11-15-2004, 02:32 PM
Grand Canyon due for another flush
Water release: The idea is to help native fish and to restore canyon beaches
By Joe Baird
The Salt Lake Tribune
Nearly nine years later, the U.S. Bureau of Reclamation is planning another beach party in the Grand Canyon.
Pending the completion of an environmental assessment, the bureau next Sunday will commence what it is calling a "high-flow test experiment" at Glen Canyon Dam in a bid to ship sediment down the Colorado River that it hopes will replace sandbars and backwaters in the Grand Canyon that have been lost over the years because of dam-regulated water fluctuations.
The goal: to help native fish species, such as the humpback chub, regain a toehold in the river that has been lost over time to non-native species, such as trout, and to restore beaches that have been washed away. It is a bid to restore the bottom of the canyon to something resembling its natural state prior to the dam's opening in 1962.
The man-made flood is a follow-up to the flush the bureau unleashed in March 1996, releasing up to 45,000 cubic feet of water per second (cfs) over a seven-day period. Sunday's event will be smaller and shorter in duration - bureau officials expect the release to top out at about 45,000 cfs. But they are hoping for a better outcome. The 1996 release, as it turned out, never quite lived up to expectations.
"We learned in 1996 that we can build beaches - terrific beaches. But we also learned that the source of the beaches was different than we thought," says Barry Wirth, a Bureau of Reclamation spokesman. "We thought we would take sediment from the bottom of the river and put it up high [on the sides of the canyon] with the high flows. Instead, we just took the sand from the beaches at the upper end [near the dam] and deposited it down lower."
In other words, the river bottom did not cough up nearly as much sediment as was anticipated. To address that problem, the bureau has been waiting for this moment, a monthlong period of tremendous rainfall in southern Utah and northern Arizona. Recent precipitation has filled the Paria River - one of the Colorado's major tributaries below the dam - with sediment near the confluence. The hope is that Sunday's scheduled release will flush out the muck to riverbanks farther downstream.
And hope is the operative word.
"This is really the only card we have left to play," says Jack Schmidt, an aquatic, watershed and earth resources professor at Utah State University. "We'll either learn that timing floods like these are the future of river management on the Colorado, or we'll find out that even this amount of sand isn't enough - in which case we'll have to start talking about transferring sediment from Lake Powell, or quit pretending we can restore the Grand Canyon."
Put environmentalists in the latter camp. They largely panned the 1996 Glen Canyon release and don't have much optimism that this one will deliver either.
"The last flood did yield a fair amount of scientific data, but it really produced little in the way of positive results," says Chris Peterson, executive director of the Grand Canyon Institute. "Right after the '96 flood, a fair amount of sediments were stirred up. Fifty new beaches were created. But within five or six months, they were gone. This new [release] is almost a miniversion of that flood. It might create more [sandbars and backwaters], but the reality is, this is another band-aid approach."
The only realistic - and inevitable - solution, environmentalists maintain, is the one they have repeated many times in recent years: Lose the dam.
"The only thing that will give the Grand Canyon what it really needs is to breach the dam and allow all that sediment built up behind to flow downriver," says Jo Johnson, co-director of River Runners for Wilderness. "Anything less than that is patchwork. It does not solve the problem."
Bureau of Reclamation spokesman Wirth says the agency officials and scientists are more optimistic - though he points out that the planned release is being called an "experiment" for a reason.
"We've got good science from before," he says. "And all of us - the states, the tribal governments and the power customers - have all been waiting through this drought for many months for these conditions. We've now got 800,000 tons of sediment built up. Mother Nature, after a period of years has finally given us a trigger for this experiment."
Wirth also says the water being used for the release will come from within the 8.3 million cubic feet that has been budgeted for Lake Powell for the water year (Oct. 1-Sept. 30). "It's a drought budget. Nothing is being taken out on top of it," he notes.
But critics of the release also have their concerns about that.
"Budget or no budget, they're still letting it out," says Johnson. "And there's still not much going in."
jbaird@sltrib.com
[signature]
Water release: The idea is to help native fish and to restore canyon beaches
By Joe Baird
The Salt Lake Tribune
Nearly nine years later, the U.S. Bureau of Reclamation is planning another beach party in the Grand Canyon.
Pending the completion of an environmental assessment, the bureau next Sunday will commence what it is calling a "high-flow test experiment" at Glen Canyon Dam in a bid to ship sediment down the Colorado River that it hopes will replace sandbars and backwaters in the Grand Canyon that have been lost over the years because of dam-regulated water fluctuations.
The goal: to help native fish species, such as the humpback chub, regain a toehold in the river that has been lost over time to non-native species, such as trout, and to restore beaches that have been washed away. It is a bid to restore the bottom of the canyon to something resembling its natural state prior to the dam's opening in 1962.
The man-made flood is a follow-up to the flush the bureau unleashed in March 1996, releasing up to 45,000 cubic feet of water per second (cfs) over a seven-day period. Sunday's event will be smaller and shorter in duration - bureau officials expect the release to top out at about 45,000 cfs. But they are hoping for a better outcome. The 1996 release, as it turned out, never quite lived up to expectations.
"We learned in 1996 that we can build beaches - terrific beaches. But we also learned that the source of the beaches was different than we thought," says Barry Wirth, a Bureau of Reclamation spokesman. "We thought we would take sediment from the bottom of the river and put it up high [on the sides of the canyon] with the high flows. Instead, we just took the sand from the beaches at the upper end [near the dam] and deposited it down lower."
In other words, the river bottom did not cough up nearly as much sediment as was anticipated. To address that problem, the bureau has been waiting for this moment, a monthlong period of tremendous rainfall in southern Utah and northern Arizona. Recent precipitation has filled the Paria River - one of the Colorado's major tributaries below the dam - with sediment near the confluence. The hope is that Sunday's scheduled release will flush out the muck to riverbanks farther downstream.
And hope is the operative word.
"This is really the only card we have left to play," says Jack Schmidt, an aquatic, watershed and earth resources professor at Utah State University. "We'll either learn that timing floods like these are the future of river management on the Colorado, or we'll find out that even this amount of sand isn't enough - in which case we'll have to start talking about transferring sediment from Lake Powell, or quit pretending we can restore the Grand Canyon."
Put environmentalists in the latter camp. They largely panned the 1996 Glen Canyon release and don't have much optimism that this one will deliver either.
"The last flood did yield a fair amount of scientific data, but it really produced little in the way of positive results," says Chris Peterson, executive director of the Grand Canyon Institute. "Right after the '96 flood, a fair amount of sediments were stirred up. Fifty new beaches were created. But within five or six months, they were gone. This new [release] is almost a miniversion of that flood. It might create more [sandbars and backwaters], but the reality is, this is another band-aid approach."
The only realistic - and inevitable - solution, environmentalists maintain, is the one they have repeated many times in recent years: Lose the dam.
"The only thing that will give the Grand Canyon what it really needs is to breach the dam and allow all that sediment built up behind to flow downriver," says Jo Johnson, co-director of River Runners for Wilderness. "Anything less than that is patchwork. It does not solve the problem."
Bureau of Reclamation spokesman Wirth says the agency officials and scientists are more optimistic - though he points out that the planned release is being called an "experiment" for a reason.
"We've got good science from before," he says. "And all of us - the states, the tribal governments and the power customers - have all been waiting through this drought for many months for these conditions. We've now got 800,000 tons of sediment built up. Mother Nature, after a period of years has finally given us a trigger for this experiment."
Wirth also says the water being used for the release will come from within the 8.3 million cubic feet that has been budgeted for Lake Powell for the water year (Oct. 1-Sept. 30). "It's a drought budget. Nothing is being taken out on top of it," he notes.
But critics of the release also have their concerns about that.
"Budget or no budget, they're still letting it out," says Johnson. "And there's still not much going in."
jbaird@sltrib.com
[signature]