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.
"All of a 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.
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.
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.
