As Extreme Weather Becomes More Common, Dams Become More Vulnerable

There are more than 90,000s dams in the U.S.; many will never be visited by federal or state inspectors.

2 minute read

July 18, 2019, 1:00 PM PDT

By Casey Brazeal @northandclark


Feather River Dam

David Brimm / Shutterstock

Climate change poses serious challenges to dams all over the world. In the United States, there are about 91,000 dams and a backlog of related maintenance projects. The Association of State Dam Safety Officials estimates those projects would cost 71 billion dollars to complete. “And scientists say the likelihood of dam failures — which not only threaten lives but also release toxic sediments trapped in reservoirs behind many dams — will increase as extreme precipitation events become more frequent in a warming world,” Jacques Leslie reports in Yale Environment 360.

Civil engineers offer a similarly bleak perspective. "Largely as a result of the funding shortfall, in its latest infrastructure report card, in 2017, the American Society of Civil Engineers (ASCE) gave the nation’s 91,000-plus dams a D grade, the same grade they have received in every ASCE report card since the first one was issued in 1998," Leslie writes.

Regulators have a difficult task in accessing the safety of dams. On average there is only one state inspector for every 200 dams, but because states vary greatly, some states have more available labor to devote to inspections than others. "Oklahoma, for example, employs just three full-time inspectors for its 4,621 dams; Iowa has three inspectors for its 3,911 dams. Largely because of its legislators’ distrust of regulation, Alabama doesn’t even have a safety program for its 2,273 dams," Leslie reports. High-hazard dams, that could threaten human lives if they fail, are supposed to be inspected every two and a half years, but many go much longer than that.

Tuesday, July 9, 2019 in Yale Environment 360

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