Fig 22 South Metro Mississippi River Total Suspended Solids Total Maximum Daily Load Mississippi River Mississippi River Minnesota River Minnesota River October 2015 wq-iw9-12e Submitted to United States Environmental Protection Agency By Minnesota Pollution Control Agency Authors/MPCA Staff Project Coordinator: Norman Senjem (up to 2012), Chris Zadak (2014-2015) Meeting Facilitation: Milt Thomas Modeling Technical Support: Khalil Ahmad, Hafiz Munir, Charles Regan Water Quality Specialists: Steven Heiskary, Howard Markus, Dennis Wasley, Mike Trojan, Marco Graziani, Greg Johnson Data Management: Brandon Smith, Steve Weiss GIS Support: Nels Rasmussen, Ashley Ignatius Planning Coordination: Larry Gunderson, Denise Leezer, Maggie Leach Information and Outreach: Cathy Rofshus Contractors Water Quality Modeling: Limno-Tech, Inc. Sediment Source Research: National Center for Earth Surface Dynamics St. Croix Watershed Research Station, Science Museum of Minnesota University of Minnesota Editing and Graphic Design Graphic design staff: Jennifer Holstad Cover photo: Minnesota-Wisconsin Boundary Area Commission The MPCA is reducing printing and mailing costs by using the Internet to distribute reports and information to wider audience. Visit our web site for more information. MPCA reports are printed on 100% post-consumer recycled content paper manufactured without chlorine or chlorine derivatives. Minnesota Pollution Control Agency 520 Lafayette Road North | Saint Paul, MN 55155-4194 | www.pca.state.mn.us | 651-296-6300 Toll free 800-657-3864 | TTY 651-282-5332 This report is available in alternative formats upon request, and online at www.pca.state.mn.us Document number: wq-iw9-12e Glossary of Acronyms Acronym Full Name BMP Best Management Practices EMAP Environmental Mapping and Assessment Program EPA U.S. Environmental Protection Agency EQIP Environmental Quality Incentive Program HUC Hydrologic Unit Code LA Load Allocation LTRMP Long-Term Resource Monitoring Program MCES Metropolitan Council Environmental Services DNR Minnesota Dept. of Natural Resources MOS Margin of Safety MPCA Minnesota Pollution Control Agency MS4 Municipal Separate Storm Sewer Systems NLCD National Land Cover Data NPDES National Pollutant Discharge Elimination System NRCS Natural Resource Conservation Service NTU Nephelometric Turbidity Units RC Reserve Capacity SAC Stakeholder Advisory Committee SAP Science Advisory Panel SAV Submersed Aquatic Vegetation SWCD Soil and Water Conservation District SWPPP Stormwater Pollution Prevention Plan TMDL Total Maximum Daily Load TSS Total Suspended Solids UMR Upper Mississippi River UMR-LP Upper Mississippi River-Lake Pepin USACE U.S. Army Corps of Engineers USGS U.S. Geological Survey WDNR Wisconsin Department of Natural Resources WLA Waste Load Allocation WPDES Wisconsin Pollutant Discharge Elimination System WWTP Wastewater Treatment Plant Contents Executive Summary ............................................................................................................... 1 1.0 Introduction ................................................................................................................ 3 1.1 Priority ranking ......................................................................................................................... 4 2.0 Waterbody Description ............................................................................................... 6 2.1 Water quality history ................................................................................................................ 7 2.1.1 Pollutant of concern ............................................................................................................................................... 12 3.0 Sediment Sources ...................................................................................................... 14 3.1 Tributary basins and watersheds ............................................................................................. 14 3.1.1 Urban and rural sources ......................................................................................................................................... 33 3.1.2 Sediment sources by landscape feature ................................................................................................................. 38 4.0 Water Quality Standards and Review of Available Data ............................................. 40 4.1 Water quality standards ......................................................................................................... 40 4.1.1 Water quality standard and numeric target ........................................................................................................... 41 5.0 Modeling Approach and Results ................................................................................ 44 5.1 Water quality models used ...................................................................................................... 44 5.1.1 Load reduction scenarios ........................................................................................................................................ 47 5.1.2 Relationships to other TMDLs within the South Metro Mississippi Watershed ..................................................... 50 6.0 TMDL Development and Determination of Allocations .............................................. 52 6.1 Waste load allocations ............................................................................................................ 58 6.1.1 Wastewater treatment facilities ............................................................................................................................. 58 6.1.2 Municipal Separate Storm Sewer Systems (MS4s) ................................................................................................. 59 6.1.3 Construction stormwater ....................................................................................................................................... 61 6.1.4 Industrial stormwater ............................................................................................................................................. 61 6.2 Load allocations and natural background ................................................................................ 62 6.3 Margin of safety ..................................................................................................................... 64 6.4 Critical conditions and seasonality ........................................................................................... 65 6.5 Future growth and wastewater reserve capacity ...................................................................... 66 6.6 Procedures for new and expanding wastewater dischargers ..................................................... 68 7.0 General Implementation Strategy .............................................................................. 71 7.1 Minnesota implementation overview ...................................................................................... 71 7.1.1 Nonpoint sources.................................................................................................................................................... 71 7.1.2 Regulated stormwater ............................................................................................................................................ 73 7.1.3 Wastewater treatment facilities ............................................................................................................................. 74 7.1.4 Implementation cost .............................................................................................................................................. 75 7.2 Wisconsin implementation activities: agricultural and rural nonpoint sources ........................... 76 7.2.1 Wisconsin performance standards and prohibitions .............................................................................................. 76 7.2.2 Primary implementation programs ........................................................................................................................ 77 7.3 Reasonable assurance ............................................................................................................. 78 7.4 Water quality monitoring plan ................................................................................................ 80 8.0 Public Participation Record ........................................................................................ 82 9.0 References ................................................................................................................ 84 Appendix A: Wastewater Treatment Facility Waste Load Allocations and Industrial Stormwater Facilities ........................................................................................................... 88 Appendix B: Regulated MS4 List......................................................................................... 112 Appendix C: Stakeholder Advisory Committee and Science Advisory Panel ........................ 121 Index of Tables Table 1: South Metro Mississippi River total suspended solids impairments .............................................. 4 Table 2: Land cover within the South Metro Mississippi TMDL drainage area (“contributing” area only). .................................................................................................................................................................... 20 Table 3: