Regional Fecal Coliform TMDL on Salt Creek of Sangamon River and Lower Sangamon River Watersheds Flat Branch Tributary Stage 3 Final Report Illinois Environmental Protection Agency Watershed Management Section Planning Unit September 2005 http://www.epa.state.il.us/water/tmdl/ September 27, 2005 Table of Contents 1. Introduction .....................................................................................................................................1 2. Physical Settings .............................................................................................................................1 2.1. Listed Water Bodies .................................................................................................................1 2.2. Watershed Characteristics ........................................................................................................3 Land Use and Land Cover............................................................................................................3 Soils..............................................................................................................................................5 Hydromodification .......................................................................................................................6 Climate .........................................................................................................................................7 Populations...................................................................................................................................9 Humans.................................................................................................................................9 Wildlife.................................................................................................................................9 Livestock ............................................................................................................................10 3. Water Quality Standard and Guideline .........................................................................................12 4. Description of Water Quality Problem/Impairment......................................................................14 5. Assessment of Bacteria Sources....................................................................................................17 5.1. Point and Nonpoint Sources....................................................................................................17 Point Sources..............................................................................................................................18 NPDES Permitted Facilities...............................................................................................18 Failing Septic Systems .......................................................................................................21 Combined Sewer Overflows ..............................................................................................22 Confined Animal Feeding Operations................................................................................22 Nonpoint Sources .......................................................................................................................23 Failing Septic Systems .......................................................................................................23 Land Application of Municipal Waste Biosolids...............................................................23 Pets .....................................................................................................................................23 Livestock ............................................................................................................................23 Wildlife...............................................................................................................................24 6. TMDL Development .....................................................................................................................25 6.1 Load Duration Curve...........................................................................................................27 6.2 TMDL...................................................................................................................................28 Allocations .............................................................................................................................28 Margin of Safety.....................................................................................................................30 Seasonality .............................................................................................................................30 Critical Conditions .................................................................................................................31 6.3 Implementation....................................................................................................................31 6.4 Public Participation .............................................................................................................31 7. References .....................................................................................................................................32 Appendix A. Individual Watersheds Appendix B. TMDL Development from the “Bottom Up”- Part II: Using Duration Curves to Connect the Pieces Appendix C. Data Tables Appendix D. Responsiveness Summary i September 27, 2005 Figures Figure 1. Segment Map .......................................................................................................................2 Figure 2. Land Use in Watershed........................................................................................................5 Figure 3. Soil Orders of the United States ..........................................................................................6 Figure 4. Tile Outlets in Lake Fork Watershed....................................................................................7 Figure 5. Monthly Precipitation for Springfield 1995-2004 ...............................................................8 Figure 6. Deer Densities per county (per square mile) .....................................................................10 Figure 7. Livestock per County.........................................................................................................11 Figure 8. Livestock Density per County (animals per acre) .............................................................12 Figure 9. Monitoring Stations ...........................................................................................................15 Figure 10. Fecal Coliform Data from All Segments .........................................................................17 Figure 11. NPDES Permitted Facilities in the Salt Creek of Sangamon River Watershed...............18 Figure 12. NPDES Permitted Facilities in the Lower Sangamon River Watershed .........................20 Figure 13. Combined Sewer Overflows............................................................................................22 Figure 14. Livestock per Cropland Acre...........................................................................................24 Figure 15. Deer Populations in Watershed Counties ........................................................................25 Figure 16. Water Quality Durvation Curve.......................................................................................26 Figure 17. Flow Duration Curve ........................................................................................................27 Figure 18. Load Duration Curve .......................................................................................................28 Tables Table 1. Impaired Segments................................................................................................................3 Table 2. Land Use in Watersheds........................................................................................................3 Table 3. Land Cover in Counties ........................................................................................................4 Table 4. Climate Summary for Springfield Station 118179 (1971-2000)...........................................7 Table 5. Precipitation for Springfield Station (1995-2004) ................................................................8 Table 6. Populations for larger cities...................................................................................................9 Table 7. Deer Populations ...................................................................................................................9 Table 8. Livestock Populations by County .......................................................................................11 Table 9. Guidelines for Assessing Primary Contact (Swimming) Use in Illinois Streams...............13 Table 10. Segments on current and previous 303(d) Lists................................................................14 Table 11. Assessment of Primary Contact Use for 305(b) Listing ...................................................16 Table 12. Fecal Coliform Geometric Means.....................................................................................16 Table 13. NPDES Permitted Facilities in the Salt Creek of Sangamon River Watershed................19 Table 14. NPDES Facililities in the Lower Sangamon River