Assessment Report of Selected Lakes within the Buffalo River Watershed Red River of the North 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 (CWA) 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 un-impaired 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, condition monitoring or other special projects. This report details the assessment of selected lakes within the Buffalo River Hydrologic Unit Code (HUC)-8 watershed. The Buffalo River Watershed is made up of nine 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 lakes identified as impaired. A full list of the assessed lakes within the Buffalo River Watershed, including their morphometric characteristics, is located in Appendix A. Approximately one quarter of the lakes in the watershed had assessment level data; of these, half were determined to be not supporting recreational use. Of the 43 lakes that had complete datasets available for assessment, 16 were considered to be supporting aquatic recreation use and 18 were not supporting aquatic recreation use. Because of the high number of lakes in the Buffalo River, an in depth discussion for all 43 lakes was not possible; however a subset of impaired or otherwise prominent lakes were discussed further.