Minnesota River Basin Impaired Waters by Watershed

Impaired Waters in the Minnesota River Basin by Major Watersheds  
Minnesota River Basin Impaired Waters  

What are Impaired Waters?


The federal Clean Water Act (CWA) requires states to adopt water-quality standards to protect waters from pollution. These standards define how much of a pollutant can be in the water and still allow it to meet designated uses, such as drinking water, fishing and swimming.

During the 1970s, each lake and stretch of stream or river in Minnesota was designated for a specific use, like for contact recreation such as swimming or fishing; for drinking water; or for maintaining a healthy population of fish and other aquatic life.

If the water quality in the stream or lake does not allow it to meet its designated use, it does not meet Minnesota’s water quality standards and is considered "impaired." Water quality standards are set on a wide range of pollutants, including bacteria, nutrients, turbidity and mercury. A water body is “impaired” if it fails to meet one or more water quality standards.

The waterbody is then placed on the "303(d)" list, commonly known as the "impaired waters list." It is named after the section of the Clean Water Act in which the impaired waters law is found.  Lakes, rivers and streams on the list are known to exceed water quality standards. Every two years, the Minnesota Pollution Control Agency (MPCA) releases the 303(d) list of impaired waters in Minnesota. Once placed on the impaired waters list, the stream or lake needs a water quality improvement (TMDL) plan written.

Learn more about Minnesota’s Impaired Waters on the MPCA website




This page was last updated 8/08