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FLAGSTAFF, Ariz. — 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.
On the Net:
Bureau of Reclamation, Upper Colorado Region: http://www.usbr.gov/uc/
Grand Canyon National Park: http://www.nps.gov/grca/
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.
On the Net:
Bureau of Reclamation, Upper Colorado Region: http://www.usbr.gov/uc/
Grand Canyon National Park: http://www.nps.gov/grca/
