A bioswale is a specially designed vegetated channel with engineered soil mix that captures water runoff, slows it down, and soaks it into the ground to improve water quality.
This 10,800 square feet bioswale captures water runoff from over 23 acres of hard surfaces including from the parking lot at the White Bear Lake Sports Center, South Birch Lake Boulevard and adjacent neighborhoods. It also stabilizes an eroding channel to Birch Lake. Notable features include:
- 2 pretreatment structures to capture sediment, trash, and trash from South Birch Lake Boulevard and the Sports Center parking lot.
- Amended soil mix and drain tile to promote drainage.
- Soil lift and shrubs native to MN to reconstruct and stabilize an eroding channel to Birch Lake.
- Native plant seed mix to enhance pollinator habitat and stabilize the swale.
- Riprap rock checks to slow runoff and stabilize the outlet of the swale before runoff reaches the lake.
This project was a partnership between the City of White Bear Lake, Ramsey County Soil and Water Conservation Division, and VLAWMO. The City and VLAWMO provided funding through local cash match. Funding was also provided by RCSWCD through a Minnesota Board of Water and Soil Resources (BWSR) Conservation Contracts grant, and by VLAWMO through its Landscape Level 2 grant program and BWSR's Watershed Based Implementation Funding program.
The City of White Bear Lake completed a parking lot retrofit project at the Sports Center that provided a good opportunity to add a water quality treatment practice. A feasibility study was completed through the partnership between the City, RCSWCD, and VLAWMO, which found retrofitting a swale adjacent to the Sports Center parking lot with a bioswale to be the best opportunity to reduce water runoff volume and improve water quality to protect Birch Lake.
This bioswale annually captures about 750,000 gallons of water, and removes 7.3 pounds of total phosphorus and 2,100 pounds of total suspended solids from water runoff.
