Sustainable by Nature
Great River School (GRS) is a Montessori charter school in the Energy Park neighborhood of Saint Paul serving primary and secondary students from throughout the city. As part of an ongoing plan to reinvent its outdoor space and become better environmental stewards, GRS sought innovative stormwater solutions that would reduce the school’s runoff and improve water quality.
Prior to beginning the project, there had been no stormwater management practices on site. GRS is located on polluted land, part of an historic industrial corridor that has been in transition to mixed-use development since the 1980s. This meant that stormwater planning needed to account for capping soil contamination and implementing filtration strategies throughout the site to treat all surface water.
“Site pollution was perhaps the biggest challenge facing the project at Great River School. Traditional infiltration improvements for stormwater would not be possible, so we needed to rely on creativity and innovation to make the project a reality.” – Nate Zwonitzer, Water Resource Project Manager
One of the most visible and unique parts of the GRS project is a natural play area installed on an existing parking lot, which was retained to prevent stormwater infiltration through contaminated soil. The natural play area acts like a green roof since the soil and vegetation absorb much of the rainwater that falls. Additionally, a 4,500 cistern that harvests rainwater from 7,500 square-feet of roof surface supplies the irrigation system for the play area. Not only does this reduce runoff from the roof, it also conserves our drinking water resources.
A proprietary and highly effective Jellyfish® filtration system also treats runoff from all of the school’s parking surfaces. Jellyfish filters use membrane filtration to remove floatable debris, oil, phosphorus, nitrogen, heavy metals and suspended solids from stormwater leaving the site. These filters are installed under the parking lot.
When completed in 2015, the GRS project had converted 0.17 acres of parking lot space to a natural play surface, provided filtration for all remaining parking areas, and installed a system to capture 45,000 gallons of rainwater annually for reuse. In total, stormwater best management practices (BMPs) at GRS will help reduce total phosphorus (TP) pollution loads by 1.8 pounds per year and total suspended solids (TSS) by 427.5 pounds per year, accounting for 90 percent of TSS flows and 60 percent of TP flows from the site.
