An investigation over two-years long has identified 1,688 high-hazard dams, which could be life-threatening for communities if the dams don’t hold.
An investigation by the Associated Press over two-years long has identified 1,688 high-hazard dams nationwide.
These dams loom over homes, businesses, highways or entire communities that could face life-threatening floods if the dams don't hold, according to the Associated Press.
The dams are rated in poor or unsatisfactory condition as of last year in 44 states as well as Puerto Rico. The actual number is probably higher, however, as some states declined to provide condition ratings for their dams.
Other states have not rated their dams due to lack of funding, staffing or authority. The Associated Press identified some of the issues with the dams, including leaks that can indicate a dam is failing internally; unrepaired erosion from overtopping; holes from burrowing animals; tree growth that can destabilize earthen dams; and spillways too small to handle large floods.
Close to 1,000 dams have failed over the past four decades, killing 34 people, according to Stanford University's National Performance of Dams Program.
The nation's dams are over a half-century old on average, most no longer able to handle the intense rainfall and floods of a changing climate. There is also no national standard for inspecting dams, leading to a patchwork of state regulations, according to the Associated Press.
"There are thousands of people in this country that are living downstream from dams that are probably considered deficient given current safety standards," said Mark Ogden, technical specialist with the Association of State Dam Safety Officials.
It would take more than $70 billion to repair and modernize over 90,000 dams.