U.S. Department of the Interior U.S. Geological Survey SIMULATION OF STREAMFLOW AND WATER QUALITY IN THE WHITE CLAY CREEK SUBBASIN OF THE CHRISTINA RIVER BASIN, PENNSYLVANIA AND DELAWARE, 1994-98 by Lisa A. Senior and Edward H. Koerkle Water-Resources Investigations Report 03-4031 In cooperation with the DELAWARE RIVER BASIN COMMISSION, DELAWARE DEPARTMENT OF NATURAL RESOURCES AND ENVIRONMENTAL CONTROL, and the PENNSYLVANIA DEPARTMENT OF ENVIRONMENTAL PROTECTION New Cumberland, Pennsylvania 2003 U.S. DEPARTMENT OF THE INTERIOR GALE A. NORTON, Secretary U.S. GEOLOGICAL SURVEY Charles G. Groat, Director For additional information Copies of this report may be write to: purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 215 Limekiln Road Box 25286 New Cumberland, Pennsylvania 17070-2424 Denver, Colorado 80225-0286 Email: [email protected] Telephone: 1-888-ASK-USGS Internet Address: http://pa.water.usgs.gov ii CONTENTS Page Abstract . 1 Introduction . 2 Purpose and scope . 4 Previous studies . 5 Acknowledgments . 5 Description of study area . 5 Physical setting . 5 Climate . 5 Geology . 6 Soils. 6 Hydrology . 6 Land use. 6 Water use . 8 Description of model . 8 Data for model input and calibration . 10 Model-input data . 10 Meteorologic data . 10 Water-use data . 14 Spatial data. 16 Model-calibration data. 18 Hydrologic data. 18 Water-quality data. 20 Simulation of streamflow . 25 Assumptions . 30 Model calibration . 30 Model sensitivity analysis . 39 Model limitations . 41 Simulation of water quality . 42 Model calibration . 42 Water temperature . 44 Suspended sediment. 44 Dissolved oxygen and biochemical oxygen demand. 53 Nitrogen . 60 Phosphorus . 72 Model sensitivity analysis . 79 Model limitations . 81 Model applications. 82 Summary and conclusions . 87 References cited . 90 Appendix 1—Stormflow and base-flow water-quality data . .93 Appendix 2—Simulated stormflow and water quality for sampled storms in 1998 . 97 Appendix 3—User control input (UCI) file for HSPF model of White Clay Creek Basin . 109 Contents iii ILLUSTRATIONS Page Figures 1-3. Maps showing: 1. Location of the Christina River Basin and its four major stream basins and water-quality monitoring sites, Pennsylvania, Delaware, and Maryland . 3 2. Mapped soil associations in the White Clay Creek Basin, Pennsylvania and Delaware . 7 3. Location of National Oceanic and Atmospheric Administration meteorological stations and calculated Thiessen polygons in the vicinity of the White Clay Creek Basin and other parts of the Christina River Basin, Pennsylvania, Delaware, and Maryland . 11 4-6. Graphs showing: 4. Cumulative difference in daily precipitation at National Oceanic and Atmospheric Administration meteorological stations Newark University Farm and Coatesville 2 W for the period October 1, 1994, through October 29, 1998 . 13 5. Monthly precipitation measured at the National Oceanic and Atmospheric Administration Coatesville 2 W, Pennsylvania, and Newark University Farm, Delaware, meteorological stations . 13 6. Monthly estimates of potential evapotranspiration for Wilmington Airport, Delaware . 14 7-8. Maps showing: 7. Generalized 1995 land-use map for the White Clay Creek Basin, Pennsylvania and Delaware . 17 8. Location of streamflow-measurement stations and water-quality monitoring sites, White Clay Creek Basin, Pennsylvania and Delaware . 19 9-10. Graphs showing: 9. Relation between water-quality constituents and streamflow for stormflow and base-flow samples collected in 1998 at streamflow-measurement station 01478137, Trout Run at Avondale, Pa. 23 10. Relation between water-quality constituents and streamflow for stormflow and base-flow samples collected in 1998 at streamflow-measurement station 01479000, White Clay near Newark, Del.. ..