Agenda - Council Work Session - 02/23/2021

Home

many waterbodies in the LRRWMO, stormwater runoff is a major contributor of pollutants. Pollutants in stormwater runoff include phosphorus and other nutrients, sediment, chlorides, oil, grease, chemicals (including hydrocarbons), metals, litter (e.g., plastics, Styrofoam), and pathogens which can severely reduce water quality. Nutrient and sediment loading to waterbodies from stormwater runoff can far exceed what would be expected from an undeveloped watershed. Chloride loading from runoff carrying road salt applied to roadways, parking lots, sidewalks, and other developed areas throughout the winter months is also a significant pollutant source. In District lakes and wetlands, phosphorous is the pollutant of most concern. As total phosphorus (TP) loads increase, it is likely that water quality degradation will accelerate, resulting in unpleasant consequences such as profuse algae growth or algal blooms (reflected in high chlorophyll -a concentrations). Algal blooms, overabundant aquatic plants, and nuisance/exotic species, such as Eurasian watermilfoil, purple loosestrife, and curly -leaf pondweed, will flourish and interfere with ecological function as well as recreational use and the aesthetics of waterbodies. Sediment is also a pollutant of concern. Sediment contributes to poor water clarity that affects vegetation growth and deposits onto stream and lake beds, impacting aquatic habitat. It is also a substrate to which phosphorus and other pollutants bind. The Minnesota Pollution Control Agency (MPCA) is the state regulatory agency primarily tasked with protecting and improving water quality in Minnesota. In administering the CWA in Minnesota, the MPCA also maintains a list of impaired waters (see Section 0). The MPCA performs Total Maximum Daily Load (TMDL) studies and watershed restoration and protection strategy (WRAPS) to address impaired waters. Both TMDLs and WRAPSs may result in implementation plans to address water quality issues of the affected waterbodies. Often pollutant loading from tributary watersheds must often be reduced to control or reverse water quality degradation in impaired water bodies. TMDL and/or WRAPS implementation presents an opportunity for the LRRMWO to coordinate water quality improvement efforts between cities and other partners. Regular water quality monitoring performed by the ACD, MPCA, and other partners is necessary to identify water quality issues and trends (see Section 2.7.3). Specific water quality issues identified within the LRRWMO include: • Cedar Creek is impaired for aquatic recreation due to E. coli • Trott Brook is impaired for aquatic life due to dissolved oxygen, fish bioassessments, and invertebrate bioassessments • Protection of good water quality conditions observed in LRRWMO priority lakes • Sediment and other pollutant loading to the Rum River and Mississippi River Addressing water quality issues in the Rum River and Mississippi River is challenging because of the size and location of the LRRWMO within the respective watersheds of these resources. While the LRRWMO focuses on reducing the pollutant loading to the Rum River and Mississippi River within its jurisdiction, the benefits of its actions may not be observable in river water quality data. 3-4