Many hydroelectric dams across the U.S. may be at risk, according to research from Virginia Tech that analyzed satellite data. Their findings don’t indicate immediate danger, but could mean additional maintenance is necessary.
“And the current observation may suggest that some of those dams are experiencing some problem,” said Manoochehr Shirzaei, a professor of environmental security at Virginia Tech who was on the research team.
He said it’s natural for dams to sink a little each year, but their data suggests some of these dams could be weakening, or sinking in some places faster than others.
Geophysicist Mohammad Khorrami is the lead author on the study and presented preliminary findings in December at the American Geophysical Union.
They used radar from space satellites to analyze 41 dams across the United States to detect if they are subtly sinking. They analyzed dams in North Carolina, California, Texas, Puerto Rico, New York, Washington, Vermont, Oregon, Minnesota, Alabama, Georgia, Maine, Michigan, None of the dams they studied are in Virginia.
If these dams fail, it could flood towns below the dams, killing people, and also wrecking havoc on the economy.
“Because some of those dams are used to produce electricity and also provide water for agricultural activities,” Shirzaei said.
According to the Department of Energy, 6% of the electricity we use comes from hydroelectric dams.
Shirzaei compared the research to a preliminary health scan, not a definite diagnoses.
“I want to highlight, there is no reason to panic at this moment,” Shirzaei said.
Dams are inspected on a regular basis by the government. Shirzaei said dam operators and policy makers should consider this research as a signal that further testing and maintenance may be needed. That’s especially important because more heavy flooding is expected in the future.
“What we think and what we believe is going to happen is due to this weather extremes that are exasperated by climate change, we have additional stress applied to these dams,” Shirzaei said. “And how these dams would perform under those new stressors is something that we want to study.”
He said this type of satellite analysis could also help communities near dams update their emergency plans, by calculating the impacts extreme weather may bring.
David F. Muñoz is an assistant professor of Civil Engineering at Virginia Tech. He wasn’t involved in the study, but said learning more about how land subsidence affects dams can help engineers better understand potential risks for communities downstream.
Muñoz said more information about each dam should be available to the public, and points to the Claytor Dam as an example of a dam where communities have limited access to data through the National Inventory of Dams website.
“There is some missing information, for example the flood maps. That could be associated if the dam fails. So that information is important to have.”
Shirzaei expects their final analysis to be published in the next few months.
