Integrating flood risk into decision-making for transportation infrastructure

The Detroit Metro region, like many other areas of the country, has experienced several severe flooding events in recent years that have affected the transportation system. The region’s aging infrastructure and a large deferred maintenance backlog make it all the more challenging for the region to manage its flood risks.

Recognizing that flooding and other extreme weather challenges are likely to persist and potentially worsen into the future due to climate change, the Southeast Michigan Council of Governments (SEMCOG) and Michigan Department of Transportation (MDOT) needed to fully understand their flood risks—and how to use that understanding to inform long-range planning and infrastructure investment decisions.

We produced the Climate Resiliency and Flooding Mitigation Study, which included:

• A GIS-based risk assessment identifying roads, bridges, culverts, and pump stations at greatest risk of flooding.
• A repeatable GIS risk assessment tool SEMCOG can use to update the results as needed.
• An interactive GIS dashboard for regional stakeholders to view results.
• An estimated economic impact of flood risks in the region.
• A practical, actionable implementation plan for SEMCOG and MDOT to apply the risk assessment results into their day-to-day decision making processes.

The GIS tool allows SEMCOG and MDOT to recognize vulnerabilities in the transportation network and to guide planning and investment decisions for the continued safe and efficient operation of a resilient transportation network.

SEMCOG and MDOT have committed to actively using the flooding risk information to inform their long-range planning and investment decisions. The flooding risk scores will now be included as part of the flooding audit for all project reviews.

The data from the Flooding Risk Analysis will be integrated with other MDOT data—such as pavement condition, traffic levels, safety, etc.—to inform project and investment prioritization. Going forward, MDOT is incorporating flooding risk GIS tool results into existing asset management programs, ensuring it's not an extra step to consider climate resilience in their decisions. They’ve also committed to improving the way they track and share information on actual flood events to improve tool outputs over time.

SEMCOG will use the tool to conduct annual updates and share results with partners, and will develop and annually update online maps/dashboards showing flooding risk scores for the assets in the region. They will also host informational and training sessions to highlight the tool, data needs, and results for local municipalities. These sessions will offer suggestions for implementation of the flooding risk results—as well as solicitation of feedback on how to make the tool approachable—at the local level. In partnership with the county road agencies, SEMCOG will use the tool results to identify collaborative partnerships to address flooding challenges across infrastructure owners.