Lower Minnesota River Watershed Total Maximum Daily Load Report Part I—Southern and Western Watersheds

The Clean Water Act, Section 303(d) requires TMDLs to be produced for surface waters that do not meet
applicable water quality standards necessary to support their designated uses. A TMDL determines the
maximum amount of a pollutant a receiving waterbody can assimilate while still achieving water quality
standards, and allocates allowable pollutant loads to various sources. This TMDL study addresses the
stream and lake impairments in the Lower Minnesota River Watershed in south central Minnesota. The
causes of impairment in the watershed include high levels of total phosphorus (TP), TSS, Escherichia coli
(E. coli), and chloride, affecting aquatic recreation, aquatic life, and limited resource value designated
uses. Nineteen lake TMDLs and 56 stream TMDLs were developed for phosphorus (5), TSS (14), E. coli
(36), and chloride (1).