Adapting to Changing Rainfall in the SEMCOG Region

The Southeast Michigan Council of Governments, SEMCOG, recently finalized a 7-county analysis of water infrastructure investment needs through 2045 for linear drinking water, sanitary sewer and stormwater assets. Based on the findings, an estimated $3.5 billion is necessary for continued protection of public health. Combined with transportation investment needs, the total annual investment is nearly $5 billion just to keep linear assets in good condition. This does not take into account other significant investment needs to address water treatment, wastewater treatment and extreme flooding events. With recent (June – July 2021), severe flooding events in the 7-county, Southeast Michigan Region, regional flood mitigation planning for future infrastructure investments has risen to the forefront. To support local, regional and state infrastructure planning efforts, SEMCOG is utilizing results from a future precipitation analysis, a flood risk study, and a regional asset data collection and condition assessment effort to address increased rainfall and extreme flooding events. Based on the future precipitation analysis, it is expected that the lack of stormwater collection capacity and flooded property and roadways will be exacerbated unless there are significant investment efforts and implementation of a collaborative management strategy. This presentation will share findings and products from that address regional climate resiliency including: - Precipitation estimates using regional climate models for 2050 and 2100; - A flood risk tool for transportation assets including roads, bridges, culverts, and pump stations; - A flooding app to track localized flooding locations; - A regional guidance document with alternatives to addressing future rain events in infrastructure planning and design; - Water infrastructure investment need estimates and background methodology for continued updates; and - A collaborative capital improvement project coordination tool across public and private utilities for future infrastructure planning. These regional projects represent valuable insight into the interwoven practices of transportation planning, stormwater management, and capital improvement investment. Learning Objectives Attendees of this session will learn about the methodology to estimate investment needs across a large regional metropolitan area. They will also learn about the flood risk tool for roads, bridges, culverts and pump stations; the flooding app to track local flooded locations; and their applicability in the long-range transportation planning process. Additionally, participants will learn of the future precipitation estimates for the region for small and large rain events and understand alternative approaches to integrating these estimates into planning/design efforts. Finally, attendees will understand how the region is supporting more coordinated project planning efforts for long-term cost savings and protection of public health.