The U.S. Environmental Protection Agency (EPA) has approved a Total Maximum Daily Load (TMDL) study for phosphorus in Lake Pepin and two tributaries in Wisconsin, establishing a framework for reducing nutrient pollution entering the waterbody.

Approved July 21, the TMDL addresses Wisconsin’s portion of the Lake Pepin drainage basin and complements a Minnesota Pollution Control Agency (MPCA) TMDL approved by EPA in 2021. Lake Pepin, along with Lost Creek and Bogus Creek, is listed as impaired because of excessive phosphorus.

The Wisconsin Department of Natural Resources (DNR) developed the multi-year study with partners including MPCA, county land and water departments and agricultural stakeholders. The effort evaluated agricultural cropping, tillage and management practices and translated allowable phosphorus loads from agricultural sources into formats compatible with implementation tools such as Wisconsin’s SnapPlus nutrient management software.

The DNR said the TMDL will guide management measures and targeted resource deployment to reduce phosphorus pollution while supporting agricultural production and recreational uses. The agency will continue working with partners to help agricultural producers and wastewater dischargers implement pollution-reduction measures.