The landscape is mainly flat, though it includes some hilly areas, ravines, bluffs, natural prairies and forested areas. The vast majority of the watershed is farmland. The Rapidan Dam, constructed for the purpose of hydroelectricity generation in 1910, impounds the river 12 miles upstream from its mouth. Above the Rapidan Dam, the river meanders through farmland banks and bluffs from the town of Blue Earth to the lake impounded behind the Rapidan Dam. Below the Rapidan Dam, the river runs through a gorge, which features canyons, waterfalls, great limestone cliffs, and some rapids.
In the Greater Blue Earth River basin, 39 sections of streams and rivers fail to meet the state water quality standard for turbidity, meaning the water is too cloudy and affects aquatic life such as fish. Under state standards, the level of total suspended solids for rivers in the basin should be 90 parts per million. However, levels average between 175 to 675 parts per million according to water monitoring from 2000-2008.
Several stretches of streams in the Greater Blue Earth River also have bacteria levels high enough to violate the state water quality standard, indicating they are not suitable for swimming and other body-contact recreation. Restoring these streams will require reducing bacteria levels by 80 to 90%.
What's being done
The MPCA is working with local partners, focusing on feedlots and failing septic systems, to reduce bacteria levels and make streams suitable for swimming and other body-contact recreation. As part of the Minnesota River Basin, the Blue Earth and its tributaries have been the subject of several scientific studies, including research by the MPCA, WRC-Minnesota State University-Mankato, University of Minnesota, National Center for Earth Surface Dynamics, Minnesota Dept. of Agriculture and others.
The MPCA and several other agencies monitor the water quality of the rivers and streams in the watershed, an effort that spans more than 20 years. The MPCA is finalizing a Total Suspended Solids (TSS) Total Maximum Daily Load (TMDL) report for the Greater Blue Earth River Basin. In this report, the MPCA recommends a 0% reduction in sediment levels during low flow conditions and up to a 93% reduction in sediment levels during high flow conditions such as spring thaw. After public notice and approval from the U.S. Environmental Protection Agency, the MPCA will work with stakeholders to develop a Watershed Restoration and Protection Strategy (WRAPS) plan as part of the Blue Earth Watershed Approach.