What is a TMDL/Impaired Waters?

A Total Maximum Daily Load (TMDL) is a regulatory term in the U.S. Clean Water Act, describing a plan for restoring impaired waters that identifies the maximum amount of a pollutant that a body of water can receive while still meeting water quality standards.

Ongoing work on impaired waterways
In accordance with the priorities set forth in St. Louis County’s Comprehensive Water Management Plan, we focus much of our work on impaired watersheds including Miller Creek  and Amity Creek (click links to read about our work on each of these watersheds). A watershed is considered ‘impaired’ if one of its designated uses, such as human recreation or aquatic habitat, is being harmed by a pollutant. One example of this would be e. coli bacteria making a lake unsafe for swimming. Because of our clay soils and surface bedrock, many area rivers are impaired for ‘turbidity.’ That means the water is too muddy from erosion and storm runoff to make good habitat for species like brook trout. Each creek and river has its own particular issues and plans for improvement. 

Research & outreach assistance for MPCA’s Major Watershed Approach
For the past three years, we have been helping the Minnesota Pollution Control Agency (MPCA) achieve the goals and tasks set forth in their Watershed Restoration and Protection Strategies Program (WRAPS), also called the Watershed Approach. The Watershed Approach is a 10-year cycle of assessing, monitoring, and restoring lakes, rivers, and streams across the 81 major watersheds that make up our state. CLICK HERE for more information from the MPCA’s website. Our work with the MPCA involves data collection in the field, writing technical documents and engaging citizens.