Le Sueur River

Located in south-central Minnesota, the Le Sueur River flows 111 miles through a gently rolling landscape, most of it farmland, until it cuts down through high bluffs to the Blue Earth River. The Le Sueur, which is named for a French explorer, starts in Freeborn County, flowing north and west through parts of Waseca and Blue Earth counties. It passes through the city of St. Clair, which is near the regional hub of Mankato. Tributaries from Steele and Faribault Counties also flow into the Le Sueur. A total of 711,838 acres drain to the Le Sueur, and an extensive ditch and tile system facilitates movement of water throughout the watershed. Several streams (a total of 1,201 miles) flow to the Le Sueur, with its major tributaries being the Cobb and Maple rivers.

Lakes and wetlands currently comprise 3% of the watershed. Many of the lakes are shallow and provide wildlife habitat while others are deeper and popular for recreation. The vast majority of the watershed is planted with crops such as corn and soybeans or used for livestock production.

Water monitoring shows some modest improvements in water quality in the Le Sueur River over the past 10 years, though several sections of the river and its streams continue to suffer from many problems, including turbidity, low dissolved oxygen, and excess nutrients. The Le Sueur watershed is a major source of sediment and nutrients to the Minnesota River.

    What's being done

    Monitoring and assessment

    The MPCA conducted intensive watershed monitoring in the Le Sueur River Watershed in 2008. Assessing the biology of streams in the watershed is difficult because of the extensive changes in the watershed — drainage ditches, drainage tile, and straightened streams to move water off the land faster. The MPCA will consider a different type of assessment for these altered streams in the future.

    Strategy for restoration and protection

    Local partners

    The Minnesota River: Evaluating its health [highlight]