Report: 25% of US Infrastructure at Risk of Floods

House flooding

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The risk of floods across the U.S. is growing. About 25% of all critical infrastructure, or about 36,000 facilities, in the country is at risk of becoming inoperable due to flood risks, according to a new report from the First Street Foundation, the creators of Flood Factor, a nationwide flood risk tool.

About 23% of all road segments, or nearly 2 million miles of road, are at risk of becoming impassable.

Further, 20% of all commercial properties, or about 919,000--and 14% of residential properties, 12.4 million—also are at risk.

"Our work aims to determine the amount of flooding that would render infrastructure either inoperable or inaccessible," Jeremy Porter of First Street Foundation said about the report’s findings. "By applying research on depth thresholds and comparing them to flood data and probability metrics, we can determine roughly the extent of flooding that would cause a road to be impassable to cars, or a hospital to be shut down."

The report predicts that over the next three decades climate change will likely lead to higher risk for an additional 1.2 million residential properties, 66,000 commercial properties, and 63,000 miles of road.

The highest-risk communities are in Louisiana, Florida, Kentucky, and West Virginia. These four states alone have 17 of the top 20 most at-risk counties in the U.S., according to the report. The most at-risk county is Cameron Parish, La., the report notes.

"As we saw following the devastation of Hurricane Ida, our nation's infrastructure is not built to a standard that protects against the level of flood risk we face today, let alone how those risks will grow over the next 30 years as the climate changes," says Matthew Eby, founder and executive director of First Street Foundation. "This report highlights the cities and counties whose vital infrastructure are most at risk today, and will help inform where investment dollars should flow in order to best mitigate against that risk."

The report’s findings are being incorporated into Flood Factor to help others understand personal flood risk and the risks to a community, researchers note. Flood Factor is a searchable website that allows homeowners to find detailed flood risk information on specific properties nationwide. Last year,® added flood risk data from both Federal Emergency Management Agency flood zone maps and Flood Factor next to its for-sale and off-market properties listed at its site.

Read the full report.