Along the west side of Trunk Highway 238 in Albany’s North Park, several people were hard at work Sept. 27, pulling weeds around the perimeter and in the basins of what looks like two overgrown storm water holding ponds. These two basins, however, are rain gardens which act as natural filtration systems for polluted runoff.

“In 2018 the City of Albany partnered with the Stearns County Soil and Water Conservation District to design and construct storm water treatment features to reduce the amount of pollutants and nutrients entering North Lake,” said Tom Schneider, clerk and administrator for the City of Albany. 

The rain gardens in North Park are shallow depressions where polluted runoff from impervious surfaces is temporarily (1-2 days) stored as it slowly infiltrates into the ground. A chief element of this filtration system are native plants with deep root systems, such as black-eyed Susan, butterfly milkweed, prairie sedge, and smooth blue aster, to name a few. These perennials are planted in the basins to improve soil’s ability to absorb water and remove pollutants. The basins can also reduce flooding. The two rain gardens in North Park feature 23 different species of native, moisture tolerant plants.

Native plantings are also easy to maintain and provide a food source for pollinators and habitat for wildlife.

The main pollutant the city wanted to remove through these gardens was phosphorus, a common element in agricultural fertilizers, manure and organic wastes in sewage and industrial discharges.

Excess phosphorus in bodies of water causes algae to grow, making water less attractive for fishing and swimming, and degrades conditions necessary for fish, bugs, wildlife and plants to thrive, according to the Minnesota Pollution Control Agency.

Other common water pollutants include dirt, salt, oil, bacteria and garbage.

In addition to the two rain gardens, a wet sedimentation basin was also constructed on the south side of 360th Street, Schneider said.

“It features an iron-enhanced sand filter bench that helps to treat dissolved phosphorus,” he said.

Craig Bardson Excavating constructed the $217,000 project. 

“The project received $147,000 in funding through the Board of Soil and Water Resources (BWSR) legacy funds, and the City’s share of the improvements were approximately $70,000,” Schneider said.

Like any garden, rain gardens need to be maintained through occasional weeding to ensure native plants thrive, hence the visit by a few employees with Stantec Consulting (Albany’s engineering consultant) who removed weeds from the basins.

Come spring, plantings will turn green once more and flowers will bloom, adding a beautiful feature to North Park. While the plantings provide a visually appealing aesthetic aboveground, they are serving a bigger purpose five to 15 feet belowground with their extensive root systems. It is a simple solution to improve the water quality of North Lake.