Asymmetrical Information

The tragedy is that that silt accumulation reduces the capacity of the dam, reducing the water available for drinking/irrigation/hydropower. In some small number of decades, all our wonderful dams will revert to a river flowing through a flatland, ending in a waterfall over the dam. Dredging would have much the same impact tearing the dam down would.

There is a reason beavers are always building NEW dams. I've heard that they have changed the terrain of North America more than any other creature, including man.

I used to love the idea of hydropower, but I realize now that to be renewable, we must be continuously building dams (impossible with a finite number of rivers) or else dredge them with all the expense and mess that entails.

Seriously, we need to tear more of them down, and give Fish a chance. We are too close to forever losing a great number of our fisheries that rely on "upstream" hatching. It's yet another story, covered in much detail among the narrow profession, sadly missing from the MSM.

So, Mark Hoffer, please explain to me how fish can generate power? Are these electric fish you want to give a chance?

I don't like fish, I eat steak.

Depending on the location of the river and dam involved, the level of contaminents silted up near the dam can be nothing short of alarming.

The idea that we will just allow the sediment to flow on downstream if a dam is removed isn't the brightest approach.

Think PCBs, for example. As is the case in the Atlanta area along the Chattahoochee River south of Buford Dam and further downstream until the sediment reaches the dam at Westpoint Lake.

Soil tests need to run. In every case.

Seriously, we need to tear more of them down, and give Fish a chance.

All we are saying,
is "Give Fish a chance."

I have nothing useful to contribute to this topic, except to note that Sharyn McCrumb's Zombies of the Gene Pool (a sequel to Bimbos of the Death Sun) contains poems from (and, if I recall, was partly inspired by) Watauga Drawdown.

Entire towns, buildings and all, were flooded to build Watauga Dam after WWII. In 1983 the lake was (partially?) drained (forget why), allowing people to (temporarily?) return to homes that had been under water for thirty years. Don Johnson tells their stories in poetry. If I recall correctly, stinky mud flats were noted.

Be sure and check out the first edition cover of Zombies of the Gene Pool, way cooler than the reprint cover, and yet far less disturbing than the cover of Watauga Drawdown.

"The question is: How will the public respond to this? Will they say "We never should have torn down the dam!" or "We never should have built the dam!" Here's hoping for the latter, but it could well be the former..."

Why do they only list two options when they ask questions like this. I almost always want to pick answer C (other). My typical response to a dam being removed would be, Did it help?

Ironically, one would have to get massive waivers or temporary exemptions to many state and federal environmental laws if one wanted to tear down a dam; a daunting prospect at the best of times.

This is one of the cases where I am more in support of tearing down the dam than keeping it, primarily because the task group at UC Davis have determined that nearly all of the water in Hetch Hetchy can be sotred in a downstream dam... without actually making any significant changes to that dam.

When I was in fifth grade and went to Yosemite, the guide told us how long it would take to "recover" the area if they simply drained the dam and removed most of it (they can't remove all since they took a chunk out of the hillside for the footings.) Assuming that there's no seeding going on, it's about a century for full meadow recovery and forest start, and about a thousand years before the "stain" on the walls fades. (Granite bleaches out under water.)

As to tourism, I think the people who say it would "only" bleed off 40-50% of the Yosemite Valley traffic aren't thinking their objections through very well. :)

Lebanon's Parliament Speaker Rejects Rice Proposal

quite a good thing....

"Ironically, one would have to get massive waivers or temporary exemptions to many state and federal environmental laws if one wanted to tear down a dam; a daunting prospect at the best of times."

Or you could just wait until the dam comes down on it's own. That probably isn't the optional choice for the towns downstream...

The problem with dams is that most of the structures have the illusion of permancy. They are large massive structures that look permanant but are not. Silt buildup means that all dams have a finite lifespan - because that lifetime exceeds the lifetime of the average human, consequences get glossed and the untentional consequences of any engineering project (Like the Three Gorges Dam) do not show up for decades.

BSD,

Right so, that you are.

It's highly questionable whether "hydro-electric" has a positive Economic benefit over the lifetime of the Dam.

A good book on the subject is "Cadillac Desert"

Much info about it, and relating to it, is available online.

a simple search @ clusty.com : Cadillac Desert , will divulge much.

Hi there

You could drop a line to my colleague maurice@opendoors-newbusiness.co.uk - he's been in the business for 20 odd years and is happy to dispense free practical advice for these sorts of situations.
For more info check www.opendoors-newbusiness.co.uk

All the best
Antony

> A good book on the subject is "Cadillac Desert"

Umm, the author of said "good book" didn't seem to know that waterfowl are perfectly happy with rice fields. There are other howlers on which he based his conclusions.

I understand that he later learned something about ducks and reconsidered some of his positions.

"Tis' easier to destroy, than create."

There's a revised edition that has been available for some time. The body of book provides much valuable, and usually unknown to broad discourse, information in a readily accessible format.

Though, Andy, to be fair, let's exercise your comparative advantage in rock throwing: Please do delineate, for us all, the "other howlers on which he based his conclusions"

My boss tells me that people who have studied rivers intensively come to think of them primarily as sediment transport systems; the water is just the mechanism. It would be nice if that analysis were included in the decision to build dams.

MNM,

Your boss might want to conduct a simple web search with the phrase : Fish stocks depleted due to dams.

This article, speaking about the Nile:
http://www-ocean.tamu.edu/Quarterdeck/QD3.1/Elsayed/elsayed.html
Will give you a good idea that rivers are more than "sediment transport systems".

I am disappointed that no-one rose to your bait and expiated on "The unintended consequences of Saddam removal".

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