US Dam safety officials: 4000 dams at risk of imminent failure
More than 4,000 (of the 80,000) aging dams in the U.S. alone are at high risk of imminent failure, according to the Association of State Dam Safety Officials. But the problem is probably worldwide.
At the moment, the USA and China are facing unprecedented floods, putting a lot of stress on the dams.
Full article: http://www.scientificamerican.com/blog/post.cfm?id=more-dangerous-than-nuclear-power-t-2011-06-17