Ever Shrinking Lake Mead

[daepp]

Originally Posted by flatbutt

I readily admit that. It still sounds like Cali is wasting water. If drought is retarding replenishment of Lake Mead but usage has not been curtailed who is responsible?

California IS “wasting” water in that:
- we have built no new reservoirs in decades, so when we have excess water we fail to save it for the dry years
- policy makers have sided with “endangered” fish over residents, farmers and food.

And re Lake Mead, I believe CA gets much more of its water from Nor Cal and the Sierra snowpack than it does from the CO River.

[Tobra]

Originally Posted by flatbutt

I readily admit that. It still sounds like Cali is wasting water. If drought is retarding replenishment of Lake Mead but usage has not been curtailed who is responsible?

The government is supposed to be responsible, so nobody is.

The conservation efforts focus on residential use, which is a tiny percentage of total use. Does not mitigate the problem, but causes maximum amount of pain to the public.

[KNS]

It's going to get ugly...

Rio Verde Foothills North of Scottsdale is running out of water.

The usage of wells and water haulers was doable until the drought worsened in Arizona. Scottsdale will cut off its supply at the end of 2022 as a part of its drought contingency plan, the city's Nov. 1 announcement said.

“We’ve been telling them for five years since this began that we are not their permanent water solution,” said Valerie Schneider, Scottsdale Water’s public information officer. “At some point, we have to realize this is our water, we’re in a drought, we’re in a Colorado River shortage so we have to take a stance.”

https://www.usnews.com/news/best-states/arizona/articles/2022-01-22/exchange-rio-verde-foothills-homes-to-lose-water-source

[unclebilly]

Something worth pointing out in this discussion is that ALL (I think) of the agricultural water used in the Bakersfield area is actually produced water from the oil wells in that area.

As an oilfield engineer, I was mortified to learn that those little baby carrots I feed my family are grown with produced water. They are.

In the worlds of one of the former DOGGR hydrologists that so spoke with at the Western SPE conference held in Bakersfield, those ‘oil wells’ are actually water wells that produce a bit of oil. The water they produce is fresh water suitable for drinking and agricultural purposes. This is a stark contrast to the wells in Texas and other places where the produced water is a KCl brine laden with NORM, hydrogen sulfide, and bacteria.

My point is that not all water used in agriculture in CA is from lake mead.

https://www.conservation.ca.gov/calgem/Pages/Aquifer_Exemptions.aspx

[Tobra]

https://water.ca.gov/Water-Basics/The-California-Water-System

I am pretty sure they use all the water they get out of the Colorado River for SoCal drinking water.
Something like 75-80% of the water used in the state comes from the Northern California watershed, with SoCal using 2/3 of the water

[unclebilly]

This really shows the contrast between irrigated land and the desert next door...

[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.

[unclebilly]

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.

Agreed and given the temperatures in that area, the surface area per volume needs to be minimized to reduce evaporation.

I’m actually amazed how shallow this lake is given its purpose.

[Sooner or later]

Quite a project.

Mead holds about 30,000,000 acre feet. How many dump truck loads would it take to increase capacity by 0.1% (300,000 acre feet)?

300,000 is about 10 days of normal release (10,000,000 acre feet/year)

[Tobra]

I would build a conveyor system and dump it on train cars, like they did when they built it in the first place.

Okay, it looks like 5750 cu ft per train car. Found a calculator that gives me 13,068,000,133 cu ft for 300,000 acre ft. 2,272,695 train cars. They can dump it in the midwest and replenish the topsoil.

How else can they increase water storage that inexpensively? Limited number of places you can build a dam. If there were interest in actually improving the situation, this would be happening right now at Folsom, Shasta and all over the West. Instead, they do nothing.

[Sooner or later]

2.2 million train cars for 10 days of storage.

Quite a project.

[flatbutt]

Originally Posted by Sooner or later

2.2 million train cars for 10 days of storage.

Quite a project.

after 4 days of no water we die so....

[Sooner or later]

Originally Posted by flatbutt

after 4 days of no water we die so....

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.

[Daves911L]

Originally Posted by Tobra

I would build a conveyor system and dump it on train cars, like they did when they built it in the first place.

Okay, it looks like 5750 cu ft per train car. Found a calculator that gives me 13,068,000,133 cu ft for 300,000 acre ft. 2,272,695 train cars. They can dump it in the midwest and replenish the topsoil.

How else can they increase water storage that inexpensively? Limited number of places you can build a dam. If there were interest in actually improving the situation, this would be happening right now at Folsom, Shasta and all over the West. Instead, they do nothing.

Good math, but I think your estimate of hopper capacity at 5750 cu. ft. is high. Maybe close to total physical volume for light commodities (grain) but sediment will be heavy, and probably more like 3000 cu ft/car.

Plus there is something on the order of 10,000 AF of sediment entering Mead annually (10% of what it used to be, before Powell started intercepting most of it) that has to be dealt with before the hole grows any bigger.

What has been happening is a number of reservoirs have had their storage increased either by raising the dam crest, or modifying spillway/outlet works capacity to allow higher safe operating level. If memory serves, this was already done at Folsom a few years back.

[flatbutt]

Originally Posted by Daves911L

Good math, but I think your estimate of hopper capacity at 5750 cu. ft. is high. Maybe close to total physical volume for light commodities (grain) but sediment will be heavy, and probably more like 3000 cu ft/car.

Plus there is something on the order of 10,000 AF of sediment entering Mead annually (10% of what it used to be, before Powell started intercepting most of it) that has to be dealt with before the hole grows any bigger.

What has been happening is a number of reservoirs have had their storage increased either by raising the dam crest, or modifying spillway/outlet works capacity to allow higher safe operating level. If memory serves, this was already done at Folsom a few years back.

The environmental police would make dredging that sediment nearly impossible. My neighborhood wanted to dredge out the 6ft of biomass at the bottom of our pond but DEP requirements are beyond our ability to pay. I can imagine the requirements to dredge Mead would be more than onerous.

[Por_sha911]

Originally Posted by island911

Seems stupid, considering it is easier to import electricity from other States than it is to import water.

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

Daepp: The refilling in the "wet season" has not been done for 100 years and the method is based on data that is skewed. Remember that the environmental cycle is not 10's or even hundreds of years but thousands, ten thousands, or longer. What you think is acceptable works until it doesn't and then you are screwed. It is completely normal to go through dry spells for long periods of time.

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

[island911]

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"
.

To minimize evaporation? It would be cheaper to cover the surface.

The V shape is advantageous for the forces on the dam.

[island911]

Originally Posted by Por_sha911

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

Well, killed by costly Tesla charging is not as bad as being killed by lack of water.

But, as was posted earlier, a certain amount of water is required to pass the dam for other reasons, so may as well get the electricity out on the way past.

[unclebilly]

Originally Posted by island911

To minimize evaporation? It would be cheaper to cover the surface.

The V shape is advantageous for the forces on the dam.

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

[flatbutt]

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

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