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A vision for the alleviation of water scarcity in the US Southwest

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Re: A vision for the alleviation of water scarcity in the US Southwest

#81

Post by konschubert »

hnmullany wrote: post #3

Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora…

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent.

If that’s still too much, use 20 gallons.

It’s a matter of spending energy on pumps, but it’s totally doable.

Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

Re: A vision for the alleviation of water scarcity in the US Southwest

#82

Post by margalabargala »

obblekk wrote: post #57
hnmullany wrote: post #3

Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora…

There should definitely be a plan for the brine. I'm optimistic we could: * Build ocean pipelines that disperse brine over much larger volumes of water to minimize impact on wildlife * Dump the brine water in engineered desert fields where it will evaporate and deposit salt reserves. In general, we should be aware of the whole lifecycle of a solution, and optimistically believe we can solve each problem with more wor…

> Dump the brine water in engineered desert fields where it will evaporate and deposit salt reserves.

Honestly, the Salton Sea would be a great place to dump the brine. It would keep the water levels up and reduce the respiratory issues caused by drying, and any ecosystem to be destroyed has been thoroughly destroyed for decades.

Nix the "turn the manmade salt lake to a manmade fresh lake" plan, and use the created freshwater for agriculture directly, or send it off to LA, or do anything with it that isn't "refill the accidental lake that already has evaporation and pollution issues". It's a salt lake, use it as one.

Re: A vision for the alleviation of water scarcity in the US Southwest

#83

Post by bparsons »

The details might be a bit goofy, but this sort of large scale geoengineering project is going to be the only way that the SW is going to remain inhabitable.

The American southwest has a couple big things going for it -- unlimited sunshine and an extraordinary amount of empty land. You can combine these things to create huge amounts of electricity which can be used to irrigate new farm land, power mines and build new cities.

The status quo of drawing down on the increasingly precarious water supply is not feasible though. Before the unprecedented snowpack of 2022/2023, many regions were facing extreme water rationing.

Re: A vision for the alleviation of water scarcity in the US Southwest

#84

Post by jryb »

konschubert wrote: post #81
hnmullany wrote: post #3

Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora…

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

But where are you getting that pure seawater from? If it's anywhere near the outlet, there's a scale at which the concentrated brine will affect the salinity of your inlet.

Re: A vision for the alleviation of water scarcity in the US Southwest

#85

Post by BytesAndGears »

konschubert wrote: post #81
hnmullany wrote: post #3

Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants: "Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora…

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

Yeah, but if you’re pulling in water and disposing it from a specific region, eventually the water that you’re pulling in is progressively saltier, and you’re compounding the saltiness of that area.

I’m sure that ocean currents will eventually equalize the salt, but if you’re continuously dumping salt into a specific area, it’s going to make that region of the ocean saltier.

Re: A vision for the alleviation of water scarcity in the US Southwest

#86

Post by konschubert »

BytesAndGears wrote: post #85
konschubert wrote: post #81

Earlier quoted context omitted.

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

Yeah, but if you’re pulling in water and disposing it from a specific region, eventually the water that you’re pulling in is progressively saltier, and you’re compounding the saltiness of that area. I’m sure that ocean currents will eventually equalize the salt, but if you’re continuously dumping salt into a specific area, it’s going to make that region of the ocean saltier.

You need pipes to spread it out. And I think you may be underestimating the scale and force of ocean currents. Every tide probably moves more water than California uses in a year.

Re: A vision for the alleviation of water scarcity in the US Southwest

#87

Post by [deleted] »

jryb wrote: post #84
konschubert wrote: post #81

Earlier quoted context omitted.

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

But where are you getting that pure seawater from? If it's anywhere near the outlet, there's a scale at which the concentrated brine will affect the salinity of your inlet.

[deleted]

Re: A vision for the alleviation of water scarcity in the US Southwest

#88

Post by JieJie »

photonthug wrote: post #43
bradford wrote: post #18

NYT daily had a relevant podcast episode on this ( https://www.nytimes.com/2023/09/01/podcasts/the-daily/water-... ?). Discussion centered around using the water for Arizona, not California. (I'm unable to speak of the relative merits of pumping the water from one state to another). General takeaways: Proponents of the solution seemed to understate challenges and risks associated with: 1. The pipeline itself (i.e., w…

> 3. Cooperation with Mexico Yeah this seems like a big challenge. Even if the Gulf of California is closer, or if it's all downhill, the requirement for international cooperation seems like it would make this a much more complex option than just using the Pacific. Plus if I were Mexico, I'd honestly be looking at the Salton Sea disaster, noticing that some new plan calls for putting salt down in my neighborhood inst…

Maybe this, since it has to do with Colorado River water.

https://www.watereducation.org/aquapedia/mexico-and-colorado...

Re: A vision for the alleviation of water scarcity in the US Southwest

#89

Post by konschubert »

jryb wrote: post #84
konschubert wrote: post #81

Earlier quoted context omitted.

If you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.

But where are you getting that pure seawater from? If it's anywhere near the outlet, there's a scale at which the concentrated brine will affect the salinity of your inlet.

Yes, some pipes are needed. Beyond that, you rely on ocean currents. .

Re: A vision for the alleviation of water scarcity in the US Southwest

#90

Post by solardev »

konschubert wrote: post #86
BytesAndGears wrote: post #85

Earlier quoted context omitted.

Yeah, but if you’re pulling in water and disposing it from a specific region, eventually the water that you’re pulling in is progressively saltier, and you’re compounding the saltiness of that area. I’m sure that ocean currents will eventually equalize the salt, but if you’re continuously dumping salt into a specific area, it’s going to make that region of the ocean saltier.

You need pipes to spread it out. And I think you may be underestimating the scale and force of ocean currents. Every tide probably moves more water than California uses in a year.

I don't think the ocean is equally saline everywhere: https://salinity.oceansciences.org/maps-global.htm

On average it's pretty close, but you can definitely get impacts from increased local salinity: https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16859 (just random ecamples)

https://www.scientificamerican.com/article/slaking-the-world... (view in incognito)

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