Satellite images reveal that dozens of dams across the country, including the largest in Texas, may be at risk of collapse due to shifting ground beneath them. Inspections typically do not take these movements into account, suggesting that many of the country’s dams are in worse shape than previously realized.
This new discovery raises the prospect that thousands of dams that we do not monitor closely due to high costs and lack of personnel may be damaged and at risk of failure. But how big is the problem, and is it worth using satellite data to provide early warning?
changing ground
in presentation In a report submitted to the American Geophysical Union in December 2025, scientists used 10 years of radar imagery from the Sentinel-1 satellite to identify dams that have moved due to land subsidence or uplift. Depending on the dam material, this can lead to the formation of cracks, especially if different parts of the structure are moving in opposite directions or at different speeds.
“This technology can help identify potential problems and alert personnel,” said the lead researcher. Mohammad Khoramigeotechnical engineer and postdoctoral fellow at Virginia Tech and the United Nations University Institute for Water, Environment and Health told Live Science.
The results are based on 41 high-risk hydroelectric dams over 50 feet (15 meters) in height, with conditions below “poor” or “inadequate.” Classification of National Dam Inventory. These are dams that have known deficiencies that compromise operational safety and require repair.
Results are preliminary and have not been peer-reviewed. Nevertheless, previously unknown weaknesses have been uncovered in dams in 13 U.S. states and Puerto Rico, including the Roanoke Rapids Dam in North Carolina and the largest dam in Texas, the Livingston Dam.
Some of these high-risk dams have been significantly modified. For example, the northern portion of Livingston Dam supplies water to two water treatment plants. Over 3 million people Houston is sinking at a rate of about 0.3 inches (8 millimeters) per year, while the south is rising by the same amount.
“That doesn’t mean part of the dam is collapsing,” Khorami said. However, he added that such elevation differences can be problematic and require further investigation. Given that these dams are decades old, can have defects, and impact both downstream people and energy supplies, deformation of the structures can have dire consequences.
The tragic events that occurred in Libya in 2023 suggest that changes in land elevation cannot be overlooked. On September 11, two dams collapsed due to extreme rainfall caused by Storm Daniel. The failure released 1 billion cubic feet (30 million cubic meters), or the equivalent of 10,000 Olympic swimming pools, into the city of Derna, destroying buildings and bridges and causing deaths. Up to 24,000 people.
Deformation of the dam due to changes in land elevation likely contributed to the collapse. Research in 2025 reveals. “Satellite image results showed continuous and persistent deformation in both of these dams over the past decade,” Khorami said. “So these dams were already vulnerable.”
Khorami and his colleagues are finalizing their findings. The next step is to create an interactive map or database that policymakers can use to assess the safety of U.S. dams.
“This is not a replacement for testing,” Khorami said. “We’re giving you another tool to help you find early warning signs if there’s a problem, or potential problem, with your dam.”
Aging infrastructure, changing climate
But ground movement is just one factor that can put dams at risk. The United States Approximately 92,600 dams – More than 16,700 of the buildings are ‘potentially hazardous’, meaning they could cause loss of life and significant property destruction if they collapsed. According to ASDSO. Most were designed more than 50 years ago, and about 2,500 of them show signs of damage that will cost billions of dollars to repair.
Not all of these are huge like Hoover Dam. In fact, thousands of dams are small watershed dams designed to prevent flooding, provide drinking water, and protect wildlife habitat.
When these dams were built in the 1960s and 1970s, few people lived nearby, so they posed little danger to people. However, several decades have passed since then. community has rapidly increased This means failure can have devastating effects.
Additionally, most of these dams were designed to withstand the environmental conditions at the time of their construction; global warming The situation has changed completely due to changes in land use.
Drought has reduced some rivers’ flow, while other rivers have higher levels and flows than they did 50 to 60 years ago, as increased precipitation and urbanization reduce the amount of water stored in the soil. Ebrahim AhmadisharafAn assistant professor of civil and environmental engineering at Florida State University, who was not involved in the study, told Live Science.
Ahmadisharaf said the weather has also become more extreme and unpredictable, increasing the risk of sudden flooding. in 2025 studyHe and his colleagues found that the likelihood of dam overtopping (water flowing beyond the capacity of the spillway when water levels get very high) has increased for 33 dams over the past 50 years.
The dams in the study that had the highest overflow rates were large dams with relatively large populations living in cities and small towns downstream, such as the Whitney Dam in Texas, Milford Dam in Kansas, and Whiskeytown Dam in California. Populous areas that could be affected include Waco, Texas, with a population of 150,000, and Junction City, Kansas, with a population of 22,000.
“Overflowing is a possible dam failure mechanism,” Ahmadi-Sharaf explained. “It can cause catastrophic flooding downstream and even lead to structural failure. The larger the dam and the shorter the distance to downstream infrastructure and people, the greater the risk.” [overtopping is]. ”
money problem
One of the biggest hurdles to making America’s dams safer is funding. The older the dam, the higher the bill.
“Operating, maintaining and repairing dams can cost anywhere from a few thousand dollars to millions of dollars, and the responsibility for these costs lies with owners, many of whom are unable to pay these costs,” Roche said. “Repairing only the most important dams is Estimation At $37.4 billion, that cost continues to rise as maintenance, repairs and rehabilitation are delayed. ”
Deploying satellite monitoring of dams would increase the financial burden, but it could be worth the cost if it helps prioritize remediation and prevent dam failures, Roche said. According to forensic report The Oroville Dam spillway incident in 2017 resulted in the evacuation of more than 180,000 people but no deaths, but traditional dam inspections do not always identify significant structural problems.
Roche said it is difficult to determine whether using satellite data to prioritize dam repairs is useful because only preliminary results are available so far. But theoretically, “deformation of the dam structure could indicate a problem or worsening condition,” he said.
david bowlesAn expert on dam safety risks and professor emeritus of civil and environmental engineering at Utah State University, he is more skeptical. “There are many different ways a dam can fail,” Bowles told LiveScience in an email. “In my experience, foundation subsidence is not the primary root cause of dam failures, but it can be a contributing factor, especially if it is not monitored or managed.”
Ahmadi-Sharaf said satellites could also play a role in assessing the risk of dams overflowing. Satellite radar images could provide more accurate estimates of water levels and flooding, which could help spread warnings earlier.
Overall, Ahmadi-Sharaf said, satellites could provide a broader picture of dam risks than we currently know. “We can’t monitor everywhere, but satellites provide that opportunity,” he said.