Dams across the United States are in dire need of repairs, and the critical infrastructure may be even worse off than engineers anticipated. According to geoscientists, over 2,500 of the more than 16,700 structures in the country are classified as high hazard potentials and in “poor condition.” This classification means that the dams that would cause significant death and destruction if compromised. What’s more, radar analysis indicates many of these facilities may still be deteriorating out-of-sight from inspection crews.
The U.S. is home to over 92,000 dams dedicated to hydroelectric power, drinking water, and environmental protection for surrounding communities. However, the majority of these aren’t new or updated projects. Most active dams were constructed during the 1950’s and 1960’s, and the average age of a facility is 61 years old. Today, an estimated seven out of 10 dams in the country are at least 50-years-old. Despite their criticality, maintenance and monitoring remains vastly underfunded. Although the Association for State Dam Safety Officials calculates over $165 billion is needed for repairs, federal funding currently allocates a fraction of that amount towards upkeep.
“Without a more significant commitment to dam safety…the cost to bring the nation’s dams into a state of good repair will continue to rise and downstream communities will face a greater risk of danger from potential dam failure,” the American Society of Civil Engineers concluded in its 2025 annual assessment.
Unfortunately, this risk is likely more severe than anticipated. Mohammad Khorrami, a geoscientist at Virginia Tech, recently organized a team to conduct a nationwide analysis of dam structural integrity without needing to leave their campus. Using a satellite tool called the Interferometric Synthetic Aperture Radar, Khorrami and his colleagues examined the level that many high-risks dams have sunk into the earth over the past decade. They particularly focused on hydroelectric structures because of both their downstream communities as well as the amount of infrastructure that relies on them. The results stunned them. In many cases, dams believed to have been already stabilized were continuing to sink.
“I want to emphasize that this is a preliminary result. We need to do further analysis to have a concrete answer,” explained Virginia Tech geoscientist Manoochehr Shirzaei. “But some of the observations may suggest that some of these infrastructures are undergoing internal degradation.”
It’s been decades since the U.S. has experienced a catastrophic dam breakage, but Khorrami warns such an event would be “a disaster” today. They cited the Roanoke Rapids dam in North Carolina as an example. Khorrami and his team’s findings confirmed previous inspections of the site—the dam’s northern face is sinking slowly. Without vital repairs, the structural concrete could eventually crack and threaten the nearby town of over 15,000 residents. But the consequences of such a disaster go beyond their nearby communities.
“Some of the dams actually serve as a sub-buffer for water that’s used for agriculture and for electricity production,” said Shirzaei. “Those dams can create a ripple effect if they fail that can impact the national economy.”
The researchers urged that there are still ways to mitigate the worst outcomes. Citing a complimentary paper published earlier this year, Khorrami explained that a large amount of dam compromise owes to poor local management and maintenance.
“Almost 40-50 percent [of risk] is something that is in our hands,” he said. “It’s difficult to address all of these dams. If you cannot financially take care of all of them at the same time, we can provide the priority dams.”
