Improvements to Boschert Creek
Location: Chesterfield, Mo.
Client: Missouri Department of Transportation, District 6
In recent years the Boschertown area, on the north side of the City of St. Charles, Mo., has experienced flooding from Boschert Creek. The creek is flanked by levees on both sides, but the swift inflow of stormwater from upstream frequently caused the levees to be overtopped. The Missouri Department of Construction’s (MoDOT’s) construction of I-370 along the north side of St. Charles aggravated the problems.
MoDOT retained Burns & McDonnell to perform the hydrologic and hydraulic analysis necessary to determine the capacity of the existing stream channel and to formulate and evaluate alternatives for reducing the potential for flooding in the area. The analyses were performed using HEC-1 and HEC-2 computer models. Several alternatives were investigated, including channel improvements, levee upgrades, upstream detention and various combinations. A report of the investigation was prepared and submitted to MoDOT and local public agencies. Public forums informed affected property owners and solicited input in selecting the recommended improvement plan.
The selected alternative was to widen the Boschert Creek channel from Little Hills Expressway downstream for approximately 2,000 feet. Two detention basins, to be located adjacent to the creek, were designed to accommodate high flows and prevent the levees from being overtopped. These basins, totaling about 60 acres, will handle a much wider range of channel flows without flooding the surrounding area.
About 20 acres of the detention basins were designed for a constructed wetland. Areas within the wetland will include emergent vegetation, shrub wetlands and forested wetlands.