The St. Louis Metropolitan Sewer District (MSD) is the nation’s fourth largest sewer system, covering 525 square miles with 9,600 square miles of sanitation and stormwater systems. While serving 1.5 million people, the MSD experiences challenges with overflow and water management. Urban development can further exacerbate the city’s water challenges when vegetation is removed and replaced with impervious surfaces, sending stormwater into ditches, culverts and sewer pipes. Such problems cause runoff that picks up and carries a wide variety of pollutants into our local streams and rivers, adversely impacting watershed health and ecosystem integrity.
The state of Missouri has developed a long-term plan to incorporate green infrastructure approaches to control stormwater runoff, and the city of St. Louis is working in some of its poorest neighborhoods to test new strategies. Green infrastructure (GI) planning is a sustainable, environmentally-friendly, and cost-effective way to manage water in the city. Good strategies can lead to the reduction of heat, decreased flood risk, improvements in water and environment, and overall human well-being. Typical GI strategies might include reducing flow into the sewer system with rain gardens and absorbent soils, as well as low-impact drainage techniques. Furthermore, green infrastructure strategies can help beautify neighborhoods by adding plants and green spaces to the urban landscape.
Leading the way among SIUE researchers working with local municipalities to study green infrastructure is Dr. Jianpeng “Jim” Zhou, professor of civil engineering. Zhou directs multiple projects, funded by the US-EPA, the non-profit East-West Gateway, private companies, and the city of St. Louis. These projects combine the expertise of SIUE researchers with local government and non-profits to create solutions for urban water management in the greater St. Louis area.
One major initiative, funded by the USEPA and conducted with co-investigator Dr. Susan Morgan of civil engineering, includes Zhou’s current project, “Community-Rooted Green Infrastructure for Urban Water Improvements.” Zhou and Morgan are studying innovative water-management techniques in communities built by Habitat for Humanity.
The project builds on the MSD’s efforts to reduce stormwater flow into municipal sewers. The team monitors flow at particular sewer entry-points to assess the effectiveness of the green infrastructure, which includes rain gardens, planter boxes and rain barrels.
In addition, the team developed outreach events to local residents to educate them about the green infrastructure on their properties and how to maintain it. It is the team’s hope that increased knowledge and community engagement will promote the widespread use of green infrastructure.
In a complimentary project, Dr. Laurent Ahiablame, adjunct lecturer in the Department of Civil Engineering, is evaluating the environmental, social and economic benefits of the green infrastructure applications. The project examines financial, regulatory and logistical facets of GI strategies, providing benchmarks for measuring the success of these projects. Results of Ahiablame’s study will aid the St. Louis MSD in understanding the short-term and long-term returns on incorporating GI models into city planning.
By providing an analysis of the GI models’ overall effectiveness in social and financial realms, Ahiablame is also illustrating how each element of a green infrastructure system, including people, sites and neighborhoods, are connected to the city’s watershed health and community welfare.
“We all live in a watershed, and the benefits of GIs should be considered not only at the individual sites, but also at the watershed scale,” Ahiablame said. “What we do in our own home would affect everyone around us and downstream.”