Giving Back to Nature : Man-made flooding holds promise of Grand Canyon renewal
It was quite a spectacle: Man gives back to nature. U.S. Interior Secretary Bruce Babbitt pushed a button last Tuesday at Glen Canyon Dam and 45,000 cubic feet of water per second--enough to fill the Rose Bowl in 7.2 minutes--roared down the Grand Canyon. So began a bold new chapter in federal river management in the West.
How times change. Less than 35 years ago, the dam was built to harness the power of the mighty Colorado River and generate electricity for several western states. But depriving the Grand Canyon of the river’s natural flow upset the ecosystem. The waters that once flowed warm, red and muddy (Colorado means reddish brown in Spanish) came cold and clear from the depths of Lake Powell.
Life-giving nutrients have become trapped in the sediment that piles up behind Glen Canyon Dam. Consequently, two fish species--the Colorado River squawfish and the bonytail chub--have disappeared and two others are endangered.
The lack of river sediment is not only starving aquatic life, it is eroding beaches and sandbars in the canyon. The sediment trapped by the dam means that riverside beaches are no longer replenished with sand. As the beaches erode, canyon walls face weakening, a development that could jeopardize hundreds of archeological sites in the Grand Canyon.
So now, at Glen Canyon, the federal government for the first time has opened the floodgates of one of its dams to renew the environment and habitat of the Colorado. Scientists believe that careful flooding will redistribute sand and mud below the dam to other parts of the canyon’s river system. Though they disagreed on just how much water should be released, they all agree that the weeklong flooding will help to restore the natural balance of the canyon.
The power industry, not surprisingly, is rather unhappy with the experiment. Its officials cite the extra costs and inefficiencies of releasing water during a period of low electrical demand and pumping more water than the power turbines can handle. But to its credit, the Colorado River Energy Distributors Assn., a group of 100 utilities that buys much of the electric power from Glen Canyon Dam, has said that “if science supports the idea of periodic flood flow, we will accept the verdict.â€
Science and engineering helped to harness the natural power of the Colorado River for creature comforts. Now it’s time to give back to nature so all creatures can better enjoy a renewed Grand Canyon.
