Michigan E. coli TMDL Expanding in 2024

Earlier this month, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) issued a 2024 Draft Addendum to the Statewide Escherichia coli (E. coli) Total Maximum Daily Load (TMDL) for public notice and comment. In general, a TMDL is developed when a water body, or water bodies, is identified as not meeting state or federal water quality standards. The Statewide E. coli TMDL was originally approved by the U.S. Environmental Protection Agency (U.S. EPA) in 2019 and applies broadly to the state’s surface waters, which include the Great Lakes, inland lakes, streams, rivers, wetlands, and beaches; however, only those water bodies identified in Appendix 1 of the Statewide E. coli TMDL are impacted. EGLE has already updated the Statewide E. coli TMDL in 2020 and 2022, in each case adding additional impaired water bodies, and will continue to do so every two years based on future monitoring.

What impact does this have on my facility?

Depending on what type of permit coverage you have under the National Pollutant Discharge Elimination System (NPDES), there is likely already verbiage in your existing permit that identifies additional requirements around discharging to impaired waters, which are identified by the biennially updated Section 303(d)/305(b) list of impaired waterways. Individual and general permits for industrial, construction, and municipal stormwater and wastewater discharges have the potential to be impacted by this update. The areas identified by the 2024 Draft Addendum are identified in Figure 1 below:

Once the TMDL is approved by U.S. EPA, Michigan’s 303(d)/305(b) list will be updated to include the affected waterways. As a result, facilities with NPDES-covered discharges to those impaired waters will be required to consider E. coli in their stormwater pollutant source assessments, may have additional scrutiny of any E. coli permit limits for wastewater discharges, and in in all cases can expect to see additional language incorporated into permits around controlling discharges of E. coli.

When considering how this could impact your facility, keep in mind that NPDES permit requirements are evaluated during each permit renewal for consistency with approved TMDLs. It is also important to be aware of the additional conditions in most NPDES permits, which give EGLE the ability to require additional monitoring, request documentation above and beyond routine monitoring submittals, and even require the implementation of structural controls or treatment units.

How does my facility prepare?

Being proactive in identifying the implications of the 2024 Draft Addendum to your facility will save time, resources, and headache for you and your facility. Depending on the type of NPDES permit(s) at your facility, performing a review of your current permits, reviewing historical monitoring data, and surveying potential E. coli sources at your facility will help to assess how this change may impact your compliance status in the future.

EGLE is accepting comments on the 2024 Draft Addendum to the Statewide E. coli TMDL, which will be accepted via email to rippkem@michigan.gov until January 12, 2024. ALL4 has stormwater and wastewater experts available to assist your facility in preparing, reviewing, and submitting comments to EGLE. Our experts are also available to assist in identifying what risks are present at your facility and charting a path forward for eliminating sources of E. coli that could end up in a discharge. If you have any questions or would like to discuss how ALL4 can help you with these efforts, please reach out to Cody Fridley at 269.716.6537 or cfridley@all4inc.com.

EGLE TMDL Mapper: https://egle.maps.arcgis.com/apps/MapSeries/index.html?appid=2a060da30e25451292220861632b2c99