48 e838 elOO ellO e43 e40 671 ellS e42 e32 e26 e38 e69 e55 e62 el!3 e40 e26 e28 6 8 9 11 15 10 4 24 5 4 4 14 7 233 34 6 7 8 19 26 9 7 4 2 21 27 11 60 64 54 45 .33 .39 .49 .64 .79 1.2 2.0 8.1 .37 .23 .42 4.0 1.1 e931 eSO el. 8 e.80 e.87 e4.7 e!2 el.O e.62 e.30 e.25 e4.5 e4.0 e2.3 e22 e6.9 64.1 e3.4 2341 1070.60 MEAN DISCHARGE (CFS) e26 e24 e33 e37 e28 e53 e51 e28 e28 e23 e23 e21 e28 e28 e29 e31 e25 e22 e34 e23 e21 e20 e20 elOO e38 e27 e24 e23 e22 890 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) 38 32 26 6 2 24 12 5 3 2 2 5 13 14 11 8 6 4 8 5 3 4 8 22 4 4 3 3 4 e2.7 e2.1 e2.2 e.71 e.19 e6.7 e2.0 e.34 e.23 e.15 e.14 e.31 el.O el.O e.88 e.71 e.38 e.24 e.79 e.34 e.15 e.20 e.42 ell e.44 e.25 e.20 e.21 e.24 MEAN DISCHARGE (CFS) e20 e!9 e!9 e20 e78 e33 e27 e32 e45 e26 e28 e23 e20 e20 e20 e27 e23 e21 e!9 e!8 e!7 e!7 e!6 el 6 e!5 e!6 e!8 e32 e35 e!9 e!7 MEAN CONCEN- TRATION (MG/L) MARCH 5 4 3 6 8 6 15 23 13 6 3 3 5 3 1 1 1 1 1 2 3 3 4 5 6 7 8 12 5 1 3 SEDIMENT DISCHARGE (TONS/DAY) e.26 e.19 e.15 e.37 e2.3 e.48 el.l e2.0 el. 7 e.40 .19 e .20 .27 .16 .07 .07 .06 .06 .05 .08 .13 .16 .18 .21 .24 .31 .40 .3 .63 .08 .12 36.22 756 13.92 e Estimated 316 RIO MAHEYES BASIN 50065500 RIO HAMEYES NEAR SABANA,PR--Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 e!6 e!6 e!7 e357 e71 e30 e24 e23 e21 e!9 e!8 e84 e49 e26 e42 e45 e25 e40 e41 e22 e23 e28 el!4 e60 e30 e37 e31 e40 e35 e67 1451 4 5 6 193 41 19 15 12 9 9 8 25 11 7 8 9 3 5 8 3 3 4 35 14 7 8 6 8 8 15 e.19 e.23 e.27 e463 elO el. 6 el.O e.73 e.53 e.44 e.41 e9.4 el. 8 e.46 el. 3 el. 3 e.20 el. 6 el. 2 e.20 e.16 e.39 e42 e2.7 e.53 el.O e.53 el. 2 e.72 e3.4 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) MAY e31 e26 e24 e23 e24 e50 elll el08 e86 e79 e45 e47 e613 e66 e36 e27 e23 el9 e!7 e!7 el8 e22 e28 e32 e!5 el6 e!5 e!2 el2 el8 e20 12 10 7 5 4 9 23 29 17 17 11 10 167 16 13 18 26 20 15 10 7 4 7 9 5 4 3 2 1 1 1 el.O e.67 e.44 e.30 e.27 el. 7 e!3 e!6 e4.1 e4.1 el. 3 el. 2 elOlO e2.9 el. 2 el. 3 el. 6 el.l .71 .46 .31 .24 .56 .92 .22 .17 .12 .07 .05 .05 .05 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) JUNE 548.49 1680 1066.11 e58 e79 e27 e93 e40 e69 e56 e!7 e!3 e!6 e86 el!3 e20 e32 e!34 e!36 e32 e48 e20 e!4 e20 e36 e!5 e!4 e!4 e!5 e!9 e47 e20 e!8 1321 14 21 7 17 11 23 13 6 5 4 20 23 3 7 42 25 5 6 6 4 6 8 3 3 3 2 4 12 5 4 e6.1 e!2 e.54 e8.8 el. 8 e8.4 e2.6 e.29 e.18 e.17 ell e!5 e.23 e2.3 e56 e!7 e.43 e.87 e.32 e.15 e.34 e.94 e.12 e.ll e.10 e.09 e.20 el. 3 e.25 e.22 147.85 e Estimated 317 RIO MAMEYES BASIN 50065500 RIO HAHEYES NEAR SABANA.PR—Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 MEAN DISCHARGE DAY (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (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 e!6 e!5 e!5 e!7 e!5 e!4 e30 e452 e53 e20 e!4 e46 e34 e762 e69 e40 e23 e20 e23 e33 e!7 e!6 e!5 e!4 e25 e29 e20 e20 e23 e27 e30 TOTAL 1947 YEAR e 20278 Estimated 4 3 2 2 2 1 1 45 7 6 8 12 5 85 17 7 4 3 2 5 3 2 2 2 5 6 4 4 3 3 2 ... e.17 e.12 e.10 e.09 e.07 e.06 e.07 e!90 el.l e.31 e.28 e3.7 e.79 e257 e4.2 e.69 e.30 e.17 e.13 e.63 e.12 e.10 e.08 e.06 e.99 e.52 e.23 e.19 e.18 e.18 e.17 462.80 8276.12 MEAN DISCHARGE (CFS) e45 e35 e80 e62 e35 e22 e!8 e!6 e20 e!7 e!8 e!9 e21 e30 e56 e!25 e89 e43 e43 e35 e30 e27 e!23 e91 e49 e44 e45 e50 e39 e39 e37 1403 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) AUGUST 5 7 12 12 7 5 3 4 6 5 3 2 4 7 12 27 21 9 7 6 5 5 31 19 10 9 10 11 8 8 7 el.l e.65 e4.0 e2.3 e.69 e.35 e.18 e.18 e.30 e.25 e.16 e.ll e.20 e.60 el. 8 e!5 e7.0 el.l e.82 e.58 e.42 e.33 e44 e5.2 el. 3 el.l el. 2 el. 5 e.88 e.79 e.64 MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) SEPTEMBER e27 e26 e28 e37 e77 e39 e31 e61 e271 12140 e276 e92 e61 e61 e!45 e!06 e54 e60 e56 e84 e79 e48 e37 e33 e29 e30 e38 e!56 e41 e53 6 6 5 6 17 9 6 13 32 484 64 20 11 16 17 25 27 26 12 11 21 16 14 9 5 3 5 26 4 10 e.44 e.40 e.40 e.70 e7.6 e.96 e.47 e2.6 elll e4290 e55 e5.2 el. 7 e3.0 e7.2 e8.5 e3.9 e4.0 e2.0 e2.5 e5.6 e2.1 el. 4 e.82 e.43 e.28 e.59 e8.6 e.47 el. 7 94.73 4276 4529.56 318 RIO HAHEYES BASIN 50065500 RIO MAMEYES MR SABANA, PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT APR 1996 04... 23... MAY 13... 13... JUL 08... AUG 1996 23... SEP 09... APR 1996 04... 23... MAY 13... 13... JtTL 08... AUG 1996 23... SEP 09... TIME 1300 2105 1125 1210 1635 1725 2247 SED. SUSP. FALL DIAM. % FINER THAN .016 MM (70329) 54 66 71 64 53 67 72 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1860 425 1030 1850 2520 900 2000 SED. SUSP. FALL DIAM. % FINER THAN .031 MM (70330) 69 76 80 74 67 77 76 SEDI- MENT, SUS- PENDED (MG/L) (80154) 1670 979 2140 1210 559 597 479 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 76 84 86 82 75 87 86 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 8390 2000 5940 6060 3800 1450 2590 SED. SUSP. SIEVE DIAM. % FINER THAN .125 MM (70332) 92 95 93 91 89 95 93 SED. SUSP. FALL DIAM. % FINER THAN .002 MM (70326) 17 31 37 26 22 34 48 SED. SUSP. SIEVE DIAM. % FINER THAN .250 MM (70333) 96 99 97 96 96 98 97 SED. SUSP. FALL DIAM. % FINER THAN .004 MM (70327) 26 38 47 41 27 40 53 SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) 98 99 99 98 98 99 99 SED. SUSP. FALL DIAM. % FINER THAN .008 MM (70328) 36 49 56 50 33 52 60 SED. SUSP. SIEVE DIAM. t FINER THAN 1.00 MM (70335) 99 100 99 99 99 100 100 319 RIO MAMEYES BASIN 50065500 RIO MAMEYES NEAR SABANA, PR—Continued WATER QUALITY DATA, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE JAN 1996 14... 14... 14... APR 04... 04... 04... 04... 04... 04... 04... 04... 23... MAY 13... 13... 13... 13... JOL 08... 08... 08... 08... AUG 23... SEP 09... 10... 10... 10... TIME 1505 1655 1745 1325 1355 1410 1455 1515 1535 1555 1600 2117 1245 1445 1450 1517 1710 1725 1755 1835 1750 2215 0245 0405 0525 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 1120 1560 2730 1820 1520 1030 1520 1240 1190 938 764 651 764 1360 1360 724 2220 2270 2630 2100 934 1660 2500 4190 3410 SEDI- MENT, SUS- PENDED (MG/L) (80154) 814 619 580 1170 999 743 417 590 383 460 550 305 386 590 513 275 268 226 287 229 363 286 244 563 923 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 2460 2610 4280 5750 4100 2070 1710 1980 1230 1160 1130 536 796 2170 1880 538 1610 1390 2040 1300 915 1280 1650 6370 8500 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 88 82 73 86 88 91 85 81 87 93 93 88 91 86 90 93 85 89 80 83 90 79 85 74 76 320 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 Lwiuillo. DRAINAGE AREA.--3.96 mi 2 (10.26 km»). 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 A Ri« Suafajfiso iiisun i % SA8ANA GRANDE ) r-s ^ ) JUANA ( DSA7 f—- SEA ?l 0123456 KILOMETERS i...... I ........i .....I......... I i... EXPLANATION A1125 SURFACE-WATER STATION AND NUMBER yn62 QUALITY-OF-WATER STATION AND NUMBER • 132 WELL AND WELL NUMBER • 125780 LAKE-ELEVATION STATION AND NUMBER 0123 MILES Figure 24.--South coast river basins the Rio Inabon to Rio Loco basins. 372 RIO INABON BASIN 50112500 RIO INABON AT REAL ABAJO, PR LOCATION.—Lat 18°05'10", long 66°33'46", Bydrologic Unit 21010004, at bridge on private road, off Highway 511 at Hacienda La Concordia, 0.4 mi (0.6 km) upstream from diversion canal, 0.5 mi (0.8 km) north of Real Abajo, and 6.1 mi (9.8 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.--9.70 mi 3 (25.12 km')- PERIOD OF RECORD.—1962-63 (annual low-flow measurements only), February to June 1964 (monthly measurements only). July 1964 to July 1970, April 1971 to current year. GAGE.—Water-stage recorder. Elevation of gage is 410 ft (125 m), from topographic map. Prior to April 1971 non-recording gage and crest-stage gage at different datum. 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 NOV DEC APR MAY AUG 1 19 14 2 18 14 3 19 14 4 21 15 5 20 16 6 17 16 7 16 16 8 16 16 9 16 18 10 17 18 11 19 16 12 23 16 13 20 22 14 17 16 15 17 33 16 26 26 17 28 16 18 26 12 19 25 11 20 32 12 21 32 12 22 25 11 23 21 11 24 19 12 25 18 11 26 18 10 27 19 9.3 28 33 8.1 29 20 8.2 30 16 9.3 31 15 —— TOTAL 648 438.9 MEAN 20.9 14.6 MAX 33 33 MIN 15 8.1 AC-FT 1290 871 CFSM 2.15 1.51 IN. 2.49 1.68 9.9 8.7 8.7 8.6 8.2 9.0 8.7 7.4 7.2 7.5 7.9 8.0 7.9 7.2 6.9 7.0 7.3 7.4 8.3 7.9 7.1 7.1 6.9 7.2 7.1 8.5 10 7.1 6.6 6.6 6.8 240.7 7.76 10 6.6 477 .80 .92 6.7 6.8 6.0 6.4 6.4 6.7 7.4 7.5 7.5 11 6.1 5.6 5.9 18 18 8.7 6.6 6.2 6.1 8.4 7.5 5.5 5.1 5.1 5.5 6.3 7.2 6.5 5.8 5.0 4.8 226.3 7.30 18 4.8 449 .75 .87 .5 .3 .3 .1 .1 4.7 5.3 6.2 10 24 14 6.8 5.5 4.9 4.6 4.6 12 11 9.9 10 30 85 38 21 13 11 9.6 9.6 8.3 —— —— 380.3 13.1 85 4.1 754 1.35 1.46 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1964 MEAN 45.9 33.4 MAX 148 77.9 (WY) 1986 1978 MIN 14.5 8.32 (WY) 1994 1977 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 12.3 26.5 1966 4.43 1977 FOR 8.52 45.5 1992 4.11 1989 5.75 13.1 1996 3.05 1977 7.0 7.5 9.5 11 10 9.8 11 11 21 14 9.4 10 9.6 10 11 11 8.1 7.3 6.7 5.7 5.7 4.6 4.6 5.0 4.5 4.7 4.6 4.9 5.4 e7.5 e!4 266.1 8.58 21 4.5 528 .88 1.02 - 1996 5.77 16.4 1972 1.85 1977 1995 CALENDAR YEAR 4504.7 12.3 183 3.2 3.4 8940 1.27 17.28 24 7.1 4.4 Sep 16 Jan 6 Jan 1 e!4 6.8 47 e34 19 e47 19 10 11 9.1 9.0 15 13 9.5 10 8.2 7.5 8.3 6.5 11 10 6.9 5.0 7.1 9.4 7.4 9.1 11 12 11—— 403.8 13.5 47 5.0 801 1.39 1.55 , BY WATER 8.23 19.2 1992 2.76 1975 11 9.4 8.7 7.3 6.7 6.5 6.0 e7.3 7.4 7.3 7.7 7.6 16 14 9.7 e49 e25 11 24 e57 36 25 26 17 14 11 8.4 8.7 9.3 40 35 529.0 17.1 57 6.0 1050 1.76 2.03 YEAR (WY) 19.6 76.7 1969 1.94 1967 28 20 21 147 67 33 17 13 14 12 11 11 10 10 26 11 11 17 11 9.7 11 12 13 11 10 11 12 11 9.7 8.6 —— 609.0 20.3 147 8.6 1210 2.09 2.34 16.1 49.8 1969 2.75 1967 FOR 1996 WATER YEAR 7009.1 19.2 754 4.1 4.4 3870 18.37 13900 1.97 26.88 32 10 6.2 Sep 10 Feb 4 Jan 31 Sep 10 Sep 10 8.5 7.7 8.6 9.8 10 9.1 8.5 29 28 15 11 8.2 6.9 19 27 10 7.9 6.7 8.1 8.6 8.5 8.6 7.7 7.3 7.2 7.8 7.3 32 16 7.1 7.2 364.3 11.8 32 6.7 723 1.21 1.40 11.9 32.7 1979 1.77 1990 91 87 52 13 8.5 6.7 7.3 7.7 7.1 15 32 24 18 23 13 9.6 7.5 11 8.7 47 14 7.5 6.7 16 14 14 13 13 11 e33 16 647.3 20.9 91 6.7 1280 2.15 2.48 17.1 46.1 1979 4.47 1974 WATER YEARS 1964 18.1 30.9 7.44 2500 .80 1.1 19000 25.30 13090 1.86 25.30 40 9.0 3.2 Sep Jul Mar Oct Oct 12 9.5 9.5 9.9 9.5 8.1 7.4 6.8 6.7 e754 e317 e!63 e!31 e!35 e93 e59 e45 e46 e38 35 32 31 31 30 34 29 28 28 27 90—— 2255.4 75.2 754 6.7 4470 7.75 8.65 33.7 119 1975 7.70 1986 - 1996 1969 1994 16 1975 23 1977 31 1977 7 1985 7 1985 e Estimated 373 RIO BUCANA BASIN 50113800 RIO CERRILLOS ABOVE LAGO CERRILLOS NEAR PONCE, PR LOCATION.--Lat 18°07'01", long 66°36'17», Hydrologic Unit 21010004, on right bank, 0.3 mi (0.5 km) downstream from confluence with Rio San Patricio, 0.1 mi (0.2 km) southwest of Hwy 139 and 2.4 mi (3.7 km) northwest of Mayaguez. DRAINAGE AREA.-- 15.4 mi 2 (39.9 km2 ). PERIOD OF RECORD.--December 1988 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 720 ft (210 m), from topographic map. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV DEC JAN MAR APR MAY AUG 1 30 16 2 27 15 3 43 15 4 37 14 5 30 16 6 25 25 7 23 16 8 27 21 9 22 15 10 25 14 11 42 12 12 37 11 13 29 28 14 22 14 15 19 28 16 20 67 17 32 40 18 54 28 19 36 23 20 61 21 21 39 22 22 30 20 23 24 19 24 25 20 25 55 18 26 40 17 27 27 16 28 34 15 29 27 14 30 20 14 31 18 —— TOTAL 980 614 MEAN 31.6 20.5 MAX 61 67 MIN 18 11 AC-FT 1940 1220 CFSM 2.66 1.72 IN. 3.06 1.92 14 13 13 12 12 18 14 13 12 12 13 12 11 11 11 10 11 11 12 14 11 9.6 9.6 9.6 9.1 21 14 11 9.7 9.1 8.4 371.1 12.0 21 8.4 736 1.01 1.16 8.2 7.8 7.8 8.0 7.7 7.7 7.4 9.5 11 10 8.1 7.4 22 39 34 14 11 9.6 11 11 11 9.0 7.9 7.6 11 14 15 13 11 9.5 8.7 369.9 11.9 39 7.4 734 1.00 1.16 8.2 7.9 7.8 7.7 7.5 26 27 13 13 33 24 11 12 12 9.3 8.7 41 17 15 14 126 92 60 65 39 21 15 13 12 --- 758.1 26.1 126 7.5 1500 2.20 2.37 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1989 MEAN 69.0 30.5 MAX 154 59.3 (WY) 1991 1993 MIN 24.6 9.77 (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 INSTANTANEOUS LOW FLOW ANNUAL RUNOFF (AC-FT) ANNUAL RUNOFF (CFSM) ANNUAL RUNOFF (INCHES) 10 PERCENT EXCEEDS 50 PERCENT EXCEEDS 90 PERCENT EXCEEDS 15.0 26.2 1993 8.10 1995 FOR 16.8 59.0 1992 6.59 1995 12.5 26.1 1996 6.34 1990 11 11 11 9.7 9.7 9.1 8.7 8.3 25 21 19 17 14 13 16 29 17 12 11 10 9.4 9.1 9.2 9.0 8.5 8.6 8.5 8.4 8.3 8.3 9.8 379.6 12.2 29 8.3 753 1.03 1.19 - 1996 11.6 27.5 1989 4.77 1990 1995 CALENDAR YEAR 9093 24 517 4 4 18040 2 28 55 13 5 .7 .9 Sep 16 .1 Apr 29 .3 Apr 26 .09 .43 .1 10 8.6 82 48 47 57 19 12 11 12 13 28 19 15 14 12 13 13 12 27 18 13 12 11 10 9.8 9.9 9.7 9.7 8.7 --- 584.4 19.5 82 8.6 1160 1.64 1.83 8.3 7.7 26 11 8.2 7.4 7.1 6.6 6.8 6.9 6.7 6.9 18 10 11 70 32 22 102 106 51 21 21 15 13 13 14 14 12 77 42 773.6 25.0 106 6.6 1530 2.10 2.42 26 21 17 344 122 77 47 38 34 30 27 26 24 22 58 35 28 29 159 63 27 21 18 16 15 18 13 13 12 12 --- 1392 46.4 344 12 2760 3.90 4.35 11 9.5 9.3 9.2 8.8 8.4 9.0 75 65 34 24 21 17 52 85 39 27 22 19 17 16 14 14 13 12 12 11 40 18 12 18 742.2 23.9 85 8.4 1470 2.01 2.32 147 182 102 58 37 29 26 23 21 62 51 47 33 42 33 26 22 56 46 85 66 41 38 37 29 25 23 22 22 21 21 1473 47.5 182 21 2920 3.99 4.60 20 20 20 27 23 31 21 20 20 1580 388 191 135 145 119 94 117 116 92 72 60 50 43 43 54 38 33 39 29 141 3781 126 1580 20 7500 10.6 11.82 , BY WATER YEAR (WY) 14.8 24.3 1989 6.38 1990 FOR 1996 12218 33 1580 6 6 10600 10 6 24240 2 38 60 18 8 26.3 68.2 1993 4.58 1990 WATER YEAR .9 .4 Sep 10 .6 May 8 .9 May 6 Sep 10 .62 Sep 10 .2 May 11 .81 .20 .7 24.9 46.4 1996 6.37 1990 15.7 26.7 1991 3.37 1994 WATER 27 35 9 1580 3 3 10600 10 19540 2 30 59 14 4 29.9 53.1 1991 11.3 1994 YEARS 1989 .0 .7 .94 Sep .0 JUl .2 JUl Sep .62 Sep .27 .80 .9 60.4 126 1996 16.9 1994 - 1996 1993 1994 10 1996 6 1994 27 1994 10 1996 10 1996 374 RIO BUCANA BASIN 50113950 LAGO CERRILLOS AT DAMSITE NEAR PONCE, PR LOCATION.--Lat 18°04'41", long 66°34'38", Hydrologic Unit 21010004, on left bank west from intake house of dam, 0.7 mi (1.1 km) southwest from Iglesia San Mateo at Real Abajo, 3.2 mi (5.1 km) northeast from Hospital de Distrito de Ponce, and 2.2 mi (3.5 km) northwest from Escuela Yuca. DRAINAGE AREA.--17.4 mi 2 (45.1 km1 ). ELEVATION RECORDS PERIOD OF RECORD.--October 1992 to current year . REVISED RECORDS.--WDR PR-94-1: 1993,1994. GAGE.--Water-stage recorder. Datum of gage is mean sea level. REMARKS.--Lake is formed by Cerrillos Dam, a rockfilled ungated structure completed in 1992. Elevation of crest is 611 ft (186 m) above mean sea level, with a structural height of 323 ft (98 m) and a lenght of 1,555 ft (474 m). The dam has a capacity of approximately 47,900 ac-ft (59.1 hm3 ). The dam is operated by U.S. Army Corps of Engineers and its purpose is for flood control, water supply, power generation, and recreation. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.--Maximum elevation, 574.57 ft (175.13 m), Sept. 30, 1996; Minimum elevation, 416.63 ft (126.99 m), Oct. 1, 1992, (Revised). EXTREMES OBSERVED FOR WATER YEAR 1993 (Revised).--Maximum elevation, 523.07 ft (159.43 m), Sept. 30; minimum elevation, 416.63 ft (126.99 m), Oct. 1. EXTREMES OBSERVED FOR WATER YEAR 1994 (Revised).--Maximum elevation, 536.33 ft (163.47 m), Sept. 30; minimum elevation, 522.16 ft (159.15 m), Oct. 6. EXTREMES OBSERVED FOR WATER YEAR 1995.--Maximum elevation, 560.79 ft (170.93 m), Sept. 30; minimum elevation, 536.55 ft (163.54 m), Oct. 1. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 574.57 ft (175.13 m), Sept. 30; minimum elevation, 541.17 ft (164.95 m), June 4. Capacity Table Elevation , in feet 328 426 492 (based on data from U.S. Army Corps of Engineers) Contents in acre-feet Elevation, in feet 0 3,206 10,621 525 558 590 Contents in acre-feet 16,990 25,786 37,509 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1992 TO SEPTEMBER 1993 DAILY OBSERVATION AT 24:00 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 418.40 419.95 420.52 421.57 422.49 425.12 429.75 433.55 436.38 438.85 441.59 443.49 445.08 446.98 448.53 449.29 450.92 451.41 452.13 453.24 454.15 455.03 463.42 463.93 463.99 NOV 475.51 476.08 476.57 476.43 476.41 480.08 480.63 481.10 481.59 482.03 482.47 483.33 484.11 484.69 485.32 486.89 488.47 489.35 489.89 492.19 492.12 492.30 492.25 492.60 492.53 DEC 493.44 493.57 493.53 493.68 494.03 494.40 494.60 494.34 493.82 493.66 493.94 494.23 494.49 494.79 495.08 495.26 495.37 495.55 495.72 495.72 495.89 496.07 496.27 496.47 496.62 JAN 498.43 498.59 498.81 498.99 499.15 499.31 499.49 499.61 499.79 499.93 500.08 500.23 500.38 500.48 500.59 500.66 500.77 500.83 500.90 501.00 501.06 501.13 501.21 501.28 501.35 FEE 504.53 504.70 504.84 504.92 505.02 505.09 505.19 505.25 505.32 505.38 505.43 505.51 505.59 505.66 505.71 505.88 505.96 506.01 506.16 506.23 506.28 506.33 506.38 506.41 506.44 MAR 506.63 506.66 506.70 506.71 506.75 506.79 506.81 506.80 506.86 506.90 506.93 506.95 506.99 507.03 507.16 507.18 507.19 507.20 507.22 507.22 507.24 507.26 507.26 507.34 507.40 APR 507.61 507.62 507.74 507.77 507.77 507.78 507.79 507.84 507.93 507.96 508.17 508.37 509.03 509.31 509.57 509.77 509.85 509.96 510.04 510.18 510.24 510.31 510.36 510.50 510.58 MAY 516.29 518.56 519.49 519.81 520.04 520.12 519.85 519.25 520.35 519.37 519.38 519.54 519.70 519.18 519.99 520.27 520.50 520.21 519.17 519.38 521.04 519.50 519.55 519.97 519.66 JUN 519.50 519.48 519.86 520.13 519.14 519.37 519.55 519.54 519.16 519.37 519.57 519.76 519.95 519.70 519.43 519.64 519.76 520.51 519.47 519.43 519.67 519.89 520.02 520.01 520.03 JUL 520.02 520.12 519.32 519.30 519.43 519.54 519.72 519.88 519.97 519.02 519.23 519.52 519.73 519.95 519.75 519.63 519.73 A A A 519.76 519.24 519.32 519.48 519.55 AUG 519.06 519.05 519.13 519.16 519.18 519.22 519.30 519.32 519.34 519.46 519.48 519.53 519.57 519.60 516.98 517.76 517.90 517.95 518.06 518.12 518.24 518.49 517.34 516.64 516.63 SEP 517.31 517.42 517.65 517.86 517.96 518.05 518.11 518.14 518.25 519.17 519.48 519.58 519.71 519.75 519.86 519.89 519.99 520.24 520.35 520.67 520.84 520.96 521.17 521.36 521.47 466.37 467.90 469.05 471.75 473.29 474.47 492.76 493.14 492.96 493.02 493.26 496.89 497.11 497.31 497.76 498.00 498.25 501.40 501.51 502.19 503.81 504.17 504.35 506.46 506.52 506.60 ___ ___ ___ 507.43 507.46 507.50 507.54 507.54 507.60 510.62 510.69 510.97 513.42 515.09 ___ 520.35 521.14 520.27 519.51 519.58 519.63 520.12 519.22 519.53 519.72 519.92 ___ 519.69 519.78 519.88 519.93 519.99 520.03 516.66 516.87 517.03 517.10 517.09 517.21 521.76 521.94 522.50 522.54 522.92 ___ 474.47 418.40 493.26 475.51 498.25 493.44 504.35 498.43 506.60 504.53 507.60 506.63 515.09 507.61 521.14 516.29 520.51 519.14 519.60 516.63 522.92 517.31 A No gage-height record 375 RIO BUCANA BASIN 50113950 LAGO CERRILLOS AT DAHSITE NEAR PONCE, PR--Continued ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1993 TO SEPTEMBER 1994 DAILY OBSERVATION AT 24:00 VALUES DAY OCT NOV DEC JAN FEE MAR APR HAY 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 522.42 522.62 522.39 522.49 522.38 522.41 522.47 522.36 522.64 522.84 523.03 523.15 523.25 523.41 523.48 523.87 524.26 524.47 524.68 524.80 524.91 525.01 525.13 525.36 525.48 525.57 525.67 525.95 526.08 526.20 526.25 526.25 522.36 526.33 526.40 526.51 526.61 526.65 526.71 526.76 526.79 526.82 526.90 526.94 526.99 527.01 527.04 527.08 527.16 527.23 527.29 527.33 527.36 527.41 527.43 527.48 527.51 527.53 527.58 527.62 527.80 527.84 527.85 —— 527.85 526.33 527.90 527.91 527.93 527.95 527.97 527.99 528.01 528.01 528.04 528.02 528.06 528.07 528.13 528.38 528.34 528.41 528.43 528.45 528.46 528.83 528.88 528.90 528.97 528.98 528.98 528.99 529.19 529.20 529.20 529.21 529.22 529.22 527.90 529.22 529.23 529.23 529.23 529.24 529.24 529.24 529.23 529.23 529.23 529.24 529.22 529.23 529.22 529.22 529.22 529.22 529.21 529.24 A 529.22 529.23 529.67 529.75 529.79 529.80 529.81 529.81 529.81 529.81 529.80 __- —— 529.83 529.82 529.81 529.81 529.80 529.75 529.76 529.77 529.75 529.74 529.74 529.73 529.72 529.73 529.73 529.73 529.72 529.71 529.68 529.69 529.68 529.67 529.69 529.71 529.68 529.65 529.64 530.23 —— 530.23 529.64 530.40 530.51 530.53 530.54 530.55 530.56 530.57 530.57 530.57 530 . 57 530.58 530.59 530.61 530.62 530.65 530.67 530.66 530.66 530.65 530.63 530.64 530.64 530.63 530.56 530.55 530.55 530.54 530.52 530.52 530.50 530.48 530.67 530.40 530.48 530.48 530.48 530.48 530.48 530.48 530.62 530.65 530.64 530.64 530.68 530.68 530.68 530.67 530.65 530.63 530.62 530.62 530.56 530.55 530.55 530.53 530.52 530.51 530.50 530.66 530.73 530.76 530.76 530.76 —— 530.76 530.48 530.75 530.73 530.70 530.68 530.66 530.70 530.70 530.69 530.67 531.00 531.13 531.18 531.20 531.31 531.39 531.39 531.47 531.51 531.53 531.53 531.53 531.53 531.52 531.49 531.43 531.43 531.41 531.39 531.38 531.35 531.36 531.53 530.66 531.33 531.64 531.77 531.79 531.80 531.77 531.77 531.76 531.76 531.73 531.72 531.70 531.67 531.65 531.70 531.70 531.76 531.76 531.75 531.74 531.71 531.69 531.67 531.65 531.63 531.61 531.60 531.59 531.56 531.54 —— 531.80 531.33 531.52 531.50 531.54 531.50 531.49 531.46 531.43 531.41 531.37 531.34 531.32 531.30 531.30 531.21 531.28 531.21 531.18 531.20 531.19 531.17 531.14 531.11 531.10 531.03 531.09 531.05 531.03 531.02 530.98 530.93 530.92 531.54 530.92 530.89 530.87 530.84 530.86 530.82 530.83 530.82 530.91 531.01 531.00 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 A A A A A A A A A 533.10 533.08 533.08 533.16 533.31 533.30 533.84 534 . 17 534.25 534.85 535.69 535.91 536.03 536.07 536.07 536.15 536.33 —— ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1994 TO SEPTEMBER 1995 DAILY OBSERVATION AT 24:00 VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JXJL AUG SEP 1 536.55 544.94 548.07 548.21 547.02 550.91 551.22 548.97 551.58 550.39 548.13 550.94 2 536.65 545.41 548.10 548.21 546.91 551.17 551.12 548.85 551.56 550.30 548.08 550.85 3 536.75 545.77 548.13 548.22 546.93 551.37 550.98 548.75 551.59 550.18 547.99 550.80 4 536.78 545.96 548.17 548.23 546.90 551.57 550.87 548.72 551.66 550.04 547.88 550.71 5 536.81 546.07 548.16 548.24 546.93 551.70 550.73 549.07 551.88 549.92 547.79 550.67 6 536.84 546.19 548.16 548.23 546.94 551.79 550.61 549.27 552.02 549.82 547.68 551.09 7 536.91 546.31 548.16 548.22 546.98 551.86 550.51 549.50 552.07 549.74 547.58 551.77 8 538.34 546.37 548.16 548.23 547.01 551.91 550.38 550.11 552.05 549.63 547.48 552.03 9 538.77 546.57 548.15 548.23 547.08 551.96 550.26 550.37 552.00 549.49 547.36 552.11 10 538.98 546.73 548.12 548.23 547.12 552.15 550.14 550.47 552.09 549.37 547.27 552.15 11 539.12 546.84 548.11 548.26 547.11 552.38 550.13 550.47 552.09 549.22 547.17 552.56 12 539.23 546.90 548.13 548.24 547.12 552.48 550.08 550.39 552.00 549.10 547.03 552.77 13 539.26 546.98 548.12 548.19 547.14 552.55 549.96 550.31 551.93 549.02 546.88 552.84 14 539.35 547.10 548.10 548.11 547.15 552.59 549.85 550.22 551.82 548.91 546.79 552.85 15 539.39 547.16 548.11 548.12 547.18 552.65 549.73 550.50 551.77 549.04 546.69 553.04 16 539.42 547.23 548.10 548.09 547.21 552.69 549.66 550.59 551.70 549.13 547.13 556.26 17 539.62 547.32 548.10 548.07 547.22 552.64 550.34 550.54 551.62 549.04 547.18 557.41 18 539.90 547.40 548.08 548.01 547.23 552.60 550.41 550.48 551.54 548.94 548.17 557.94 19 540.06 547.45 548.07 547.96 547.23 552.51 550.34 550.42 551.40 548.83 549.84 558.63 20 540.15 547.55 548.06 547.89 547.25 552.47 550.23 550.45 551.31 548.67 550.36 559.01 21 540.56 547.59 548.07 547.82 547.57 552.41 550.14 550.41 551.21 548.55 550.58 559.27 22 541.23 547.65 548.07 547.76 547.65 552.33 550.02 550.33 551.12 548.46 550.66 559.49 23 541.90 547.70 548.11 547.67 548.05 552.30 549.91 550.22 551.02 548.35 550.70 559.90 24 542.98 547.71 548.15 547.62 548.17 552.14 549.78 550.15 550.89 548.25 550.70 560.14 25 543.96 547.81 548.16 547.55 548.61 552.05 549.68 550.27 550.78 548.10 550.66 560.30 26 544.25 547.90 548.17 547.49 550.01 551.91 549.58 550.36 550.67 547.99 550.57 560.40 27 544.45 547.98 548.19 547.43 550.38 551.80 549.45 550.92 550.74 547.87 550.51 560.53 28 544.59 548.02 548.23 547.35 550.66 551.69 549.34 551.31 550.68 547.87 550.87 560.66 29 544.69 548.03 548.22 547.28 —— 551.57 549.22 551.33 550.63 547.83 551.01 560.75 30 544.74 548.07 548.21 547.19 —— 551.47 549.09 551.47 550.52 548.15 551.02 560.78 31 544.82 —— 548.21 547.12 —— 551.35 —— 551.55 —— 548.22 551.00 —— MAX 544.82 548.07 548.23 548.26 550.66 552.69 551.22 551.55 552.09 550.39 551.02 560.78 MIN 536.55 544.94 548.06 547.12 546.90 550.91 549.09 548.72 550.52 547.83 546.69 550.67 A No gage-height record 376 RIO BUCANA BASIN 50113950 LAGO CERRILLOS AT DAMSITE NEAR PONCE, PR—Continued ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES NOV DEC MAY JUL 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 560.81 560.81 560.88 560.92 560.92 560.92 560.91 560.90 560.88 560.90 561.01 561.09 561.13 561.13 561.09 561.05 561.14 561.26 561.30 561.46 561.52 561.53 561.55 561.55 561.65 561.70 561.73 561.86 561.93 561.93 561.90 561.93 560.81 561.85 561.79 561.75 561.66 561.65 561.63 561.57 561.58 561.57 561.53 561.46 561.36 561.36 561.34 561.30 561.56 561.58 561.53 561.45 561.38 561.30 561.22 561.16 561.10 561.02 560.94 560.83 560.73 560.66 560.56 —— 561.85 560.56 560.46 560.37 560.27 560.15 560.07 559.97 559.85 559.70 559.56 559.43 559.30 559.17 559.00 558.87 558.72 558.58 558.44 558.32 558.17 558.07 557.91 557.74 557.60 557.46 557.30 557.16 557.06 556.93 556.77 556.61 556.44 560.46 556.44 556.29 556.11 555.96 555.80 555.61 555.48 555.31 555.14 555.00 554.93 554.73 554.58 554.50 554.50 554.45 554.29 554.13 554.02 553.88 553.76 553.63 553.48 553.30 553.15 552.99 552.83 552.73 552.58 552.44 552.26 552.11 556.29 552.11 551.96 551.76 551.62 551.46 551.31 551.26 551.12 551.03 551.13 551.22 551.12 551.04 550.91 550.78 550.62 550.46 550.63 550.56 550.46 550.39 550.86 551.19 551.26 551.38 551.37 551.29 551.16 551.07 550.94 —— 551.96 550.39 550.82 550.70 550.56 550.40 550.28 550.14 549.97 549.82 549.73 549.61 549.53 549.45 549.33 549.21 549.10 549.08 548.97 548.84 548.69 548.53 548.37 548.22 548.05 547.90 547.73 547.58 547.40 547.25 547.06 546.96 546.84 550.82 546.84 546.66 546.51 546.68 546.66 546.66 547.06 546.97 546.87 546.72 546.56 546.47 546.40 546.28 546.16 546.06 545.83 545.72 545.58 545.45 545.43 545.34 545.25 545.11 544.96 544.81 544.65 544.47 544.32 544.16 543.98 —— 547.06 543.98 543.83 543.55 543.40 543.27 543.09 542.92 542.75 542.60 542.48 542.28 542.11 541.94 541.99 541.86 541.72 541.88 541.87 541.78 542.14 542.35 542.37 542.25 542.22 542.09 541.93 541.81 541.70 541.58 541.43 541.57 541.57 543.83 541.43 541.49 541.39 541.26 543.55 544.12 544.32 544.35 544.28 544.24 544.19 544.12 544.08 543.98 543.88 544.12 544.11 544.05 543.98 544.93 545.14 545.17 545.16 545.08 545.01 544.93 544.87 544.76 544.61 544.47 544.32 —— 545.17 541.26 544.18 544.09 544.14 544.21 544.25 544.28 544.36 544.97 545.49 545.77 545.92 546.03 546.14 546.61 547.17 547.37 547.48 547.59 547.68 547.79 547.85 547.92 547.99 548.03 548.09 548.12 548.17 548.64 548.80 548.88 549.09 549.09 544.09 550.59 552.05 552.76 553.09 553.30 553.41 553.48 553.59 553.69 554.15 554.53 554.81 555.01 555.36 555.41 555.67 555.91 556.18 556.45 557.15 557.52 557.71 557.89 558.15 558.29 558.41 558.51 558.66 558.72 558.98 559.04 559.04 550.59 559.14 559.19 559.27 559.43 559.53 559.64 559.73 559.78 A 572.60 573.20 572.87 572.94 573.42 573.72 573.41 573.05 572.68 572.56 572.58 572.66 572.73 572.80 572.89 573.11 573.31 573.39 A 573.55 574.57 —— A No gage-height record 377 RIO BUCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR LOCATION.—Lat 18°04'15", long 66°34'51", Hydrologic Unit 21010004, on right bank off Highway 139, 0.8 mi (1.3 km) below Lago Cerrillos Dam, 2.3 mi (3.7 km) upstream from Quebrada Ausubo and 4.6 mi (7.4 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.—17.8 mi 2 (46.1 km2 ), excludes 17.4 mi 2 (45.1 km2 ) upstream from Lago Cerrillos Dam. WATER-DISCHARGE RECORDS PERIOD OF RECORD.—February to April 1964 (monthly measurements only). May 1964 to June 1985, July 1985 to April 1991 (semi-monthly measurements only). Hay 1991 to current year. GAGE.—Water-stage recorder. Datum of gage is 253.10 ft (77.145 m), above mean sea level. March 22, 1977 at site 0.15 mi (0.24 km) upstream and datum 9.90 ft (3.018 m) higher. Prior to REMARKS.—Records poor. Flow regulated by Lago Cerrillos Dam since May 1991. Gage-height and precipitation satellite telemetry at station. Prior to June 1985 some low-flow regulation by construction upstrream. Maximum discharge prior to regulation, 22,400 ftVs (6.34 mVs), Sept. 16, 1975, gage-height, 11.2 ft (3.414 m), site and datum then in use from floodmarks, from rating curve extended above 150 ftVs (4.25 mVs), on basis of slope-area measurements of peak flow; minimum discharge prior to regulation, 2.2 ftVs ( 0.062 mVs), May 28, 1967. OCT DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 .4 e6.2 2 .2 5.8 3 .0 5.5 4 .0 6.1 5 .1 6.1 6 3.8 5.2 7 3.8 5.1 8 3.7 5.0 9 3.7 5.9 10 3.9 5.5 11 3.9 5.3 12 4.1 4.7 13 4.2 4.6 14 4.2 4.8 15 4.1 4.5 16 4.1 5.1 17 5.1 e5.6 18 4.5 e5.4 19 4.9 e5.4 20 4.9 e5.2 21 5.1 eS.O 22 5.5 e4.9 23 5.6 e4.8 24 5.6 e5.2 25 5.6 e5.2 26 5.4 e5.2 27 e5.3 e4.9 28 e9.6 e5.2 29 eS.O e4.4 30 e7.0 e4.4 31 e6.4 TOTAL 152.7 156.2 MEAN 4.93 5.21 MAX 9.6 6.2 MIN 3.7 4.4 AC-FT 303 310 CFSM .28 .29 IN. .32 .33 STATISTICS OF MONTHLY MEAN MEAN 71.0 54.5 MAX 202 124 (WY) 1971 1978 MIN 4.93 5.21 (WY) 1996 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 e4.0 e3.7 e3.6 e3.6 e3.6 e3.8 e4.5 e4.4 e4.2 e6.0 e7.6 e6.5 e6.3 e5.8 e5.3 eS.O e4.7 e4.6 e4.9 e8.4 e5.8 e5.5 e5.2 e4.7 e4.3 e4.4 e4.3 e4.3 e4.4 e3.9 e4.0 151.3 4.88 8.4 3.6 300 .27 .32 DATA 21.9 49.1 1966 4.81 1995 FOR e4.1 e4.3 e4.5 e4.6 e4.5 e4.7 e4.9 e5.3 e4.9 e4.7 e4.3 e4.8 e4.7 e4.7 e4.6 5.3 5.4 5.4 5.8 6.4 6.2 6.3 6.5 6.1 6.3 5.8 5.7 5.6 5.6 5.6 5.9 163.5 5.27 6.5 4.1 324 .30 .34 6.4 6.1 6.3 6.3 6.4 6.5 17 6.2 7.2 9.5 6.5 6.0 6.3 6.2 6.2 5.1 7.7 5.4 5.0 4.8 5.2 8.1 5.0 5.1 5.0 4.8 4.7 4.7 4.8 —— 184.5 6.36 17 4.7 366 .36 .39 FOR WATER YEARS 1964 14.7 74.2 1992 4.52 1993 9.79 20.0 1969 4.37 1993 4.9 5.0 4.9 4.9 5.1 5.4 e4.7 elO e7.4 e6.3 e6.0 e6.3 e6.1 e6.3 e5.3 e8.2 e5.6 e6.4 e7.4 e6.7 e6.6 e5.4 e5.2 eS.O e4.6 e5.8 eS.l eS.l e4.8 e5.2 e5.4 181.1 5.84 10 4.6 359 .33 .38 - 1996 9.75 20.3 1969 5.07 1995 1995 CALENDAR YEAR 1910.7 5.23 40 3.1 3.1 3790 .29 3.99 6.2 5.1 3.9 Sep 16 Jun 17 Jun 16 e5.8 e6.1 e7.1 e8.2 e6.1 e7.4 e6.0 e6.3 e6.5 e6.1 e5.8 eS.l eS.l e6.0 e6.3 e6.2 e5.6 e5.9 eS.l e5.6 e3.9 e4.3 e4.6 e4.8 e5.4 e5.3 e4.7 eS.l e5.7 e5.4 —— 171.5 5.72 8.2 3.9 340 .32 .36 e5.5 e5.4 e5.8 e6.1 eS.O e4.9 eS.l e4.7 4.9 5.8 e6.6 e6.6 e5.9 e5.7 e5.5 e5.4 e5.2 eS.l e4.9 e4.8 e4.6 e4.5 e4.4 e4.2 e4.5 e4.4 e4.5 e4.6 e4.8 e4.5 e6.6 160.5 5.18 6.6 4.2 318 .29 .34 e6.6 e6.2 e5.4 e5.8 e6.2 e5.6 e5.4 e5.6 e6.8 e7.2 e6.4 e6.8 e6.4 e6.2 elO eS.O e6.8 e7.2 e6.6 eS.O e7.7 e7.0 e6.5 e6.3 e6.2 e6.4 e6.5 e6.3 e6.0 e6.4 —— 198.5 6.62 10 5.4 394 .37 .41 e6.1 e6.0 e6.0 e5.4 e4.9 eS.O e4.6 e4.5 e4.6 e4.2 e4.1 e4.1 e3.9 e4.4 e4.6 e3.7 e4.1 e4.2 e4.1 e4.0 e3.9 e4.0 e3.9 e4.0 e3.8 e3.7 e3.5 e!2 e9.0 e5.4 eS.O 150.7 4.86 12 3.5 299 .27 .31 elO ell e8.6 e5.2 e5.7 e!6 e5.9 e5.5 e4.4 e4.6 eS.l e4.3 e5.2 e4.6 e4.8 e6.4 e5.7 e4.7 e4.4 e4.6 e5.2 e5.2 eS.O e6.3 e6.6 eS.l eS.l e4.8 e4.8 e4.8 e8.6 188.2 6.07 16 4.3 373 .34 .39 e5.9 e5.5 e5.3 e6.0 e5.7 e5.4 e5.6 9.4 12 450 536 368 154 67 64 175 235 239 144 90 94 98 41 5.6 6.1 7.1 28 53 56 56 3027.6 101 536 5.3 6010 5.67 6.33 , BY WATER YEAR (WY) 15.7 106 1985 4.93 1979 FOR 1996 4886 13 536 3 3 1320 7 9690 10 8 5 4 38.4 221 1985 4.14 1967 WATER YEAR .3 .4 Sep 11 .5 Jul 27 .8 Nov 30 Sep 10 .74 Sep 10 .75 .21 .0 .4 .2 27.1 88.9 1969 3.69 1995 24.2 71.1 1968 4.75 1995 WATER 31 53 5 11500 1 1320 7 22650 1 23 74 14 5 32.5 82.4 1968 5.26 1995 YEARS 1964 .3 .9 .35 Oct .64 Aug .7 Aug Sep .74 Sep .76 .86 .1 61.8 256 1975 6.65 1995 - 1996 1969 1995 7 1985 19 1992 24 1992 10 1996 10 1996 378 RIO BUCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR--Continued Location.--Lat 18°04'15", long 66°34'51", Hydrologic unit 21010004, on right bank off Highway 139, (3.7 km) upstream from Quebrada Ausubo and 4.6 mi (7.4 km) northeast of Plaza Degetau in Ponce. DRAINAGE AREA.--17.8 mi 2 (46.1 km2 ) WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1964 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 2.3 mi NOV 02 JAN 16 FEB 16 APR 17 JUN 25 AUG 08 DATE 1995 1996 . . . DATE NOV 1995 02... JAN 1996 16... FEB 16... APR 17... JUN 25... AUG 08... 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) 0950 5.6 376 1010 5.1 352 0925 5.1 345 1010 5.2 355 1130 6.0 349 1045 5.0 376 HARD- MAGNE- NESS CALCIUM SIUM, TOTAL DIS- DIS- (MG/L SOLVED SOLVED AS (MG/L (MG/L CACO3) AS CA) AS MG) (00900) (00915) (00925) 150 52 6.0 __ -- 160 54 5.6 -- 150 51 5.7 6.4 26.0 1.5 7.2 24.5 0.50 7.2 24.5 0.50 7.3 25.0 0.30 7.5 26.5 0.30 7.1 25.5 0.30 SODIUM POTAS- SODIUM, AD- SIUM, DIS- SORP- DIS- SOLVED TION SOLVED (MG/L RATIO (MG/L AS HA) AS K) (00930) (00931) (00935) 16 0.6 0.90 __ __ 16 0.6 1.9 __ 14 0.5 0.90 6.6 8.0 7.5 7.9 6.2 6.1 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 150 140 150 160 140 150 81 95 88 96 77 74 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- <10 K170 11 220 <10 K170 11 64 14 200 <10 K120 CHLO- SULFATE RIDE, DIS- DIS- 300 K190 K130 200 220 270 SOLVED SOLVED (MG/L (MG/L AS S04) AS CL) (00945) (00940) 34 7.2 __ __ 29 7.1 __ 32 8.2 K - non-ideal count 379 DATE MOV 1995 02... JAN 1996 16... FEB 16... APR 17... JUN 25... AUG 08... MOV 1995 02... JAN 1996 16... FEB 16... APR 17... DATE NOV 1995 02... JAN 1996 16... FEB 16... APR 17... JUN 25... AUG 08.. . RIO BUCANA BASIN 50114000 RIO CERRILLOS NEAR PONCE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) 0.30 -- — 0.30 — 0.20 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) <0.20 <0.20 <0.20 0.25 <0.20 1.1 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 24 -- — 23 -- 23 NITRO- GEN, TOTAL (MG/L AS N) (00600) 0.36 0.25 <0.20 0.35 <0.20 1.2 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 230 -- -- 233 -- 225 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 1.6 1.1 0.62 1.5 0.71 5.4 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 3.50 -- — 3.28 — 3.03 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.020 <0.020 0.050 0.020 0.040 <0.020 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 1 8 6 1 3 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.200 0.130 0.120 0.090 0.070 0.130 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- — <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 <0.010 <0.010 0.010 <0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 — — 40 — -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.200 0.130 0.120 0.100 0.070 0.130 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.010 0.020 0.050 <0.010 0.010 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 " — <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 <0.20 <0.20 0.20 <0.20 1.1 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 -- — <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 160 40 <1 <1 30 20 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.02 0.03 380 RIO BUCANA BASIN 50114390 RIO BUCANA AT HWY 14 BRIDGE NEAR PONCE, PR LOCATION.—Lat 18°02'29", long 66°34'58", Hydrologic Unit 21010004, on left bank, 200 ft (61 m) upstream from bridge on Highway 14 and 4.0 mi (6.4 km) downstream from Lago Cerrillos Dam, 2.8 mi (4.5 km) northeast of Degetau Plaza in Ponce. DRAINAGE AREA.--24.9 mi 2 (64.5 km 2 ). PERIOD OF RECORD.—October 1985 to September 1986 (maximum only), published as "Rio Bucana Floodway Channel at Highway 14 bridge", October 1986 to July 1987 (maximum only), August 1987 to current year. GAGE.—Water-stage recorder and crest-stage gage. Datum of gage is 116.40 ft (35.500 m) above mean sea level. Prior to Oct. 1, 1986, crest-stage gage located at Highway 14 bridge, at elevation of mean sea level. REMARKS.--Records poor. Flow regulated by Lago Cerrillos Dam 0.4 mi upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN MAR APR MAY AUG SEP 1 7.5 7.7 2 6.2 6.5 3 5.3 5.7 4 5.0 5.7 5 4.8 6.0 6 4.9 5.9 7 5.1 5.6 8 5.3 5.0 9 5.1 5.5 10 5.6 6.6 11 5.8 5.9 12 e5.7 5.7 13 e6.3 6.1 14 e5.7 5.8 15 e5.3 5.6 16 e5.5 5.7 17 e6.3 5.7 18 e6.3 5.8 19 elO 5.7 20 e7.4 5.5 21 e6.8 5.2 22 6.6 5.1 23 7.3 5.0 24 e6.3 5.3 25 e6.6 5.4 26 e5.9 e5.4 27 e6.3 eS.l 28 e7.7 e5.3 29 e8.7 e4.6 30 8.1 e4.6 31 7.1 —— TOTAL 196.5 168.7 MEAN 6.34 5.62 MAX 10 7.7 MIN 4.8 4.6 AC-FT 390 335 CFSM .25 .23 IN. .29 .25 STATISTICS OF MONTHLY MEAN MEAN 127 58.8 MAX 527 222 (WY) 1991 1988 MIN 6.34 5.09 (WY) 1996 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 e4.1 e3.9 e3.6 e3.6 e3.6 e3.9 e4.6 4.6 4.4 6.1 8.0 6.8 6.5 6.1 e5.5 e5.3 4.9 e4.7 eS.O e8.7 e6.1 e5.7 e5.4 4.9 4.4 e4.5 4.3 e4.3 e4.4 4.0 4.0 155.9 5.03 8.7 3.6 309 .20 .23 DATA 16.2 49.1 1988 5.03 1996 FOR 4.2 4.4 4.6 e4.7 4.6 4.8 4.9 5.4 5.1 4.9 4.4 4.9 4.8 4.8 4.7 eS.l e5.9 e5.7 6.0 13 6.9 5.0 4.6 4.9 eS.O e5.5 e5.8 e6.3 e6.4 e6.5 e5.9 169.7 5.47 13 4.2 337 .22 .25 e7.4 e6.2 e5.8 e7.2 5.2 5.1 7.8 5.7 4.9 6.5 7.8 5.4 5.5 5.9 6.0 5.9 16 8.3 7.9 7.5 6.9 31 28 8.6 10 9.6 9.0 8.6 7.9 —— —— 257.6 8.88 31 4.9 511 .36 .38 FOR WATER YEARS 1987 46.6 337 1992 4.51 1994 10.5 19.3 1995 4.10 1994 1995 CALENDAR YEAR 3346.8 9.17 238 3.2 3.8 6640 .37 5.00 11 6.0 4.6 Feb 26 Aug 15 Aug 9 7.6 7.2 7.0 7.3 7.4 7.1 7.1 7.1 7.1 6.6 6.9 6.7 6.5 6.3 6.8 26 14 8.7 8.3 8.6 9.0 8.5 8.5 8.3 8.1 8.1 7.8 7.7 7.8 8.1 8.8 261.0 8.42 26 6.3 518 .34 .39 - 1996, 12.7 48.0 1989 4.49 1994 9.4 7.8 7.8 8.2 8.5 7.8 8.5 7.3 6.8 6.8 7.0 7.1 7.0 6.8 7.0 6.7 6.6 6.5 7.8 7.9 8.3 7.5 7.6 7.5 7.8 7.6 6.8 6.8 7.1 6.9 —— 223.2 7.44 9.4 6.5 443 .30 .33 BY WATER 14.8 42.5 1992 4.74 1994 7.0 6.8 6.6 6.8 6.6 7.1 6.7 6.9 7.3 7.5 6.8 6.5 6.8 7.2 6.7 e6.5 5.9 5.8 7.7 8.3 7.3 6.9 e9.7 8.0 7.6 7.0 7.2 7.6 7.3 6.6 6.6 219.3 7.07 9.7 5.8 435 .28 .33 YEAR (WY) 26.3 94.9 1992 4.29 1994 6.6 6.1 5.3 5.7 6.2 5.4 5.4 5.5 6.7 7.0 6.1 6.6 6.2 6.0 10 7.8 6.5 7.0 6.4 8.0 7.4 6.7 6.1 6.0 6.1 6.3 6.3 6.1 5.9 6.2 —— 193.6 6.45 10 5.3 384 .26 .29 25.9 80.5 1989 4.90 1994 FOR 1996 WATER YEAR 7747.4 21.2 1430 2.8 3.4 4130 13.47 15370 .85 11.57 8.7 6.2 4.3 Sep 11 Jul 27 Jul 21 Sep 10 Sep 10 5.9 5.9 5.8 5.1 4.6 3.9 4.5 5.0 5.0 4.5 4.3 4.1 3.7 6.3 7.7 5.4 5.4 5.1 4.4 4.2 4.0 3.7 3.4 3.2 3.2 3.2 2.8 10 7.6 4.3 4.1 150.3 4.85 10 2.8 298 .19 .22 18.7 51.4 1991 4.37 1994 8.3 9.2 6.7 4.3 4.1 4.1 5.7 4.3 4.2 3.9 4.3 4.5 4.1 4.1 4.5 5.5 5.0 4.0 3.8 4.0 4.5 4.5 4.3 5.5 5.7 4.4 4.4 4.2 4.2 4.2 7.6 152.1 4.91 9.2 3.8 302 .20 .23 44.0 169 1988 4.06 1994 WATER YEARS 1987 41.1 78.0 7.43 4340 2.5 2.8 17400 13.48 29750 1.65 22.41 73 9.6 4.6 Jan Sep Sep Oct oct 5.2 4.8 4.6 5.3 5.0 4.7 4.9 4.9 5.4 1420 1430 819 273 80 52 155 342 351 214 77 72 66 52 9.6 8.3 7.5 9.3 40 43 34—— 5599.5 187 1430 4.6 11110 7.50 8.37 80.5 265 1989 7.12 1993 - 1996 1991 1994 6 1992 28 1992 23 1992 7 1985 7 1985 e Estimated RIO PORTTJGUES BASIN 50115000 RIO PORTTJGUES NEAR PONCE, PR LOCATION.--Lat 18°04'45", long 66°38'01", Hydrologic Unit 21010004, on right bank 30 ft (9 m) upstream from bridge on Highway 504, 0.2 mi (0.3 km) upstream from small unnamed tributary, 4.4 mi (7.1 km) upstream from Rio Chiquito, and 4.7 mi (7.6 km) north of Plaza Degetau in Ponce. DRAINAGE AREA.--8.82 mi 2 (22.84 km2 ). WATER-DISCHARGE RECORDS 381 PERIOD OF RECORD.--February to June 1964 (monthly measurements only), July 1964 to current year. GAGE.--Water-stage recorder. Elevation of gage is 470 ft (143 m), from topographic map. Prior to Dec. 4, 1964, non-recording gage at same site and datum. REMARKS.--Records poor. Some low-flow regulation due to unknown activity upstream. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT DEC JAN AUG SEP 1 10 21 2 10 23 3 50 e!7 4 44 ell 5 22 e!5 6 18 e!8 7 17 e!2 8 16 e9.3 9 16 e!3 10 17 e!9 11 25 e20 12 17 e21 13 16 e42 14 14 e23 15 12 21 16 12 51 17 97 29 18 98 14 19 66 14 20 61 18 21 52 25 22 41 e!7 23 31 elS 24 28 elS 25 24 e!4 26 33 e!3 27 29 e!2 28 38 ell 29 23 ell 30 19 elO 31 21 —— TOTAL 977 554.3 MEAN 31.5 18.5 MAX 98 51 MIN 10 9.3 AC-FT 1940 1100 CFSM 3.57 2.09 IN. 4.12 2.34 elO elO e9.6 e9.2 e!4 ell elO e9.2 e9.4 e9.8 e9.2 e8.6 e8.4 e8.4 eS.O e8.4 e8.4 e8.8 ell e9.4 e7.4 e7.4 e7.4 e7.2 e!6 ell e9.0 e7.4 e7.0 e6.6 e6.4 283.6 9.15 16 6.4 563 1.04 1.20 STATISTICS OF MONTHLY MEAN DATA MEAN 46.0 31.5 MAX 120 80.1 (WY) 1986 1988 MIN 11.9 5.82 (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 12.1 27.3 1988 2.71 1992 e6.2 e6.0 e6.2 e6.0 e6.0 e5.8 e7.0 e8.4 eS.O e7.0 e6.0 ell e29 e27 e!2 elO e7.8 eS.O e8.6 e8.6 e4.8 e4.6 eS.O e5.4 e9.8 e!2 ell e8.9 e7.5 e6.4 e6.0 276.0 8.90 29 4.6 547 1.01 1.16 e5.6 eS.l e4.9 e4.5 e3.9 e21 e9.6 eS.5 e3.9 e51 e!8 e7.6 eS.5 e5.9 e4.4 e4.2 e9.7 e7.2 e4.9 elO c74 62 22 28 17 9.1 e6.7 5.9 5.4 ___ --- 422.5 14.6 74 3.9 838 1.65 1.78 FOR WATER YEARS 1964 8.73 45.5 1992 3.65 1989 6.51 14.6 1996 2.62 1989 4.9 4.5 4.3 4.7 5.3 3.8 3.5 3.4 3.6 7.8 11 8.9 6.5 5.4 5.7 e!3 ell e6.0 eS.O e4.6 e4.4 e4.2 e4.0 e4.0 e3.8 e4.0 e3.6 e3.6 e3.4 e3.7 e4.3 165.9 5.35 13 3.4 329 .61 .70 - 1996 5.72 13.4 1976 2.08 1977 FOR 1995 CALENDAR YEAR 7005.6 19.2 402 2.3 2.4 13900 2.18 29.55 45 8.4 2.7 Sep 16 Feb 3 Feb 13 e4.5 e3.8 e35 e25 e21 22 11 6.9 6.2 5.1 4.7 9.2 6.9 4.8 5.7 4.8 4.8 5.4 4.7 7.4 8.4 5.4 7.1 4.6 4.5 4.2 4.1 3.9 4.2 4.0 --- 249.3 8.31 35 3.8 494 .94 1.05 , BY WATER 7.50 27.1 1983 2.45 1974 4.0 3.8 18 11 4.6 4.2 3.5 3.8 6.1 8.5 4.4 3.9 3.3 3.0 3.0 40 10 5.6 100 40 9.7 6.3 8.4 5.5 4.9 4.9 12 9.6 5.9 5.0 5.8 358.7 11.6 100 3.0 711 1.31 1.51 YEAR (WY) 19.7 72.9 1985 1.65 1973 4.4 4.2 3.7 236 e79 e26 11 7.9 6.8 4.6 4.6 5.7 4.8 4.0 35 23 16 14 244 e40 e30 e23 e!9 e!7 e!4 e!8 19 13 12 11—— 950.7 31.7 244 3.7 1890 3.59 4.01 15.5 48.3 1979 2.33 1974 FOR 1996 WATER YEAR 11484.6 31.4 1470 3.0 3.7 3070 9.90 22780 3.56 48.44 51 10 4.4 Sep 10 May 14 Mar 24 Sep 10 Sep 10 11 10 11 10 11 13 21 elSO e700 e200 e60 20 14 40 88 52 41 23 10 14 18 17 17 20 25 29 30 35 e!7 e!3 309 2029 65.5 700 10 4020 7.42 8.56 15.7 65.5 1996 1.49 1994 WATER 19. 38. 7. 2440 . 1. 21000 20. 13790 2. 29. 40 8. 3. 200 693 130 57 27 18 16 13 9.8 62 33 22 19 50 51 37 22 125 116 63 42 20 21 34 16 12 10 8.8 8.7 16 9.1 1961.4 63.3 693 8.7 3890 7.17 8.27 21.6 87.5 1979 4.20 1972 YEARS 1964 0 0 04 Sep 61 Jul 0 Jul Oct 20 Oct 16 32 1 0 7.5 7.0 11 18 49 106 26 8.3 6.0 1470 728 220 32 49 9.8 5.0 96 112 51 22 15 11 8.6 7.1 25 8.2 5.7 31 7.0 104 --- 3256.2 109 1470 5.0 6460 12.3 13.73 36.8 132 1975 7.22 1991 - 1996 1979 1994 16 1975 29 1994 9 1994 7 1985 7 1985 e Estimated 382 RIO PORTUGUES BASIN 50115000 RIO PORTUGUES HEAR PONCE, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Hater years 1964 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 08. .. JAN 1996 22... FEE 20... APR 19... JUN 25... AUG 08... DATE NOV 1995 08... JAN 1996 22... FEB 20... APR 19... JUN 25... AUG 08... DATE NOV 1995 08... JAN 1996 22... FEB 20... APR 19... JUN 25... AUG 08... 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) 0945 9.8 290 6.8 23.0 7.0 8.5 99 <10 3600 K1800 0930 4.6 314 7.4 20.0 4.9 8.8 96 <10 340 2900 1005 11 308 7.6 21.0 580 8.4 94 32 3800 9400 0945 5.0 321 7.7 21.5 29 8.9 101 11 K1600 3400 0910 14 0900 15 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 140 — -- 150 -- 130 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- — <0.10 -- <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 43 -- — 46 -- 41 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 22 — — 20 -- 20 302 304 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 8.1 — — 8.1 -- 7.3 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 177 — -- 194 — 173 7.7 23 7.7 22 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 10 -- -- 11 -- 8.2 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 4.71 — -- 2.62 -- 6.79 .0 4 .5 7 SODIUM AD- SORP- TION RATIO (00931) 0.4 — -- 0.4 — 0.3 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 8 9 736 48 6 30 .2 .1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 — -- 1.6 — 1.4 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.920 0.070 1.10 1.69 1.20 1.40 8.0 8.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 130 160 130 150 130 130 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 <0.010 0.010 <0.010 <0.010 94 93 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- 0.6 -- -- NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 0.920 0.080 1.10 1.70 1.20 1.40 11 480 690 <10 2100 2400 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 6.4 -- — 8.6 -- 8.9 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.070 0.020 0.050 0.010 0.010 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 7.7 -- — 8.8 -- 8.6 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.22 0.41 1.1 <0.20 <0.20 <0.20 K = non-ideal count RIO PORTUGOES BASIN 50115000 RIO PORTUGUES NEAR PONCE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 383 DATE NOV 1995 08... JAN 1996 22. .. FEE 20... APR 19... JUN 25. . . AUG 08.. . NOV 1995 08 ... JAN 1996 22. .. FEB 20. . . APR 19. .. JUN 25. .. AUG 08. . . NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.23 0.48 1.1 <0.20 <0.20 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 0.56 2.2 1.9 1.3 1.4 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.1 2.5 9.7 8.3 5.9 6.2 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.030 0.040 0.400 0.080 0.040 0.040 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) <1 — — <1 — -- SELE- NIUM, TOTAL (UG/L AS SB) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — -- <100 — -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — — 20 — -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- — <1 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 1200 <1 20 80 <0.10 <0.10 <1 <1 <1 <0.010 <0.010 <0.02 384 RIO PORTUGUES BASIN 50116200 RIO PORTUGUES AT PONCE, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°00'20", long 66°36'28", 1,300 ft (400 m) south of Las Americas Avenue Bridge, 1.2 mi (1.9 km) south of CSC 50115900, 0.8 mi (1.3 km) west of Highways 1 and 2 junction, and 0.7 mi (1.1 km) southeast of Ponce. DRAINAGE AREA.--18.9 mi 2 (49.0 km2 ). PERIOD OF RECORD.--Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 1995 17... 0950 9.5 382 6.9 26.0 2.3 7.6 93 <10 45000 2900 DEC 14... 0750 5.5 412 6.6 23.0 1.0 3.9 45 <10 6000 2200 FEB 1996 12... 1020 11 359 7.4 23.0 24 7.8 89 24 3500 5100 APR 12... 0905 9.3 500 7.1 25.0 5.0 6.4 77 110 43000 K17000 JUN 06... 1045 50 245 7.0 25.0 210 7.5 89 <10 28000 26000 AUG 23... 0900 19 374 7.2 24.5 6.7 7.9 94 <10 34000 42000 ALKA- DATE OCT 1995 17. .. DEC 14. .. FEB 1996 12... APR 12. .. JUN 06. .. AUG 23. .. DATE OCT 1995 17... DEC 14... FEB 1996 12... APR 12... JDN 06... AUG 23... HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 160 -- __ 180 -- 150 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- — 0.10 __ 0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 42 -- -- 52 -- 45 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 16 -- -- 15 -- 20 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 12 __ -- 11 -- 8.3 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 239 -- — 301 -- 207 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 36 __ -- 35 -- 16 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 6.24 _- -- 7.56 -- 10.7 SODIUM AD- SORP- TION RATIO (00931) 2 __ -- 1 -- 0.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 38 10 26 21 302 31 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.4 -_ -- 2.7 -- 1.7 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.24 0.170 1.23 0.060 1.49 1.44 LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 140 180 150 160 92 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.060 0.060 0.070 0.020 0.010 0.060 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 0.230 1.30 0.080 1.50 1.50 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 52 __ -- 57 -- 18 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.090 0.480 0.110 0.370 0.020 0.100 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 34 -- -- 32 -- 14 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.77 0.22 0.99 0.43 <0.18 0.29 K - non-ideal count 385 DATE OCT 1995 17... DEC 14... FEB 1996 12.. . APR 12.. . JUN 06... AUG 23... DATE OCT 1995 17. .. DEC 14. .. FEB 1996 12. .. APR 12. .. JUN 06. . . AUG 23. .. RIO PORTUGUES BASIN 50116200 RIO PORTUGUES AT PONCE, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.86 0.70 1.1 0.80 0.20 0.39 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.2 0.93 2.4 0.88 1.7 1.9 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS N03) (71887) 9.6 4.1 11 3.9 7.5 8.4 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.310 0.090 0.310 0.080 0.130 0.170 MERCURY TOTAL RECOV- ERABLE (UG/L AS EG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- — <1 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 200 — -- 100 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 — -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 20 -- -- <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 400 <1 30 50 <0.10 <0.010 <0.010 0.06 PESTICIDE ANALYSES DATE JUN 1996 06... 1045 PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) DANE, TECH- NICAL TOTAL (UG/L) (39350) P,P' - ODD UNFILT RECOVER (UG/L) (39360) DDE, TOTAL (UG/L) (39365) P,P'- DDT UNFILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- 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 JUN 1996 06... ENDRIN WATER UNPLTRD REC (UG/L) (39390) ETHION, TOTAL (UG/L) (39398) 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 1996 06... PARA- PCNS THION, UNFILT TOTAL (UG/L) (39540) RECOVER (UG/L) (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, 2,4,5-T 2, 4-DP SILVEX, TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (39730) (39740) (82183) (39760) 0.040 <0.010 <0.010 <0.010 386 RIO GUAYANILLA BASIN 50124200 RIO GUAYANILLA NEAR GUAYANILLA, PR LOCATION.—Lat 18°02'40", long 66°47'53", Hydrologic Unit 21010004, on left bank, 0.7 ml (1.1 km) north of junction of Highways 2 and 132, 0.6 mi (1.0 km) downstream from Quebrada Consejo, 1.8 mi (2.9 km) north-northwest from Plaza de Guayanilla. DRAINAGE AREA.--18.9 mi 2 (49.0 km2 ). PERIOD OF RECORD.—March 1981 to current year. GAGE.—Hater-stage recorder. Elevation of gage is 80 ft (24 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 1995 TO SEPTEMBER 1996 DAY OCT NOV 1 e23 el? 2 e26 e!8 3 e30 e21 4 e26 e24 5 el? e24 6 el2 e24 7 e!2 e25 8 e28 e30 9 e60 e80 10 e50 e30 11 e23 e29 12 el? e31 13 e!4 e20 14 e!2 e!8 15 e!2 e23 16 e54 e31 17 e72 e31 18 e96 e28 19 ellO e31 20 e64 e22 21 e62 e!9 22 e48 el? 23 e40 el6 24 e32 e!5 25 e30 el4 26 e26 e37 27 e26 e48 28 e25 e24 29 e38 e24 30 e22 e22 31 e!9 —— TOTAL 1126 793 MEAN 36.3 26.4 MAX 110 80 MIN 12 14 AC-FT 2230 1570 CFSM 1.92 1.40 IN. 2.22 1.56 DEC e!8 el6 e!5 e!4 e!3 e!6 e20 e!3 e!2 e20 e40 e45 e21 e!8 e!6 e!4 e!3 e!2 ell elO elO e9.6 e9.2 e9.0 e8.6 e8.4 e8.6 e8.6 e7.9 e7.6 e7.2 451.7 14.6 45 7.2 896 .77 .89 JAN e7.0 e6.6 e6.4 e6.2 e7.0 e7.4 e7.0 e6.6 e6.6 e6.4 5.6 5.7 8.0 8.8 7.5 6.2 5.9 5.8 5.9 6.5 7.6 5.7 5.8 5.7 6.7 7.7 7.3 6.6 6.3 5.5 5.0 203.0 6.55 8.8 5.0 403 .35 .40 DAILY FEB 5.0 4.9 4.9 4.9 5.8 12 5.7 5.3 5.5 32 23 7.6 e6.2 e5.8 e5.8 e5.0 e4.8 e4.6 e5.0 6.8 57 35 15 19 15 12 8.8 7.6 7.3 —— 337.3 11.6 57 4.6 669 .62 .66 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1981 MEAN 60.2 47.9 MAX 167 110 (WY) 1986 1988 MIN 16.0 17.0 (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 18.4 41.9 1988 6.72 1994 FOR 10.1 27.5 1992 4.21 1994 7.46 11.6 1996 3.10 1990 MEAN VALUES MAR 7.0 6.6 6.2 6.0 6.6 6.1 5.4 5.3 6.3 10 9.9 14 12 8.6 8.2 29 22 11 9.2 8.4 7.9 7.7 7.9 7.7 7.3 7.2 7.6 6.7 6.6 7.2 8.0 279.6 9.02 29 5.3 555 .48 .55 - 1996 6.25 13.2 1989 2.85 1981 1995 CALENDAR YEAR 5513. 15. 170 1. 1. 10940 . 10. 32 8. 2. 5 1 Sep 16 4 May 3 7 Apr 28 80 85 4 3 APR 7.8 6.1 10 24 21 17 11 7.9 e9.0 e7.1 e7.0 ell elO e7.5 e7.0 e5.0 5.5 6.6 5.9 9.8 7.0 e4.0 e3.5 e4.2 e5.0 e4.1 e4.7 e5.4 e6.0 e6.4 —— 246.5 8.22 24 3.5 489 .43 .49 MAY e5.8 e5.8 e5.0 e4.5 e3.8 3.0 2.8 2.8 4.7 6.2 4.1 3.2 3.1 3.2 2.9 3.6 4.6 3.9 28 43 ell e9.8 e9.6 e9.4 e9.2 ell ell e8.8 e7.2 e6.4 e6.4 243.8 7.86 43 2.8 484 .42 .48 JUN e6.8 e5.8 e5.4 e5.0 e5.2 e5.0 e4.6 e4.4 e5.2 e9.8 e7.8 e5.8 e5.0 e6.4 e7.6 e8.8 e9.8 e7.2 66 93 29 20 15 13 11 54 49 23 18 15 --- 521.6 17.4 93 4.4 1030 .92 1.03 JUL 13 12 11 9.6 9.8 9.5 35 12 48 33 18 13 11 18 24 15 57 53 27 22 18 16 14 13 12 12 12 12 15 15 21 610.9 19.7 57 9.5 1210 1.04 1.20 AUG 23 20 31 29 16 13 20 26 13 12 13 37 26 28 24 22 15 31 46 63 44 28 23 21 16 14 12 11 11 e56 24 768 24.8 63 11 1520 1.31 1.51 SEP 20 15 11 11 24 18 14 11 9.6 922 244 172 89 96 83 73 67 65 58 49 58 44 39 36 45 40 33 40 43 53 ___ 2482.6 82.8 922 9.6 4920 4.38 4.89 , BY WATER YEAR (WY) 10.2 26.6 1983 2.76 1995 FOR 1996 8064 22 922 2 3 4260 14 2 15990 1 15 45 12 5 27.0 80.4 1985 2.33 1994 WATER YEAR .0 .0 Sep 10 .8 May 7 .5 May 12 Sep 10 .08 Sep 10 .1 May 7 .17 .87 .1 14.8 41.0 1987 3.28 1991 12.3 25.9 1986 2.45 1994 WATER 22. 33. 8. 1500 . 1. 14700 20. . 16290 1. 16. 49 9. 3. 17.8 48.5 1988 6.24 1994 YEARS 1981 5 1 94 Oct 77 Jul 1 Sep Sep 40 Sep 70 Apr 19 17 8 4 41.6 102 1981 7.46 1983 - 1996 1986 1994 7 1985 30 1994 4 1994 12 1982 12 1982 19 1995 e Estimated 387 RIO GUAYANILLA BASIN 50124700 RIO GUAYANILLA AT CENTRAL RUFINA, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°00'40", long 66°46'49", at dirt road bridge, 0.7 mi (1.1 tan) from mouth, 0.9 mi (1.4 km) east of Central Rufina and 0.9 mi (1.4 tan) southeast of Guayanilla. DRAINAGE AREA.--22.8 mi 1 (59.1 tan 1 ). PERIOD OF RECORD.—Water years 1960-65, 1974 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 07... JAN 19 FEB 28 APR 30 JUN 20 AUG 16 1996 ... DATE NOV 1995 07. .. JAN 1996 19. .. FEB 28. .. APR 30. .. JUN 20. . . AUG 16. . . DATE NOV 1995 07... JAN 1996 19... FEB 28... APR 30... JUN 20... AUG 16... 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) 0910 19 400 6.6 25.0 47 7.1 84 15 21000 43000 0935 4 1000 5 1130 3 1100 77 1100 21 HARD- NESS TOTAL (MG/L AS CACO3) (00900) 180 -- -- 190 -- 160 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 — -- <0.10 — <0.10 .7 .5 .2 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 42 -- -_ 48 -- 46 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 18 -- -- 19 -- 18 550 462 490 316 369 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 18 -- -- fl6 -- 12 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 230 -- — 283 -- 222 7.7 23 7.3 22 7.7 25 7.3 24 7.2 26 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 15 -- -_ 26 -- 13 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 11.7 -- — 2.45 -- 12.5 .5 3. .0 2. .5 1. .0 25 .5 7. SODIUM AD- SORP- TION RATIO (00931) 0.5 -- -- 0.8 -- 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 64 4 7 2 31 15 5 5 2 0 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.2 -- -- 2.3 -- 1.9 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.36 4.49 2.47 2.49 3.48 1.38 6.8 4.6 3.2 7.1 8.0 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 140 180 160 160 87 140 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.040 0.110 0.030 0.010 0.020 0.020 79 52 39 84 99 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.40 4.60 2.50 2.50 3.50 1.40 <10 370 <10 2900 25 K730 960 510 2400 17 47000 58000 <10 4200 CHLO- SULFATE RIDE, DIS- DIS- 620 SOLVED SOLVED (MG/L (MG/L AS SO4) AS CL) (00945) (00940) 34 17 __ __ 50 26 _. 34 13 NITRO- NITRO- GEN, GEN, AMMONIA ORGANIC TOTAL TOTAL (MG/L (MG/L AS N) AS N) (00610) (00605) 0.350 0.51 0.090 0.45 0.070 0.29 0.030 0.24 0.050 0.52 0.050 0.27 K » non-ideal count 388 NOV 1995 07... JAN 1996 19... FEB 28. .. APR 30... JUN 20... AUG 16... NOV 1995 07. .. JAN 1996 19. .. FEB 28. .. APR 30. .. JUN 20. . . AUG 16. . . RIO GUAYANILLA BASIN 50124700 RIO GUAYANILLA AT CENTRAL RUFINA, PR—Continued WATER-QUALITY. DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.86 0.54 0.36 0.27 0.57 0.32 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 2.3 5.1 2.9 2.8 4.1 1.7 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS N03) (71887) 10 23 13 8.3 18 7.6 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.260 0.810 0.290 0.080 0.130 0.170 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) 5 -- — 1 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — -- <100 — — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- — 60 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 5 -- -- <1 -- — PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 — -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 3400 190 <0.10 <0.10 <1 <0.010 <0.010 PESTICIDE ANALYSES CHLOR- DANE, P,P'- P,P'- ENDO- TECH- ODD DOT DI- DI- SULFAN, PCB, ALDRIN, NICAL UNFILT DDE, UNFILT AZINON, ELDRIN I DATE TIME TOTAL TOTAL TOTAL RECOVER TOTAL RECOVER TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (UG/L) (39516) (39330) (39350) (39360) (39365) (39370) (39570) (39380) (39388) JUN 1996 20... 1100 <0 ENDRIN WATER UNFLTRD DATE REC (UG/L) (39390) JUN 1996 20... <0.010 PARA- THION, DATE TOTAL (UG/L) (39540) JUN 1996 20... <0.010 .100 <0 ETHION, TOTAL (UG/L) (39398) <0.010 PCNS UNFILT RECOVER (UG/L) (39250) <0.100 .010 <0 HEPTA- CHLOR, TOTAL (UG/L) (39410) <0.010 PER- THANE TOTAL (UG/L) (39034) <0.100 .100 <0 HEPTA- CHLOR EPOXIDE TOTAL (UG/L) (39420) <0.010 TOX- APHENE, TOTAL (UG/L) (39400) <1.00 .010 <0 LINDANE TOTAL (UG/L) (39340) <0.010 TOTAL TRI- THION (UG/L) (39786) <0.010 .010 <0 MALA- THION, TOTAL (UG/L) (39530) <0.010 2,4-D, TOTAL (UG/L) (39730) 0.140 .010 <0 METH- OXY- CHLOR, TOTAL (UG/L) (39480) <0.010 2,4,5-T TOTAL (UG/L) (39740) <0.010 .010 <0 METHYL PARA- THION, TOTAL (UG/L) (39600) <0.010 2, 4 -DP TOTAL (UG/L) (82183) <0.010 .010 <0.010 MIREX, TOTAL (UG/L) (39755) <0.010 SILVEX, TOTAL (UG/L) (39760) <0.010 389 RIO YAUCO BASIN 50125780 LAGO LUCCHETTI AT DAHSITE NEAR YAUCO, PR LOCATION.—Lat 18°05'37", long 66°51'54, Hydrologic Unit 21010004, at Antonio Lucchetti Dam on Rio Yauco, 3.9 mi (6.3 km) north of Yauco. DRAINAGE AREA.—17.4 mi* (45.1 km2 ). ELEVATION RECORDS PERIOD OF RECORD.—December 1989 to current year. Prior to October 1994, published as Lago Lucchetti at Damsite. GAGE.—Water-stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Lucchetti was completed in 1952. The dam is on Rio Yauco and is a unit of the Southwestern Puerto Rico Project. It provides 16,500 acre-feet (20.3 hm3 ) of usable storage for power generation and irrigation. The dam is a concrete gravity structure with a total length of 591 ft (180 m), a maximum height of 178 ft (54 m), and a maximum width at the base of 150 ft (46 m). An ungated, overflow tupe spillway with a clear length of 171 ft (52 m), and a maximum capacity of 62,800 ftVs (1,778 m'/s) at a design head of 20 ft (6 m). 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, 572.19 ft (174.40 m), May 27, 1993; minimum elevation, 512.09 ft (156.08 m), Sept. 9, 1994. EXTREMES OBSERVED FOR CURRENT YEAR.—Maximum elevation, 571.37 ft (174.15 m), Sept. 11, minimum elevation, 531.79 ft (162.09 m), Oct. 10. Capacity Table (based on data from Puerto Rico Water Resources Authority) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 512 1,505 540 5,165 520 2,385 550 7,020 525 2,965 561 9,600 527 3,255 563 10,125 530 3,695 571 12,125 532 3,975 573 12,645 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 538.22 568.74 562.97 562.61 561.11 566.85 565.02 568.01 570.27 560.64 564.63 562.05 2 538.70 570.08 562.57 562.26 561.06 566.78 565.48 567.67 568.67 560.66 564.45 562.10 3 537.77 569.49 561.97 562.46 560.84 566.73 566.10 567.97 568.67 560.67 563.81 562.16 4 537.57 568.90 561.06 562.43 560.53 566.94 566.42 567.77 569.31 560.67 564.07 562.27 5 536.35 568.70 560.90 562.37 560.48 566.89 566.38 567.66 566.96 559.17 564.11 562.10 6 534.76 568.37 561.52 562.36 560.43 567.78 566.63 567.74 567.53 559.18 564.02 562.23 7 533.83 567.84 561.71 562.23 560.37 568.41 567.07 566.94 562.38 559.37 564.82 561.14 8 533.36 567.45 561.68 562.22 560.34 568.70 567.04 566.40 561.19 558.97 565.04 559.45 9 532.65 566.74 561.68 560.79 560.93 568.81 566.97 566.01 561.23 560.27 563.65 A 10 531.87 565.24 561.68 560.29 561.50 569.12 567.24 566.15 559.84 561.10 562.82 A 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 532.82 534.50 536.03 537.61 538.02 538.84 540.43 542.22 543.63 547.58 549.07 551.10 552.51 554.07 556.05 564.03 563.90 563.30 562.04 560.79 560.72 560.87 560.93 561.27 561.71 561.73 561.74 561.75 561.58 561.86 561.78 561.83 562.08 561.94 562.17 562.45 562.46 563.41 563.40 562.46 563.05 563.62 563.60 563.57 563.49 559.26 558.96 559.67 559.67 560.15 560.49 561.30 562.09 562.50 562.82 563.02 563.19 562.30 562.36 561.63 561.98 562.09 560.57 558.91 559.19 559.12 559.17 559.12 559.06 559.94 560.82 562.36 563.20 563.70 564.18 569.05 568.96 568.90 568.41 567.81 567.63 567.57 567.77 568.25 568.16 568.10 568.04 566.98 566.51 565.76 567.05 566.92 566.89 566.20 566.03 565.96 565.91 565.89 565.46 565.76 565.87 567.03 567.02 567.27 567.85 566.08 566.02 566.36 566.24 566.25 566.32 566.65 566.75 568.70 569.42 569.63 569.71 569.87 570.23 570.09 557.44 559.94 A A A A A A A A A A A 559.45 559.71 561.19 561.25 561.31 561.45 561.55 561.55 562.94 563.10 563.40 563.97 564.05 563.94 563.77 563.62 563.69 562.41 562.21 561.88 560.76 560.15 559.35 558.48 558.66 559.63 561.70 562.07 561.37 560.75 560.78 561.45 570.83 569.86 567.79 A A 564.81 563.69 A 563.97 564.15 564.08 563.25 563.39 563.81 563.66 26 27 28 29 30 31 558.26 559.17 561.25 563.01 564.97 567.01 562.50 562.92 562.92 562.99 562.97 —— 563.30 563.27 563.08 563.06 562.70 562.66 560.24 560.46 560.96 561.05 561.77 561.15 A 565.00 566.04 567.00 ___ —— 565.64 565.57 565.52 564.12 564.67 565.08 567.63 567.82 568.09 568.19 568.00 —— 570.09 570.01 570.05 569.89 570.56 570.34 560.03 560.86 560.80 561.11 561.15 —— 563.57 563.61 563.64 563.59 563.68 563.74 560.78 A A 560.54 A 561.75 563.73 563.77 A 565.95 567.08 —— MAX 567.01 570.08 563.62 563.19 —— 569.12 568.19 570.56 —— 564.05 MIN 531.87 560.72 560.90 558.96 —— 564.12 565.02 566.01 —— 558.97 A No gage-height record. 390 RIO LOCO BASIN 50128900 LAGO LOCO AT DAMSITE NEAR YAUCO, PR LOCATION.--Lat 18°02'41", long 66°53'16", Hydrologic Unit 21010004, at Damsite, 2.60 mi (4.18 km) northwest from Yauco plaza, 0.45 mi (0.72 km) northeast from Escuela Rio Cafias and 0.95 mi (1.53 km) northwest from Escuela Susua Alta. DRAINAGE AREA.—8.40 mi> (21.8 km» ) . ELEVATION RECORDS PERIOD OF RECORD.—Hay 1995 to current year. GAGE.—Water stage recorder. Datum of gage is mean sea level. REMARKS.—Lago Loco was completed in 1951. The dam is a concrete gravity structure with a total lenght of 600 ft (183 m), maximum structural height of 72 ft (21.9 m), the ungated overflow spillway is 150 ft (47.7 m) long with crest at elevation of 230 ft (70.1 m). It has a normal storage capacity of 1,950 acre-feet (2.40 hm3 ) as for Hay 4, 1979. The Loco Dam is owned by the Puerto Rico Electric Power Authority (P.R.E.P.A) and its part of the Southwestern Puerto Rico Project which was developed for electric power generation and irrigation of the lands in the Lajas Valley, some of the Project waters are used for water supply in the Lajas area. The maximum drawdown of the Dam is from 230 ft (70.1 m) to 220 ft (67.1 m) and the Capacity Table provided by P.R.E.P.A includes only that portion of the storage for the dam. Gage-height and precipitation satellite telemetry at station. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum elevation, 231.76 ft (70.6 m), Sept. 14, 1996; minimum elevation, 219.87 ft (67.0 m), Feb. 13, 1996. EXTREMES OBSERVED FOR CURRENT YEAR.--Maximum elevation, 231.76 ft (70.6 m), Sept. 14; minimum elevation, 219.87 ft (67.0 m), Feb. 13. Capacity Table (based on data from Puerto Rico Electric Power Authority) Elevation, in feet Contents, in acre-feet Elevation, in feet Contents, in acre-feet 220 0 230 639 225 299 232 787 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 230.45 226.23 229.84 229.80 228.49 230.06 229.49 228.29 229.07 227.09 226.36 228.81 2 230.46 224.32 230.26 229.99 227.75 230.00 228.01 227.00 229.16 225.50 225.90 228.67 3 230.63 230.21 230.43 229.29 230.21 230.20 228.45 226.59 228.42 223.70 226.45 228.04 4 230.46 230.73 230.21 230.10 230.35 229.92 228.24 226.11 227.33 221.43 225.59 226.78 5 230.47 230.41 230.51 229.66 229.14 229.73 228.00 225.62 226.21 226.93 225.98 226.91 6 230.51 230.25 229.94 229.55 227.48 229.18 229.37 224.12 228.93 226.10 225.66 228.84 7 230.54 230.20 229.61 229.89 225.74 228.71 229.17 225.05 A 227.16 225.91 230.91 8 230.53 230.25 230.09 229.82 224.45 228.46 230.32 225.58 228.93 227.06 225.84 230.37 9 230.46 230.31 230.01 230.14 223.38 230.15 230.41 226.02 228.82 226.71 226.08 A 10 230.28 230.39 230.03 230.19 222.86 230.16 230.00 225.17 228.51 227.26 225.83 230.86 11 229.89 230.42 229.67 230.22 222.29 229.94 229.80 229.32 228.79 227.05 226.04 230.75 12 228.86 230.31 229.19 230.30 220.71 230.15 229.21 229.19 228.69 227.10 225.90 230.98 13 228.27 230.23 230.43 229.97 227.84 229.92 229.37 230.27 228.60 227.27 225.84 230.97 14 227.88 230.21 230.17 229.91 230.16 230.04 230.08 229.28 228.59 226.49 226.82 231.09 15 228.13 230.23 230.00 230.17 229.47 230.38 230.15 226.93 228.59 226.15 226.85 230.99 16 228.79 230.01 230.00 229.35 229.04 230.15 229.09 224.69 228.17 227.34 227.32 230.86 17 227.35 229.78 230.02 228.90 228.61 230.40 227.65 226.20 228.50 226.92 228.46 230.96 18 226.18 229.93 229.72 228.49 228.17 229.77 226.07 226.13 228.36 226.81 228.95 230.94 19 225.31 230.06 229.26 230.14 227.72 229.82 228.49 230.24 228.26 226.59 229.34 230.92 20 224.95 230.21 230.21 230.26 227.07 230.16 228.52 229.71 227.28 226.59 229.77 230.94 21 230.44 230.03 229.64 230.09 226.40 229.85 229.08 229.62 227.93 225.82 230.32 230.94 22 230.17 229.98 229.48 230.03 225.91 230.17 229.66 229.52 227.83 227.02 230.88 230.94 23 229.93 230.02 230.16 230.08 225.61 230.18 229.89 229.56 227.72 226.95 230.48 230.53 24 230.14 230.09 230.12 228.58 225.80 230.42 230.04 229.40 227.81 226.90 230.29 230.91 25 229.34 230.07 230.32 230.12 225.79 230.15 229.93 229.66 228.09 226.24 230.13 230.33 26 27 28 29 30 31 MAX 230.63 230.73 230.51 230.30 230.35 230.60 230.73 230.27 —— 227.34 MIN 224.95 224.32 229.19 227.99 220.71 227.15 226.07 224.12 —— 221.43 A No gage-height record 228.50 230.14 230.06 230.00 229.18 227.80 230.09 230.02 229.79 229.54 229.90 229.75 230.13 229.91 229.65 230.21 229.92 230.21 229.84 229.33 229.41 227.99 229.89 230.27 229.96 229.86 229.77 229.76 228.64 227.15 230.40 230.60 230.55 230.15 230.73 229.88 229.52 229.55 229.30 229.32 229.26 228.63 229.05 229.28 228.24 227.35 228.01 227.90 227.45 226.28 226.78 225.91 226.05 226.32 226.17 230.31 230.12 A 229.37 A 228.89 230.35 230.94 A 230.95 230.39 391 RIO LOCO BASIN 50129700 RIO LOCO AT QUANICA, PR WATER-QUALITY RECORDS LOCATION.—Lat 17°58'33", long 66°54'52", 0.6 mi (1.0 km) northwest of Guanica and 1.2 mi (1.9 km) northeast of Ensenada. DRAINAGE AREA.--Indeterminate. PERIOD OF RECORD.—Hater years 1975 to current year. HATER-QUALITY DATA, HATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 06... JAN 1996 19... FEB 27... APR 25... JUN 20... AUG 16... DATE NOV 1995 06... JAN 1996 19... FEB 27. .. APR 25. . . JUN 20. . . AUG 16. .. DATE NOV 1995 06... JAN 1996 19... FEB 27... APR 25... JUN 20... AUO 16... TIME 0950 0820 0930 1045 1000 0930 HARD- NESS TOTAL (MG/L AS CAC03 ) (00900) 160 -- -- 150 -- 150 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.20 — -- 0.40 -- 0.10 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 460 35000* 44000* 14400* 317 412 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 37 -- -- 120 -- 34 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 21 — — 14 — 25 PH HATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.3 7.0 7.2 7.0 7.3 7.0 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 16 -- -- 290 -- 15 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MQ/L) (70301) 235 -- — 8840 — 251 TEMPER- ATURE WATER (DEG C) (00010) 25.0 26.0 24.0 27.5 25.5 26.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 37 -- -- 2400 -- 28 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MQ/L) (00530) 9 4 18 10 12 18 TUR- BID- ITY (NTU) (00076) 5.3 0.60 7.4 2.0 3.0 2.5 SODIUM AD- SORP- TION RATIO (00931) 1 -- -- 27 -- 1 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.490 0.400 0.140 <0.010 0.450 0.380 OXYGEN, DIS- SOLVED (MG/L) (00300) 3.8 2.8 5.1 1.4 4.6 3.7 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 3.7 -- -- 100 -- 3.3 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 <0.010 0.010 <0.010 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 45 33 60 18 56 45 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 100 190 130 170 120 170 NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.500 0.410 0.150 <0.020 0.460 0.380 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) 14 330 23 340 16 18 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.030 0.070 0.060 0.150 0.050 0.060 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 5300 K110 2300 470 410 53000 SULFATE DIS- SOLVED (MG/L AS S04) (00945) 21 -- -- 710 -- 18 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.53 0.33 0.62 0.53 0.32 0.39 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 2200 44000 24000 620 K1300 580 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 39 -- -- 5100 -- 26 NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.56 0.40 0.68 0.68 0.37 0.45 * - Salin* water wedge effect K • Non-ideal count 392 DATE NOV 1995 06... JAN 1996 19... FEB 27... APR 25. .. JUN 20... AUG 16... RIO LOCO BASIN 50129700 RIO LOCO AT OUANICA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 CHRO- BARIUM, BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 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) TOTAL RECOV- ERABLE (UG/L AS BA) (01007) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) MIDM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CD) (01042) IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) 1.1 0.81 0.83 0.68 0.83 0.83 4.7 3.6 3.7 3.0 3.7 3.7 0.050 0.060 0.270 0.270 0.050 0.100 100 <100 60 1300 <10 10 380 260 DATE NOV 1995 06. .. JAN 1996 19. .. FEB 27.. . APR 25. .. JUN 20. .. AUG 16. . . LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (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) 30 270 <0.10 <0.10 <1 <1 <1 10 <0.010 <0.010 0.02 0.06 JUN 1996 20.. . PCS, TOTAL (UG/L) PESTICIDE ANALYSES 1000 ALDRIN, TOTAL CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (UG/L) P,P'- DDD UNFILT RECOVER (UG/L) DDE, TOTAL P,P'- DDT DI- UNFILT AZINON, RECOVER TOTAL (UG/L) (UG/L) (UG/L) ENDO- DI- SULFAN, ELDRIN I TOTAL TOTAL (UG/L) (UG/L) (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 1996 20... 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 1996 20... PARA- PCNS THION, UNFILT TOTAL RECOVER (UG/L) (39540) (UG/L) (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) 0.060 <0.010 <0.010 <0.010 01 23456 KILOMETERS MILES '**s"r~"""'\ _,—^-~- I "»'o 3rond« d« EXPLANATION A 138° SURFACE-WATER STATION AND NUMBER V 1297 QUALITY-OF-WATER STATION AND NUMBER A 1364 DAILY SEDIMENT STATION AND NUMBER 143 WELL AND WELL NUMBER CARIBBEAN SEA Figure 25.--Rio Guanajibo basin. CO <0 CO 394 RIO GUANAJIBO BASIN 50131990 RIO GUANAJIBO AT HWY 119 AT SAN GERMAN, PR LOCATION. —-Lat 18°05'06", long 67°02'02", Hydrologic Unit 21010003, on left bank, at bridge on Hwy 119, 0.6 mi (1.0 km) southwest of junction of Highways 119 and 2, 0.2 mi (0.3 km) northeast of junction of Highways 119 and 102, 0.7 mi (1.1 km) east from public Plaza of San German. DRAINAGE AREA.—34.6 mi 3 (89.6 km3 ). PERIOD OF RECORD.—April 1991 to current year. GAGE.—Water-stage recorder and crest-stage gage. Elevation of gage is 148 ft (45 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV JAN MAR JUN JUL AUG SEP 1 36 28 2 34 27 3 30 28 4 31 48 5 30 e29 6 27 39 7 26 31 8 25 64 9 39 30 10 39 e23 11 30 103 12 27 29 13 25 23 14 22 e24 15 20 e24 16 23 121 17 119 e49 18 308 36 19 340 24 20 216 22 21 171 18 22 164 e20 23 103 el9 24 60 el9 25 47 19 26 40 27 27 41 29 28 42 17 29 69 14 30 31 18 31 30 —— TOTAL 2245 1002 MEAN 72.4 33.4 MAX 340 121 MIN 20 14 MED 36 27 AC-FT 4450 1990 CFSM 2.09 .97 IN. 2.41 1.08 14 15 15 14 13 el5 22 15 14 13 15 22 16 17 e!5 14 13 13 el3 e!2 e!3 e!2 ell 9.8 9.9 e!2 e!2 9.9 9.6 10 9.8 419.0 13.5 22 9.6 13 831 .39 .45 STATISTICS OF MONTHLY MEAN DATA MEAN 90.3 61.2 MAX 205 123 (WY) 1993 1993 MIN 20.4 15.8 (WY) 1992 1992 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 25.0 52.2 1993 8.21 1992 9.2 e8.4 8.1 8.2 8.8 12 9.2 8.9 e!2 e8.4 e8.9 68.9 e8.0 69.2 e!3 67.3 13 17 8.2 8.3 17 12 9.6 68.6 68.8 69.7 610 612 e8.8 67.7 e6.9 306.1 9.87 17 6.9 8.9 607 .29 .33 65.9 66.1 66.7 66.2 68.5 69.5 e7.3 66.4 11 104 17 7.3 5.9 5.8 5.3 5.1 4.9 10 9.2 5.8 69 28 24 157 53 20 14 13 11 —— 636.9 22.0 157 4.9 9.2 1260 .63 .68 FOR WATER YEARS 1991 20.0 37.3 1992 9.87 1996 19.2 36.5 1995 4.32 1992 9.5 9.0 9.0 7.5 7.4 6.3 6.8 67.6 68.5 65.8 66.5 69.4 elO 65.9 7.8 35 23 7.5 6.5 6.6 6.5 6.4 6.1 6.4 5.5 66.3 66.3 67.3 5.2 6.8 8.4 266.8 8.61 35 5.2 6.8 529 .25 .29 - 1996 11.8 25.8 1995 3.52 1992 FOR 1995 CALENDAR YEAR 16961.0 46.5 913 5.3 5.6 33640 1.34 18.24 101 15 7.2 Sep 16 Apr 26 Apr 26 6.9 6.7 94 130 297 223 64 37 30 28 621 614 12 11 10 10 10 11 12 17 230 167 102 32 23 19 17 15 14 12—— 1675.6 55.9 297 6.7 18 3320 1.61 1.80 10 11 10 12 9.4 8.1 7.7 7.9 8.1 30 19 12 9.1 8.0 7.5 79 44 73 427 320 69 41 34 31 622 622 636 629 626 618 21 1461.8 47.2 427 7.5 21 2900 1.36 1.57 51 25 18 17 16 15 14 14 14 16 14 12 14 13 36 38 22 17 57 103 34 26 21 17 20 329 190 51 35 28 —— 1277 42.6 329 12 20 2530 1.23 1.37 23 21 18 18 16 16 15 17 62 46 27 21 19 21 22 16 32 50 29 22 18 15 14 13 13 12 12 14 15 34 19 690 22.3 62 12 18 1370 .64 .74 111 82 61 33" 26 22 374 171 39 30 72 94 130 55 41 35 28 31 34 26 25 24 638 179 82 43 37 34 32 644 623 2056 66.3 374 22 38 4080 1.92 2.21 e!9 619 e!8 619 621 e23 24 21 20 659 487 211 91 302 227 86 58 89 63 46 40 35 32 30 29 30 44 70 150 165 --- 3128 104 659 18 42 6200 3.01 3.36 , BY WATER YEAR (WY) 24.3 55.9 1996 8.63 1995 FOR 1996 15164 41 659 4 6 2460 10 30080 1 16 92 19 7 45.4 72.0 1995 5.11 1994 WATER YEAR .2 .4 Sep 10 .9 Feb 17 .2 Mar 23 Sep 10 .09 Sep 10 .20 .30 .5 20.9 46.3 1993 3.91 1994 19.7 37.6 1995 6.68 1994 WATER 38 58 16 913 1 1 6610 13 28070 1 15 87 15 5 43.2 109 1995 17.2 1994 YEARS 1991 - .7 .6 .6 Sep 16 .5 May 9 .8 May 6 Jan 6 .23 Jan 6 .12 .21 .0 62.4 119 1995 12.9 1991 1996 1995 1994 1995 1992 1992 1992 1992 e Estimated 395 RIO GUANAJIBO BASIN 50133600 RIO GOANAJIBO NEAR SAN GERMAN, PR WATER-QUALITY RECORDS LOCATION.--Lat 18°07'18", long 67°03'56", at bridge on Highway 347, 2.2 mi (3.5 km) northwest of San German. DRAINAGE AREA.--45.5 mi 2 (117.8 km2 ). PERIOD OF RECORD.--Water years 1979 to current year. WATER QUALITY DATA, WATER YEARS OCTOBER 1995 TO SEPTEMBER 1996 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 07 JAN 19 FEB 27 APR 30 JUN 19 AUG 15 1995 0730 55 1996 0730 15 1100 27 0935 18 0945 18 1005 51 HARD- NESS TOTAL (MG/L DATE AS CAC03 ) (00900) NOV 1995 07... 200 JAN 1996 19... FEB 27... APR 30. .. 260 JUN 19. .. AUG 15... 210 K = non- ideal count 422 6.7 24.0 9.6 6.7 510 7.6 22.5 0.70 5.0 494 7.7 23.0 3.7 5.2 656 7.8 24.5 1.9 5.5 490 7.3 26.0 1.4 5.4 475 7.4 25.5 4.6 6.7 ALKA- MAGNE- SODIUM POTAS- LINITY CALCIUM SIUM, SODIUM, AD- SIUM, WAT WH DIS- DIS- DIS- SORP- DIS- TOT FET SOLVED SOLVED SOLVED TION SOLVED FIELD (MG/L (MG/L (MG/L RATIO (MG/L MG/L AS AS CA) AS MG) AS NA) AS K) CACO3 (00915) (00925) (00930) (00931) (00935) (00410) 23 34 16 0.5 2.7 200 200 230 28 46 34 0.9 3.4 170 210 22 38 17 0.5 3.4 220 78 12 27000 56 10 K950 60 28 K1400 65 22 280 66 15 K810 81 <10 2200 CHLO- SULFATE RIDE, SULFIDE DIS- DIS- TOTAL SOLVED SOLVED (MG/L (MG/L (MG/L AS S) AS S04) AS CD (00745) (00945) (00940) <0.5 15 20 __ __ <0.5 30 44 __ 19 20 3500 2700 990 3100 210 510 396 RIO GUANAJIBO BASIN 50133600 RIO GUANAJIBO NEAR SAN GERMAN, PR—Continued WATER QUALITY DATA, WATER YEARS OCTOBER 1995 SEPTEMBER 1996 DATE NOV 1995 07... JAN 1996 19... FEE 27.. . APR 30. .. JUN 19... AUG 15... NOV 1995 07. .. JAN 1996 19. .. FEE 27 ... APR 30.. . JUN 19... AUG 15. .. NOV 1995 07. .. JAN 1996 19... FEE 27... APR 30... JUN 19... AUG 15... 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) 0.71 1.2 0.61 0.71 0.88 0.55 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 33 — -- 35 -- 34 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 2.5 2.1 2.7 2.2 1.5 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 264 -- -- 322 -- 285 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.5 11 9.3 12 9.6 6.9 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 38.8 -- — 15.4 -- 39.4 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.190 0.760 0.320 0.520 0.530 0.260 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 12 6 7 6 1 13 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.11 1.19 1.43 1.77 1.22 0.930 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.090 0.110 0.070 0.230 0.080 0.070 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 80 -- -- 140 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.20 1.30 1.50 2.00 1.30 1.00 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 — -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.200 0.720 0.180 0.250 0.360 0.210 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 7 -- -- 4 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.51 0.48 0.43 0.46 0.52 0.34 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 560 260 30 60 <0.10 <0.10 <1 <0.010 <0.010 <0.02 0.04 397 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORHI60EROS, PR LOCATION.--Lat 18°09'36", long 67°05'08", Hydrologic Unit 21010003, at bridge on Highway 348, 0.5 mi (0.8 km) southwest of Rosario plaza. DRAINAGE AREA.--18.3 mi 2 (47.4 tan*). WATER-DISCHARGE RECORDS PERIOD OF RECORD.--October 1985 to current year. GAGE.--Water-stage recorder. Elevation of gage is 50.0 ft (15.2 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 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN FEB MAR APR MAY JUN AUG SEP 1 39 35 2 61 34 3 97 35 4 63 35 5 45 33 6 37 69 7 35 45 8 70 90 9 281 118 10 124 59 11 76 62 12 56 48 13 47 37 14 42 34 15 45 45 16 76 39 17 180 33 18 130 62 19 96 46 20 96 34 21 88 30 22 66 28 23 53 26 24 46 26 25 44 26 26 46 71 27 69 65 28 78 38 29 56 37 30 42 40 31 38 —— TOTAL 2322 1380 MEAN 74.9 46.0 MAX 281 118 MIN 35 26 AC-FT 4610 2740 CFSM 4.09 2.51 IN. 4.72 2.81 STATISTICS OF MONTHLY MEAN MEAN 105 69.2 MAX 206 117 (WY) 1986 1990 MIN 33.2 16.1 (WY) 1992 1992 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 35 33 33 30 29 62 51 36 32 32 61 47 32 29 28 27 27 26 25 24 23 23 22 26 23 23 22 22 22 22 21 948 30.6 62 21 1880 1.67 1.93 22 20 19 18 18 20 20 19 17 18 23 17 18 22 29 24 27 20 19 22 27 20 18 17 17 19 18 18 17 16 16 615 19.8 29 16 1220 1.08 1.25 16 16 15 16 16 19 37 24 16 23 31 18 17 16 15 15 15 25 25 25 56 42 32 30 56 35 24 20 18 ___ --- 713 24.6 56 15 1410 1.34 1.45 DATA FOR WATER YEARS 1986 31.8 53.7 1995 9.92 1992 FOR 21.6 34.4 1995 15.1 1994 19.3 37.8 1995 8.55 1992 17 15 15 14 13 13 13 12 12 11 11 11 9.8 11 19 14 11 11 11 9.7 9.8 9.3 e9.2 69.4 e8.6 69.4 69.6 elO 69.0 ell e!2 360.8 11.6 19 8.6 716 .64 .73 - 1996 22.4 77.0 1989 10.1 1992 1995 CALENDAR YEAR 15641 42.9 520 12 13 31020 2.34 31.79 87 27 17 Aug 22 Jun 23 jun 20 elO e20 e54 elOO elSO ellO e45 e42 e40 e37 629 e!9 e!7 616 615 615 e!5 618 28 27 22 116 88 48 24 19 19 18 16 17 1194 39.8 150 10 2370 2.17 2.43 16 16 16 23 16 16 22 24 80 67 18 19 18 17 17 19 56 60 262 158 65 44 35 32 34 103 73 50 47 42 41 1506 48.6 262 16 2990 2.65 3.06 31 28 29 29 25 25 24 23 97 52 38 29 47 61 91 69 71 106 132 109 60 48 41 38 44 53 43 36 35 32 --- 1546 51.5 132 23 3070 2.82 3.14 31 30 29 28 26 51 87 67 154 71 48 42 38 36 34 34 142 136 97 57 44 39 35 34 33 36 37 41 119 111 73 1840 59.4 154 26 3650 3.24 3.74 137 235 127 66 50 43 114 106 56 57 49 51 44 39 48 42 36 53 41 39 34 113 109 175 117 68 55 52 50 48 44 2298 74.1 235 34 4560 4.05 4.67 41 42 39 37 38 38 36 34 31 214 156 88 61 76 60 48 71 65 44 40 36 34 34 49 43 35 47 110 186 131 --- 1964 65.5 214 31 3900 3.58 3.99 , BY WATER YEAR (WY) 25.2 57.7 1989 11.9 1991 FOR 1996 16686 45 281 8 9 3040 10 33100 2 33 97 35 15 47.2 122 1993 15.8 1990 WATER YEAR .8 .6 Oct 9 .6 Mar 25 .3 Mar 23 Oct 9 . 05 Oct 9 .49 .92 44.3 91.1 1993 12.0 1992 43.3 75.2 1989 23.2 1990 WATER 48 70 30 1550 3 4 7480 13 3 35200 2 36 113 28 11 60.3 102 1989 25.1 1991 YEARS 1986 - .6 .6 .8 Oct 7 .9 May 9 .2 May 6 Aug 24 .64 Aug 24 .7 May 9 .66 .08 91.8 157 1993 32.7 1986 1996 1993 1992 1985 1992 1992 1988 1988 1992 e Estimated 398 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR—Continued WATER-QUALITY RECORDS PERIOD OF RECORD.—Water years 1979 to current year. PERIOD OF DAILY RECORD.-- SUSPENDED-SEDIMENT DISCHARGE: October 1985 to current year. INSTRUMENTATION.—US D-49 sediment sampler since October 1985. Automatic sediment sampler since 1986. REMARKS.—sediment samples were collected by a local observer once daily during low flow. During high flow events sediments samples were collected by a local observer and automatic sediment sampler. EXTREMES FOR PERIOD OF DAILY RECORD.— SEDIMENT CONCENTRATIONS: Maximum daily mean, 8,150 mg/L October 7, 1985; Minimum daily mean, 1.0 mg/L several days. SEDIMENT LOADS: Maximum daily, 74,700 tons (67,800 tonnes) October 7, 1985; Minimum daily, 0.05 ton (0.04 Tonne) several days. EXTREMES FOR CURRENT YEAR 1996.— SEDIMENT CONCENTRATIONS: Maximum daily mean, 1,230 mg/L October 9, 1995; Minimum daily mean, 3.0 mg/L several days. SEDIMENT LOADS: Maximum daily, 3,750 tons (3,400 tonnes) October 9, 1995; Minimum daily 0.14 ton (0.13 tonne) May 15, 1996. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 06... JAN 1996 18... FEE 27... APR 29... JUN 19... AUG 15... TIME 1140 1035 1215 1050 1145 1115 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 32 20 23 16 54 37 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 275 290 262 280 302 280 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.9 7.9 7.8 7.7 7.4 7.5 TEMPER- ATURE WATER (DEG C) (00010) 27.0 21.5 23.0 24.0 23.0 25.0 TUR- BID- ITY (NTU) (00076) 1.9 1.2 7.2 1.6 23 0.50 OXYGEN, DIS- SOLVED (MG/L) (00300) 8.3 8.6 8.2 8.2 7.2 8.0 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 102 95 93 97 84 96 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 <10 15 64 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) K1700 K700 370 220 2600 2100 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 300 6100 410 K160 3500 2700 DATE NOV 1995 06... JAN 1996 18... FEE 27... APR 29... JUN 19... AUG 15... HARD- NESS TOTAL (MG/L AS CAC03) (00900) 120 -- — 130 -- 130 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 25 — — 25 -- 23 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 14 __ — 17 -- 18 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 9.6 — -- 20 -- 6.7 SODIUM AD- SORP- TION RATIO (00931) 0.4 — -- 0.8 -- 0.3 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.0 — — 2.3 — 1.5 ALKA- LINITY WAT WH TOT PET FIELD MG/L AS CACO3 (00410) 160 130 120 110 120 150 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 — — SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 4.8 -- -- 8.2 — 7.0 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 7.8 -- — 17 — 8.2 non-ideal count 399 DATE NOV 1995 06... JAN 1996 18... FEB 27... APR 29... JUN 19... AUG 15... DATE NOV 1995 06... JAN 1996 18... FEB 27... APR 29... JUN 19... AUG 15... DATE NOV 1995 06... JAN 1996 18... FEB 27... APR 29... JUN 19... AUG 15... RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR--Continued WATER QUALITY DATA, WATER YEARS OCTOBER 1995 TO SEPTEMBER 1996 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 0.73 <0.20 <0.20 0.31 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 30 -- -- 29 -- 30 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 1.5 1.1 0.97 1.3 0.99 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 189 — — 184 — 184 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 4.8 6.4 4.7 4.3 5.7 4.4 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 16.3 — — 7.87 -- 18.2 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.060 0.250 0.070 0.050 0.030 <0.020 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEC. C, SUS- PENDED (MG/L) (00530) <1 3 11 2 19 <1 ARSENIC TOTAL (UG/L AS AS) (01002) <1 — — <1 -- — SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.890 0.710 0.880 0.810 0.960 0.850 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.010 0.010 <0.010 0.010 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — — 20 — — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.890 0.720 0.890 0.810 0.970 0.850 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — — <1 — — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.290 0.030 0.030 0.010 0.010 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 5 — — 3 — — PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) <0.20 0.44 <0.20 <0.20 0-.30 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 — -- <10 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 100 140 <1 <1 10 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <1 <0.02 <0.02 400 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER 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 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 39 61 97 63 45 37 35 70 281 124 76 56 47 42 45 76 180 130 96 96 88 66 53 46 44 46 69 78 56 42 38 5 44 155 42 15 12 11 68 1230 116 22 12 8 9 20 96 460 87 29 119 76 55 44 26 14 18 58 100 66 30 23 .52 18 76 7.8 1.9 1.2 1.0 31 3750 44 4.7 1.9 1.0 .99 3.5 42 757 32 8.4 72 19 9.7 6.3 3.3 1.7 2.8 20 44 11 3.4 2.4 NOVEMBER 35 34 35 35 33 69 45 90 118 59 62 48 37 34 45 39 33 62 46 34 30 28 26 26 26 71 65 38 37 40 18 14 10 7 4 69 37 155 131 50 52 53 16 14 32 41 29 57 52 20 21 17 19 21 13 133 61 17 14 41 1.7 1.2 .98 .66 .39 30 4.7 125 49 8.2 15 7.4 1.6 1.2 7.5 4.3 2.6 22 7.3 1.9 1.8 1.3 1.4 1.4 .93 107 13 1.8 1.6 4.5 ___ DECEMBER 35 33 33 30 29 62 51 36 32 32 61 47 32 29 28 27 27 26 25 24 23 23 22 26 23 23 22 22 22 22 21 40 36 16 6 3 68 45 11 8 7 63 56 28 17 9 7 6 5 5 5 7 9 9 7 7 6 6 6 6 6 6 3.8 3.2 1.5 .48 .26 30 7.6 1.1 .69 .68 20 8.1 2.5 1.3 .71 .51 .43 .36 .34 .33 .42 .57 .51 .50 .40 .37 .36 .35 .35 .36 .34 TOTAL 2322 4978.51 1380 427.36 948 88.42 RIO GUANAJIBO BASIN 50136400 RIO ROSARZO NEAR HORMIGUEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 401 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) 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 22 20 19 18 18 20 20 19 17 18 23 17 18 22 29 24 27 20 19 22 27 20 18 17 17 19 18 18 17 16 16 6 6 7 8 7 9 15 32 46 26 16 16 13 13 18 11 27 23 22 27 22 8 7 8 10 10 9 9 8 8 9 .36 .33 .34 .37 .31 .49 .84 1.7 2.1 1.3 .98 .71 .61 .81 1.6 .80 2.0 1.2 1.2 1.8 1.7 .41 .35 .38 .47 .52 .46 .41 .38 .35 .38 FEBRUARY 16 16 15 16 16 19 37 24 16 23 31 18 17 16 15 15 15 25 25 25 56 42 32 30 56 35 24 20 18 ___ ___ 10 10 9 9 8 11 25 16 6 12 24 13 12 19 23 22 21 90 137 21 52 40 92 47 251 69 22 17 15 ___ .42 .40 .38 .37 .35 .82 4.5 1.1 .26 1.2 2.3 .67 .57 .79 .96 .91 .87 11 10 1.7 10 5.5 8.7 8.1 41 7.0 1.4 .90 .74 __- MEAN MEAN CONCEN- SEDIMENT DISCHARGE TRATION DISCHARGE (CFS) (MG/L) (TONS/DAY) TOTAL 615 25.66 713 122.91 17 15 15 14 13 13 13 12 12 11 11 11 9.8 11 19 14 11 11 11 9.7 9.8 9.3 e9.4 e9.2 e9.2 e9.2 e9.5 e9.0 e8.8 ell ell 358.9 MARCH 14 15 22 35 30 22 16 13 16 20 24 20 14 11 11 8 7 6 12 22 17 10 7 7 8 13 20 18 13 9 7 .66 .61 .92 1.3 1.0 .78 .54 .41 .50 .61 .72 .56 .38 .31 .63 .33 .19 .18 .33 .57 .45 .26 e.17 e.17 e.20 .31 .51 .45 .32 .22 .18 14.77 e Estimated 402 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY>, WATER 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 DISCHARGE (CFS) ell e9.8 e!2 elOO ellO e!30 e60 e43 e31 e26 e21 e!9 el? e!5 e!5 e!4 e!3 e!8 28 27 22 116 88 48 24 19 19 18 16 17 ___ MEAN CONCEN- TRATION (MG/L) APRIL 8 11 16 25 40 51 20 7 4 3 4 5 6 8 10 22 39 28 30 13 14 326 108 50 30 24 19 14 11 9 ___ SEDIMENT DISCHARGE (TONS/ DAY) e.24 e.31 e.46 e3.1 ell e!6 eS.l .93 .43 .25 .23 .25 .29 .33 .43 e.85 el. 4 el.O 3.1 1.1 .83 330 32 7.5 2.0 1.2 .93 .72 .49 .40 -__ MEAN DISCHARGE (CFS) 16 16 16 23 16 16 22 24 80 67 18 19 18 17 17 19 56 60 262 158 65 44 35 32 34 103 73 50 47 42 41 MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) MAY MEAN DISCHARGE (CFS) MEAN CONCEN- SEDIMENT TRATION DISCHARGE (MG/L) (TONS/DAY) JUNE 16 16 16 23 16 16 22 24 80 67 18 19 18 17 17 19 56 60 262 158 65 44 35 32 34 103 73 50 47 42 41 7 5 5 5 5 5 12 9 90 59 9 6 5 4 3 3 71 57 652 277 12 4 2 2 16 196 59 55 43 32 21 .28 .22 .22 .30 .22 .22 1.0 .61 39 15 .44 .31 .24 .18 .14 .15 37 11 2310 154 2.5 .47 .22 .21 2.7 124 13 7.4 5.9 3.6 2.3 31 28 29 29 25 25 24 23 97 52 38 29 47 61 91 69 71 106 132 109 60 48 41 38 44 53 43 36 35 32 15 11 8 6 4 5 7 10 134 50 16 8 42 52 118 62 69 124 413 87 35 17 9 5 17 41 20 11 7 6 1.2 .80 .61 .44 .30 .36 .48 .59 74 7.5 1.8 .66 10 10 37 12 21 53 344 29 5.8 2.3 .99 .47 2.5 11 2.3 1.1 .63 .52 1106.8 422.87 1506 2732.83 1546 632.35 e Estimated 403 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR— Continued SEDIMENT DISCHARGE, SUSPENDED (TONS/DAY), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 31 30 29 28 26 51 87 67 154 71 48 42 38 36 34 34 142 136 97 57 44 39 35 34 33 36 37 41 119 111 73 1840 16597.7 JULY 6 7 7 8 6 41 102 92 145 24 12 9 7 6 6 6 394 317 100 25 13 10 8 6 6 6 6 10 384 76 18 —— AUGUST .51 .52 .56 .57 .43 12 37 17 67 5.0 1.5 .98 .66 .58 .56 .54 500 188 29 4.0 1.6 1.1 .75 .57 .54 .58 .59 1.3 442 26 3.5 1344.94 16160.96 137 235 127 66 50 43 114 106 56 57 49 51 44 39 48 42 36 53 41 39 34 113 109 175 117 68 55 52 50 48 44 2298 609 925 152 49 22 8 221 65 17 35 37 45 24 8 27 35 14 44 32 27 18 514 219 473 140 23 9 7 9 13 10 —— 684 1240 58 8.9 3.0 .88 181 25 2.6 6.7 5.1 6.6 3.0 .79 5.6 4.2 1.4 11 3.7 3.1 1.7 499 117 421 49 4.3 1.4 .94 1.2 1.6 1.2 3352.91 SEPTEMBER 41 42 39 37 38 38 36 34 31 214 156 88 61 76 60 48 71 65 44 40 36 34 34 49 43 35 47 110 186 131 —— 1964 7 5 4 5 7 10 12 13 13 566 252 77 26 80 172 139 151 62 12 7 6 7 7 29 28 11 44 278 580 175 —— —— .81 .61 .46 .54 .77 1.0 1.1 1.2 1.2 468 115 19 4.3 27 28 18 40 13 1.4 .75 .61 .61 .67 6.3 3.2 1.1 8.8 222 964 68—— 2017.43 404 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS, PR—Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 PARTICLE-SIZE DISTRIBUTION OF SUSPENDED SEDIMENT OCT 1995 17... AUG 1996 24... TIME 1627 1744 DIS- CHARGE, INST. CUBIC FEET PER SECOND SEDI- MENT, SUS- PENDED (MG/L) SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) SED. SUSP. FALL DIAM. H FINER THAN .002 MM SED. SUSP. FALL DIAM. % FINER THAN .004 MM SED. SUSP. FALL DIAM. H FINER THAN .008 MM (00061) (80154) (80155) (70326) (70327) (70328) 900 302 11400 27700 2940 2400 18 35 22 39 24 DATE OCT 1995 17... AUG 1996 24... SED. SUSP. FALL DIAM. * FINER THAN .016 MM (70329) SED. SUSP. FALL DIAM. H FINER THAN .031 MM (70330) SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) SED. SUSP. SIEVE DIAM. H FINER THAN .125 MM (70332) SED. SUSP. SIEVE DIAM. H FINER THAN .250 MM (70333) SED. SUSP. SIEVE DIAM. % FINER THAN .500 MM (70334) SED. SUSP. SIEVE DIAM. * FINER THAN 1.00 MM (70335) 29 44 32 56 40 58 47 60 54 62 65 71 82 85 405 RIO GUANAJIBO BASIN 50136400 RIO ROSARIO NEAR HORMIGUEROS , PR--Continued WATER QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SILT AND CLAY PERCENT OF SUSPENDED SEDIMENT DATE OCT 1995 17... FEE 1996 19... 25... MAY 07... AU6 24... 29... TIME 1627 0906 0900 1435 1744 1625 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 900 24 59 16 302 807 SEDI- MENT, SUS- PENDED (MG/L) (80154) 11400 212 276 991 2940 5680 SEDI- MENT, DIS- CHARGE, SUS- PENDED (T/DAY) (80155) 27700 14 44 43 2400 12400 SED. SUSP. SIEVE DIAM. % FINER THAN .062 MM (70331) 40 97 98 99 58 30 406 RIO GUANAJIBO BASIN 50138000 RIO GUANAJIBO NEAR HORMIGUEROS, PR LOCATION.--Lat 18°08'36", long 67°08'57", Hydrologic Unit 21010003, at bridge on Highway 100, 1.4 mi (2.3 km) west of Hormigueros, and 2.0 mi (3.2 km) downstream from Rio Rosario. DRAINAGE AREA.--120 mi 2 (311 km 2 ). WATER-DISCHARGE RECORDS PERIOD OF RECORD.—Annual low-flow measurements 1959, monthly measurements April 1959 to November 1967, January 1973 to current year. GAGE.—Water-stage recorder. Datum of gage is at mean sea level. Previous to Nov. 7, 1980, at site 0.3 mi (0.5 km) upstream at datum 7.36 ft (2.243 m) higher. REMARKS.—Records fair. Gage-height and precipitation satellite telemetry at station. Daily discharges affected by sewage treatment plant about 2.1 mi (3.4 km) upstream from gage. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 145 115 2 140 108 3 182 114 4 165 148 5 119 146 6 108 149 7 101 151 8 117 303 9 368 511 10 334 191 11 170 168 12 139 199 13 120 126 14 110 115 15 103 112 16 147 193 17 411 196 18 583 181 19 677 202 20 402 139 21 382 124 22 307 109 23 265 100 24 201 92! 25 203 86 26 170 209 27 166 307 28 163 156 29 245 143 30 153 149 31 126 —— TOTAL 7022 5042 MEAN 227 168 MAX 677 511 MIN 101 86 AC-FT 13930 10000 CFSM 1.89 1.40 IN. 2.18 1.56 STATISTICS OF MONTHLY MEAN MEAN 471 408 MAX 1254 1518 (WY) 1986 1978 MIN 97.5 42.7 (WY) 1992 1992 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 118 102 97 89 80 84 126 81 75 79 248 287 142 117 104 93 86 78 73 68 65 61 59 58 55 53 54 54 49 50 46 2831 91.3 287 46 5620 .76 .88 44 42 41 40 40 48 48 41 42 40 41 37 35 38 50 105 79 83 63 106 95 64 55 49 47 50 50 54 50 45 42 1664 53.7 106 35 3300 .45 .52 DATA FOR WATER 129 422 1976 15.4 1992 FOR 58.7 110 1993 13.8 1973 40 39 38 38 39 53 58 67 45 106 148 64 56 56 50 46 44 97 85 94 235 208 201 400 380 290 191 150 128 ___ 3446 119 400 38 6840 .99 1.07 YEARS 1973 51.0 119 1996 13.9 1977 113 101 91 83 81 70 61 53 46 42 40 37 34 33 40 52 73 40 34 31 29 29 29 28 28 28 29 28 27 27 35 1472 47.5 113 27 2920 .40 .46 - 1996 47.1 244 1989 10.6 1977 1995 CALENDAR YEAR 42985 118 909 22 22 85260 . 13. 258 78 31 Aug 23 Mar 30 Mar 28 98 33 35 30 36 330 336 397 187 121 95 76 65 58 52 46 45 44 40 59 60 85 239 304 262 148 95 75 63 61 53 51 —— 3548 118 397 30 7040 .99 1.10 46 42 41 45 39 36 43 42 81 149 91 59 47 41 38 48 120 184 278 1260 428 289 211 164 134 171 170 119 88 82 83 4669 151 1260 36 9260 1.26 1.45 87 70 59 57 59 51 47 44 108 104 65 55 70 90 98 116 80 129 169 237 137 104 83 68 134 347 359 134 94 78 3333 111 359 44 6610 .93 1.03 68 64 59 55 51 51 82 84 160 116 74 62 60 58 58 51 150 197 145 85 68 59 54 51 51 48 46 48 114 110 80 2459 79.3 197 46 4880 .66 .76 311 740 430 208 146 115 403 731 285 222 203 241 221 218 183 169 131 118 126 119 98 149 183 332 272 144 118 107 100 89 95 7007 226 740 89 13900 1.88 2.17 79 75 71 67 79 85 81 68 64 498 966 482 314 329 457 239 181 248 183 147 126 111 101 96 118 101 123 243 316 478 —— 6526 218 966 64 12940 1.81 2.02 , BY WATER YEAR (WY) 71.4 316 1989 16.1 1977 FOR 1996 49019 134 1260 27 28 1860 19 97230 1 15 289 92 40 174 636 1980 12.7 1977 WATER YEAR May 20 Mar 29 Mar 24 May 20 .21 May 20 .12 .20 107 504 1979 9.23 1977 101 240 1984 26.4 1976 WATER 194 402 69. 35000 5. 5. 128000 28. 4. 140500 1. 21. 420 77 21 220 757 1988 42.3 1976 YEARS 1973 6 Sep 0 Jun 5 Jun Sep 50 Sep 6 Jun 62 96 464 2075 1975 95.4 1991 - 1996 1979 1994 16 1975 18 1977 17 1977 16 1975 16 1975 22 1977 407 RIO GUANAJIBO BASIN 50138000 RIO OUANAJIBO NEAR HORMIGOEROS, PR--Continued WATER-QUALITY RECORDS PERIOD OF RECORD.--Water years 1958 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NOV 06 JAN 18 FEB 29 APR 29 JUN 20 ADG 16 DATE 1995 1996 ... DATE NOV 1995 06. . . JAN 1996 18. .. FEB 29. . . APR 29... JUN 20. .. AU6 16... DATE NOV 1995 06... JAN 1996 18... FEB 29... APR 29... JUN 20... AUO 16... 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) 1325 116 392 6.8 25.0 30 7.3 87 14 K9800 2400 1220 74 445 7.7 24.0 27 6.8 79 13 K7500 8700 0930 131 1255 53 0720 286 0715 176 HARD- NESS TOTAL (MG/L AS CAC03 ) (00900) 170 -- -- 230 -- 180 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- — 0.10 — <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 26 -- -- 32 __ 27 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 29 -- — 32 -- 30 350 485 283 386 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 25 -- __ 37 -- 28 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 224 -- -- 283 — 235 7.5 7.8 7.0 7.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 12 __ -_ 18 -- 11 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 70.1 -- -- 40.4 -- 112 23.5 12 25.5 6 23.5 120 25.5 7 SODIUM AD- SORP- TION RATIO (00931) 0.4 __ __ 0.5 -- 0.4 RESIDUE TOTAL AT 105 DEG . C , SUS- PENDED (MG/L) (00530) 39 34 34 11 280 32 .4 .0 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.8 -_ __ 2.7 -- 2.5 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.890 1.07 0.410 0.850 0.820 0.690 4.2 6.8 6.3 5.4 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 170 180 150 200 120 180 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.030 0.020 0.010 0.020 0.020 49 83 73 65 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -_ <0.5 __ -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS. N) (00630) 0.910 1.10 0.430 0.860 0.840 0.710 32 31 3200 K1700 4200 420 38 53000 67000 18 SULFATE DIS- 5600 2700 CHLO- RIDE, DIS- SOLVED SOLVED (MG/L AS SO4) (00945) 13 -- -- 20 -- 16 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.040 0.150 0.040 0.040 0.050 0.040 (MG/L AS CL) (00940) 14 -- -- 21 -- 13 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.48 0.47 0.61 0.25 1.5 0.44 K - non-ideal count 408 RIO GUANAJIBO BASIN 50138000 RIO GUANAJIBO NEAR HORMXGUEROS, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NOV 1995 06.. . JAN 1996 18.. . FEB 29. . . APR 29... JUN 20... AUG 16.. . 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 TOTAL RECOV- ERABLE (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.52 0.62 0.65 0.29 1.6 0.48 1.4 1.7 1.1 1.2 2.4 1.2 6.3 7.6 4.8 5.1 11 5.3 0.200 0.400 0.430 0.230 0.420 0.230 100 <100 60 80 NOV 1995 06. .. JAN 1996 18. .. FEB 29. .. APR 29. .. JUN 20. .. AUG 16. .. 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) 1500 480 80 80 <0.10 <0.10 10 <0.010 <0.010 0.03 PESTICIDE ANALYSES JUN 1996 20... TIME PCB, TOTAL (UG/L) (39516) ALDRIN, TOTAL (UG/L) (39330) DANE, TECH- NICAL TOTAL (UG/L) (39350) P, P' - ODD UNFILT RECOVER (UG/L) (39360) DDE, TOTAL (UG/L) (39365) P, P' - DOT UNFILT RECOVER (UG/L) (39370) DI- AZINON, TOTAL (UG/L) (39570) DI- ELDRIN TOTAL (UG/L) (39380) ENDO- SULFAN, I TOTAL (UG/L) (39388) 0720 <0.100 <0.010 <0.100 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 JUN 1996 20... ENDRIN WATER UNFLTRD REC (UG/L) (39390) ETHION, TOTAL (UG/L) (39398) 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 1996 20... PARA- THION, TOTAL (UG/L) (39540) <0.010 PCNS UNPILT 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, TOTAL (UG/L) (39730) 2,4,5-T TOTAL (UG/L) (39740) 2, 4-DP TOTAL (UG/L) (82183) SILVEX, TOTAL (UG/L) (39760) 0.440 <0.010 <0.010 <0.010 EXPLANATION A U4° SURFACE-WATER STATION AND NUMBER 1388 QUALITY-OF-WATER STATION AND NUMBER U15 LAKE-ELEVATION STATION AND NUMBER 01234 MILES Figure 26.--Rio Yaguez and Rio Grande de Anasco basins. •u o 410 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 Mayagiiez 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 1995 TO SEPTEMBER 1996 DATE NOV 1995 06... JAN 1996 18. .. FEB 27... APR 30. .. JUN 19. .. AUG 15. .. TIME 1530 1335 1335 0720 1250 1300 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 11 3.4 2.9 8.5 18 7.4 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 320 300 299 262 222 322 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 6.5 7.8 7.8 7.3 7.4 7.8 TEMPER- ATURE WATER (DEC C) (00010) 25.0 23.0 23.5 21.5 24.5 25.5 TUR- BID- ITY (NTU) (00076) 4.2 2.0 3.6 52 59 0.40 OXYGEN, DIS- SOLVED (MG/L) (00300) 7.3 8.0 7.6 7.8 7.8 7.2 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 87 92 87 88 93 87 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 <10 <10 14 16 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 2400 K960 470 4300 5300 K640 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 4200 31000 2700 21000 5100 720 DATE NOV 1995 06. . . JAN 1996 18.. . FEB 27. .. APR 30. .. JUN 19. .. AUG 15. .. HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 130 -- -- 110 -- 140 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 31 -- -- 30 -- 38 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 13 -- -- 9.0 -- 10 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 11 -- -- 9.5 -- 11 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- -- 0.4 -- 0.4 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 2.7 -- -- 2.8 -- 2.6 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 120 110 110 100 90 150 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 5.8 -- -- 9.2 -- 7.1 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 9.4 -- -- 9.8 -- 10 K = non-ideal count 477 NOV 1995 06... JAN 1996 18. .. FEB 27. .. APR 30. .. JUN 19... AUG 15. .. NOV 1995 06. .. JAN 1996 18 ... FEB 27 ... APR 30. .. JUN 19.. . AUG 15. . . NOV 1995 06... JAN 1996 18... FEB 27... APR 30... JUN 19... AUG 15... RIO YAGUEZ BASIN 50138800 RIO YAGUEZ NEAR HAYAGdEZ, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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) 0.22 3.0 3.5 0.30 0.46 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 30 -- — 25 — 32 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.1 3.9 4.3 1.1 1.7 0.98 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 175 -- — 155 — 201 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 5.1 17 19 4.8 7.3 4.4 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 5.19 -- -- 3.55 -- 3.99 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.300 0.280 0.080 0.080 0.040 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 4 5 30 32 ^ ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 0.930 0.850 0.720 0.760 1.18 0.830 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) 100 -- -- 100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) <0.010 0.050 0.070 0.020 0.020 <0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 30 -- -- 50 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 0.930 0.900 0.790 0.780 1.20 0.830 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- — CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 2.20 0.570 0.020 0.020 0.020 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- 1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.20 0.80 2.9 0.28 0.44 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- - METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 200 870 14 10 40 <0.10 <0.10 <0.010 <0.010 <0.02 <0.02 412 RIO GRANDE DE ANASCO BASIN 50141500 LAGO GUAYO AT DAHSITE 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* (24.86 km*). ELEVATION RECORDS PERIOD OF 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, 1460.75 ft (445.23 m), Jun. 19; minimum elevation recorded 1439.07 ft (438.28 m), Aug. 31. 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 1460 1465 Contents, in acre-feet 13,550 15,000 ELEVATION (FEET NGVD), WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY OBSERVATION AT 24:00 VALUES 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 MAX MIN NOV DEC MAY JUL SEP 1452.99 1451.90 1451.50 1451.03 1450.80 1450.56 1450.06 1449.60 1449.22 1448.91 1448.82 1448.84 1448.57 1448.13 1448.20 1450.51 1452.89 1453.45 1453.41 1455.13 1455.89 1456.42 1456.46 1455.81 1455.92 1455.17 1454.45 1454.51 1454.08 1453.10 1451.76 1456.46 1448.13 1450.58 1449.72 1449.43 1448.75 1448.64 1448.59 1448.43 1448.04 1448.08 1448.82 1449.29 1449.20 1449.92 1450.87 1451.36 1451.67 1452.34 1452.82 1453.04 1452.89 1453.25 1453.66 1454.05 1454.45 1454.53 1454.88 1455.14 1455.56 1455.95 1456.35 --- 1456.35 1448.04 1456.76 1457.12 1457.34 1457.52 1456.48 1457.09 1457.80 1458.10 1458.45 1458.78 1459.27 1459.68 1458.81 1458.27 1458.34 1458.38 1458.68 1458.14 1458.45 1458.62 1458.37 1458.12 1458.13 1458.26 1458.14 1458.33 1458.31 1458.27 1458.52 1458.42 1458.67 1459.68 1456.48 1458.92 1458.62 1458.57 1458.33 1458.57 1458.79 1459.01 A A A A 1457.74 1457.34 1457.74 1457.56 1457.54 1456.84 1456.09 1455.24 1454.74 1454.69 1453.69 1453.43 1453.55 1453.63 1453.86 1453.91 1453.83 1453.74 1453.28 1453.06 ___ 1453.29 1453.52 1452.52 1452.39 1452.57 1452.81 1453.03 1453.10 1452.74 1453.16 1453.09 1453.15 1453.36 1453.54 1453.46 1453.65 1453.77 1453.97 1454.16 1453.59 1453.72 1452.86 1452.77 1453.40 1453.64 1452.71 1452.05 1451.18 1450.38 ___ —— 1454.16 1450.38 1450.05 1450.08 1449.96 1449.76 1449.88 1449.06 1448.49 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 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 A A A A .__ A A A A A A A A A A A A A 1447.94 1448.44 1448.98 1449.40 A 1454.32 1456.93 1457.91 1458.55 1458.63 1458.47 1457.79 1458.97 1459.71 1459.81 1460.09 1460.30 1460.30 1460.21 1460.18 1460.16 1460.10 1460.28 1460.21 1460.17 1459.98 1459.87 1459.81 1460.09 1460.15 1460.24 1460.20 1460.48 1460.26 1460.20 1460.17 1460.75 1460.31 1460.14 1460.18 1460.17 1459.16 1458.33 1457.78 A A A 1457.97 ___ 1458.32 1458.64 1458.92 1459.19 1459.44 A A 1460.43 A 1459.89 1459.12 1458.67 1458.67 1459.13 1459.56 1459.13 1458.90 1458.67 1457.78 1457.53 1457.90 1456.63 1455.24 1454.07 1453.72 1452.63 1451.72 1451.69 1450.77 1449.59 1448.95 1448.20 1447.98 1447.38 1447.07 1445.56 1444.32 1444.46 1443.82 1443.95 1443.56 1443.37 1442.70 1441.90 1441.63 1441.65 1442.49 1442.22 1442.44 1441.87 1441.98 1441.82 1441.55 1441.26 1440.91 1440.86 1440.41 1440.45 A 1439.68 A 1439.10 1439.41 1439.74 1439.89 1440.08 1441.47 A 1442.23 1441.64 A 1455.66 1457.33 1458.25 1458.96 1460.28 1460.27 1460.23 1459.37 1458.33 1457.23 1455.36 1454.69 1453.93 A 1451.12 1450.34 1449.31 1448.16 A 1446.53 1445.08 ___ A No gage-height record 413 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 2 (68.1 km 2 ) this does not include 36.2 mi 2 (93.8 km 2 ) which contributes only dur- ing high floods, and 3.5 mi 2 (9.1 km2 ) which contributes only part of its storm runoff. PERIOD OP RECORD.--Water years 1959-68, 1970 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 06... JAN 1996 18... FEB 13... APR 09. .. JUN 10. .. AUG 09. .. TIME 1130 1345 0950 0930 1030 1030 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) 72 28 29 23 41 31 SPE- CIFIC CON- DUCT- ANCE (US/CM) (00095) 275 294 289 296 290 292 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.6 8.5 8.0 7.6 8.2 7.9 TEMPER- ATURE WATER (DEG C) (00010) 25.0 23.5 21.5 23.0 25.0 25.5 TUR- BID- ITY (NTU) (00076) 9.0 7.9 5.4 2.2 0.30 2.1 OXYGEN, DIS- SOLVED (MG/L) (00300) 8.0 8.2 8.2 8.9 8.3 8.1 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 96 96 93 104 101 99 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (MG/L) (00340) <10 13 11 <10 <10 <10 COLI- FORM, FECAL, 0.45 UM-MF (COLS./ 100 ML) (31616) 460 230 520 K140 K120 390 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 820 K890 580 310 K100 500 DATE NOV 1995 07. .. JAN 1996 18. . . FEB 13. . . APR 09 ... JUN 10. .. AUG 09. .. HARD- NESS TOTAL (MG/L AS CAC03 ) (00900) 110 -- -- 130 -- 130 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 28 -- -- 36 -- 33 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 9.2 -- -- 10 -- 11 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 9.2 -- -- 12 -- 33 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- -- 0.5 -- 1 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.7 -- -- 1.8 -- 2.9 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 110 110 110 120 110 110 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0 .5 -- -- SULFATE DIS- SOLVED (MG/L AS S04) (00945) 7.6 -- -- 20 -- 24 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 7.3 -- -- 11 -- 11 non-ideal count 414 RIO GRANDE DE ANASCO BASIN 50143000 RIO GRANDE DE ANASCO NEAR LARES, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 SOLIDS, RESIDUE NOV 1995 07. .. JAN 1996 18. .. FEB 13. .. APR 09.. . JUN 10... AUG 09... NOV 1995 07. .. JAN 1996 18. .. FEB 13 ... APR 09. .. JUN 10. . . AUG 09. . . NOV 1995 07. .. JAN 1996 18... FEB 13... APR 09... JUN 10... AUG 09... 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 0.46 <0.20 <0.20 <0.20 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 29 — — 29 -- 33 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.3 2.1 2.3 1.1 1.4 1.1 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 155 — -- 192 -- 214 NITRO- GEN, TOTAL (MG/L AS N03) (71887) 5.9 9 .1 10 4.8 6.1 4.9 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 31 -- -- 11.8 -- 17.9 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.050 0.080 0.050 <0.020 <0.020 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) 24 22 6 3 6 6 ARSENIC TOTAL (UG/L AS AS) •(01002) <1 -- -- <1 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.09 1.59 2.09 0.940 1.20 1.00 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.010 0.010 0.010 •eO.010 •eO.010 •eO.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 10 -- -- 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, N02+N03 TOTAL (MG/L AS N) (00630) 1.10 1.60 2.10 0.940 1.20 1.00 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.040 0.040 0.030 0.010 0.030 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.23 0.42 <0.20 <0.20 <0.20 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 830 180 80 30 <0.10 <0.10 •eO.010 <0.010 <0.02 0.02 415 RIO GRANDE DE ANASCO BASIN 50144000 RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN, PR 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 2 (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.—March 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-ft (21.3 hmj ). Limited storm runoff is contributed to basin by 3.5 mi 2 (9.1 km2 ) above Rio Toro Diversion dam. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN JUN JUL AUG SEP 1 482 258 2 980 243 3 1880 233 4 669 223 5 290 208 6 229 211 7 221 424 8 384 738 9 379 883 10 318 325 11 232 253 12 1240 259 13 823 235 14 1100 289 15 684 235 16 952 237 17 3140 209 18 1330 199 19 623 201 20 1510 190 21 943 190 22 701 182 23 407 180 24 345 182 25 704 190 26 654 1000 27 662 523 28 576 223 29 609 194 30 331 202 31 283 —— TOTAL 23681 9119 MEAN 764 304 MAX 3140 1000 MIN 221 180 AC-FT 46970 18090 CFSM 8.10 3.22 IN. 9.34 3.60 STATISTICS OF MONTHLY MEAN MEAN 667 432 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 292 218 185 179 238 265 432 211 190 318 313 344 206 186 177 172 167 166 164 162 177 159 153 153 148 152 147 147 142 139 137 6239 201 432 137 12380 2.13 2.46 DATA 225 482 1966 103 1992 136 134 132 129 126 125 124 123 122 130 131 120 117 119 185 132 147 120 118 114 128 115 111 109 109 123 126 121 118 110 108 3862 125 185 108 7660 1.32 1.52 FOR WATER 139 215 1970 83.6 1965 106 104 102 103 103 118 139 173 115 1120 492 147 123 118 110 108 107 107 114 347 913 1970 762 857 732 276 200 170 157 —— 9993 345 1970 102 19820 3.65 3.94 YEARS 1963 114 345 1996 62.3 1992 147 141 136 131 129 128 125 122 119 117 116 114 112 138 149 119 101 98 96 96 93 92 92 90 88 88 87 87 89 89 314 3643 118 314 87 7230 1.25 1.44 - 1996 104 271 1972 54.4 1965 FOR 1995 CALENDAR YEAR 116077 318 3830 58 66 230200 3. 45. 680 185 Sep 16 May 2 Apr 28 37 79 239 116 101 228 239 174 171 116 103 99 100 118 103 97 96 99 93 108 130 213 205 436 1090 332 160 129 117 111 106 103 —— 5532 184 1090 93 10970 1.96 2.18 102 100 186 241 119 125 132 122 120 152 259 179 135 114 112 313 354 531 4970 2250 500 382 261 215 191 477 1040 999 1120 1460 922 18183 587 4970 100 36070 6.22 7.17 798 671 390 510 618 475 340 316 233 235 250 221 391 756 562 652 811 1350 854 1270 506 333 306 318 274 218 265 212 213 192 —— 14540 485 1350 192 28840 5.14 5.74 179 205 176 170 165 160 160 226 698 532 261 380 197 171 179 184 157 207 267 183 159 152 146 142 140 145 147 134 155 248 155 6580 212 698 134 13050 2.25 2.60 242 562 352 209 elSO el40 e!30 e!70 e240 elSO e360 e700 e270 e490 e240 e440 e2500 e690 e4200 el300 e430 e350 e310 e240 e250 e!90 elSO e!70 e!90 el80 e!60 16185 522 4200 130 32100 5.54 6.38 elSO el45 elSO 436 547 656 332 271 220 15700 5570 2160 1010 1360 1260 669 1230 733 507 410 380 348 322 439 1050 852 455 528 648 858 ___ 39396 1313 15700 145 78140 13.9 15.54 , BY WATER YEAR (WY) 146 313 1971 49.3 1968 FOR 1996 156953 429 15700 87 88 51200 21 86 311300 4 61 857 200 379 1084 1986 63.7 1967 WATER YEAR Sep 10 Mar 27 Mar 24 Sep 10 .33 Sep 10 Mar 26 .55 .92 293 815 1979 71.2 1977 271 657 1979 111 1990 WATER 312 460 189 19400 32 35 140000 33 31 226200 3 44 658 185 359 936 1979 152 1967 YEARS 1963 Sep Apr Apr Sep .90 Sep Apr .31 .98 620 1422 1984 206 1983 - 1996 1979 1967 16 3,975 18 1965 14 1965 16 1975 16 1975 19 1965 416 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 1995 TO SEPTEMBER 1996 DATE NOV 1995 09... JAN 1996 23. .. FEB 06... APR 19... JUN 25. .. SEP 04... DATE NOV 1995 09. . . JAN 1996 23. .. FEB 06. . . APR 19. .. JUN 25. . . SEP 04.. . DATE NOV 1995 09... JAN 1996 23... FEB 06... APR 19... JUN 25... 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) 1030 512 165 7.6 23.5 45 7.7 89 <10 K13000 K28000 1025 109 249 7.8 22.0 2.9 8.1 91 <10 K170 K150 1115 101 260 7.9 23.0 3.1 8.8 102 <10 K82 K120 1015 124 219 7.8 24.0 40 8.2 96 11 K6300 6800 1100 240 1300 172 HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 81 -- -- 93 -- 100 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) <0.10 -- -- <0.10 -- <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 22 -- -- 24 -- 27 SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 24 -- -- 26 -- 29 220 235 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 7.6 -_ -- 8.1 -- 8.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 121 -- — 141 — 159 7.6 8.0 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 8.4 -- -- 8.9 -- 8.9 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 170 — — 47.1 — 70.6 25.0 38 28.0 52 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- -- 0.4 -- 0.4 RESIDUE TOTAL AT 105 DEG . C , SUS- PENDED (MG/L) (00530) 5 7 4 46 54 56 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.6 -- -- 1.9 -- 1.8 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.28 0.870 0.730 1.54 1.89 2.49 8.1 8.1 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 64 110 110 90 92 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 <0.010 <0.010 0.060 0.010 0.010 97 103 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.30 0.870 0.730 1.60 1.90 2.50 25 2000 4400 <10 K1500 610 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 10 -- -- 10 -- 10 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.020 0.030 0.030 0.180 0.040 0.030 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 7.5 -- -- 7.7 -- 7.1 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.52 <0.20 <0.20 2.1 <0.16 0.25 K • non- ideal count RIO GRANDE DE ANASCO BASIN 50144000 RIO GRANDE DE ANASCO NEAR SAN SEBASTIAN, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 417 NOV 1995 09. .. JAN 1996 23. .. FEB 06. . . APR 19. .. JUN 25. .. SEP 04. .. NOV 1995 09. .. JAN 1996 23. .. FEB 06. . . APR 19. . . JUN 25. . . SEP 04. .. NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.54 <0.20 <0.20 2.3 0.20 0.28 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.8 1.1 0.86 3.9 2.1 2.8 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS N03) (71887) 8.1 4.7 3.8 17 9.3 12 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MM) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.210 0.020 0.020 0.880 0.140 0.250 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- -- <1 — -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- — 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 — -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) 1 -- -- 1 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- ' <10 — -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 910 110 80 <1 <0.10 <0.010 <0.010 418 RIO ORANDE DB ANASCO BASIN 50146000 RIO ORANDE DB 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 Anasco plaza. DRAINAGE AREA.--139 mi 2 (360 km2 ) this does not include 39.7 mi 2 (102.8 km2 ), flow is diverted to south coast. PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 07... JAN 1996 18.. . FEB 23... APR 16... JUN 25. . . AUG 30. . . DATE NOV 1995 06. .. JAN 1996 18.. . FEE 23. . . APR 16. .. JUN 25. .. AUG 30. . . DATE NOV 1995 06... JAN 1996 18... FEB 23... APR 16... JUN 25... AUG 30... 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) 0800 355 232 7.3 24.5 1.4 7.5 88 <10 410 490 1005 163 239 7.7 23.0 4.1 7.6 87 <10 330 K110 0700 E550 124 6.5 21.0 740 7.4 82 68 K60000 51000 0900 113 1340 354 0930 277 HARD- NESS TOTAL (MG/L AS CACO3 ) (00900) 130 -- -- 110 -- 100 FLUO- RIDE, DIS- SOLVED (MG/L AS F) (00950) 0.10 -- -- <0.10 — <0.10 CALCIUM DIS- SOLVED (MG/L AS CA) (00915) 35 -- -- 28 -- 27 SILICA, DIS- SOLVED (MG/L AS SI02) (00955) 36 -- -- 29 — 30 237 235 235 MAGNE- SIUM, DIS- SOLVED (MG/L AS MG) (00925) 10 -- -- 9 .5 -- 8.9 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 192 -_ -- 163 -- 160 7.7 7.2 7.3 SODIUM, DIS- SOLVED (MG/L AS NA) (00930) 12 -- -- 9.9 -- 9.0 SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 187 -- -- 49.6 — 120 24.5 2 27.0 44 27.0 23 SODIUM AD- SORP- TION RATIO (00931) 0.5 -- -- 0.4 -- 0.4 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 15 1180 11 104 42 .6 POTAS- SIUM, DIS- SOLVED (MG/L AS K) (00935) 1.9 -- -- 1.7 -- 2.0 NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.58 0.890 1.50 0.910 0.930 0.730 7.2 6.8 6.8 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CACO3 (00410) 100 100 43 110 100 110 NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.010 0.100 0.060 0.010 0.070 85 84 85 SULFIDE TOTAL (MG/L AS S) (00745) <0.5 -- -- <0.5 -- -- NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.60 0.900 1.60 0.970 0.940 0.800 15 240 K100 24 K7200 K2000 <10 K1500 640 SULFATE DIS- SOLVED (MG/L AS SO4) (00945) 19 -- -- 11 -- 9.4 NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) <0.010 0.030 0.180 0.190 0.020 0.120 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 10 -- -- 7.7 -- 7.5 NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.33 <0.20 3.8 0.39 0.38 0.44 K • non-ideal count E - estimated RIO GRANDE DE ANASCO BASIN 50146000 RIO GRANDE DE ANASCO NEAR ANASCO, PR—Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 419 DATE NOV 1995 06.. . JAN 1996 18.. . FEB 23. . . APR 16. . . JUN 25. .. AUG 30. .. NOV 1995 06. .. JAN 1996 18. .. FEB 23. .. APR 16. .. JUN 25. . . AUG 30.. . NITRO- GEN, AM- MONIA + ORGANIC TOTAL (MG/L AS N) (00625) 0.33 <0.20 4.0 0.58 0.40 0.56 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.9 1.1 5.6 1.6 1.3 1.5 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 8.5 4.7 25 6.9 5.9 6.0 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.030 0.020 0.680 0.240 0.100 0.150 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- — <1 — — SELE- NIUM, TOTAL (UG/L AS SE) (01147) BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 — -- <100 -- — SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 20 — -- 20 -- -- ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- — <1 -- — CYANIDE TOTAL (MG/L AS CN) (00720) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 -- -- PHENOLS TOTAL (UG/L) (32730) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- — <10 — — METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 70 <0.10 0.10 <0.010 JUN 1996 25... 1340 PCB, TOTAL (UG/L) PESTICIDE ANALYSES ALDRIN, TOTAL CHLOR- DANE, TECH- NICAL TOTAL (UG/L) (UG/L) P,P'- DDD UNFILT RECOVER (UG/L) P,P'- DDT DDE, UNFILT TOTAL RECOVEI (UG/L) (UG/L) DI- AZINON, TOTAL (UG/L) ENDO- DI- SULFAN, ELDRIN I TOTAL (UG/L) TOTAL (UG/L) (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 DATE JUN 1996 25... ENDRIN WATER UNPLTRD ETHION, REC TOTAL (UG/L) (UG/L) (39390) (39398) HEPTA- HEPTA- CHLOR CHLOR, EPOXIDE LINDANE TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (39410) (39420) (39340) MALA- THION, TOTAL (UG/L) (39530) METH- OXY- CHLOR, TOTAL (UG/L) (39480) METHYL PARA- THION, TOTAL (UG/L) (39600) MI REX, TOTAL (UG/L) (39755) <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 <0.010 DATE JUN 1996 25... PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (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) 0.060 <0.010 <0.010 <0.010 420 THIS PAGE WAS LEFT BLANK INTENTIONALLY Drainage boundary uncertain EXPLANATION ±1478 SURFACE-WATER STATION AND NUMBER ^1476 QUALITY-OF-WATER STATION AND NUMBER • 200 WELL AND WELL NUMBER 0123456 KILOMETERS 01234 MILES Figure 27.--Rio Culebrinas basin. IS) 422 RIO CULEBRINAS BASIN 50147600 RIO CULEBRINAS 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 km) 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 2 (150.7 km2 ). PERIOD OF RECORD.—Water years 1979 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NOV 07 JAN 18 FEB 22 APR 16 JUN 06 AUG 21 DATE 1995 1996 . . . . . . DATE NOV 1995 07... JAN 1996 18. .. FEB 22.. . APR 16. . . JUN 06. .. 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 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) 1030 98 250 7.5 25.0 3.2 1145 41 275 8.0 24.0 5.0 1430 128 276 7.8 23.0 150 1310 35 276 8.1 27.5 3.1 0925 181 296 7.8 24.0 45 1140 228 273 7.5 24.5 89 HARD- MAGNE- SODIUM POT AS - NESS CALCIUM SIUM, SODIUM, AD- SIUM, TOTAL DIS- DIS- DIS- SORP- DIS- (MG/L SOLVED SOLVED SOLVED TION SOLVED AS (MG/L (MG/L (MG/L RATIO (MG/L CACO3) AS CA) AS MG) AS NA) AS K) (00900) (00915) (00925) (00930) (00931) (00935) 110 33 5.8 10 0.4 2.0 __ __ 110 35 5.7 14 0.6 0.90 __ 130 43 4.4 8.8 0.3 3.1 8.5 8.4 7.9 9.5 7.7 7.5 ALKA- LINITY WAT WH TOT FET FIELD MG/L AS CAC03 (00410) 98 110 110 110 130 120 101 <10 98 <10 3000 570 92 20 56000 119 11 90 66 89 11 SULFATE SULFIDE DIS- TOTAL SOLVED (MG/L (MG/L AS S) AS SO4) (00745) (00945) <0.5 5.8 __ __ <0.5 9.3 __ 12 2200 5900 5600 CHLO- RIDE, DIS- SOLVED (MG/L AS CL) (00940) 9.4 -- -- 13 -- 9.5 380 290 6500 K54 9800 5700 K = non-ideal count RIO CULEBRINAS BASIN 50147600 RIO CULEBRINAS NEAR SAN SEBASTIAN, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 423 SOLIDS, RESIDUE DATE NOV 1995 07... JAN 1996 18... FEB 22... APR 16... JUN 06... AUG 21.. . NOV 1995 07. .. JAN 1996 18. . . FEB 22. . . APR 16... JUN 06... AUG 21. . . DATE NOV 1995 07... JAN 1996 18... FEB 22... APR 16... JUN 06... AUO 21... 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 0.30 0.22 0.53 0.40 <0.20 IRON, TOTAL RECOV- ERABLE (UG/L AS FE) (01045) SILICA, DIS- SOLVED (MG/L AS SIO2) (00955) 36 -- -- 33 -- 19 NITRO- GEN, TOTAL (MG/L AS N) (00600) 1.6 1.6 1.8 1.5 1.6 0.94 LEAD, TOTAL RECOV- ERABLE (UG/L AS PB) (01051) SUM OF CONSTI- TUENTS, DIS- SOLVED (MG/L) (70301) 161 -- -- 177 -- 172 NITRO- GEN, TOTAL (MG/L AS NO3) (71887) 7.3 7.1 8.1 7.9 7.1 4.2 MANGA- NESE, TOTAL RECOV- ERABLE (UG/L AS MN) (01055) SOLIDS, DIS- SOLVED (TONS PER DAY) (70302) 42.4 -- -- 16.6 -- 106 PHOS- PHORUS TOTAL (MG/L AS P) (00665) 0.040 0.110 0.080 0.120 0.040 0.060 MERCURY TOTAL RECOV- ERABLE (UG/L AS HG) (71900) TOTAL AT 105 DEG. C, SUS- PENDED (MG/L) (00530) <1 9 154 9 78 86 ARSENIC TOTAL (UG/L AS AS) (01002) <1 -- -- <1 -- -- SELE- NIUM, TOTAL (UG/L AS SE) (01147) NITRO- GEN, NITRATE TOTAL (MG/L AS N) (00620) 1.38 1.28 1.54 1.21 1.17 0.830 BARIUM, TOTAL RECOV- ERABLE (UG/L AS BA) (01007) <100 -- -- <100 -- -- SILVER, TOTAL RECOV- ERABLE (UG/L AS AG) (01077) NITRO- GEN, NITRITE TOTAL (MG/L AS N) (00615) 0.020 0.020 0.060 0.090 0.030 0.010 BORON, TOTAL RECOV- ERABLE (UG/L AS B) (01022) 40 -- -- 40 -- — ZINC, TOTAL RECOV- ERABLE (UG/L AS ZN) (01092) NITRO- GEN, NO2+NO3 TOTAL (MG/L AS N) (00630) 1.40 1.30 1.60 1.30 1.20 0.840 CADMIUM TOTAL RECOV- ERABLE (UG/L AS CD) (01027) <1 -- -- <1 -- -- CYANIDE TOTAL (MG/L AS CN) (00720) NITRO- GEN, AMMONIA TOTAL (MG/L AS N) (00610) 0.010 0.040 0.060 0.300 0.050 0.010 CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) <1 -- -- <1 — -- PHENOLS TOTAL (UG/L) (32730) NITRO- GEN, ORGANIC TOTAL (MG/L AS N) (00605) 0.23 0.26 <0.16 0.23 0.35 <0.20 COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) <10 -- -- <10 -- -- METHY- LENE BLUE ACTIVE SUB- STANCE (MG/L) (38260) 250 260 <1 20 40 <0.10 <0.10 <1 <1 <1 <1 <0.010 <0.010 <0.02 0.02 424 RIO CULEBRINAS BASIN 50147800 RIO CULEBRINAS AT HIGHWAY 404 NEAR HOCA, PR LOCATION.—Lat 18°21'42", 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 Hoca. DRAINAGE AREA.—71.2 mi 2 (184.4 km2 ). 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. Gage-height and precipitation satellite telemetry at station. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES OCT NOV DEC JAN FEB APR MAY JUN JUL SEP 1 577 169 2 1060 160 3 1010 157 4 1470 147 5 910 140 6 334 135 7 265 130 8 235 239 9 207 203 10 186 151 11 260 119 12 266 115 13 781 112 14 2970 108 15 1120 160 16 2390 129 17 3500 108 18 908 105 19 444 98 20 376 95 21 323 183 22 357 133 23 247 99 24 231 108 25 443 122 26 978 156 27 367 144 28 275 90 29 236 85 30 190 85 31 179 —— TOTAL 23095 3985 MEAN 745 133 MAX 3500 239 MIN 179 85 AC -FT 45810 7900 CFSM 10.5 1.87 IN. 12.07 2.08 STATISTICS OF MONTHLY MEAN MEAN 631 329 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 89 82 79 76 83 94 76 72 72 134 128 108 75 71 70 70 67 71 76 76 193 119 76 71 68 68 63 63 62 60 58 2570 82.9 193 58 5100 1.16 1.34 DATA 145 424 1982 72.1 1992 FOR 59 59 59 56 57 57 55 56 56 65 el38 e74 e69 e67 e65 e65 e64 e63 e!02 105 75 66 62 59 59 69 102 92 82 67 60 2184 70.5 138 55 4330 .99 1.14 FOR WATER 77.1 151 1971 51.2 1979 55 50 49 48 46 111 351 135 90 238 321 119 87 77 72 69 66 236 194 347 560 3490 1830 1030 397 225 183 156 141 —— 10773 371 3490 46 21370 5.22 5.63 YEARS 1967 80.0 371 1996 37.0 1992 129 121 116 111 105 101 98 94 115 124 95 86 86 119 1100 187 129 121 113 105 99 94 90 89 85 74 66 63 72 78 64 4129 133 1100 63 8190 1.87 2.16 - 1996 71.2 319 1981 30.4 1979 1995 CALENDAR YEAR 111818 306 4750 30 34 221800 4. 58. 779 128 46 May 28 May 3 Apr 29 30 42 112 89 64 61 66 96 74 70 60 57 56 124 72 60 59 54 53 105 82 95 59 77 101 153 93 116 69 57 51 46 —— 2331 77.7 153 46 4620 1.09 1.22 47 47 45 63 42 1280 273 98 86 70 384 507 452 249 127 204 133 150 450 226 162 162 133 120 114 225 337 1010 1250 2800 1360 12606 407 2800 42 25000 5.71 6.59 582 638 405 375 386 1990 521 1420 446 300 301 252 1030 435 320 764 433 711 298 237 212 213 188 171 162 153 179 447 1790 442 —— 15801 527 1990 153 31340 7.40 8.26 253 194 174 171 166 155 147 255 374 193 205 1360 325 238 200 183 170 162 266 267 169 153 146 140 140 134 136 136 134 128 130 7004 226 1360 128 13890 3.17 3.66 132 201 211 191 141 129 123 159 214 138 325 632 240 427 217 399 2240 599 3750 1080 378 310 278 220 230 176 160 152 176 162 144 13934 449 3750 123 27640 6.31 7.28 141 138 140 723 323 259 196 255 188 e!270 699 319 262 285 306 1760 1060 1720 433 450 341 275 247 547 538 562 301 223 205 201 14367 479 1760 138 28500 6.73 7.51 , BY WATER YEAR (WY) 134 621 1986 26.4 1970 FOR 1996 112779 308 3750 42 49 24500 27 39 223700 4 58 656 144 62 474 2054 1986 96.7 1973 WATER YEAR Aug 19 May 5 Apr 29 Sep 10 .41 Sep 10 May 6 .33 .92 392 769 1984 82.7 1974 298 847 1979 66.7 1994 WATER 292 457 179 13300 19 20 69000 36 16 211300 4 55 600 135 43 331 831 1979 119 1970 YEARS 1967 Oct Apr Apr Sep .60 Sep Apr .10 .65 514 1350 1978 145 1986 - 1996 1986 1977 21 1972 16 1979 13 1979 16 1975 16 1975 17 1979 e Estimated 425 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* (251.2 tan*)- PERIOD OP RECORD.--Water years 1958, 1970 to current year. WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DATE NOV 1995 07... JAN 1996 17... wn lr£o 22... APR 17... JUN 06... AUG 21... DATE NOV 1995 07... JAN 1996 17... FEE 22... APR 17... JUN 06... AUG 21... DATE NOV 1995 07... JAN 1996 17... FEE 22... APR 17... JUN 06... AUG 21... TIME 1200 1600 1540 1015 0645 0915 STREP- TOCOCCI FECAL, (COLS. PER 100 ML) (31679) 260 330 6700 5100 25000 37000 CHLO- RIDE, DIS- SOLVED (HG/L AS CL) (00940) 12 -- — 15 -- 8.3 DIS- CHARGE, INST. CUBIC FEET PER SECOND (00061) E350 E65 E271 E51 E275 E368 HARD- NESS TOTAL (HG/L AS CACO3) (00900) 130 -- -- 140 -- 110 FLUO- RIDE, DIS- SOLVED (HG/L AS F) (00950) 0.10 -- -- 0.10 _-. <0.10 SPE- CIFIC CON- DUCT- ANCE (US /CM) (00095) 284 300 255 314 300 252 CALCIUM DIS- SOLVED (HG/L AS CA) (00915) 43 -- __ 46 -- 38 SILICA, DIS- SOLVED (HG/L AS SI02) (00955) 35 -- __ 33 __ 14 PH WATER WHOLE FIELD (STAND- ARD UNITS) (00400) 7.4 7.9 7.6 7.7 7.6 7.1 MAGNE- SIUM, DIS- SOLVED (HG/L AS HG) (00925) 5.8 __ __ 6.3 — 3.6 SOLIDS, SUM OF CONSTI- TUENTS, DIS- SOLVED (HG/L) (70301) 187 __ -- 204 __ 149 TEMPER- ATURE WATER (DEG C) (00010) 26.0 25.0 23.0 26.0 25.0 24.5 SODIUM, DIS- SOLVED (HG/L AS MA) (00930) 11 -_ __ 15 -_ 6.6 RESIDUE TOTAL AT 105 DEG. C, SUS- PENDED (HG/L) (00530) 14 23 490 29 300 480 TUR- BID- ITY (NTU) (00076) 18 16 370 8.5 120 340 SODIUM AD- SORP- TION RATIO (00931) 0.4 -- -- 0.6 -- 0.3 NITRO- GEN, NITRATE TOTAL (HG/L AS N) (00620) 0.940 0.860 0.770 0.820 0.790 0.820 OXYGEN, DIS- SOLVED (HG/L) (00300) 7.5 7.0 7.3 6.4 6.7 5.2 POTAS- SIUM, DIS- SOLVED (HG/L AS K) (00935) 2.2 — -- 2.7 -- 3.0 NITRO- GEN, NITRITE TOTAL (HG/L AS N) (00615) 0.010 0.010 0.050 0.010 0.080 0.010 OXYGEN, DIS- SOLVED (PER- CENT SATUR- ATION) (00301) 90 83 85 78 80 61 ALKA- LINITY WAT WH TOT FET FIELD HG/L AS CACO3 (00410) 120 130 100 130 140 110 NITRO- GEN, NO2+NO3 TOTAL (HG/L AS N) (00630) 0.950 0.870 0.820 0.830 0.870 0.830 OXYGEN DEMAND, CHEM- ICAL (HIGH LEVEL) (HG/L) (00340) <10 <10 53 28 37 52 SULFIDE TOTAL (HG/L AS S) (00745) <0.5 -- __ <0.5 -- -- NITRO- GEN, AMMONIA TOTAL (HG/L AS N) (00610) 0.030 0.090 0.120 0.060 0.090 0.060 COLI- FORM, FECAL, 0.45 UM-HF (COLS./ 100 ML) (31616) K1300 2700 K85000 2000 K13000 20000 SULFATE DIS- SOLVED (HG/L AS S04) (00945) 5.7 __ -- 8.1 -- 9.5 NITRO- GEN, ORGANIC TOTAL (HG/L AS N) (00605) 0.25 0.42 1.6 <0.20 1.0 <0.20 E - estimated K - non-ideal count 426 RIO CULEBRINAS BASIN 50149100 RIO CULEBRINAS NEAR AGUADA, PR--Continued WATER-QUALITY DATA, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 NOV 1995 07... JAN 1996 17... FEB 22... APR 17... JUN 06... AUG 21... NITRO- GEN, AM- MONIA + ORGANIC TOTAL (HG/L AS N) (00625) NITRO- GEN, TOTAL (HG/L AS N) (00600) NITRO- GEN, TOTAL (HG/L AS NO3) (71887) PHOS- PHORUS TOTAL (HG/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 TOTAL RECOV- ERABLE (UG/L AS CD) (01027) CHRO- MIUM, TOTAL RECOV- ERABLE (UG/L AS CR) (01034) COPPER, TOTAL RECOV- ERABLE (UG/L AS CU) (01042) 0.28 0.51 1.7 0.34 1.1 <0.20 1.2 1.4 2.5 1.3 2.0 1.0 5.4 6.1 11 5.6 8.7 4.4 0.030 0.130 0.310 0.060 0.180 0.070 <100 <100 30 30 <10 <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 MM) (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 (HG/L AS CN) (00720) PHENOLS TOTAL (UG/L) (32730) METHY- LENE BLUE ACTIVE SUB- STANCE (HG/L) (38260) NOV 1995 07... JAN 1996 17... FEE 22... APR 17... JUN 06... AUG 21... 650 690 JUN 1996 06... TIME 0645 60 <0.10 80 <0.10 <10 <0.010 <10 <0.010 <0.02 0.03 PESTICIDE ANALYSES PCB, TOTAL (UG/L) ALDRIN, TOTAL (UG/L) CHLOR- DANE, TECH- NICAL TOTAL (UG/L) P,P'- DDD UNFILT RECOVER (UG/L) DDE, TOTAL (UG/L) P,P'- DDT UNFILT RECOVER (UG/L) DI- AZINON, TOTAL (UG/L) DI- ELDRIN TOTAL (UG/L) ENDO- SULFAN, I TOTAL (UG/L) (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 JUN 1996 06... ENDRIN HATER UNFLTRD ETHION, REC TOTAL (UG/L) (UG/L) HEPTA- METH- HEPTA- CHLOR MALA- OXY- CHLOR, EPOXIDE LINDANE THION, CHLOR, TOTAL TOTAL TOTAL TOTAL TOTAL (UG/L) (UG/L) (UG/L) (UG/L) (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 JUN 1996 06... PARA- THION, TOTAL (UG/L) (39540) PCNS UNFILT RECOVER (UG/L) (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) 0.560 <0.010 <0.010 <0.010 427 VIEQUES, PR 50232000 QUEBRADA LA. MINA NEAR ESPERANZA, VIEQUES, PR LOCATION.--Lat 18°06'54", long 65 0 28'15", Hydrologic Unit 21010006, on left bank 300 ft (91 m), west from state road 996, 1.4 mi (2.2 km) south of Cerro Martineau, 0.7 mi (1.1 km) east-northeast of Colonia Puerto Real on road 201 and 1.2 mi (1.9 km) north of Esperanza. DRAINAGE AREA.—0.68 mi* (1.76 km 1 ). WATER-STAGE RECORDS PERIOD OF RECORD.--July 1991 to March 1996. (discontinued) GAGE.—Water-stage recorder. Elevation of gage is 98 ft (30 m), from topographic map. REMARKS.—Gage-height and precipitation satellite telemetry at station. All gage-heights of 9.20 ft or lower are considered zero flow. EXTREMES OBSERVED FOR PERIOD OF RECORD.—Maximum gage-height, 9.90 ft (3.018 m), June 29, 30, 1993; minimum, 8.76 ft (2.670 m), May 18-24, 1994. EXTREMES FOR CURRENT YEAR.—Maximum gage-height, 8.82 ft (2.688 m), Oct. 1; minimum, 8.82 ft (2.688 m), Oct. 1. GAGE HEIGHT, FEET, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 8.82 8.82 8.82 8.82 8.82 8.82 2 8.82 8.82 8.82 8.82 8.82 8.82 3 8.82 8.82 8.82 8.82 8.82 8.82 4 8.82 8.82 8.82 8.82 8.82 8.82 5 8.82 8.82 8.82 8.82 8.82 8.82 6 8.82 8.82 8.82 8.82 8.82 8.82 7 8.82 8.82 8.82 8.82 8.82 8.82 8 8.82 8.82 8.82 8.82 8.82 8.82 9 8.82 8.82 8.82 8.82 8.82 8.82 10 8.82 8.82 8.82 8.82 8.82 8.82 11 8.82 8.82 8.82 8.82 8.82 8.82 12 8.82 8.82 8.82 8.82 8.82 8.82 13 8.82 8.82 8.82 8.82 8.82 8.82 14 8.82 8.82 8.82 8.82 8.82 8.82 15 8.82 8.82 8.82 8.82 8.82 8.82 16 8.82 8.82 8.82 8.82 8.82 8.82 17 8.82 8.82 8.82 8.82 8.82 8.82 18 8.82 8.82 8.82 8.82 8.82 8.82 19 8.82 8.82 8.82 8.82 8.82 8.82 20 8.82 8.82 8.82 8.82 8.82 8.82 21 8.82 8.82 8.82 8.82 8.82 22 8.82 8.82 8.82 8.82 8.82 23 8.82 8.82 8.82 8.82 8.82 24 8.82 8.82 8.82 8.82 8.82 25 8.82 8.82 8.82 8.82 8.82 26 8.82 8.82 8.82 8.82 8.82 27 8.82 8.82 8.82 8.82 8.82 28 8.82 8.82 8.82 8.82 8.82 29 8.82 8.82 8.82 8.82 8.82 30 8.82 8.82 8.82 8.82 —— 31 8.82 —— 8.82 8.82 —— MAX 8.82 8.82 8.82 8.82 8.82 —— MIN 8.82 8.82 8.82 8.82 8.82 —— CAL YR 1995 MEAN 8.82 MAX 8.89 MIN 8.79 MED 8.82 428 VIEQUES, PR 50233000 QUEBRADA PILON AT COLONIA PUERTO REAL, VIEQOES, PR LOCATION.—Lat 18°06'37", long 65°28'51", Hydrologic Unit 21010006, on left bank, 1.2 mi (1.9 km), southeast of Cerro Sonadora, 1.2 mi (1.9 km) northwest of Esperanza, 0.4 mi (0.6 km) south of junction of Highways 895 and 201. DRAINAGE AREA.—0.67 mi 2 (1.74 km*). WATER-STAGE RECORDS PERIOD OF RECORD.—JUly 1991 to March 1996. (discontinued) GAGE.—Water-stage recorder. Elevation of gage is 131 ft (40 m), from topographic map. REMARKS.—Gage-height and precipitation satellite telemetry at station. All gage-heights of 8.36 ft or lower are considered zero flow. EXTREMES FOR PERIOD OF RECORD.--Maximum gage-height, 9.13 ft (2.783 m), July 23, 1993; minimum, 6.68 ft (2.036 m), Sept. 14, 15, 1993. EXTREMES FOR CURRENT YEAR.—Maximum gage-height, 7.41 ft (2.258 m), Oct. 18; minimum, 7.24 ft (2.206 m), Dec. 24. GAGE HEIGHT, FEET, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 DAILY MEAN 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 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.26 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.26 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.26 7.25 NOV 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 DEC 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.24 7.25 7.25 7.25 7.25 7.25 7.25 7.26 JAN 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.25 7.25 .25 .25 .25 7. 7. 7. 7.25 FEB 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 .26 .26 MAR 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 7.25 APR MAY JUN JUL AUG SEP 7. 7. 7.26 25 25 25 25 7.25 7.25 7.26 7.24 7.25 7.26 7.26 7.26 7.25 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.25 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.26 7.25 7.25 7.25 7.25 7.25 7.26 7.25 7.25 7.25 7.25 7.25 7.25 429 430 DISCHARGE AT PARTIAL-RECORD STATIONS As the number of streams on which streamflow information is likely to be 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 1996 PUBLICATION RECORD STATION NUMBER 50010520 STATION Rio Guajataca above sewage plant at Lares, PR 50013000 Rio Camay near Lares, PR 50014000 Rio Criminales near Lares, PR 50014500 Rio Camay off Highway 129 near Lares, PR 50020150 Rio Vacas near Adjuntas, PR 50020295 Rio Cidra at Adjuntas, PR 50020500 Rio Grande de Arecibo near Adjuntas, PR LOCATION 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. Rio Camay basin Lat 18°17'49", long 66°49'31", Hydrologic Unit 21010001, at bridge on Highway 111, 1.1 mi (1.8 km) upstream from Rio Criminales, 1.8 mi (2.9 km) downstream from Rio Angeles and Rio Piedras confluence, and 3.5 mi (5.6 km) east of Lares. Lat 18°17'57", long 66°49'22", Hydrologic Unit 21010001, at bridge on Highway 111, 0.7 mi (1.1 km) upstream from Rio Camay, and 3.7 mi (5.6 km) east of Lares. Lat 18°19'01", long 66°49'38", Hydrologic Unit 21010002, at barrio Callejones, 1.1 mi (1.8 km) downstream from Rio Criminales, 1.9 mi (3.1 km) east from Cueva pajita, and 4.0 mi (6.4 km) northeast from Lares. Rio Grande de Arecibo basin Lat 18°10'29", long 66°44'16", Hydrologic Unit 21010001, at barrio Garzas on Highway 522, 0.6 mi (1.0 km) upstream from Highway 135, 2.2 mi (3.5 km) north of Lago Garzas, and 1.2 mi (1.9 km) northwest of Adjuntas plaza. Lat 18°09'58", long 66°43'37", Hydrologic Unit 21010001, at Adjuntas, 0.1 mi (0.2 km) downstream from Highway 10, 1.9 mi (3.1 km) northeast of Lago Garzas, and 0.3 mi (0.5 km) northwest of Adjuntas plaza. Lat 18°10'54", long 66°44'12", Hydrologic Unit 21010001, at bridge on Highway 135, 1.0 mi (1.6 km) upstream from Lago Adjuntas, and 1.5 mi (2.4 km) northwest of Adjuntas plaza. DRAINAGE AREA mi 2 (km») 5.40 (14.0) DATE 3/25/96 5/06/96 TIME 1330 1345 7.62 (19.7) 4.68 (12.1) 13.6 (35.2) 3/25/96 5/06/96 3/25/96 5/06/96 3/25/96 5/06/96 1100 1115 1145 1200 1000 1030 3.10 (8.03) 6.67 (17.3) 12.7 (32.9) 3/20/96 5/02/96 3/20/96 5/02/96 3/20/96 5/02/96 1330 1230 1245 1315 1130 1130 STREAM- FLOW Cfs (cms) 4.31 (0.122) 5.63 (0.159) 9.73 (0.276) 9.25 (0.262) 6.18 (0.175) 5.55 (0.157) 16.1 (0.456) 13.6 (0.385) 3.57 (0.101) 3.96 (0.112) 5.96 (0.169) 5.86 (0.166) 11.3 (0.320) 12.5 (0.354) 431 STATION NUMBER 50021000 STATION NAME DISCHARGE AT PARTIAL-RECORD STATIONS Low-flow partial-record stations—Continued LOCATION AND BASIN Rio Pellejas at Central Pellejas, PR 50021800 Rio Guadnica near Utuado, PR 50021900 50021905 Quebrada Arenas near Utuado, PR Rio Grande de Arecibo near Utuado, PR 50023000 Rio Vivi near Central Pellejas , PR 50024995 Rio Caguana on Highway 10 near Utuado, PR 50025165 Rio Caricaboa at Jayuya, PR 50025175 50025600 Rio Grande de Jayuya at Jayuya, PR Rio Jauca near Jayuya, PR DRAINAGE AREA mi' (tan') Rio Grande de Arecibo basin Lat 18°12'07», long 66°42'16", 5.46 Hydrologic Unit 21010001, at (14.1) barrio Pellejas near Highway 524, 0.1 mi (0.2 km) upstream from unnamed tributary and diversion tunnel, 1.0 mi (1.6 km) upstream from Lago Pellejas, and 2.9 mi (4.7 km) northeast of Adjuntas plaza. Lat 18°15'18", long 66°43'47", 6.10 Hydrologic Unit 21010001, at (15.8) barrio Guadnica 50 ft (15 m) off Highway 603, 0.5 mi (0.8 km) upstream from Rio Grande de Arecibo, 0.4 mi (0.6 km) downstream from Rio Roncador, and 2.2 mi (3.5 km) southwest of Utuado plaza. Lat 18°15'40», long 66°43'19", 2.59 Hydrologic Unit 21010001, at (6.71) barrio Arenas on Highway 10, 200 ft (61 m) upstream from Rio Grande de Arecibo, and 1.5 mi (2.4 km) southwest of Utuado plaza. Lat 18»15'46», long 66°43'15", 39.9 Hydrologic Unit 21010001, at (103) barrio Arenas, 200 ft (61 m) off Highway 10, 0.1 mi (0.2 km) downstream from Quebrada Arenas, 1.7 mi (2.7 km) upstream from Rio Vivi, and 1.4 (2.2 km) southwest from Utuado plaza. Lat 18°12'52", long 66°40'25", 5.66 Hydrologic Unit 21010001, at (14.6) barrio Vivi Arriba on Highway 605, 2.0 mi (3.2 km) upstream from Lago Vivi, 2.1 mi (3.4 km) northeast from Lago Pellejas, and 1.3 mi (2.1 km) northwest from Cerro Prieto. Lat 18°18'09", long 66°42'20" 4.49 Hydrologic Unit 21010001, at (11.3) barrio Sabana Grande, 3.4 mi (5.5 km) southwest of Lago Dos Bocas spillway, 2.2 mi (3.5 km) northeast from Parcelas Cayuco, and 2.4 mi (3.9 km) north of Utuado plaza. Lat 18°13'10", long 66°35'12", 4.22 Hydrologic Unit 21010001, at (10.9) barrio Veguitas on Highway 144, 0.4 mi (0.6 km) upstream from Rio Grande de Jayuya, 1.6 mi (2.6 km) northwest of Hacienda Gripinas, and 0.5 mi (0.8 km) east of Jayuya plaza. Lat 18°13'01", long 66°36'28", 18.8 Hydrologic Unit 21010001, 1.5 (48.7) mi (2.4 km) downstream from Rio Caricaboa, 1.4 (2.2 km) upstream from Rio Zamas, 1.0 mi (1.6 km) southwest from Jayuya plaza. Lat 18°11'16", long 66°38'25", 4.44 Hydrologic Unit 21010001, at (11.5) barrio Jauca on Highway 140, 1.7 mi (2.7 km) southeast from Cerro Prieto, 4.6 mi (7.4 km) southeast from Lago Pellejas, and 3.8 mi (6.1 km) southwest of Jayuya. DATE 3/20/96 5/02/96 TIME 1030 1030 3/19/96 5/01/96 1130 1000 3/19/96 5/01/96 3/19/96 5/01/96 3/19/96 5/01/96 3/19/96 5/01/96 3/14/96 5/03/96 3/14/96 5/03/96 3/14/96 5/03/96 1015 1045 1045 1115 1230 1245 1345 1345 1245 1115 1145 1200 1045 1345 STREAM FLOWS Cfs (cms) 5.78 (0.164) 4.97 (0.141) 9.52. (0.270) 7.32 (0.207) 2.30 (0.065) 2.10 (0.059) 18.6 (0.526) 15.1 (0.428) 7.48 (0.212) 6.30 (0.178) 4.04 (0.114) 3.10 (0.088) 5.62 (0.159) 3.23 (0.091) 24.5 (0.694) 14.6 (0.413) 6.78 (0.192) 4,.19 (0.119) 432 DISCHARGE AT PARTIAL-RECORD STATIONS STATION NUMBER STATION NAME 50025900 Rio Jauca at mouth near Jayuya, PR 50026050 Rio Caonillas above Lago Caonillas, PR 50026250 Rio Limon on Highway 613 near Tetuan, PR 50026350 50026925 Rio Limon above confluence with Rio Yunes, PR Rio Yunes at Fronton, PR 50026950 Rio Yunes at mouth near Mameyes Abajo, PR 50027900 Rio Tanama near Caguana, PR 50028100 Rio Tanama above Observatorio de Arecibo, PR 50028200 Rio Tanama at Esperanza, PR Low-flow partial-record stations—Continued LOCATION AND BASIN DRAINAGE AREA mi 2 (tan2 ) DATE TIME (km2 ) Rio Grande de Arecibo basin Lat 18°13'08", long 66°38'35", 7.14 3/14/96 0945 Hydrologic Unit 21010001, at (18.5) barrio Paso Palma on Highway 5/03/96 1300 140, 0.2 mi (0.3 km) upstream from Rio Grande de Jayuya, 2.5 mi (4.0 km) southeast from Lago Vivi, and 2.0 mi (3.2 km) south of Lago Caonillas. Lat 18°14'26", long 66°38'22", 40.4 3/13/96 1315 Hydrologic Unit 21010001, at (105) barrio Caonillas Arriba, 300 4/23/96 1315 feet (91 m) off Highway 531, 700 ft (213 m) upstream from Lago Caonillas, and 3.3 mi (5.3 km) northwest of Jayuya plaza. Lat 18°16'57", long 66°35'52", 5.55 3/13/96 1200 Hydrologic Unit 21010001, at (14.4) barrio Tetuan on Highway 613, 4/23/96 1200 0.4 mi (0.6 km) upstream from Rio Naranjito, 1.3 mi (2.1 km) northwest from Cerro Hagoyo, and 1.3 (2.1 km) from Escuela Segunda Unidad de Mameyes. Lat 18°19'26", long 66°36'42", 16.7 3/13/96 1000 Hydrologic Unit 21010001, 3.4 (43.2) mi (5.5 km) upstream from Lago 4/23/96 1015 Caonillas, 100 ft (30 m) upstream from Rio Yunes, and 4.0 mi (6.4 km) southwest of Florida plaza. Lat 18°18'11", long 66°34'09", 9.63 3/13/96 0845 Hydrologic Unit 21010001, at (24.9) barrio Front6n, 0.9 mi (1.4 km) 4/23/96 0915 southwest from Escuela Segunda Unidad de Fronton, 2.9 mi (4.7 km) northeast fron Cerro Hagoyo, and 4.2 mi (6.8 km) of Florida Plaza. Lat 18°19'30", long 66°36'39", 13.5 3/13/96 1045 Hydrologic Unit 21010001, 3.4 (35.0) mi (5.5 km) upstream from Lago 4/23/96 1100 Caonillas, 100 ft (30 m) upstream from Rio Limon, 1.5 mi (2.4 km) northwest from Hacienda Piedra Gorda, and 4.0 mi (6.4 km) southwest of Florida plaza. Lat 18°15'42", long 66°46'55", 10.8 3/21/96 1245 Hydrologic Unit 21010001, near (30.0) barrio Caguana, 4.4 mi (7.1 km) 4/30/96 1300 upstream from Highway 111, 2.5 mi (4.0 km) south of Parqrie Ceremonial Indigena Caguana, and 2.1 mi (3.4 km) southeast of comunidad Angeles. Lat 18°20'22", long 66°45'25", Indeter- 3/21/96 1000 Hydrologic Unit 21010002, at minate barrio Esperanza, 0.5 mi 4/30/96 1000 (0.8 km) southwest from the Observatorio de Arecibo, 3.2 mi (5.1 km) southeast of comunidad Bayaney, and 3.2 mi (5.1 km) northeast of Parque Ceremonial Indigena Caguana. Lat 18°22'45", long 66044'02", Indeter- 3/21/96 0845 Hydrologic Unit 21010002, at minate barrio Esperanza, 0.9 mi (1.4 4/30/96 0845 km) upstream from Highway 623, 200 ft upstream of AAA intake, 3.2 mi (5.1 km) west from Rio Grande de Arecibo, and 6.7 mi (11 km) southwest from Arecibo plaza. STREAM FLOWS cfs (cms) 9.27 (0.262) 6.68 (0.189) 49.0 (1.388) 41.0 (1.161) 14.1 (0.399) 9.17 (0.260) 28.6 (0.802) 21.6 (0.612) 17.6 (0.498) 13.1 (0.371) 17.6 (0.498) 13.2 (0.374) 17.5 (0.496) 13.6 (0.385) 37.2 (1.054) 31.8 (0.900) 55.4 (1.569) 51.0 (1.444) 433 STATION NUMBER STATION NAME 50029800 Rio Grande de Hanati near Barranquitas, PR 50029900 Rio Grande de Hanati near Corozal, PR 50030250 Rio Botijas near Carro, PR 50030300 Rio Botijas near Botijas, PR 50030600 Rio Orocovis at Orocovis, PR 50031500 Rio Sana Huerto near Orocovis, PR 50032050 Quebrada Riachuelo at mouth, PR 50032100 Quebrada Grande near Horovis, PR 50032400 Rio Toro Negro on Highway 157 at Cacaos, PR DISCHARGE AT PARTIAL-RECORD STATIONS Low-flow partial-record stations--Continued LOCATION AND DRAINAGE AREA mi* (km2 ) BASIN Rio Grande de Manati basin Lat 18°14'00", long 66°18'53", 3.81 Hydrologic Unit 21010001, at (9.87) barrio Barrancas, 300 ft (91 m) east of Highway 771, 2.4 mi (3.9 km) northeast from Cerro La Torrecilla, 0.7 mi (1.1 km) southwest of Cerro El Farallon, and 3.1 mi (5.0 km) from Barranquitas plaza. Lat 18°16'48", long 66°20'03", 13.2 Hydrologic Unit 21010001, at (34.2) barrio Negros on Highway 568, 0.2 mi (0.3 km) upstream from Highway 568, 1.7 mi (2.7 km) northeast of El Salto Grande, and 4.4 mi (7.1 km) southwest of Corozal plaza. Lat 18°11'45", long 66°21'09", 3.82 Hydrologic Unit 21010001, at (9.89) barrio Palo Hincado, 200 ft (61 m) upstream from Highway 156, 100 ft (30 m) upstream from pumping station intake, 1.4 mi (2.2 km) southwest from Cerro La Torrecilla, and 3.1 mi (5.0 km) west of Barranquitas plaza. Lat 18°14'15", long 66°22'36", 12.5 Hydrologic Unit 21010001, at (32.4) barrio Botijas on Highway 548, 0.5 mi (0.8 km) upstream from Rio Orocovis, 0.8 mi (1.3 km) north from Highway 156, and 1.1 mi (1.8 km) northeast of Orocovis plaza. Lat 18°13'58", long 66°23'23", 8.78 Hydrologic Unit 21010001, at (22.7) Orocovis, 0.5 mi (0.8 km) downstream from Quebrada Los Saltos, 1.3 mi (21 km) upstream from Rio Botijas, and 0.3 mi (0.5 km) northeast of Orocovis plaza. Lat 18°16'14", long 66°24'47", 3.68 Hydrologic Unit 21010001, at (9.53) barrio Pesas, 2.5 mi (4.0 km) southwest from Cerro Hagueyes, 2.5 mi (4.0 km) upstream from Rio Grande de Manati, and 4.0 mi (6.4 km) south of Morovis plaza. Lat 18°18'18", long 66°26'15". 1.69 Hydrologic Unit 21010001, at (4.38) barrio San Lorenzo, 50 ft (15 m) off Highway 567, 0.2 (0.3 km) upstream from Rio Grande de Manati, 1.0 mi (1.6 km) north from Cerro Avispa, and 2.5 mi (4.0 km) southwest of Morovis plaza. Lat 18°18'45", long 66°26'40", 2.63 Hydrologic Unit 21010001, at (6.81) barrio San Lorenzo, 50 ft (15 m) off Highway 567, 0.6 mi (1.0 km) upstream from Rio Grande de Manati, 2.3 mi (3.7 km) southeast from Ciales, and 2.6 (4.2 km) southwest from Morovis plaza. Lat 18°13'57", long 66°30'46", 11.8 Hydrologic Unit 21010001, at (30.6) barrio Cacaos on Highway 157, 0.5 mi (0.8 km) upstream from Quebrada Palma, 2.2 mi (3.5 km) northeast of Los Tres Picachos, and 5.3 mi (8.5 km) northeast of Jayuya plaza. DATE 2/27/96 4/29/96 TIME 1300 1300 2/27/96 4/26/96 2/28/96 4/29/96 1200 1130 0830 1115 2/28/96 4/29/96 2/28/96 4/29/96 3/08/96 4/24/96 2/27/96 4/26/96 0945 1015 1045 0930 1130 1330 0915 0915 2/27/96 4/26/96 0830 0845 3/05/96 4/24/96 1230 1200 STREAM FLOWS Cfs (cms) 3.09 (0.088) 2.41 (0.068) 14.5 (0.411) 11.1 (0.314) 2.38 (0.067) 1.79 (0.051) 8.05 (0.228) 6.74 (0.191) 9.60 (0.272) 5.92 (0.168) 4.23 (0.120) 3.90 (0.110) 1.98 (0.056) 1.30 (0.037) 2.16 (0.061) 1.71 (0.043) 10.6 (0.300) 9.12 (0.258) 434 STATION NUMBER STATION NAME 50032700 Rio Matrullas at mouth, PR 50033000 Rio Toro Negro near Ciales, PR 50033500 Rio Bauta near Divisoria, PR 50034500 Rio Bauta at Pozas, PR 50035600 Rio Cialitos at Cialitos, PR 50035700 50035950 Rio Cialitos on Highway 614 near Ciales, PR Rio Cialitos on Highway 649 at Ciales, PR 50037200 Rio Grande de Manati near Manati, PR 50038295 Rio de Los Negros at mouth at Corozal, PR DISCHARGE AT PARTIAL-RECORD STATIONS Low-flow partial-record stations—Continued LOCATION AND BASIN DRAINAGE AREA mi* «J (VH 1 1 1 1 1 1 1 1 1 1 1 OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1996 WATER YEAR 468 GROUND-WATER LEVELS RIO GRANDE DE ARECIBO BASIN 182209066340600. Local number, FL-1. LOCATION.--Lat 18°22'09", long 66°34'06", Hydrologic Unit 21010002, 0.20 north of the intersection of Hwy 140 with Hwy 642, 1.15 mi south of the intersection of Hwy 140 with Hwy 641, and approximately 100 ft west of Hwy 140. Owner: Puerto Rico Aqueduct and Sewer Authority, Name: Florida 1. AQUIFER.--Cibao Formation. WELL CHARACTERISTICS.--Drilled water-table well, diameter 12 in (0.30 m), Depth 200 ft (61.0 m). INSTRUHENTATION.--Pressure transducer with data logger set at 60-minute interval. DATUM.--Elevation of land-surface datum is about 607.0 ft (185.0 m) above mean sea level from topographic map. Measuring point: Shelter floor 4.00 ft (1.22 m) above land-surface datum. REMARKS.--Recording observation well. Data Logger installed on August 12, 1996. PERIOD OF RECORD.--August 12, 1996 to September 30, 1996. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 139.90 ft (42.64 m) below land-surface datum, Sept. 20, 1996; lowest water level recorded, 157.63 ft (48.04 m) below land-surface datum, Aug. 14, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 FEB APR JUL AUG 6 .._ ___ — — — — — — — — — — — 7 _ _ _ _ _ _ _ _ _ _.»_ _ _ _ « « . _ _ _ _ _ _ ___ 11 ___ ___ ___ ___ ___ — __ — .... -.-.-. ...... 10 .............. .LJ — — — — — — — — — — — — — — — — — — — 14 ___ —__ ___ _ — — —-.. ___ -.-... ...... ...... 1C ................ .L9 — — — — — — — — — — — — — — — — — — 18 —— —— —— —— —— —— —— —— —— 19 —— —— —— —— —— —— —— —— —— 22 — — — — — — — — . — — — — — — _ _ _ — — -. » _ _ —«.«. 27 28 —— —— —— —— —— —— —— —— —— 29 — — — ...... ... ... ..— . — _ — —. —.. ... 31 ... ... ... ... .... ... ... ... ... MEAN —— —— —— —— —— —— —— —— —— WTR YR 1996 MEAN 148.67 HIGHEST 139.90 SEPT. 20, 1996 LOWEST 157.63 AUG. 14, 1996 157.60 157.62 157.62 157.16 156.97 149.90 150.42 154.27 154.94 155.57 155.89 155.25 155.69 156.08 156.38 156.63 156.80 149.31 152.89 SEP 154.70 155.40 150.19 149.75 144.05 144.01 148.27 143.63 144.22 140.51 140.19 140.16 140.71 140.09 140.78 142.57 140.02 142.18 143.93 139.91 142.98 144.39 145.11 145.78 146.41 146.95 147.39 146.19 141.18 146.02 155.10 144.59 -£ 148 158 i i I I I I OCT' N(W DEC JAN FEB MAR APR MAT JUR~JUL7^AUG SEF 1996 WATER YEAR GROUND-WATER LEVELS RIO GRANDE DE ARECIBO BASIN 469 182626066345100. Local number, TI-1. . LOCATION.--Lat 18°26'26", long 66°34'51", Hydrologic Unit 21010002, 1.45 mi south of Hwy 682, 1.15 mz 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: Puerto Rico Aqueduct and Sewer Authority, Name: Tiburones 1. AQUIFER.—Aymamon Limestone. WELL CHARACTERISTICS.--Drilled water-table well, diameter 12 in (0.30 m) . Depth 320 ft (97.5 m) . INSTRUMENTATION.--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.--Recording observation well. Data logger installed on May 14, 1996. PERIOD OF RECORD.--May 14, 1996 to September 30, 1996. 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 recorded, 292.44 ft (89.14 m) below land-surface datum, June 5, 1996. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 DAY OC 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 1996 JAN — ___ ___ ___— _ ___ ___ ___ 292.25 292.27 292.25 292.26 292.26 292.28 292.30 292.32 292.31 292.31 292.32 292.28 292.28 292.29 292.28 292.28 292.26 292.26 292.27 292.32 292.34 292.36 292.38 292.39 292.41 292.40 292.39 292.36 292.33 292.31 292.32 292.30 292.29 292.27 292.29 292.29 292.34 292.35 292.36 292.33 292.32 292.33 292.35 292.35 292.34 292.30 292.28 ___ 292.30 292.31 292.32 292.34 292.32 292.34 292.34 292.30 292.19 292.22 292.26 292.30 292.27 292.25 292.23 292.24 292.22 292.26 292.27 292.24 292.28 292.32 292.30 292.28 292.34 292.36 292.31 292.26 292.26 292.26 292.24 292.24 292.27 292.29 292.28 292.31 292.33 292.30 292.30 292.30 292.27 292.28 292.26 292.22 292.22 292.19 292.18 292.11 292.06 292.06 292.07 292.08 292.11 292.13 292.13 292.08 292.08 292.04 291.97 291.94 291.92 291.92 291.94 291.97 292.01 292.03 291.98 291.97 292.01 291.92 291.90 291.72 291.26 290.96 290.89 290.90 290.99 291.06 291.14 291.21 291.27 291.34 291.37 291.39 291.42 291.39 291.36 291.38 291.41 291.45 291.46 291.48 ___ ___ ___ __ ___ --- 292.28 292.33 292.28 MEAN 292.09 HIGHEST 290.88 SEPT. 13, 14, 1996 LOWEST 292.44 JUNE 5, 1996 292.16 291.49 290 293 J______I OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1996 WATER YEAR 470 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182549066304300. Local number 166. LOCATION.--Lat 18°25'49", long 66°30'43", Hydrologic Unit 21010002, 0.95 mi east of the Rio Grande de Manati Hwy 2 bridge, 0.40 mi southwest of Central Monserrate, 1.07 mi east of the intersection of Hwy 666 with Hwy 2, 1.20 mi west of the intersection of Hwy 685 with Hwy 2, 0.01 mi north of Hwy 2. Owner: Puerto Rico Aqueduct and Sewer Authority, Name: Manati 3. AQUIFER.--Alluvial deposits. WELL CHARACTERISTICS.--Drilled unused water-table well, diameter 20 in (0.51 m), cased 0-100 ft (0-39.49 m), diameter 14 in (0.36 m), cased 0-140 ft (0-42.68 m), slotted 80-90 ft (24.39-27.44 m), and 130-140 ft (39.63- 42.68 m). Depth 140 ft (42.68 m) . INSTRUMENTATION.--Digital water level recorder--60-minute punch. DATUM.--Elevation of land-surface datum is about 29.50 ft (9.0 m) above mean-sea level, from topographic map. Measuring point: A hole in the side of the 20 in (0.51 m) diameter well casing, 1.65 ft (0.50 m) above land-surface datum. Prior May 31, 1996, top of 14 in (0.36 m) casing, 0.80 ft (0.24 m) above land-surface datum. REMARKS.--Recording observation well. Automated Digital Recorder (ADR) installed on May 31, 1996. Formerly published as 182542066305200. PERIOD OF RECORD.--January 1982 to December 1984, discontinued, May 31, 1996 to September 30, 1996. EXTREMES FOR PERIOD OF RECORD.—Highest water level recorded, 22.43 ft (6.84 m) below land-surface datum, Sept. 20, 1996; lowest water level measured, 26.36 ft (8.04 m) below land-surface datum, Feb. 3, 1983. WATER LEVEL, IN FEET BELOW LAND-SURFACE DATUM, WATER YEAR OCTOBER 1995 TO SEPTEMBER 1996 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 MEAN OCT NOV DEC JAN FEB MAR JUN AUG SEP WTR YR 1996 MEAN 23.66 HIGHEST 22.43 SEPT. 20, 1996 LOWEST 24.03 JULY 31, 23.72 23.73 23.73 23.83 23.86 23.86 23.89 23.87 23.95 23.85 23.80 23.92 23.91 23.85 23.78 23.74 23.79 23.71 23.71 23.72 23.72 23.78 23.77 23.76 23.72 23.82 23.88 23.88 23.84 23.79 --- 23.81 1996 23.77 23.77 23.83 23.83 23.83 23.84 23.77 23.74 23.64 23.61 23.70 23.74 23.79 23.80 23.67 23.78 23.80 23.78 23.70 23.78 23.69 23.73 23.80 23.79 23.79 23.77 23.77 23.89 23.85 23.92 23.99 23.78 23.92 23.89 23.84 23.86 23.84 23.85 23.89 23.86 23.88 23.91 23.80 23.92 23.91 23.83 23.81 23.77 23.71 23.67 23.64 23.66 23.63 23.60 23.65 23.61 23.55 23.55 23.54 23.54 23.49 23.55 23.52 23.73 23.52 23.53 23.51 23.49 23.47 23.40 23.40 23.38 23.37 23.39 ___ ___ ___ ___ ___ ___ ___ ___ 22.53 22.62 22.69 22.73 22.83 22.89 22.95 22.99 23.04 23.09 --- 23.14 21 -£ 23 25 I I I_____I \ OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1996 WATER YEAR 477 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182757066325600. Local number, 206. LOCATION.--Lat 18°27'57", long 66°32'56", Bydrologic 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 OP 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 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 OCT NOV DEC APR MAY JUN JUL MEAN 4.94 5.00 WTR YR 1996 MEAN 5.31 5.05 5.27 5.45 5.58 HIGHEST 3.99 SEPT. 12, 13, 1996 5.64 5.62 LOWEST 5.85 MAR. 28, 5.64 5.54 29, 1996 AUG 5.33 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 4 29 < 30 < 31 4 .87 .87 .86 .87 .88 .88 .90 .92 .92 .90 .89 .01 .96 .93 .90 .88 .87 .88 .93 .99 5.02 5.02 5.03 5.03 5.16 5.16 5.05 1.98 1.92 1.88 1.85 5.10 5.10 5.09 5.06 5.05 4.92 4.94 4.98 4.81 4.90 4.97 5.01 5.02 5.02 5.03 4.98 5.01 5.00 4.99 4.98 4.98 4.97 4.97 4.97 4.98 5.00 5.02 5.06 5.08 5.10 ___ 5.07 5.08 5.07 5.06 5.06 5.07 5.07 5.08 5.10 5.12 5.15 5.19 5.16 5.15 5.12 5.12 5.10 4.85 4.78 4.79 4.82 4.89 4.95 4.98 5.01 5.01 5.05 5.09 5.13 5.17 5.21 5.24 5.22 5.22 5.24 5.27 5.31 5.34 5.35 5.33 5.32 5.27 5.20 5.16 5.10 5.11 5.16 5.19 5.22 5.22 5.24 5.26 5.29 5.33 5.31 5.32 5.35 5.39 5.37 5.37 5.39 5.43 5.42 5.42 5.43 5.45 5.48 5.47 5.44 5.44 5.36 5.37 5.41 5.43 5.42 5.42 5.42 5.40 5.39 5.38 5.36 5.38 5.42 5.44 5.50 5.57 5.60 5.60 5.59 5.59 5.58 ___ 5.56 5.54 5.53 5.53 5.55 5.55 5.58 5.57 5.56 5.55 5.55 5.53 5.49 5.46 5.47 5.48 5.47 5.50 5.48 5.52 5.53 5.57 5.61 5.64 5.69 5.70 5.76 5.80 5.80 5.73 5.66 5.63 5.63 5.64 5.62 5.62 5.63 5.64 5.64 5.65 5.65 5.62 5.58 5.62 5.62 5.59 5.58 5.58 5.60 5.59 5.60 5.63 5.70 5.74 5.75 5.72 5.68 5.66 5.65 5.65 5.64 ___ 5.64 5.63 5.62 5.62 5.63 5.66 5.69 5.69 5.68 5.66 5.67 5.65 5.60 5.56 5.56 5.57 5.56 5.55 5.58 5.60 5.62 5.63 5.64 5.64 5.64 5.62 5.62 5.61 5.61 5.61 5.60 5.60 5.61 5.64 5.67 5.68 5.70 5.72 5.71 5.72 5.70 5.68 5.65 5.63 5.64 5.60 5.60 5.59 5.59 5.60 5.61 5.63 5.64 5.62 5.62 5.64 5.66 5.66 5.64 5.60 5.57 ___ 5.57 5.59 5.60 5.60 5.60 5.61 5.62 5.57 5.46 5.48 5.53 5.58 5.56 5.53 5.50 5.49 5.48 5.54 5.53 5.53 5.55 5.57 5.55 5.53 5.58 5.59 5.53 5.50 5.50 5.48 5.45 5.43 5.45 5.45 5.49 5.51 5.53 5.50 5.49 5.50 5.49 5.47 5.44 5.41 5.38 5.34 5.31 5.27 5.20 5.21 5.21 5.24 5.25 5.28 5.27 5.25 5.22 5.18 5.11 5.10 5.09 5.08 5.09 5.10 5.13 5.17 5.12 5.13 5.15 5.10 5.08 4.17 4.14 3.99 4.01 4.06 4.13 4.24 4.31 4.40 4.46 4.52 4.57 4.59 4.62 4.62 4.59 4.60 4.63 4.66 4.68 4.70 4.63 5 - 1992 1993 1994 WATER YEAR 1995 1996 472 GROUND-WATER LEVELS RIO GRANDE DE HANATI BASIN 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 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT DEC JAN APR 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 EAN rPR YR 38.88 38.90 38.92 38.94 38.95 38.96 38.96 38.97 38.98 39.00 39.00 38.44 38.56 38.61 38.65 38.70 38.75 38.76 38.76 38.75 38.75 38.75 38.75 38.75 38.73 38.69 38.67 38.67 38.68 38.70 38.74 38.78 1996 38.76 38.77 38.78 38.79 38.81 38.78 38.74 38.73 38.58 38.56 38.57 38.59 38.59 38.59 38.59 38.61 38.62 38.63 38.65 38.65 38.66 38.68 38.68 38.68 38.68 38.69 38.71 38.73 38.73 38.74 —— 38.68 MEAN 39.03 38.74 38.74 38.76 38.77 38.79 38.81 38.83 38.87 38.89 38.91 38.94 38.97 38.97 38.96 38.94 38.94 38.95 38.72 38.34 38.36 38.36 38.39 38.41 38.44 38.46 38.49 38.52 38.56 38.60 38.62 38.66 38.70 HIGHEST 38.72 38.74 38.76 38.78 38.84 38.88 38.89 38.90 38.90 38.89 38.84 38.70 38.65 38.64 38.63 38.63 38.64 38.65 38.66 38.66 38.65 38.67 38.69 38.69 38.69 38.69 38.72 38.73 38.71 38.71 —— 38.73 37.22 ___ —— ___ —— ___ —— —— 38.81 38.82 38.81 38.81 38.82 38.82 38.81 38.85 38.87 38.88 38.93 38.96 38.98 38.99 39.00 39.00 —— —— 38.88 SEPT. 11, 39.00 39.01 39.02 39.04 39.05 39.06 39.06 39.06 39.06 39.07 39.08 39.09 39.08 39.06 39.06 39.07 39.07 39.08 39.09 39.11 39.13 39.17 39.18 39.20 39.25 39.27 39.29 39.32 39.33 39.32 39.30 39.13 1996 39.30 39.30 39.30 39.30 39.30 39.29 39.30 39.30 39.32 39.32 39.32 39.31 39.31 39.32 39.31 39.31 39.33 39.35 39.34 39.34 39.35 39.37 39.40 39.41 39.41 39.41 39.41 39.42 39.42 39.42 —— 39.34 LOWEST 39.53 39.42 39.42 39.42 39.41 39.42 39.42 39.43 39.44 39.44 39.43 39.42 39.42 39.41 39.40 39.40 39.40 39.41 39.40 39.41 39.41 39.41 39.42 39.42 39.43 39.43 39.43 39.42 39.42 39.42 39.42 39.42 39.42 JULY 25, 39.42 39.43 39.43 39.46 39.48 39.49 39.50 39.50 39.51 39.50 39.47 39.45 39.44 39.45 39.44 39.43 39.43 39.42 39.43 39.44 39.45 39.46 39.45 39.45 39.47 39.49 39.49 39.46 39.44 39.43 —— 39.46 30, 1996 39.42 39.43 39.45 39.46 39.45 39.45 39.46 39.45 39.37 39.37 39.40 39.43 39.44 39.44 39.43 39.44 39.44 39.46 39.46 39.46 39.47 39.48 39.47 39.47 39.51 39.47 39.45 39.45 39.47 39.48 39.48 39.45 39.50 39.51 39.50 39.50 39.50 39.51 39.51 39.48 39.48 39.48 39.47 39.46 39.45 39.43 39.42 39.38 39.36 39.33 39.32 39.31 39.31 39.31 39.32 39.31 39.28 39.26 39.25 39.23 39.22 39.22 39.21 39.38 39.21 39.21 39.22 39.20 39.18 39.15 39.18 39.12 39.09 38.17 37.22 37.37 37.46 37.56 37.66 37.76 37.86 37.95 38.01 38.06 38.12 38.17 38.20 38.24 38.27 38.30 38.33 38.36 38.39 38.42 —— 38.35 37 39 41 1992 1993 1994 WATER YEAR 1995 1996 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 473 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. DATDM.--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 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 DAY OCT NOV DEC JAN MAR 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 MEAN WTR YR 75.95 75.98 76.01 76.04 76.08 76.12 76.15 76.18 76.22 76.25 76.26 76.27 76.27 76.27 76.28 76.29 76.30 76.32 76.34 76.35 76.36 76.37 76.36 76.33 76.24 76.07 75.88 75.58 75.25 75.00 74.79 76.07 1996 74.61 74.52 74.44 74.38 74.35 74.33 74.31 74.30 74.29 74.23 74.13 74.05 74.01 74.00 74.01 74.02 74.01 74.00 74.00 74.01 74.01 74.01 74.00 74.00 74.00 74.00 74.02 74.05 74.06 74.02 --- 74.14 MEAN 74.91 73.97 73.93 73.88 73.84 73.78 73.70 73.62 73.52 73.43 73.27 73.10 72.93 72.77 72.61 72.49 72.41 72.37 72.34 72.32 72.24 72.12 71.99 71.88 71.78 71.70 71.64 71.62 71.61 71.60 71.59 71.58 72.63 HIGHEST 71.58 71.64 71.74 71.89 72.08 72.32 72.53 72.69 72.94 73.16 73.34 73.46 73.49 73.49 73.48 73.50 73.46 73.40 73.34 73.26 73.18 73.11 73.03 72.99 72.97 72.96 72.95 72.94 72.86 72.76 72.57 72.87 66.19 72.48 72.40 72.31 72.24 72.19 72.15 72.15 72.18 72.22 72.25 72.27 72.31 72.35 72.40 72.45 72.51 72.59 72.69 72.82 72.89 73.02 73.11 73.20 73.31 73.41 73.51 73.59 73.68 73.74 —— 72.70 SEPT. 15, 73.82 73.87 73.96 74.03 74.10 74.17 74.23 74.29 74.34 74.41 74.46 74.51 74.56 74.61 74.66 74.70 74.74 74.78 74.86 74.89 74.91 74.94 74.97 74.99 75.01 75.01 75.01 75.02 75.01 75.00 74.99 74.61 74.99 75.00 75.00 75.01 75.02 75.02 75.02 75.03 75.03 75.06 75.12 75.17 75.20 75.22 75.24 75.25 75.25 75.25 75.24 75.29 75.25 75.25 75.26 75.26 75.26 75.25 75.26 75.27 75.28 75.31 --- 75.17 1996 LOWEST 79.85 75.32 75.34 75.36 75.38 75.41 75.43 75.46 75.49 75.51 75.51 75.51 75.51 75.51 75.51 75.52 75.53 75.54 75.57 75.57 75.58 75.61 75.65 75.67 75.72 75.75 ___ ___ ___ ___ ___ —— 75.52 AUG. 21, ___ ___ ___ ___ —— __ — ___ ___ ___ —— 75.96 75.92 75.86 75.78 75.72 75.71 75.74 75.78 75.81 75.86 75.90 75.95 75.99 76.03 76.09 76.13 76.18 76.22 76.28 76.33 —— 75.96 22, 23, 76.43 76.49 76.57 76.65 76.74 76.83 76.90 76.96 77.01 77.09 77.19 77.27 77.33 77.39 77.46 77.51 77.57 77.63 77.67 77.71 77.76 77.80 77.83 77.88 77.90 77.92 77.95 77.98 78.02 78.04 78.06 77.40 1996 78.10 78.18 78.25 78.32 78.40 78.46 78.50 78.73 78.85 79.00 79.12 79.26 79.38 79.47 79.56 79.64 79.71 79.76 79.81 79.84 79.85 79.85 79.85 79.81 79.74 79.65 79.58 79.52 79.49 79.46 79.43 79.24 79.40 79.38 79.35 79.33 79.31 79.30 79.29 79.28 79.28 79.19 77.54 72.01 68.22 66.55 66.20 66.31 66.66 67.11 67.66 68.21 68.68 69.01 69.49 70.03 70.46 70.88 71.22 71.50 71.82 72.12 72.83 66 76 86 1992 1993 WATEI^EAR 1995 1996 474 GROUND-HATER LEVELS RIO GRANDE DE HANATI BASIN 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: Puerto Rico 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. PERIOD OF RECORD.—July 11, 1994 to September 30, 1996. 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 1995 TO SEPTEMBER 1996 INSTANTANEOUS OBSERVATION AT 1200 NOV DEC MAR APR 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 31 258.86 258.88 258.90 258.91 258.92 258.93 258.95 258.96 258.96 258.97 258.98 258.78 258.68 258.62 258.55 258.50 258.45 258.44 258.41 258.38 258.35 258.29 258.26 258.17 258.05 257.90 257.79 257.69 257.62 257.61 257.63 257.65 257.67 257.69 257.70 257.70 257.68 257.66 257.63 257.46 257.42 257.41 257.41 257.42 257.44 257.46 257.44 257.46 257.49 257.51 257.52 257.55 257.58 257.62 257.62 257.62 257.63 257.65 257.67 257.66 257.64 —— 257.60 257.64 257.67 257.68 257.70 257.70 257.72 257.76 257.78 257.79 257.80 257.83 257.84 257.85 257.85 257.85 257.83 257.74 257.60 257.47 257.44 257.43 257.43 257.43 257.43 257.39 257.34 257.33 257.34 257.36 257.36 257.36 257.36 257.36 257.39 257.43 257.45 257.50 257.53 257.57 —— 257.64 257.66 257.71 257.76 257.91 258.00 258.03 258.06 258.06 258.08 258.08 258.08 258.08 258.06 258.03 258.00 257.97 257.96 258.01 258.00 258.03 258.07 258.11 258.16 258.21 258.26 258.31 258.32 258.33 258.34 258.35 258.35 258.36 258.38 258.40 258.41 258.42 258.46 258.47 258.51 258.53 258.54 258.56 258.56 258.62 258.66 258.70 258.72 258.74 258.75 258.76 258.77 258.82 258.83 259.04 259.05 259.06 259.08 259.11 259.13 259.14 259.15 259.16 259.15 259.15 259.16 259.17 259.18 259.21 259.22 259.27 259.29 259.31 259.34 259.35 259.37 259.44 259.49 259.51 259.52 259.53 259.52 259.53 259.53 259.55 259.55 259.55 259.55 259.56 259.57 259.59 259.59 259.61 259.62 259.65 259.68 259.69 259.71 259.73 259.74 259.74 259.74 259.75 259.76 259.77 259.78 259.80 259.87 259.87 259.88 259.89 ___ 259.91 259.91 259.92 259.94 259.94 259.95 259.96 259.98 259.99 259.99 259.98 259.97 259.98 259.97 259.98 259.98 259.99 259.99 260.00 260.02 260.03 260.04 260.05 260.05 260.06 260.06 260.07 260.07 260.09 260.11 260.12 260.15 260.16 260.17 260.18 260.18 260.19 260.21 260.22 260.22 260.22 260.22 260.23 260.23 260.23 260.24 260.24 260.23 260.23 260.23 260.23 260.24 260.25 260.25 260.25 260.27 260.30 260.31 260.32 260.32 260.32 260.33 260.34 260.36 260.39 260.40 260.40 260.40 260.39 260.29 260.30 260.32 260.37 260.40 260.41 260.40 260.40 260.41 260.41 260.41 260.40 260.41 260.42 260.42 260.43 260.43 260.44 260.44 260.43 260.44 260.44 260.44 260.44 260.44 260.45 260.46 260.46 260.46 260.47 260.46 260.48 260.50 260.50 260.51 260.51 260.51 260.52 260.49 260.47 260.47 260.45 260.42 260.41 260.41 260.42 260.42 260.42 260.30 260.22 260.30 260.36 260.39 260.29 260.22 260.19 260.23 260.18 260.22 260.26 260.31 260.32 260.35 260.35 260.31 258.82 257.53 256.15 256.21 256.27 256.32 256.38 256.51 256.59 256.72 256.83 256.97 257.06 257.17 257.25 257.34 257.42 257.47 257.57 ___ MEAN 258.46 257.57 257.61 257.81 258.43 259.19 259.68 260.00 260.23 260.40 260.43 258.18 WTR YR 1996 MEAN 259.01 HIGHEST 256.13 SEPT. 13, 14, 1996 LOWEST 260.52 AUG. 12-15, 1996 254 262 ii iii i i ii i i j_____i i_____i OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1996 WATER YEAR 475 GROUND-WATER LEVELS RIO GRANDE DE MANATI BASIN 182506066280200. Local number, HI-2. LOCATION.--Lat 18°25'06 N , 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). INSTRUMENTATION.—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. Data Logger installed on May 28, 1996. PERIOD OF RECORD.--May 28, 1996 to September 30, 1996. EXTREMES FOR PERIOD OF RECORD.--Highest water level recorded, 282.62 ft (86.14 m) below land-surface datum, Sept. 10, 1996; 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 1995 TO SEPTEMBER 1996 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 1996 NOV DEC JAN FEB JUL —— —— —— —— —— —— 290.30 290.91 291.92 MEAN 291.00 HIGHEST 282.62 SEPT. 10, 1996 LOWEST 293.09 SEPT. 5, 6, 1996 SEP —— 290.37 —— 290.42 —— 290.43 —— 290.50 —— 290.49 —— 290.55 —— 290.55 —— 290.66 --- 290.72 —— 290.70 —— 290.72 —— 290.83 —— 290.85 —— 290.86 —— 290.84 —— 290.93 —— 290.98 —— 291.03 —— 291.09 —— 291.08 —— 291.11 —— 291.16 —— 291.22 —— 291.27 —— 291.31 —— 291.32 —— 291.29 —— 291.34 290.25 291.39 290.31 291.43 290.34 --- 291.56 291.49 291.53 291.62 291.73 291.68 291.64 291.46 291.61 291.81 291.85 291.85 291.88 291.91 292.04 292.03 292.03 292.02 292.01 292.00 292.10 292.14 292.13 292.08 292.10 292.12 292.20 292.23 292.32 292.21 292.14 292.07 292.07 292.17 292.28 292.26 292.32 292.35 292.43 292.46 292.48 292.52 292.61 292.61 292.61 292.64 292.63 292.64 292.68 292.74 292.73 292.75 292.85 292.92 292.78 292.71 292.76 292.83 292.82 292.79 292.77 292.81 292.83 292.86 292.94 292.95 293.03 293.05 292.98 292.93 292.95 287.09 285.39 286.02 287.54 287.93 287.90 287.67 287.30 287.00 286.70 286.57 286.51 286.42 286.30 286.24 286.23 286.27 286.35 286.38 286.46 286.56 ___ 292.58 288.58 282 294 OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1996 WATER YEAR 476 GROUND-WATER LEVELS RIO CIBUCO BASIN 182647066201700. Local number, 70. 21010002, 1.52 mi north of Vega Alta plaza, 4.78 mi' Sewer Authority, Name: Sabana Hoyos. AQUIFER.—Limestone of Tertiary Age. ^amatar 8 in (0 20 m), cased 0-90 ft (0-27.43 m), perforated. WELL CHARACTERISTICS.—Drilled unused artesian well, diameter 8 in