Construction Underway on Innovative Stormwater Management Project

The Minnehaha Creek Watershed District (MCWD) has begun construction in Minnetrista on an innovative new filter system to improve water quality in Dutch Lake and downstream wetlands.

The MCWD is using a sand/iron filter to reduce the amount of phosphorus that enters Dutch Lake, which is considered impaired for its nutrient concentration.  It’s a relatively new technique in stormwater management.

“This is an exciting technology that will allow us to protect water quality in ways that stormwater ponds and other traditional stormwater management approaches do not,” said MCWD Project Manager Renae Clark. “The filter uses sand mixed with iron filings to both react with dissolved phosphorous and remove it from the water.”

Traditional stormwater ponds allow phosphorus particles to settle before the water moves into a water resource, but don’t capture the phosphorus that is dissolved.

The new system will divert a portion of the flow of a nearby nutrient-laden stream through the filter and return the water to the stream before it flows into Dutch Lake. The MCWD also is managing buckthorn and installing native plantings in the area.

Dutch Lake flows into Lake Minnetonka’s Jennings Bay, which tied for the lowest MCWD lake grade among Lake Minnetonka’s 30 bays in 2011. The MCWD will monitor the filter’s effect on Dutch Lake and downstream resources to determine whether to use it in other parts of the watershed.

“The Minnehaha Creek Watershed District is known for innovative approaches to protecting water quality in our District,” said MCWD Administrator Eric Evenson. “The project is another way we are taking the lead and creating a model that we hope others who are just as passionate about water quality can use.”

The project is located at 6800 Game Farm Road in Minnetrista. Construction was substantially completed this month.