Due to insufficient capacity of a stormwater pond located in Fountain Park and the upstream storm sewer system, adjacent streets often flooded during large rainfall events. The pond was not designed to provide adequate water quality treatment for the 60-acre urban watershed and excess pollutant loading was being discharged to Lake Waconia, the city’s most valuable water resource. Bolton & Menk presented the city with several best management practices (BMPs) to reduce stormwater runoff volume and pollutant loads. Sump manholes with SAFL or preserver baffles, rain gardens, bioretention areas, tree grates, permeable pavement, and an iron enhanced sand filter were all installed to combat the issues. Additionally, the pond was expanded, streets were widened, and an outlet control structure was installed. By installing all BMPs presented, the city was able to achieve a 1.5 acre/foot reduction in stormwater runoff volume, a 4,100 pound reduction in total suspend solids, and a 15.6 pound reduction in phosphorus loading. Kiosks and signage were also installed to provide public education regarding all flood mitigation and water quality treatment measures installed.
American Council of Engineering Companies of Minnesota – 2016 Honor Award