Assessment Report of Selected Lakes Within the Le Sueur River Watershed Minnesota River Basin

The Minnesota Pollution Control Agency (MPCA) conducts and supports lake monitoring for a variety of objectives. Staff within the MPCA's Lakes and Streams Monitoring Unit sample approximately 100 lakes per year, coordinate citizen volunteer monitoring through the Citizen Lake Monitoring Program, and manage Surface Water Assessment Grants given to local groups to monitor lake and stream water quality. Watershed-based monitoring emphasizes large lakes (500 acres or greater) whenever possible. All water quality data from these activities are compared to state water quality standards to determine if a given lake is fully supporting or not supporting standards set for recreational use (e.g., swimming, wading, etc.). Lakes not supporting aquatic recreational use are termed "impaired" and are placed on a list biennially. This list is formally termed the 303(d) list (referencing the section within the federal Clean Water Act that requires us to assess for condition); it is also commonly called the "Impaired Waters List". A lake placed on the Impaired Waters List is required to be intensively researched through a Total Maximum Daily Load (TMDL) study to determine the source and extent of the pollution problem. The study also requires the development of a restoration plan. For unimpaired waters, a protection plan will be developed following the assessment process. It should be noted that a great deal of lake monitoring is also carried out by various other MPCA staff and local groups who are undertaking TMDL studies or other, special projects. This report details the assessment of lakes within the Le Sueur River Hydrologic Unit Code (HUC)-8 watershed. The Le Sueur River watershed is made up of eleven HUC-11 intensively monitored watersheds. A general description at the eight-digit HUC level is provided, followed by discussions for each 11-digit HUC that has one or more assessed lakes. A full list of the assessed lakes, including their morphometric characteristics, within the Le Sueur River watershed is located in Appendix A. Many of the Le Sueur River watershed lakes possessing assessment level data were determined to be nonsupporting of recreational use. Of the four lakes (Buffalo, Minnesota, Bass, and Rice) that have insufficient data to complete an assessment, only one (Bass Lake) indicates improving water conditions. Two lakes (St. Olaf and Reeds) within the watershed have been determined to be fully supporting of recreational use.