Under normal circumstances, hearing that a flood was occurring would be very bad news. But on November 19, the Grand Canyon was flooded by the Colorado River from the Glen Canyon Dam as part of a deliberate attempt by the U.S. Department of the Interior to rebuild the canyon’s beaches and fish habitat.
The Interior Department explained that this was the first “high-flow experimental release” at Glen Canyon Dam. The dam release initiative is a first step that’s part of a 10-year protocol. The U.S Geological Survey (USGS) notes that, “The new protocol calls for experimental releases from the dam (through 2020) to send sediment downstream to rebuild sandbars, beaches, and backwaters. The rebuilt areas will provide key wildlife habitat, enhance the aquatic food base, protect archeological sites, and create additional camping opportunities in the canyon.”
Jack Schmidt, Chief of the USGS Grand Canyon Monitoring Research Center, told TakePart that, “What is meant by first steps is that the real question is whether over a long period of time the benefits of these high-flow releases outweigh the effect on normal operations—power plant operations and the general need to transfer water downstream to meet water delivery requirements—in intervening times.”
“Basically we’ve had three of these controlled floods—in 1996, 2004, 2008,” said Schmidt, who is also a professor of Watershed Sciences at Utah State University and wrote his dissertation on how sand bars form in the Grand Canyon. “Each of those was managed as a discrete experiment. So by the time the third one was completed we knew that the sand would be transferred and we needed to respond very quickly after the sand was deposited because there’s little time to redistribute it up to the banks before the river will redistribute it. We developed modeling tools to know what the transport would be and continue to work on what the beneficial deposits will be. We don’t need to repeat the experiment anymore since we know what happens with the flood.”
He added that, “On December 1, we’re going to return to normal power plant operations and that will begin to erode the deposits we just created. The next time we’d have one of these controlled releases would be next fall and we’ll only do that if we get a real rainy season again.”
“The question is, ‘Does the release offset the power plants’ erosion so that by the time we have the event next fall will there will be a positive legacy from the previous event?’ If we keep adding a little bit more in the release each year than we take away during operations then we are doing collective good. If not, and we don’t see a lasting impact after all this effort, then people will ask why go to this expense,” said Schmidt.
Prior to the completion of the dam in 1963, USGS estimates that flows of at least 50,000 cubic feet per second occurred every year in the canyon, and floods of at least 125,000 cubic feet per second occurred every eight years on average. As time passed, the environmental consequences of the dam became apparent: the loss of large beaches that were used for camping along the river in the Grand Canyon, a narrowing of rapids that hampered navigation, and changes in the distribution and composition of the vegetation along the river’s banks.
And they note that when Glen Canyon Dam was planned in the 1950s, “little consideration was given to how dam operations might affect downstream resources. The dam was completed before enactment of the National Environmental Policy Act of 1969 and the Endangered Species Act of 1973, which mandated such considerations.”
In terms of future releases, Schmidt said, “The one thing that definitely changes is the amount of water used in each of these releases. The benchmark for each year is how much sand was brought to the Colorado River by the Paria River, which is a natural tributary that comes in below the dam. The protocol calls for staging a controlled flood release that will just transport that amount of sand, but not more than that, and basically what you’re doing is you have a protocol in place that asks what’s the most good we can do with what nature has given us.”
So let’s hope there’s a good amount of rain next summer and, odd as it sounds, we get floods and the sediment that comes along with them flowing into the Colorado River.
Do you support all the effort and money that’s being used to rebuild the beaches and wildlife habitats in the Grand Canyon?
Lawrence Karol is a writer and editor who lives with his dog, Mike. He is a former Gourmet staffer and enjoys writing about design, food, travel and lots of other stuff. @WriteEditDream | Email Lawrence | TakePart.com