Manmade Flood to Nourish Grand Canyon Ecosystem

Dr. Eggman writes "The Associated Press brings us news of a flood in the Grand Canyon. This flood is no ordinary flood, however. This is a man-made flood released from the Glen Canyon Dam. The Dam is releasing four to five times its normal amount of water over the course of a three day artificial flood. Scientists are conducting this massive experiment in order to document and better understand the complex relation of the aquatic habitats, natural floods, and the sediment they bring. Floods no longer bring sediment to these parts of the canyon as the Dam keeps it locked up and released in small, drawn out intervals. The Dam prevents the floods from bringing the sediments in to replenish the sandbars and allow the river to maintain its warm, murky habitat rather than a cool, clear one. It is thought that this cool clear environment brought on by the dam is responsible for helping to extinguish 4 species of fish and push 2 more towards the brink. It is hoped that this terra-reformation experiment will positively impact the habitat and fish populations, warranting further artificial floods at an increased rate of every one to two years rather than the time span between the two previous floods and this one of 8 and 4 years."

Comments

Re:enough sediment

[Dr. Eggman]

The natural state of the river did not, according to theory, see the average flow building up sediment, but rather from the sound of the article swept away more sediment than it deposited. It was the natural flooding of the Arizona monsoon seasons that deposited enough sediment to replenish the habitat, often enough to prevent species populations from collapsing. The artificial floods are meant to mimic those flood, every one to two YEARS (if the practice proves beneficial then on a continuing basis) and restore the habitats to a state similar to before the Dam. Removing the Dam is out of the question. Frankly, I'd be happy they're concerned enough to warrant the possibility of making this an annual event; considering the last two times this flooding occured just to flush out the sediment were in 1996 and 2004. 8 years and 4 years before they need to dump sediment for the Dam's sake, but purpose every year or two years for the environment's sake.

Re:enough sediment

[Tiger4]

Are they really flushing the sediment behind the dam, or just eroding the banks near the floodgates to redeposit it further downstream?

I realize that some sediment will leave the dam. But, really most sediment from upstream drops out of the flow when the water slows as it enters Lake Powell. The sediment near the dam has been there for years, since the dam was new and the lake first filled. If you look at the released water, it is significantly clearer than the muddy stuff entering the lake upstream.