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."

Re:enough sediment

[E IS mC(Square)]

Mod parent up. If they really want to 'restore' the earlier eco-system, the dam should be removed. How can effect of years of flow be achieved with one or two 'manmade' floods?

Re:And also see the other side..

[Smordnys s'regrepsA]

" Far from restoring crucial sand banks and other areas, the flows could destroy habitat, [Grand Canyon National Park Supt. Steve Martin] said. One flood was not enough, Martin said Monday. Holding off follow-up flows for months would leave endangered humpback chub fish, sandbars used by river rafting trips, and archaeological treasures at river's edge diminished "almost to the point of no return," he said."

Those habitats survived thousands of years of flooding before we created the dam, what makes him think a single flood would destroy it? And, why does he say both that the flood will destroy the habitat and that without the flood the habitat will be destroyed? Superintendent, yes. Elegant speaker/thinker and specialist, I think not.

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.

Re:And also see the other side..

[Geek Prophet]

Those habitats survived thousands of years of flooding before we created the dam, what makes him think a single flood would destroy it?

He doesn't think the one flood will destroy it. He thinks the one flood could excessive damage. This is in part because the canyon's habitat is already damaged, and thus vulnerable. In addition, this is a large flood, and large floods are often more damaging than beneficial.

And, why does he say both that the flood will destroy the habitat and that without the flood the habitat will be destroyed?

He didn't say that the flood would both destroy and prevent the destruction of habitats. He said that floods, plural, on a regular basis would build up habitats, and that one big flood every year or two would destroy them.

Once upon a time, the Colorado ("Colored") River was famous for being filled with red silt. Species of fish that evolved in this environment lived in the Canyon. Sand bars were created almost continuously due to the silt that built up. Silt replenished the shores. Moderately frequent light floods would replenish the banks near the river further, and drag more silt into the river in other areas to supply more silt for maintaining the river's muddy quality. Very occasional large floods would both replenish and clear away some of this silt, preventing the river from being clogged while "spreading around" some of the silt to places where it was thin.

Today, the Colorado river runs clear. The fish that naturally evolved there are almost wiped out. Sand bars are disappearing. The shores that used to be replenished by the river are scoured clean by the clear water. The floods that built up the flood plains don't happen any more, and there is some question as to whether big floods are good or not anymore, with a river already cleaning itself too well.

The dissenting view is that the large floods without the small floods is bad.

Small floods frequently leave the water muddy for long periods of time, much more like the natural state of the Colorado ("Colored") River, and thus protecting the fish that naturally find this to be their habitat. Small floods leave deposits that create sandbars, which are normal for the Colorado, and are disappearing in the current conditions. Small floods rebuild shoreline habitats, which evolved to have frequent small quantities of mud deposited on them. Thus "without the flood(s) the habitat will be destroyed."

Big floods run muddy for days, then run clear again. This does not help with the problem of clear water which is killing those species of fish that evolved to live in the muddy Colorado. Big floods wash away sandbars. Big floods wash away shoreline habitats. Big floods wash away archaeological treasures that are above the high water mark for small floods. Thus "the flood will destroy the habitat."

His speaking may not have been elegant, but his thinking may be better than those in favor of this flood.

Re:I have a better idea!

[Maint_Pgmr_3]

Then where is Las Vegas going to get all of its electrical power?

hydroelectric is the most 'green' source of power

It may be green, but so Las Vegas, in the middle of no where.