Integrating flood risk into decision-making for transportation infrastructure

We developed a practical and user-friendly risk assessment tool that directly informs transportation agency decisions around flood mitigation.
RESULTS AT A GLANCE

+71K

roads assessed for risk

>50%

road segments at moderate flood risk
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.

Challenge

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.

Solution

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

  • A risk assessment identifying roads, bridges, culverts, and pump stations at greatest risk of flooding.
  • A repeatable risk assessment tool SEMCOG can use to update the results as needed.
  • An interactive 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 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.

Study findings:

>50%

Road segments in the SEMCOG region at at least moderate flood risk

7.9%

Bridges in the region at high flood risk

+$36M

Total cost of user delays if all road segments in the region identified as highly exposed were to be closed to flooding for just 1 hour

Results

Read the full study

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 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 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.

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