Watershed Existing Condition Report for the Anacostia River Watershed December 31, 2014 RUSHERN L. BAKER, III COUNTPreparedY EXECUTIV for:E Prince George’s County, Maryland Department of the Environment Stormwater Management Division Prepared by: 10306 Eaton Place, Suite 340 Fairfax, VA 22030 COVER PHOTO CREDITS: 1. M-NCPPC _Cassi Hayden 8. M-NCPPC _Cassi Hayden 2. M-NCPPC _Cassi Hayden 9. MD DNR _SCA 3. M-NCPPC _Cassi Hayden 10. MD DNR _SCA 4. M-NCPPC _Cassi Hayden 11. M-NCPPC _Cassi Hayden 5. M-NCPPC _Cassi Hayden 12. M-NCPPC _Cassi Hayden 6. MD DNR _SCA 13. M-NCPPC _Cassi Hayden 7. Tetra Tech, Inc. Anacostia River Watershed Existing Conditions Report Contents Acronyms and Abbreviations .................................................................................................... v 1 Introduction ........................................................................................................................... 1 1.1 Purpose of Report and Restoration Planning ............................................................................... 1 1.2 Impaired Water Bodies and TMDLs .............................................................................................. 3 1.2.1 Water Quality Standards ..................................................................................................... 4 1.2.2 Problem Identification and Basis for Listing ........................................................................ 6 1.2.3 TMDL Identified Sources .................................................................................................... 7 1.2.4 Previous Studies ................................................................................................................. 8 2 Watershed Description ....................................................................................................... 10 2.1 Physical and Natural Features .................................................................................................... 13 2.1.1 Hydrology .......................................................................................................................... 13 2.1.2 Climate/Precipitation ......................................................................................................... 13 2.1.3 Topography/Elevation ....................................................................................................... 13 2.1.4 Soils .................................................................................................................................. 15 2.2 Land Use and Land Cover .......................................................................................................... 17 2.2.1 Land Use Distribution ........................................................................................................ 17 2.2.2 Percent Imperviousness ................................................................................................... 20 3 Water Quality and Flow Conditions ................................................................................... 24 3.1 Water Quality Data ...................................................................................................................... 26 3.1.1 Fecal Bacteria ................................................................................................................... 26 3.1.2 DO and BOD ..................................................................................................................... 28 3.1.3 Nitrogen ............................................................................................................................. 30 3.1.4 Phosphorus ....................................................................................................................... 32 3.1.5 Sediment ........................................................................................................................... 34 3.1.6 PCBs ................................................................................................................................. 35 3.2 Biological Station Data ................................................................................................................ 36 3.3 Flow Data .................................................................................................................................... 39 4 Pollutant Source Assessments ......................................................................................... 42 4.1 NPDES Permitted Facilities ........................................................................................................ 42 4.1.1 MS4 (Phase I, Phase II, SHA, Federal) ............................................................................ 42 4.1.2 Other NPDES Permitted Facilities .................................................................................... 43 4.1.3 Wastewater ....................................................................................................................... 46 4.2 Nonpoint and Other Sources ...................................................................................................... 49 4.3 Existing BMPs ............................................................................................................................. 49 4.4 Existing Condition Analysis ......................................................................................................... 52 4.5 Stressor Loading Analysis .......................................................................................................... 57 5 Next Steps............................................................................................................................ 65 6 References ........................................................................................................................... 67 Appendix A: TMDL Factsheets .............................................................................................. A-1 Appendix B: Water Quality Summaries ................................................................................ B-1 Table B-2. Summary of available BOD and DO data in the Anacostia River watershed ................... B-2 Table B-3. Summary of available total nitrogen data in the Anacostia River watershed ................... B-4 Table B-4. Summary of available total phosphorus data in the Anacostia River watershed.............. B-4 Table B-5. Summary of available TSS data in the Anacostia River watershed ................................. B-5 Table B-6. Summary of available PCB data in the Anacostia River watershed ................................. B-6 Appendix C: NPDES Permitted Dischargers ........................................................................ C-1 Table C-1. Active NPDES permits in the Anacostia River watershed in Prince George’s County .... C-1 i Anacostia River Watershed Existing Conditions Report Table C-2. Available permit limits for NPDES permits in the Anacostia River watershed in Prince George’s County ..................................................................................................................... C-11 Table C-3. Summary of available discharge information for NPDES permits in the Anacostia River watershed in Prince George’s County .................................................................................... C-13 ii Anacostia River Watershed Existing Conditions Report Figures Figure 1-1. Schematic for typical pollution diet (TMDL). ............................................................................... 2 Figure 2-1. Location of the Anacostia River watershed. ............................................................................. 11 Figure 2-2. Population density (people per square mile) in the Anacostia River watershed. ..................... 12 Figure 2-3. Elevation in the Anacostia River watershed. ............................................................................ 14 Figure 2-4. Hydrologic soil groups in the Anacostia River watershed. ....................................................... 16 Figure 2-5. Land use in the Anacostia River watershed. ............................................................................ 18 Figure 2-6. Impervious areas in the Anacostia River watershed. ............................................................... 22 Figure 2-7. Percent impervious areas in the Anacostia River watershed. .................................................. 23 Figure 3-1. Flow and water quality monitoring stations in the Anacostia River watershed. ....................... 25 Figure 3-2. Plot of enterococci over time in the Anacostia River watershed. ............................................. 27 Figure 3-3. Plot of E. coli over time in the Anacostia River watershed. ...................................................... 28 Figure 3-4. Plot of BOD over time in the Anacostia River watershed. ........................................................ 30 Figure 3-5. Plot of DO over time in the Anacostia River watershed. .......................................................... 30 Figure 3-6. Plot of total nitrogen over time in the Anacostia River watershed. ........................................... 32 Figure 3-7. Plot of total phosphorus over time in the Anacostia River watershed. ..................................... 33 Figure 3-8. Plot of TSS over time in the Anacostia River watershed. ......................................................... 35 Figure 3-9. Plot of total PCBs over time in the Anacostia River watershed. ..............................................