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GTG Was lost but now am found
Joined: 30 Dec 2002 Posts: 2387 Location: Peoria, Arizona, originally from Rocket City, USA
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Posted: 11/9/2004, 3:41 pm Post subject: Grand Canyon may be flooded later this month |
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From today's Arizona Republic -
http://www.azcentral.com/news/articles/1109wst-grandcanyon09-ON.html#
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Grand Canyon may be flooded later this month
Associated Press
Nov. 9, 2004 12:48 PM
FLAGSTAFF - A new controlled flood at the Grand Canyon could occur later this month.
The Bureau of Reclamation wants to release extra water from Glen Canyon Dam beginning Nov. 21. If approved, the extra flow would run for 90 hours, stirring up an estimated 800,000 metric tons of sediment.
Officials first flooded the canyon in 1996 with an 18-day water release, designed to return some of the natural sediment along the Colorado River within the canyon.
Because of Glen Canyon Dam, the silt that normally occurs in the ecosystem is not deposited, affecting the natural environment, scientists say. Before the addition of dams, which help secure the West's water supply, torrential floods would have shaped the river's ecosystem.
Barry Wirth, a spokesman for BOR, said the right amount of sediment is available in the system to do the water release now. Two major October storms pushed silt and debris down the Paria River, a tributary to the Colorado.
BOR officials hope the simulated flood caused by the dam release will aid river species including an endangered fish, the humpback chub.
Nikolai Ramsey of the Flagstaff-based Grand Canyon Trust said flooding helps the environment.
"It's about everything related to sediment, which benefits everything within the Grand Canyon," he said.
Native vegetation does better in flooding, and the waters can create habitat for spawning and rearing native fish.
"We're mimicking what happened naturally before the dam was there," Ramsey said.
The flood tentatively scheduled for Nov. 21 will be shorter than the one done in 1996, because scientists learned that the longer release wasn't necessary, Wirth said.
The release from Glen Canyon Dam will not affect the total water in Lake Powell because the flood flow will be offset by lower flows during other periods.
BOR is required to release 8.3 million acre feet a year from Lake Powell.
The increased flow is not expected to have much effect on canyon recreation either, national park officials said.
November is not a prime time for river rafters, and park officials will notify those that are running trips, said Leah McGinnis, management assistant at Grand Canyon National Park.
"We'll get the word out to them so that they'll be aware of it," she said.
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On the Net:
Bureau of Reclamation, Upper Colorado Region: http://www.usbr.gov/uc/
Grand Canyon National Park: http://www.nps.gov/grca/
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_________________ Good things come to those who walk. |
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Arizonaheat Got Supes Juice?
Joined: 04 Jan 2003 Posts: 1741 Location: Mesa, AZ
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Posted: 11/9/2004, 5:14 pm Post subject: |
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I did a trip with my daughter down the Tanner and across the Escalante Route, exiting at Grand View, after the 1996 flood. The white sand beaches left behind were totally awesome, reminded me of the Caribbean, we slept on beach front each night along the River. _________________ Our lives are not determined by what happens to us but by how we react to what happens, not by what life brings to us, but by the attitude we bring to life. |
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oriole_scott
Joined: 18 Jul 2004 Posts: 166 Location: the cornfields
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Posted: 11/9/2004, 6:00 pm Post subject: |
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Arizonaheat wrote: |
The white sand beaches left behind were totally awesome, reminded me of the Caribbean. |
If I recall right, sadly, the beaches didn't last long and the '96 flood experiment was viewed as only a temporary success. It did create a lot of beaches, but they just didn't last long. There wasn't enough sediment in the river to keep nourishing them.
Hopefully the planned flood will help, but if they're looking for suggestions to fix the river I can think of a more permanent solution...if the drought doesn't do it first _________________ "We are here on the planet only once, and might as well get a feel for the place" - Annie Dillard |
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Daryl
Joined: 07 Feb 2003 Posts: 1168 Location: Everett, Washington
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Posted: 11/10/2004, 11:13 am Post subject: |
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Is there enough water in lake powell to do this? _________________
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oriole_scott
Joined: 18 Jul 2004 Posts: 166 Location: the cornfields
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Posted: 11/10/2004, 11:46 am Post subject: |
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Yes and no. The Colorado River Compact allocates water from the Colorado River to the states that are in its watershed. The Upper Basin states (Wyoming, Utah, New Mexico, and Colorado) are required to send a certain amount downstream to the Lower Basin States (AZ, California, and Nevada) each year. So, drought or no drought, the upper basin states have to send x amount of water downstream through Glen Canyon Dam each year.
With the drought, they've had to realease more water from the dam each year than is flowing into the reservoir, so the lake is dropping (it's currently at 38% of its full volume). But there's no restriction on exactly when the water has to be released. That means that the Bureau of Reclamation can increase the outflow for a week during the flood and decrease the water release later on to make up for it. Either way, over the year, the same amount of water gets released.
So, yes, there's enough water for the flood because the same amount of water would get released downstream regardless of the flood. But also no, because the releases from the dam are more than the reservoir is taking in each year. If the drought continues, the lake will basically dry up within 4 years or so. Then things will start to get really interesting in terms of the water situation, especially in California. _________________ "We are here on the planet only once, and might as well get a feel for the place" - Annie Dillard |
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