Mapping flood risk for Washington, D.C.
We helped the Metropolitan Washington Council of Governments better understand their flood risk and uncover hidden vulnerabilities of critical transportation infrastructure.
Our groundbreaking flood risk assessment has given the Metropolitan Washington Council of Governments (MWCOG) a clear, urgent picture of the vulnerability of its critical infrastructure. By combining advanced modeling with FEMA data, MWCOG uncovered vulnerabilities that were previously hidden—empowering smarter planning and resilience investments across D.C., Maryland, and Virginia.
Challenge
The Washington metropolitan region is no stranger to flooding, but recent flash floods and extreme weather events exposed vulnerabilities that traditional flood maps didn't capture. MWCOG’s Transportation Planning Board needed a more accurate and forward-looking understanding of flood risk to protect roads, rail, and transit systems across D.C., Maryland, and Virginia.
Solution
We worked with water risk intelligence firm Fathom to conduct a groundbreaking inland flood risk assessment using our advanced modeling technology and their US Flood Map.
Our team developed a detailed risk assessment for regional transportation infrastructure under a range of potential scenarios and leveraging Fathom’s US Flood model. The combined product enabled us to resolve previously unappreciated and underestimated flood risk in the DC region across various time horizons and scenarios, providing a more complete and actionable picture of how the transportation system could be impacted by worsening storms and extreme weather.
By seamlessly integrating FEMA's foundational floodplain data with Fathom's high-resolution models of pluvial (surface water) and fluvial (riverine) flooding—and leveraging ICF’s advanced capabilities and domain expertise trained to the transportation sector—the team delivered tailored insights to effectively address flood risk and drive data-informed justification and prioritization of resilience investments.
Results
Our analysis revealed that flood risk across the region’s transportation network is 2–3x higher than previously estimated:
39%
of lane miles on roads and highways at risk, up from 14%
11%
of bus stops at risk, up from 4%
21%
of rail stops at risk, up from 7%
64%
of rail lines at risk, up from 39%
The new flood risk insights are already informing MWCOG’s Transportation Resilience Improvement Plan and helping planners prioritize infrastructure investments. The data is also publicly available through an interactive mapping tool, enabling local governments and transit agencies to assess vulnerabilities and apply for resilience funding with greater specificity.