Flood Set for Grand Canyon

A controlled flood at the Grand Canyon could be initiated this month, officials said Tuesday.

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 880,000 tons of sediment.

Officials first flooded the canyon in 1996 for 18 days to return some of the natural sediment along the Colorado River within the canyon.

Glen Canyon Dam keeps silt from being deposited, affecting the natural environment, scientists say. Before the construction of dams, which help secure water for the West, torrential floods shaped the river’s ecosystem.

Barry Wirth, a spokesman for the bureau, said the right amount of sediment was 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.

Officials hope their simulated flood will aid river species including an endangered fish, the humpback chub.

Nikolai Ramsey of Flagstaff-based Grand Canyon Trust said flooding helped 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.

The flood tentatively scheduled for Nov. 21 will be shorter than the one done in 1996 because scientists learned that the longer duration wasn’t necessary, Wirth said.

The release from Glen Canyon Dam will not affect the total water in Lake Powell, which the dam created, because the flood will be offset by lower flows during other periods.

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,” she said.