Overview
The City of St. Charles contracted Horner & Shifrin to provide engineering design of a stormwater system to alleviate surcharging in a residential area adjacent to the Missouri River. More than 4,000 feet of sewer, 12-inch to 84-inch, were designed to manage the 15-year, 20-minute design storm and add additional protection during smaller rain events.
Horner & Shifrin survey staff conducted boundary, topographic, and utility surveys over a 50-acre area containing 120 parcels throughout the project area. The project also includes replacement of a flood gate near the levee, and reconstruction of the outfall pipe and channel discharging into the Missouri River. The conceptual design provided by the City was revised when a more efficient and cost-effective alignment was analyzed by H&S.
Environmental concerns arose when research provided information the existing flood gate was constructed at the site of an old railroad fuel storage location. Design of new water lines were added to the project to incorporate efficiency in design and construction of City-funded projects through the same corridor.
The project was broken into two separate projects to allow the flood gate, outfall, and levee work to begin while obtaining additional property owner agreement along the upstream project alignment.
Permitting assistance provided by H&S included the US Army Corps of Engineers for 408 and 404 permitting, Missouri Department of Natural Resources for 401 and Parks permits for crossing the Katy Trail, and City Floodplain Development permitting for work within the floodplain and floodway of the Missouri River.
