Michigan’s Statewide E. coli Total Maximum Daily Load Michigan Department of Environment, Great Lakes, and Energy Prepared By: Molly Rippke Water Resources Division July 2019 Michigan.gov/EGLE Environmental Assistance Center 800-662-9278 Table of Contents 1. INTRODUCTION ..................................................................................................................... 1 Legal Background ........................................................................................................... 1 Future TMDL Applicability ............................................................................................... 2 Adding or Removing Impaired Waters .......................................................... 2 Updating Previously Approved E. coli TMDLs .............................................. 3 Problem Statement ......................................................................................................... 3 2. GEOGRAPHY AND BACKGROUND INFORMATION ............................................................. 5 Watersheds and Subwatersheds (HUCs) ........................................................................ 5 Land Cover ..................................................................................................................... 7 Human Population ........................................................................................................ 11 3. NUMERIC TARGET ............................................................................................................... 13 4. TMDL DEVELOPMENT ......................................................................................................... 14 Loading Capacity (LC) Development ............................................................................ 14 WLA .............................................................................................................................. 15 LA .............................................................................................................................. 15 Margin of Safety (MOS) ................................................................................................ 15 Upstream Waters .......................................................................................................... 15 5. DATA DISCUSSION .............................................................................................................. 16 STATEWIDE PROBABILISTIC E. COLI SAMPLE COLLECTION AND ANALYSIS METHODS ............................................................................................................. 16 CONCLUSIONS ........................................................................................................... 16 6. INTERPRETING E. COLI DATA ............................................................................................ 19 USING PRECIPITATION DATA .................................................................................... 19 LOAD DURATION CURVE ANALYSIS WITH EXAMPLES FROM PREVIOUS TMDLS 21 What is a Load Duration Curve? ................................................................. 21 Interpreting Load Duration Curves .............................................................. 22 7. SOURCE ASSESSMENT (SA) AND REASONABLE ASSURANCE (RA) .............................. 27 Knowing your Watershed .............................................................................................. 28 Information for NPDES Permittees ................................................................................ 28 NPDES Discharges....................................................................................................... 29 MS4s .......................................................................................................... 30 Industrial Storm Water ................................................................................ 33 Wastewater Treatment Plants (WWTPs) and Wastewater Stabilization Lagoons (WWSLs) ..................................................................................... 36 Concentrated Animal Feeding Operations (CAFO) ..................................... 37 Combined Sewer Overflows (CSOs) .......................................................... 41 Biosolids ..................................................................................................... 44 Nonpoint Sources ......................................................................................................... 47 Livestock and Land-Application of Manure ................................................. 49 Failing, Aging, and Poorly-Designed On-Site Septic Systems .................... 61 Septage ...................................................................................................... 68 Groundwater Discharges ............................................................................ 70 Pets ............................................................................................................ 70 Wildlife ....................................................................................................... 72 Illegal Sources .............................................................................................................. 76 Sanitary Sewer Overflows (SSOs) and Failing Collection Systems............. 76 Illicit Discharges of Raw or Partially Treated Sewage from Private Residences and Buildings .......................................................................... 79 Other Illegal Discharges ............................................................................. 82 8. FUTURE ........................................................................................................................... 82 Future Monitoring .......................................................................................................... 82 Planning for Future Change .......................................................................................... 83 9. IMPLEMENTATION PROCESS ............................................................................................. 85 10. REFERENCES ...................................................................................................................... 86 Appendix 1. Impaired Water Bodies and Percent Reductions ........................................ 92 Appendix 2. TMDL Update Process ............................................................................. 111 Appendix 3. Converting Concentrations to Loads ......................................................... 115 Appendix 3.1 Rivers ....................................................................................................... 116 Appendix 3.2 Lakes, Wetlands, and Ponds with an Outlet Flow ..................................... 118 Appendix 3.3 Beaches ................................................................................................... 120 Appendix 4. Data Analysis - Results of Statistical Analysis of WCMP Data .................. 123 Appendix 4.1 ANOVA and Tukey HSD test of all results by sampling year. .................... 123 Appendix 4.2 ANOVA and Tukey HSD test for all results by sampling event (1-4). ........ 126 Appendix 4.3 Correlation of site-specific E. coli data to spatial variables for each site .............................................................................................. 129 Appendix 4.4 Correlation of E. coli with Prior Precipitation (24 and 48 hours) ................ 131 ACRONYMS AFO Animal Feeding Operation ANOVA Analysis of Variance AUID Assessment Unit Identification Number BMP Best Management Practices CAFO Concentrated Animal Feeding Operation CFR Code of Federal Regulations CNMP Comprehensive Nutrient Management Plan COC Certificate of Coverage CSO Combined Sewer Overflow CWA Clean Water Act EGLE Department of Environment, Great Lakes, and Energy GAAMP Generally Accepted Agricultural and Management Practices GLISA Great Lakes Integrated Science and Assessments HSD Honest Significant Difference HUC Hydrologic Unit Code IDEP Illicit Discharge Elimination Program LA Load Allocation LC Loading Capacity MAEAP Michigan Agriculture Environmental Assurance Program MDARD Michigan Department of Agriculture and Rural Development MDEQ Michigan Department of Environmental Quality (currently EGLE) MDNR Michigan Department of Natural Resources MOS Margin of Safety mL Milliliters MS4 Municipal Separate Storm Sewer System MSU Michigan State University NOAA National Oceanic and Atmospheric Administration NOC Notice of Coverage NPDES National Pollutant Discharge Elimination System NREPA Natural Resources and Environmental Protection Act PBC Partial Body Contact RA Reasonable Assurance SA Source Assessment SAW Stormwater, Asset Management, and Wastewater Program SSO Sanitary Sewer Overflow SWMP Storm Water Management Program SWPPP Storm Water Pollution Prevention Plan TBC Total Body Contact TMDL Total Maximum Daily Load USDA United States Department of Agriculture USEPA United States Environmental Protection Agency USGS United States Geological Survey WCMP Water Chemistry Monitoring Program WLA Waste Load Allocation WQS Water Quality Standards WRD Water Resources Division WWSL Wastewater Stabilization Lagoon WWTP Wastewater Treatment Plant Statewide E. coli TMDL Michigan’s Statewide E. coli Total Maximum Daily Load 1. INTRODUCTION Keeping our residents and visitors safe while recreating in Michigan’s waters is an EGLE priority. To help attain the goal of enhancing recreational waters and tie together the efforts