Construction is wrapping up at the Chisago County courthouse in Center City. The past month has seen major changes at the front main entrance of the courthouse. Gone are the large raised planters. In their place, innovative water quality Best Management Practices (BMPs) have been installed.
This project was a partnership between the County, the Chisago Lakes Lake Improvement District (LID) and the Chisago Soil and Water Conservation District (SWCD). The county provided funding for non-water quality portions of the project, while the majority of the funding was provided by the LID and Clean Water Fund grant money through the SWCD.
The new look may appear to just be a shift in landscaping, but it has important water quality goals at its core. Rainwater runoff from portions of the roof used to run across the sidewalk, creating slipping hazards in the winter and damaging the sidewalk. New gutters and pipes that run beneath the sidewalk to the large rain garden help solve this problem. Runoff from the sidewalk itself is able to enter the rain gardens or the two “tree pits” through small cuts in the concrete curbing. The runoff from the parking lot can also enter into the rain gardens or tree pits.
The rain gardens and tree pits are designed to capture and infiltrate the water that comes off the impervious surfaces. Water will pond up during a rain event (up to a maximum of nine inches deep), and slowly soak into the surrounding soils. Buried beneath the entire project is a perforated pipe that will also carry some water to the existing storm drain system. This pipe ensures that water will not stay in the gardens for longer than 24-48 hours. The water that drains through the pipe will be cleaner because it was able to filter through the pretreatment chambers, plants, and soil before entering the storm drain system and the lake.
For more information on projects completed by the Chisago SWCD, visit our website at www.chisagoswcd.org.