Fairmont Chain of Lakes-Nutrient Treatment Train

The project goal is to reduce pollutant loading to Amber Lake (46-0034-00), which is designated as a Class 1, Domestic Consumption use within the Drinking Water Source Management Area - Surface Water (DWSMA-SW) for the City of Fairmont. In recent years, there have been concerns with high nitrate concentrations entering the drinking water source. Harmful algal blooms (HABs) have also been identified in the Fairmont Chain of Lakes as a potential concern for public health, due to the potential for HAB toxins to cause illness through skin contact, breathing in water droplets, or ingestion.

The project includes design and construction of a sediment and nutrient treatment train, which includes an 11-acre nutrient treatment wetland and an 8,000 linear feet two-stage ditch upstream of Amber Lake. The project will reduce 12,827 pounds/year of nitrate, 463 pounds/year of total phosphorus, and 28.7 tons/year of sediment to Amber Lake. These reductions support goals detailed in the Minnesota Department of Health (MDH) 2019 Source Water Assessment (SWA) for the City of Fairmont Public Water System.

The project also aligns with the Martin County Local Water Plan (Water Plan) priority concern of surface water and objective of protecting surface water quality/quantity. Water Plan objectives for surface water quality are to ?reduce nitrate, phosphorus, and sediment concentrations in all county waterbodies.? This project will support those goals by reducing nitrate, phosphorus, and sediment loading to Amber, Hall, and Budd Lakes, which are listed on the 303(d) list as impaired for excess nutrients.

Water Plan objectives for surface water quantity include decreasing ?the amount of surface runoff entering water bodies? and decreasing ?the impact of peak flow events regarding erosion.? The proposed project will provide both permanent storage to support reduced annual runoff and temporary storage to reduce peak flows and reduce the frequency of erosive discharges.