Thompson Lake has long been one of the highlights of Thompson County Park. But for the last few years, elevated levels of pollutants have dampened recreational activity on the lake.
Storm water runs into the lake, and over the years polycyclic aromatic hydrocarbons (from now-banned coal-tar based asphalt sealants) have accumulated as a result of sediment runoff. Studies have shown the pollutant concentration to be above the ingestion and dermal exposure limits set by the Minnesota Department of Health.
Dakota County is committed to cleaning up the lake, so families can better enjoy the spot as a great place to recreate. The county is pumping $1.3 million into the removal of contaminated sediments and water and investing in its future protection with a storm water management project that will clean water before it enters the lake. The projects will cost a combined $2.02 million and be jointly funded with the City of West St. Paul and the Lower Mississippi River Watershed Management Organization. Following the cleanup, the lake will be a better place to fish and explore other recreational activities, like canoeing.
Engineers will get the project started within the next month. They’ll be looking at several possible methods to dispose of the contaminated sediments and designing how to clean the current — and future — water supplies. Both projects are projected to be complete by the end of 2018.