Flooding the Grand Canyon
A national landmark is flooded on purpose to help both wildlife and tourists
By flooding the Canyon, authorities hope to rebuild habitats for local animals. (Bureau of Reclamation)
The Colorado River flooded the dry caverns of the Grand Canyon last week for six days. But this was no natural disaster. Engineers carefully filled the popular tourist attraction with water on purpose.
The Grand Canyon is one of America’s most magnificent wonders—and now one of its driest. Located in Arizona, the canyon was created by the Colorado River over millions of years. The river’s powerful waters cut through walls of rock, forming a canyon that is about 6,000 feet deep at its deepest point. Fish and plants thrived along the canyon’s waters and beaches.
But this ancient riverbed has been dry for decades. The Glen Canyon Dam, begun in 1956, built up reservoirs along other sections of the Colorado River. Although these reservoirs created water supplies in times of drought (severely dry weather), the dam has damaged the canyon’s rich habitat for wildlife.
Now authorities are working to save species that once thrived in the canyon. Last week’s grand gusher was only the first of many floods planned for the next eight years. Authorities hope the controlled floods will help restore some of what has been lost.
HOW TO REBUILD A RIVER
Authorities are planning two major floods each year until 2020. They hope these floods will match the effect of the seasonal flooding that once occurred in the canyon before the dam was built.
What will these floods accomplish?
“The beaches have changed rather dramatically since the dam was put into place, and we can rebuild those beaches to an extent,” says Glen Knowles of the Bureau of Reclamation. “The same sandbars that create the beaches also create backwater habitat for native fish.”
Opening the dam helps stir up sediment, or soil, from the river bottom. The Colorado River used to distribute sediment along the canyon floor, creating beaches and sandbars. Authorities believe the river’s flow will restore these sections of sediment and create shallow pools of water behind them. These pools form backwater habitats for endangered fish like the humpback chub.
The floods should help tourists too. Sandy spots are popular grounds for sightseers and hikers. Many of these areas have eroded, or slowly worn away, over time. Flooding might help restore these areas along tourist trails and remove plant life that has grown over campsites along the riverbed.
“We have some great science that’s led us to this point to say, if indeed we can do this on a regular basis, that we may be able to restore some of those processes and habitats we’ve been losing over the years,” says Jan Balsom, chief of science at Grand Canyon National Park.