Des Moines River Headwaters Watershed River Eutrophication Total Maximum Daily Load

This report addresses two river eutrophication standard (RES) impaired stream reaches listed on the Section 303(d) impaired waters list within the Des Moines River Headwaters Watershed, 8-digit hydrologic unit code (HUC-08) 07100001. River eutrophication impairments are treated as phosphorus impairments. Addressing multiple impairments in one TMDL report is consistent with Minnesota's Water Quality Framework that seeks to develop watershed-wide protection and restoration strategies rather than focus on individual reach impairments. The Des Moines River Headwaters Watershed, located in southwestern Minnesota, drains approximately 801,772 acres of six counties (Cottonwood, Jackson, Lyon, Murray, Nobles, and Pipestone). There are 14 communities in the watershed, the largest of which are the cities of Worthington, Slayton, Windom, Lakefield, Heron Lake, and Fulda. Heron, Shetek, and Sarah lakes are in this watershed. Larger streams and rivers include Okabena Creek, Elk Creek, Jack Creek, Beaver Creek, Lime Creek, and the West Fork Des Moines River. The outlet of the Des Moines River Headwaters flows into the Lower Des Moines River (07100002) in Jackson, Minnesota. This TMDL report used a variety of methods to evaluate current loading contributions by the various pollutant sources, as well as the allowable pollutant loading capacity (LC) of the impaired water bodies. These methods include the Hydrological Simulation Program – FORTRAN (HSPF) model and the flow duration curve approach. This TMDL report was developed in conjunction with a basin-wide TMDL report, which addresses multiple impairments throughout the watersheds of the basin, including the Des Moines River Headwaters Watershed (07100001) and the Minnesota portions of the Lower Des Moines River (07100002) Watershed and the East Fork Des Moines River (07100003).