 A growing concern is more than 4,000 dams in the U.S. are in poor or unsatisfactory condition, according to the Army Corps of Engineers, which says could result in death or environmental harm if they fail. Our dams are old. Martin McCann, Jr. serves as director of the National Performance of Dams Program at Stanford University. The average age of U.S. dams is 60. Dams have not been maintained. They have not been rehabilitated, upgraded.