The Metropolitan St. Louis Sewer District Strikes Gold with Strapped Plumbing

The Metropolitan St. Louis Sewer District (MSD) assisted by URS Corporation (URS) has performed investigations and completed a Cityshed Facilities Plan with recommendations to alleviate street flooding and building backups for rainstorms up to a 20-year return period storm within the Western Mill Creek (WMC) Combined Sewer System (CSS) Cityshed basin in the City of St. Louis, Missouri (the City).As a secondary goal, improvement alternatives were also evaluated with respect to their usefulness in providing a worthwhile source of supplemental stormwater to the Chouteau Lake and Greenway System (CLGS) Master Plan project. The CLGS Master Plan, if implemented, would result in the restoration of a portion of the original, pre-development Mill Creek watershed through the creation of a surface water system of lakes and wetlands that would drain to the Mississippi River. The CLGS Plan would provide a setting for a revitalized urban eco-scape with cultural and environmental amenities for residents and visitors. The plan is in the conceptual stage, and is not yet funded.The Cityshed Facilities Plan also provides recommendations for a program of activities to minimize future collection system structural deterioration of existing facilities; and a preliminary design study was prepared for improvements in the Gaslight Square area, a neighborhood subject to building backup conditions during certain wet weather events.The major improvements recommended as part of the Cityshed Facilities Plan include the design and installation of elevated or “strapped” basement plumbing; combined sewage storage tanks; and targeted partial sewer separation.The recommended improvements are planned to be implemented in phases. The implementation plan will benefit MSD by allowing flexibility and the opportunity to make mid-course adjustments and conserve budget as progress and performance are assessed. The various proposed facilities will ultimately work in concert to accomplish the multiple purposes of:Minimizing the frequency and severity of building backups and street flooding;Providing a source of supplemental water to the planned CLGS;Decreasing wet-weather flows to the Bissell Point Wastewater Treatment Plant; andEnhancing performance of other collection system improvements planned as part of the MSD Wet Weather Long Term Control Plan.