AP analysis finds growing number of poor and high-hazard dams
More than 2,200 dams built upstream from homes or communities are in poor condition across the U.S., likely endangering lives if they were to fail, according to an Associated Press analysis.
The number of high-hazard dams in need of repairs is up substantially from a similar AP review conducted just three years ago.
There are several reasons for the increased risk. Longdeferred maintenance has added more dams to the troubled list. A changing climate has subjected some dams to greater strain from intense rainstorms. Homes, businesses and highways also have cropped up below dams that were originally built in remote locations.
“All of the sudden, you’ve got older dams with a lower design criteria that now can potentially cause loss of life if they fail,” said Del Shannon, an engineer who is president of the U.S. Society on Dams.
“The number of deficient, high-hazard dams is increasing,” he said, adding that without investment in upgrades, that number will continue to rise.
The actual number of high-hazard dams in poor or unsatisfactory condition is likely even higher than the AP’s tally, although it’s unclear because some states don’t track such data and many federal agencies refuse to release that information.
The nation’s dams are on average over a half-century old. They have come under renewed focus following extreme floods, such as the one that caused the failure of two Michigan dams and the evacuation of 10,000 people in 2020.
The $1 trillion infrastructure bill signed last year by President Joe Biden will pump about $3 billion into dam-related projects, including hundreds of millions for state dam safety programs and repairs.
Yet it’s still just a fraction of the nearly $76 billion needed to fix the tens of thousands of dams owned by individuals, companies, community associations, state and local governments, and other entities besides the federal government, according to a report by the
Association of State Dam Safety Officials.
Since 2019, California regulators have downgraded four of San Diego’s water supply dams from fair to poor condition due to deterioration and concerns they could fail due to an earthquake or extraordinary rainfall.
During “a big earthquake, you never know what’s going to happen, if this is going to hold,” said Samuel Santos, a longtime resident who frequently fishes near El Capitan Dam
As a safeguard, the water level of El Capitan Reservoir is intentionally kept low, meaning there is less water available amid a severe drought.
“These reservoirs are very important,” said Republican state Sen. Brian Jones, whose district includes El Capitan Dam. “We need to start spending the money on them to retrofit them, to get them up again back to full capacity.”
The number of high-hazard dams in poor or unsatisfactory condition has risen partly because some states have stepped up inspections and reassessed whether old dams endanger new downstream developments.