Addressing Combined Sewer Overflows in the Brightmoor Neighborhood of Detroit through Community Driven Nature Based Solutions

Introduction: This presentation will describe the process being undertaken by the Detroit Water & Sewerage Department (DWSD) to address combined sewer flows in the Brightmoor neighborhood of Detroit, Michigan. The Brightmoor neighborhood is primarily serviced by a network of large diameter combined sewers which frequently overflow to the nearby Rouge River. The sewershed captures about 1,930 acres of land. DWSD has a NPDES permit obligation to significantly reduce combined sewer overflows by 2037 and evaluates both green (i.e., nature based solutions) and grey infrastructure alternatives (i.e., large scale underground storage) when determining how best to address combined sewer events. The Brightmoor neighborhood was chosen for a nature-based solutions (NBS) plan to address combined sewer overflows because of existing social, environmental, and economic challenges that provide opportunities for stormwater management and neighborhood improvement. First, the housing density varies across the neighborhood which provides an opportunity to direct stormwater into significant vacant land repurposed into green stormwater infrastructure features and parks. The neighborhood is historically underserved and represents a highly vulnerable population (neighborhood consists of 96% minority and 69% of low economic means). Furthermore, the area has a high level of social vulnerability according to the Center for Disease Control and Prevention (CDC). As such, environmental justice concerns are paramount to the planning process. By improving tree canopy, creating habitat, providing pedestrian mobility and recreational opportunities, and potentially increasing property values of surrounding residential housing, this project adds significant social value to the neighborhood. A quintessential reason the neighborhood was chosen is the existence of historic drainage pathways in the neighborhood which are still visible in surface topography. This allows the planning and design team to leverage existing topographic relief to maximize surface catchment flow opportunities. In strategic low-lying locations in the neighborhood, streets could be decommissioned and removed. This will reduce impervious cover in the neighborhood and further address flooding concerns reported by residents in the neighborhood as well. Planning & Design: Starting in early 2023, the City of Detroit initiated a large-scale neighborhood framework planning effort centered on community engagement. DWSD's stormwater management efforts are included to assess the best approach for using NBS in the Brightmoor neighborhood. Community engagement includes meetings with stakeholders, surveys, and design charrettes to inform residents about the planning process and elicit feedback on design alternatives. This community engagement informs a technical planning process focused on delivering cost effective solutions for stormwater management. Tangible projects are developed through preliminary engineering that test fits proven neighborhood scale solutions. The solutions are confirmed through hydraulic modeling, existing conditions surveys and geotechnical investigations which validate designs in real space. Designs are spatially coordinating with neighborhood framework initiatives including housing, economic development, and open space. Ultimately, the framework plan delivers these implementable, holistic stormwater solutions that are coordinated with the unified neighborhood vision. To support the framework plan with tangible progress, DWSD has piloted a series of NBS projects within the neighborhood. These are being collectively referred to as the Fenkell Stormwater Projects in reference to Fenkell Avenue and the Fenkell Combined Sewershed. The Fenkell Stormwater Projects are funded through successful grant applications from State of Michigan Environment, Great Lakes, and Energy (EGLE), U.S. Environmental Protection Agency, National Fish & Wildlife Foundation, U.S. Department of Agriculture Forest Service with DWSD providing matching funds to more than double the impact of the grant funds. The Fenkell Stormwater Projects include a robust community engagement plan, the installation of twenty-two bioretention cells, the vacation/removal of a street for the creation of an urban forest, replacement of aging underground infrastructure, and the creation of common greenspaces. Collectively, the Projects will manage approximately 9 MG of stormwater annually by capturing and treating runoff from approximately 50 acres. Lessons learned through the planning and design phase of the Fenkell Stormwater Projects are being applied to the future Brightmoor NBS designs. Of particular interest is the removal of the street for one block and the impact on city services and existing utilities. There are significant complexities, both social and technical, with street removal that are being documented for the potential removal of other residential streets in the neighborhood. The design of the Fenkell Stormwater Projects has been completed and construction is slated for Spring of 2024. As part of the assessment process, pre- and post-construction in-pipe flow monitoring is occurring at strategic locations to determine the effectiveness of these projects reducing combined sewer flows. Conclusion: Removing stormwater from the combined sewer system in the Brightmoor neighborhood will create capacity and reduce the burden on existing infrastructure. There are significant additional environmental and social benefits to implementing NBS into the neighborhood as well, which are driving the planning and design process. The audience will learn about DWSD's approach to community engagement and planning and the ultimate design of NBS that resulted from those efforts. The presentation will also discuss in detail the value in piloting specific NBS intervention and how small-scale NBS approaches can be scaled up across the neighborhood.