Monday, May 28, 2012
Sediment floods approved from Glen Canyon dam
The US Dept. of Interior plans to release controlled floods from Glen Canyon dam on a more regular basis, to try to rebuild beaches and sandbars, and return the Colorado River to a more natural state. The releases are supposed to occur when conditions are right on the Paria River coming from Utah, and on the Little Colorado on the Arizona side to maximize sediment transport. Without the sediment, the cold waters during tests reportedly did more harm than good on native fish. [Right, controlled flood from the Glen Canyon dam. Credit, USGS]
Proponents cheered the move as helpful to the humpback chub but questions rose almost immediately, including one about the wisdom of spring flushes, on the basis that previous flood tests in the spring benefited non-native fish that eat the native population. Energy managers warned that release of large volumes of river water cost energy consumers $3-4 million each time, and could complicate legal requirements of water delivery from the upper Colorado River basin to the lower.
at 8:23 PM