On January 22, the Minnesota Board of Water and Soil Resources approved $13.9 million in Clean Water Fund grants to improve water quality in lakes, streams, and groundwater aquifers across the state. Forest Lake emerged as a big winner in this round of funding, with the Comfort Lake – Forest Lake Watershed District securing two grants totaling more than $1.2 million for projects to improve water quality in Forest Lake and the Sunrise River. In addition, the Middle St. Croix Watershed Management Organization secured $513,500 in funding for a project to restore Lily Lake in Stillwater and remove it from the state’s impaired waters list. Smaller grants were awarded to Carnelian‐Marine‐St. Croix Watershed District to address stormwater concerns in Marine on St. Croix and to Washington Conservation District to protect drinking water quality in southern Washington County.
The largest grant, $747,000, will be given to Comfort Lake – Forest Lake Watershed District to treat 50% of the runoff flowing into the east basin of Forest Lake through Washington Judicial Ditch 6 . The project will employ a multi‐cell, iron‐enhanced sand filtration treatment system and is expected to keep 85 pounds of phosphorus out of Forest Lake every year. The reduction in phosphorus will be the equivalent of removing more than 40,000 pounds of algae from the lake.
Iron-enhanced sand filtration is a technology developed at University of Minnesota, St. Anthony Falls Laboratory in 2005. Iron-sand filters utilize a chemical process that causes phosphorus molecules to bind with iron in the sand as water passes through. The ability to pull ‘dissolved’ phosphorus out of water makes iron-sand filters unique compared with other practices like stormwater ponds and sediment basins that can only catch phosphorus attached to sediment and organic waste. Iron-enhanced sand filters are also able to treat stormwater runoff in places with clay soil or high water tables where raingardens don’t work.
In 2020, Comfort Lake–Forest Lake Watershed District will also receive $492,000 in Clean Water funds to restore an existing ditched wetland complex that discharges directly into the Sunrise River, just north of Forest Lake. The project will increase flood storage capacity within 41.7 acres of District‐owned, tax forfeited property, and will keep 54 pounds per year of phosphorus out of the Sunrise River and Comfort Lake. Because the Sunrise is one of the tributaries that carries the highest amount of nutrients to the St. Croix River, the project is expected to produce benefits downstream as well.
In Stillwater, the Lily Lake project will be the final step in a multi-year effort to reduce runoff pollution and limit the amount of phosphorus available to feed algae in Lily Lake. In 2007, studies conducted as part of the Lily Lake Management Plan set a goal of reducing phosphorus input to Lily Lake by 145 pounds per year. To date, the Middle St. Croix Watershed Management Organization and City of Stillwater have achieved a 115 pound phosphorus reduction by constructing raingardens in surrounding neighborhoods, redesigning streets and parking lots, modifying existing stormwater ponds, and stabilizing gullies. Water monitoring data collected by Middle St. Croix WMO and the Washington Conservation District shows that Lily Lake’s water quality is gradually improving as a result.
With these new grant funds, Middle St. Croix WMO will install a stormwater management practice that will capture an additional 30 pounds of total phosphorus discharging directly to Lily Lake from 15 acres of urban residential and institutional land. Afterwards, two alum treatments will be conducted to bind an additional 120 pounds of phosphorus already in the lake so that it can no longer recirculate. Diagnostic studies suggest that the combined efforts will bring Lily Lake back to a clear-water state and allow it to meet state standards for aquatic health and recreation.
Elsewhere in Washington County, Carnelian‐Marine‐St. Croix Watershed District will receive $97,600 in Clean Water funds to install nine green infrastructure projects in downtown Marine on St. Croix that will intercept and treat stormwater runoff from 20 acres of high density urban land. The project will keep 27 pounds per year of phosphorus out of the St. Croix River, which is a federally-protected Wild and Scenic River.
Washington Conservation District will receive $75,000 to protect drinking water quality in areas of rural southern Washington County that are vulnerable to groundwater contamination from nitrogen fertilizer. As part of this project, the Washington Conservation District will provide technical and financial assistance to agricultural landowners to promote nitrogen fertilizer best management practices and implement alternative land management tools. The district hopes to address nutrient management on 200 acres of agricultural land as part of the project, and reach over 200 community members through education and community engagement.
The Minnesota Clean Water Fund was created by a voter-approved constitutional amendment in 2008. The Legacy Amendment allocates three-eighths of one percent of all sales tax revenue to projects that protect, enhance, and restore wetlands, prairies, forests, and fish, game, and wildlife habitat; preserve arts and cultural heritage; support parks and trails; and protect, enhance, and restore lakes, rivers, streams, and groundwater. Since 2008, the Legacy Amendment has generated $971.5 million for the Minnesota Clean Water Fund.