The New York Times, May 23, 2012, by FELICITY BARRINGER

"The Interior Department announced a plan on Wednesday to allow periodic increases in the flow of Colorado River water through the Grand Canyon, alleviating the environmental disruption caused by the construction of the Glen Canyon Dam in Arizona in the 1960s."

http://www.nytimes.com/2012/05/24/science/earth/dam-limits-loosened-to-feed-grand-canyon.html