Water Use Classifications and Impairments within the MWMO

Minnesota regulations require that the MWMO protect water quality in the watershed. Minnesota Rules Chapter 7050 requires that all waterbodies comply with state water quality standards. Furthermore, section 303(d) of the Federal Water Pollution Control Act (commonly known as the Clean Water Act) requires states to develop TMDLs for waters with impaired uses. Impaired waters are those waters that exceed water quality standards for their classified use. Some typical classifications include drinking water, aquatic life, and recreation (swimming and fishing). According to Minnesota Rules Chapter 7050, the stretch of the Mississippi River within the MWMO watershed is divided into two reaches for classification. Table 1 highlights the most restrictive water use classifications.

The MWMO’s stretch of the Mississippi River is listed on MPCA’s 303(d) list of impaired waters for fecal coliform/E. coli, nutrients, mercury, and polychlorinated biphenyls (PCBs). Table 1 also lists the impaired reaches of the river and the corresponding pollutants of concern. Both Sullivan Lake and Highland Lake in Columbia Heights are listed on the 303(d) list of impaired waters for nutrient/eutrophication and biological indicators. All three of the Kasota Ponds in St. Paul and Loring Pond in Minneapolis are listed on the 2020 Impaired Waters List for chloride impairments.

*Current as of April 2020