More dams are in danger of collapse, but the Army Corps won't disclose the condition of some 'high-profile' dams

More than 2,200 of the nation's 92,000 dams are in poor condition and likely to cause deaths if they fail. Alabama doesn't have a dam safety program and Illinois doesn't assign condition ratings to its dams. (Associated Press map)

"An Associated Press analysis tallied more than 2,200 high-hazard dams in poor or unsatisfactory condition across the U.S. — up substantially from a similar AP review conducted three years ago. The actual number is likely even higher, although it’s unclear because some states don’t track such data and many federal agencies refuse to release details about their dams’ conditions," David Lieb, Michael Casey and Michelle Minkoff report for The Associated Press. The U.S. Army Corps of Engineers maintains the National Inventory of Dams, a federal database that discloses the condition and hazard rating of most dams nationwide, but it doesn't list data for many prominent dams such as Hoover Dam or California's Oroville Dam. More than 180,000 residents near Oroville had to evacuate in 2017 after its spillway failed. The dam was found to be poorly designed, built and maintained.

"The nation’s dams are on average over a half-century old and often present more of a hazard than envisioned when designed because homes, businesses or highways have cropped up below them. Meanwhile, a warming atmosphere can bring stronger storms with heavier rainfall that could overwhelm aging dams," AP reports. "Decades of deferred maintenance has worsened the problem. But a changing climate and extreme floods — such as the one that caused the failure of two Michigan dams and the evacuation of 10,000 people in 2020 — have brought a renewed focus to an often overlooked aspect of America’s critical infrastructure."

Last year's $1 trillion infrastructure bill allotted about $3 billion into dam-related projects, including repairs and state dam safety programs. "Yet it’s still just a fraction of the nearly $76 billion needed to fix the almost 89,000 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."

Some states are trying to deal with dam problems, but it can be difficult. "Addressing the problems posed by old, unsafe dams can be challenging. Repairs can be costly and take years to complete," AP reports. "Attempts to remove dams — and empty the lakes they hold back — can spawn legal battles and a public outcry from those who rely on them for recreation or to sustain nearby property values."