U.S. Department of the Interior U.S. Geological Survey PREPARED IIN COOPERATIION WIITH THE MUNIICIIPIIO AUTÓNOMO DE PONCE,, PUERTO RIICO,, OFFIICE OF THE MAYOR SSuurrffaaccee--WWaatteerr,, WWaatteerr--QQuuaalliittyy,, aanndd GGrroouunndd--WWaatteerr AAsssseessssmmeenntt ooff tthhee MMuunniicciippiioo ooff PPoonnccee,, PPuueerrttoo RRiiccoo,, 22000022--22000044 Scientific Investigations Report 2005-5243 Cover photograph View towards the southeast of Lago Cerrillos from Highway 505. Highway 139 is in the foreground. Highway 52 is in distance to the right. Removal of earth material for a housing development is occurring near the Río Inabón to the left hand side of the photograph. Photograph taken by Jesús Rodríguez-Martínez on November 27, 2001. Surface-Water, Water-Quality, and Ground-Water Assessment of the Municipio of Ponce, Puerto Rico, 2002-2004 By Jesús Rodríguez-Martínez, Luis Santiago-Rivera, José M. Rodríguez, and Fernando Gómez-Gómez Chapter A Surface-Water Resources Assessment of the Municipio of Ponce, Puerto Rico, 2002-2004 By Luis Santiago-Rivera and Fernando Gómez-Gómez Chapter B Sanitary Quality of Surface Water During Base-Flow Conditions in the Municipio of Ponce, Puerto Rico, 2002 By José M. Rodríguez and Fernando Gómez-Gómez Chapter C Hydrogeologic Terranes and Ground-Water Resources in the Municipio of Ponce, Puerto Rico, 2002-2004 By Jesús Rodríguez-Martínez and Fernando Gómez-Gómez Prepared in cooperation with the MUNICIPIO AUTÓNOMO DE PONCE, PUERTO RICO OFFICE OF THE MAYOR Scientific Investigations Report 2005-5243 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey P. Patrick Leahy, Acting Director U.S. Geological Survey, Reston, Virginia: 2006 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. Suggested citation: Rodríguez-Martínez, Jesús, Santiago-Rivera, Luis, Rodríguez, J.M., and Gómez-Gómez, Fernando, 2005, Surface-water, water-quality, and ground-water assessment of the municipio of Ponce, Puerto Rico, 2002-2004: U.S. Geological Survey Scientific Investigations Report 2005-5243, 95 p., 2 pls. iii Contents Abstract. 1 Sumario. 1 Introduction . 2 Acknowledgments . 4 Description of the Study Area. 4 Physical Features . 4 General Geology . 4 Climate. 7 Previous Studies . 8 Chapter A: Surface-Water Resources Assessment of the Municipio of Ponce, Puerto Rico, 2002-2004 Purpose and Scope . 11 Methodology. 11 Results and Interpretation . 13 Low-Flow Characteristics at Continuous-Record Gaging Stations . 13 Low-Flow Characteristics at Partial-Record Stations . 13 Flow-Duration Characteristics. 13 Drainage-Basin Area/Discharge Relation . 13 Map Features . 14 Reservoir Sites. 14 Flood-Prone Areas. 14 Salt Water Wedge at Streams. 14 Public-Supply Water Filtration Plants and Waste-Water Treatment Facilities. 15 Chapter B: Sanitary Quality of Surface Water During Base-Flow Conditions in the Municipio of Ponce, Puerto Rico, 2002 Purpose and Scope . 33 Background. 33 Methodology. 35 Field-Data Collection . 35 Analytical Techniques. 40 Stream Ranking Rationale. 42 Results and Interpretation . 44 Río Inabón Basin. 44 Río Bucaná Basin. 44 Río Matilde Basin . 49 Chapter C: Hydrogeologic Terranes and Ground-Water Resources in the Municipio of Ponce, Puerto Rico, 2002-2004 Purpose and Scope . 51 Recent Impacts on the Ground-Water Flow Pattern in the Municipio of Ponce. 51 Methodology. 52 Hydrogeologic Terranes. 52 Base-Flow Measurements. 52 Ground-Water Quality. 56 Oxygen-18 and Deuterium Composition . 62 Streamflow Seepage Surveys. ..