Florence floods put stress on North Carolina dams, call attention to the poor shape of nation's dams

A map of U.S. dams shows that many are rated "high hazard.
(Federal Emergency Management Agency map)

Devastating flooding in North Carolina in the aftermath of Hurricane Florence has raised concerns about whether dams across the state, some of them already in poor condition, will be able to hold up under the strain," reports Sarah Rankin of The Associated Press. "State and local officials have been monitoring dam safety and say there have been at least two breaches so far that caused no major issues. But there have been several other locations of concern and false alarms about dam failures that have caused panic."

Of North Carolina's 5,700 dams, 1,445 have been rated high-hazard -- that is, their failure would likely kill at least one person. According to the Army Corps of Engineers' National Inventory of Dams, recent inspections showed that 185 of those high-hazard dams were in poor or unsatisfactory condition; many were in flooded areas, Rankin reports. Before Florence hit, state Dam Safety Program workers tried to reduce the likelihood of dam failure by contacting dam owners and operators to inform them of the threat and ask them to lower water levels temporarily to make room for heavy rains, she reports. 

But though North Carolina appears to have pulled through Florence without major dam failure, the hurricane draws attention to the poor condition of dams nationwide. "The American Society of Civil Engineers gave a 'D' grade to the state of the country’s dams in a 2017 report, noting the average age of the dams is 56 years old," Rankin reports. "The ASCE estimated there are more than 2,000 'deficient high-hazard' dams lacking investment in repairs and upgrades." Along with earthquakes and age, flooding is a leading cause of dam failure, she reports. And as climate change makes extreme weather more common, the risk of dam failure grows.