Mississippi River – La Crescent Area Watershed Total Maximum Daily Load

The Clean Water Act (1972) requires that each state develop a plan to identify and restore any waterbody that is deemed impaired by state regulations. A total maximum daily load (TMDL) study is required by the United States Environmental Protection Agency (EPA) as a result of the federal Clean Water Act to address impaired waters. A TMDL identifies the pollutant that is causing the impairment and how much of that pollutant can enter the waterbody and still meet water quality standards.
The waterways of the Mississippi River – La Crescent Area Watershed drain to the Mississippi River near La Crescent, Minnesota. Four stream reaches in the watershed were assessed for aquatic life, and a fifth stream reach did not have enough monitoring data available for assessment (Miller Valley Creek). Of the reaches assessed, three are meeting aquatic life water quality standards (Pine Creek in Winona County, Rose Valley Creek, and Dakota Creek). Only one reach (Pine Creek in Houston County) had Escherichia coli (E. coli) monitoring data available for aquatic recreation assessment, and is impaired by excess bacteria on Minnesota’s 2018 303(d) list of impaired waters. While fish community and turbidity data assessments for Pine Creek in Houston County determined impairment, listing of the impairments on the impaired waters list is being deferred until a proposed use class change from 2B (cool or warm water aquatic biota community) to 2A (cold water aquatic biota community) is finalized. Given this pending change in use class designation, this report proactively includes a TMDL for the total suspended solids (TSS) impacting the fish community in Pine Creek.