SCIENCE IN THE NEWS DAILY
Dam's Flow Limit Loosened to Feed Grand Canyon
from the New York Times (Registration Required)
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.
The secretary of the interior, Ken Salazar, said the plan would allow the river's managers to release excess water--more than twice as much as average flows--through and over the hydroelectric dam at will to help propel silt and sediment downstream into the canyon. By mimicking the river's original dynamics, Interior Department officials said, the flows could help restore the backwater ecosystems in which native fish are most at home.
The goal is partly to enhance sandbars that create backwaters for an endangered fish, the humpback chub. The excess sand also nourishes beaches used by wildlife, hikers and rafters. Environmental groups like the Grand Canyon Trust strongly support the high-flow releases, which have been carried out experimentally three times before, most recently in 2008.