Minnesota River Basin

The Minnesota River


Outline of Minnesota River Basin and the watersheds within.

This could be a pivotal year for the Minnesota River and its tributaries. The MPCA is releasing new studies that emphasize the need for widespread changes to the Minnesota River Basin, which covers 10 million acres in southern Minnesota.

One study looked at sediment pollution (also called total suspended solids) clouding the water in the major portion of the Minnesota River. The study calls for decreasing sediment in the river by 50%. The Minnesota River Basin has erodible soils and is naturally vulnerable to sediment pollution. But some practices, such as artificial drainage, worsen the situation by bringing too much water, too quickly, into the system. Increasing flows are a major threat to water quality in the basin, accelerating riverbank erosion and threatening infrastructure. In the past 80 years, flow amounts have doubled in the Minnesota River.

The increased flow isn’t just due to increased rainfall; the river actually carries more water now per inch of rain than in previous decades. Increased artificial drainage, fewer wetlands to store water, and lack of perennial vegetation all contribute to higher flows and erosion of fields and streambanks.

The muddy water then makes it hard for fish and other aquatic species to breathe, find food, and reproduce. The sediment is also filling in the Lower Minnesota River and even Lake Pepin downstream at a much faster rate than before European settlement and intensive farming of the basin.

The MPCA studies also include three focused specifically on the Lower Minnesota River, Minnesota River-Mankato, and Watonwan River watersheds. The studies show many bodies of water that are not meeting water quality standards for bacteria, sediment, chloride, phosphorus, and nitrogen. The reports describe the strategies needed to restore and protect water quality in the watershed.

All of the studies were open for public comment from July 22 to September 20. The MPCA thanks everyone who submitted comments. Each comment was fully considered and in many cases resulted in edits to the report. Public comments and responses are posted.

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