Urban Green infrastructure Implementation in St. Louis, Missouri

• Yirang Tan
• Tiffany Barron
• Camille Ferrer
• Kitty Chen

The Metropolitan Sewer District (MSD) of St. Louis, Missouri uses a combined sewer conveyance system to collect both stormwater and wastewater. Like many combined sewer systems across the country, St. Louis’ sewer system overflows due to high levels of precipitation during storm events and a lack of effective stormwater management practices. The role of stormwater runoff in combined sewer overflow (CSO) is the primary concern of the project. To mitigate the overflow, St. Louis requires green infrastructure (GI) to be implemented. The following three locations are under investigation: Wells-Goodfellow neighborhood, Midtown St. Louis, and the property of 325 North Newstead Avenue. The main design objective is runoff reduction and to minimize disturbance. To determine the best management practice (BMP), all GI methods under investigation are analyzed for cost and performance. To alleviate the concerns of CSO, specific GI solutions are proposed. Runoff volume and other MSD protocols are used to measure effectiveness. The existing conditions at each location require a unique evaluation of potential GI implementation. Wells-Goodfellow is a residential area, has many undeveloped lots, and has a sizable amount of pervious land. The Midtown location sits on a commercial, significantly developed part of St. Louis. Finally, the property of 325 North Newstead Avenue has both developed and undisturbed land. Based on publicly available data such as hydrological soil types, curve numbers, precipitation amounts and drainage areas, several BMPs are chosen. The design of each BMP complies with the St. Louis MSD standard protocols. Proposed GI technologies include pervious concrete and amended soils in Wells-Goodfellow, and permeable interlocking concrete pavement (PICP) and bioretention cells in both Midtown and 325 North Newstead Avenue. Using the MSD maximum extent practicable spreadsheet tool, the objective of stormwater runoff reduction is achieved in Wells-Goodfellow, Midtown and 325 North Newstead Avenue.