(YouTube link)
On October 26th, explosives opened the Condit Dam in Washington State to allow the free flow of the White Salmon River after 98 years. The reservoir took about two hours to drain, shown here in time-lapse. Read about the dam dismantling project at National Geographic. Link -via the Presurfer
Eventually it dryed up and started to look like the surface of Mars. The soil was incredible for growing crops. It's been over thirty years and last time I looked, you couldn't tell there was ever a lake there. It's filled with trees and bushes. A stream flowing through the middle is all that is left of the old lake.
@Jon A. since it clearly wasn't a disaster why would you say that?
Please explain why you feel that it's a tragedy, though, and you may convince others.