City of Eagan Water Quality Improvement Program

In the “Land of 10,000 Lakes,” the City of Eagan has improved or maintained water quality in its own lakes through a comprehensive management program. Recognizing that water quality in lakes and wetlands can be negatively impacted by phosphorus as impervious surfaces increase in a watershed, the program set aggressive goals to reduce nutrients entering area lakes. To achieve these goals, our water experts designed and implemented a variety of strategies to reduce phosphorus.

At LeMay Lake, we designed an infiltration trench to create subsurface storage that filters and slowly drains stormwater, helping to reduce the speed and quantity of pollutants entering LeMay Lake. The infiltration trench has helped achieve the City’s nutrient reduction goal of 35 pounds per year of phosphorus. At Carlson Lake, we achieved a nearly 16 pound per year nutrient reduction by rerouting 90 acres of watershed runoff to an underground filter, far surpassing the City’s target for the lake of 12 pounds. Iron-enhanced sand filters were integrated into the existing ponds at Cliff and Fitz lakes. Installed within created pond “benches,” iron filings within the sand filters strip soluble pollutants, effectively reducing phosphorus export downstream.

With our support, the City’s water quality management program has been critical in reducing nutrient loads and excess algae growth. The cleaner lakes offer residents more recreational opportunities, such as fishing, and more sustainable aquatic environments.