Duluth Area Beaches Total Maximum Daily Load Report

The Duluth Area Beaches TMDL is the first beach TMDL in Minnesota; however, beach TMDLs have been developed and approved for other Great Lakes beaches. The Duluth Area Beaches TMDL includes Escherichia coli (E. coli) TMDLs for five impaired beaches within the St. Louis River Watershed (Hydrologic Unit Code [HUC] 04010201) and the Lake Superior South Watershed (HUC 04010102). The overall implementation strategy highlights an adaptive management process to achieving water quality standards and restoring beneficial uses. Implementation strategies for impaired beaches are largely encompassed within the recommendations provided in the completed Duluth Urban Area Streams TMDL and WRAPS and include addressing discharge of untreated wastewater (e.g., failing septic systems, leaky wastewater infrastructure, lack of restrooms in strategic locations), stormwater management, land use planning and ordinance development, education and outreach activities, and pet and wildlife waste management. If current Municipal Separate Storm Sewer Systems (MS4) permit requirements for bacteria wasteload allocations (WLAs) remain similar in the next MS4 general permit (expected to be issued in 2025), MS4s would be required to maintain a written or mapped inventory of bacteria sources, as well as a prioritization plan to reduce those bacteria sources.