Upper Watershed TMDL Studies for Clearwater River Watershed District

Agency (MPCA) to identify water bodies that do not meet water quality standards and to develop total maximum daily pollutant loads for those water bodies. A total maximum daily load (TMDL) is the amount of a pollutant that a water body can assimilate without exceeding the established water quality standard for that pollutant. Through a TMDL, pollutant loads are allocated to point and non-point sources within the watershed that discharge to the water body. The Clearwater River Watershed District (CRWD) has reduced nutrient and sediment loads in the watershed through watershed best management practices (BMPs) and capital projects improving water quality reducing concentrations many watershed lakes and the Clearwater River by an order of magnitude. However, some 303(d) impairments remain. This upper watershedwide TMDL study was prepared by Wenck Associates, Inc. (Wenck) for the CRWD and addresses: • Six lake nutrient impairments, • A stream bacteria impairment. The total drainage area of the sub-watersheds draining to the impaired portion of the Clearwater River and Chain of Lakes is approximately 93 square miles. The progression of lakes in the Clearwater River Chain of Lakes System from upstream to downstream is Clear Lake, Lake Betsy, Union Lake, Scott Lake, Lake Louisa and Lake Marie. The 10-mile reach of the Clearwater River (river miles 35.0 to 25.0) impaired for bacteria lies between Clear Lake and Lake Betsy. The impairments in this watershed were addressed together because the tributary watersheds for the impairments overlap. This means that the implementation plans to address each of the impairments and meet the TMDLs set forth in this report will also overlap.