Worsening floods and deterioration pose threats to U.S. dam safety

 

Early last week, floodwater in rural Minnesota pushed debris against a more than century-old dam and then carved a path around it, eroding so much of the riverbank that most of a house fell into the river. Several days later, intense rain damaged a dam that holds drinking water for Houston, forcing officials to issue a potential failure warning.

“Something like this could happen, and it has happened, all over the country,” said Del Shannon, former president of the U.S. Society on Dams.

There are roughly 90,000 significant dams in the U.S. At least 4,000 are in poor or unsatisfactory condition and could kill people or only harm the environment if they failed, according to data from the U.S. Army Corps of Engineers. They need inspections, upgrades and even emergency repairs.

It's a difficult problem in part because dams in the U.S. are roughly 60 years old, on average. It requires costly maintenance to keep decades of wear and tear from degrading dams, and resources to fix problems are often scarce, Shannon said...more