The downtown Chanhassen stormwater best management practice (BMP) retrofit assessment project will reduce watershed phosphorus loads to Rice Marsh Lake and improve the water quality in downstream Lake Riley, impaired for excess nutrients. This project will identify innovative BMP retrofit opportunities that target soluble phosphorus and promote infiltration and groundwater recharge within this highly-developed area. The downtown Chanhassen BMP retrofit assessment project will be performed in partnership with the City of Chanhassen.
This is a joint grant application from the Riley-Purgatory-Bluff Creek Watershed District (RPBCWD) and the City of Chanhassen. In 2010, the Minnesota Pollution Control Agency listed Lake Susan as a shallow lake impaired for excess nutrients. A 2013 report recommended a project located at the park pond immediately northwest of Lake Susan as the most cost-effective watershed implementation project. The project calls for an outlet control structure at a higher elevation that will provide increased dead pool storage and the installation of a Minnesota Filter to treat dissolved phosphorus.
At almost 4,000 acres, Trout Brook is the largest subwatershed in the Capitol Region Watershed District and the City of Saint Paul. The restored stream is part of the 42 acre Trout Brook Nature Sanctuary project, whose goal is to return the area back to some resemblance of its pre-industrialized valley of stream floodplain and wetlands. Monitoring results within the corridor show that phosphorus, sediments, bacteria, lead and copper are the pollutants of most concern.