To reduce flooding downstream of a 200 acre watershed, EDM designed enhancements to the existing drainage infrastructure in the Frontenac Forest Subdivision. The 3-foot wide tie-wall channel was converted to a natural, meandering channel with a 7-foot wide bottom and 2H:IV side slopes. A hydraulic and cost study was conducted to review alternative solutions. The recommended solution had the least downstream impacts and had an estimated cost savings of $250,000.
EDM used a rugged tablet to enhance GPS to collect geomorphic data on each of the four reaches. The results of the assessment were used to generate design recommendations for each reach and locate pertinent features such as storm outfalls, areas of bank erosion, locations of channel modifications, nick points, riffles, pools and utility crossings. The channel top width of 25 feet presented access issues for two residents. Prefab steel bridges seemed out of character for backyard use, so a low water crossing was designed to provide opposite bank access. This also provided an opportunity for residents’ children to be “stream level” with life in the creek.
This project is the recipient of two 2017 St. Louis Chapter Awards: APWA Public Works Project of the Year and the ACEC Project of the Year.
EDM has been providing stormwater services to the City of Frontenac since 2005.
Civil Engineering and Project Management