Ever Shrinking Lake Mead

[pwd72s]

I wonder what Tabs has planned.

[tabs]

Originally Posted by pwd72s

I wonder what Tabs has planned.

Looking for water out between Dead Dog and Lizard..

[tabs]

Originally Posted by Sooner or later

The problem is input has been far less than output for many years. If that doesn't change it doesn't matter how large the storage vessel is.

Exactly what I have been saying the problem is with the US govt..

[daepp]

Originally Posted by Por_sha911

Way too expensive. Residents are already being killed by utility costs.

As far as diverting water from going to the sea, the impact is severe a number of plant and animal species.

Well, call me stupid but I care more about humans than I do about plants and animals.
Further, there’s emerging evidence that one of the “endangered” fish they’re supposedly trying to protect isn’t even native to California.

[3rd_gear_Ted]

Side note:
Sea of Cortez water from Mexico is going to be diverted into the Salton Sea.

[3rd_gear_Ted]

Two choices,
Desalinated ocean water or Mississippi River water

[daepp]

Originally Posted by Tobra

Wonder if it has occurred to any of the geniuses running water policy to get some earth moving equipment out there and make the hole behind the dams a little less shaped like a "V" and a little more shaped like a "U"

Every cubic yard of dirt would give you that much more water behind the dam, assuming it ever rains again. I wonder how many dump trucks you could fill and drive out of there every day, and how many days until it rains.

They did this for half a century in the foothills east of LA. Dig a hole, use the rock they removed as aggregate for concrete and sand, and in the winter trap the water and let it percolate into the aquifer. Then the citrus farmers (and later the cities) pumped the water back out.
They also routinely dug out the rock, sand and silt from a little ways behind our local dam, increasing its capacity and providing addl materials.

But 15-20 years ago local environmentalists in Claremont et al. began a “ban the strip mining” movement. So now no more digging.
And so it goes…

[KNS]

Originally Posted by 3rd_gear_Ted

Two choices,
Desalinated ocean water or Mississippi River water

Yep, those really are the only choices. Unfortunately whichever one they choose (If they actually choose one) would be ten years out until completion. Lake Mead will be dry by then.

[Tobra]

No, those are not the only choices, those are the easy choices.

[KNS]

^^

They may be the "easy" choices but they're still massively expensive and enormous undertakings.

[Tobra]

My money is on they don't do anything.

[masraum]

Originally Posted by 3rd_gear_Ted

Two choices,
Desalinated ocean water or Mississippi River water

expensive and don't fark up our side of the US because yours is farked up (which would probably also be expensive).

[flatbutt]

Originally Posted by 3rd_gear_Ted

Two choices,
Desalinated ocean water or Mississippi River water

It may be easier to desalinate ocean water than clean up Mississippi river water.

[Por_sha911]

Originally Posted by daepp

Well, call me stupid but I care more about humans than I do about plants and animals.
Further, there’s emerging evidence that one of the “endangered” fish they’re supposedly trying to protect isn’t even native to California.

I will resist the temptation to call you stupid even though you asked for it.

As far as the endangered species is concerned. I tend to agree but there are tree hugging environmental wackos in Congress who think otherwise. We will avoid which party has the addiction to "green" .

[island911]

Originally Posted by unclebilly

How does the V shape work better than a U shape for a dam? I thought is was all down to hydrostatic pressure.

P=densityxgravityxdepth

Yep, but...

Originally Posted by flatbutt

Just a WAG but it seems that the V presents less surface area than the U so less pressure on the wall.

Pretty much this ^ but that should read: so less pressure force on the wall.

IOW, the bottom of the dam is seeing the highest pressure (force per area) so by minimizing the area down there (with a V rather than U) the force is minimized.

[Scott R]

I'm reading this with fascination, learning a lot from this thread. Before I went into IT was doing other engineering courses. In one course there was a lecture about LA in the 1900's I think, very early. where they declared an emergency and drained a lake, or built an aqueduct to a lake to solve it. I can't find it on Google tonight, maybe it never happened. Of course that would never work today, but I remember it was a great history lesson. Anyone know it?

[a2jon]

Originally Posted by Scott R

I'm reading this with fascination, learning a lot from this thread. Before I went into IT was doing other engineering courses. In one course there was a lecture about LA in the 1900's I think, very early. where they declared an emergency and drained a lake, or built an aqueduct to a lake to solve it. I can't find it on Google tonight, maybe it never happened. Of course that would never work today, but I remember it was a great history lesson. Anyone know it?

There was a PBS series about this (Flood in the Desert), it was interesting. All I could find was a short YouTube video clip of it. https://www.youtube.com/watch?v=_KrLoujJRn4

PBS site https://www.pbs.org/wgbh/americanexperience/features/flood-desert-william-mulholland/

[Daves911L]

Originally Posted by island911

Yep, but...



Pretty much this ^ but that should read: so less pressure force on the wall.

IOW, the bottom of the dam is seeing the highest pressure (force per area) so by minimizing the area down there (with a V rather than U) the force is minimized.

Beat me too it. Also, the toe of the dam has to be the thickest (in an upstream/downstream direction). If the toe is the point of a V, a whole lot less concrete (or other material) has to poured than if its a U.

But I think the original thought was not so much about the shape of the dam, but the hole behind it. The hole doesn't have to mimic the shape of the dam. The limiting factor is simply, as was calculated by others, the immense amount of earth that must be moved. Dam sites are chosen to take advantage of a large naturally occurring hole (canyon or valley), that needs the smallest possible plug (dam) to become a reservoir.

[KNS]

The base of Hoover Dam under construction. Note how "thick" the base is and the individual concrete pours.

[unclebilly]

V vs. U…

You don’t make it a U shape at the dam, just upstream where you want to store the water. At the Dam, it could be an l shape which would be preferable.