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Comment by dimal | Hacker News Reader

Can we start to talk about massive desalination projects? The Israelis seem to have made it work.[1]

[1] https://www.scientificamerican.com/article/israel-proves-the...

Desalinations projects would not solve the issue. The 'water crisis' is really an economic problem with the underpricing of water leading to suboptimal practices not a engineering one. Even if desalination worked moderately -- Californian farmers would end up farming more rice and walnut trees and you'd end up in the same situation.

Increasing the price of water would not work effectively either. Almonds have high margins and more pricing power than most crops. To say nothing of the obnoxious fact that around 2/3 of the US almond crop is exported (ie California is depleting their water supply to line the pockets of a billionaire almond cartel and exporting their scarce water resources in the process).

And even if the rich almond growers could somehow afford dramatically higher water prices, it still doesn't make sense to allow them to consume so much of California's water - water which is a critical, scarce public good being converted to very narrow private wealth.

The correct solution is to ban the growing of all almond, pistachio and walnut crops in California. The minimum they should do is ban the export of those crops, although that is likely still not enough.

Increasing the price of water would of course work. There is nothing inherently special about water. What is special is how water has been underpriced for so long as well as the use of aquifers through wells temporarily 'increasing the supply' until they run out. Banning almonds, pistachos, walnut crops etc... is really just an indirect way of increasing the price of water for farmers.

I've heard other suggestions to mandate more conservative water practices aka drip irrigation and ban water hungry crops and sure that kinda works -- but this is exactly what higher prices is supposed to fix already. There is no magical solution to the now permanent decreased water per year, it's not a 'temporary drought' anymore. Eventually the price of water will be set back to normal either through dollar cost or with lottery random shortages as the agency is currently forced to do.

This is a terrible idea, From the perspective of someone who knows nothing about agriculture, and the water cycle. Trees encourage the retention of water in the ground, Their roots penetrate the clay soils, which on a microscopic level appeal as layers of paper: pour water on a pile of newspaper and it sheds off, allow water to penetrate and that clay can hold 1/3 of it's volume in water. The removal of beaver dams, building of fences and roadways, is what has caused your environmental damage. Before people began to manage the land in this way, It was rich with water and fertile. When you think to take water from farmers, so that you can take a long shower or grow a landscape in your yard, you are part of the problem.

IDK. I love roasted almonds as a snack but they are pretty expensive. If they went much higher I'd cut back or stop buying them. As it is I only buy them on sale.

Desalination plants are vastly more expensive than current water conservation solutions. Solving a problem with tech is sexy, especially on HN, but simple programs like canal lining and drip irrigation are much cost effective for now. It's not a forever solution, but conserving water resources will take a patchwork of half-measures and incremental progress. There does not appear to be a silver bullet.

Association between exposure to desalinated sea water and ischemic heart disease, diabetes mellitus and colorectal cancer; A population-based study in Israel https://www.sciencedirect.com/science/article/abs/pii/S00139...

Ah, mineral deficiency. This would be the same for people drinking distilled water they bought at the grocery store, so it might not be fair to pin it on desalinated water.

The link title implies all of these things were associated, but the article summary says only ischemic heart disease, and no association for the others, if I read correctly.

Investing some public money in research to make desalination more economically would be worthwhile, even if it isn’t a very viable solution right now. Or bringing down the price of energy as renewable sources themselves become more economical could change the economics by itself. It would be a pity to give up on almonds.

Right now, many farmers spend under $100 per acre-foot of water; 80% of non-environmental water goes to agriculture.

Water prices in urban areas are $1000 per acre-foot of water, because distribution is expensive. Desalination of brackish water can cost $1200-1500 per acre foot, and moderate improvements in costs could make desalination economically viable for urban water.

But it would require a truly massive improvement to be competitive for agricultural water use, and because most use of water is agricultural, we can only reap small benefits from desalination.

Not to mention that we'd need to pump those millions of acre-feet uphill into the various agricultural regions. Some are lower lying but if California is serious about its GHG targets, it won't be building the massive power stations required to pump all of that water in addition to desalinating it.

Assuming the the other challenges can be met, me solution to distribution is to use desalinated water to fill up underground aquifers. The other option is simply to move agriculture closer to the coasts.

The Central Valley aquifer does not extend to the coast and is poorly connected to the coastal aquifier: https://www.usgs.gov/mission-areas/water-resources/science/c...

There is not enough flat, cultivatable land closer to the coasts to move much agriculture out of the central valley towards the coast, even if desal'd water was free.

Desalination allows the now unused surface water to be collected and diverted further upstream, slowing the decline of upstream aquifers.

For the upstream cities that use the Colorado River this could be quite beneficial.

But now we are talking about building a tunnel rather than an aqueduct. It isn’t weird to drill water tunnels for a hundred or so miles.

Other than the fact that this is even more capex and opex that will exceed any economic use of water in agriculture.

Sure, either desalination must become more energy efficient or energy must become cheaper for it to be usable in agriculture (well, the third option is that such food becomes a lot more expensive). Either of those seems hard but not impossible.

Power is only about 40% of OPEX of desal plants and very little of CAPEX. Even if energy were free, and there were brackish water right next to the farmers, you're not hitting the water prices above.

It seems to me that we already do tidal power, so combining a tidal power and desalination plan into an all-in-one solution seems interesting to me.

We are about to pass a trillion dollar nebious Infractructure Bill passed, which I imagine is filled with pork.

I pretty sure most Californians would be happy if they got a few strategically placed desalination plants.

The other problem with desalination is pollution. Brine, for example, needs to be released somewhere.

Just dump it back in the ocean (at a suitable depth/distance from shore). Almost all of the purified water will eventually return to the ocean so there won't be a net concentration of salt (not to mention the ocean is really, really big).

For SoCal it could be detained in the Salton Sea and likely have quite a positive impact in improving water quality there.

Could it be turned into table salt?

Sea salt is filled with mondo micro-plastic particles, so I think this would be that, plus other "stuff" thrown in. EG, leakage/contaminants from the desalination process.

The best table salt we can currently get, it stuff mined from old oceans. No contaminants, no plastic, etc. For example, Windsor has huge mines in rural Windsor, ON, Canada.. and doesn't just supply table salt, but road salt, water softener salt, etc, the supply has been used for 100 years, sold internationally, and shows no sign of exhaustion... from one old-sea underground deposit.

(There's plenty of table salt, no shortages...)

I doubt there is that much demand for table salt. Maybe it could be used to deice roads in areas that have freezing weather in the wintertime, now most places use mined salt for that.

The exhaust muffler industry would love that.

It’s expensive to build and takes time, but is feasible especially if we have nuclear energy to meet increased demands. Sam Diego built a giant desalination plant a few years ago and hoped it would supply more of the city’s needs, but it is only good for about 7% of their demand (https://en.wikipedia.org/wiki/Claude_%22Bud%22_Lewis_Carlsba...). California the state would need a huge number of these.

The issue with these is that the other side of the output is hyper-salty brine, which kills pretty much any life it encounters, and that brine does get dumped to the ocean. The ocean has more than enough capacity to absorb the hit, but it still damages the ecosystem at the exit point nevertheless. Israel and Saudi Arabia do it because, well, if they don’t their country pretty much ceases to exist, but it’s much better cost/performance ratio to focus on whatever water California has before we go there.

It’s also that even the most water-conscious agriculture practice uses obnoxious amounts of water just because of the sheer size of land involved. Supplying that kind of water via desalination plants pretty much by definition means having done all prior optimisations to the max before tapping into that stream.

If you’re interested in agriculture from a layman’s perspective, I recommend Clarkson’s Farm on Amazon Prime Video, where Jeremy Clarkson of Top Gear figures out how to farm right, long way round.

Dilute it with more sea water and send it to the Salton Sea. This would improve water quality in the Salton Sea while detaining the brine.

I doubt that desalination would work at agriculture scale because most of the fields and orchards are too far away from the ocean, and the water is just too expensive.

That said, seeing water prices from desalination, I'm very frustrated California wants me to take a shorter showers when I would very happily pay an extra 50 cents for that long shower.

One thing you could do is desalinate water in Los Angeles, and thus keep the water in the central valley rather than pumping it over the grapevine. I'm pretty sure agricultural use of water in CA dwarves urban use, so maybe it wouldn't make that much of a difference. (Maybe someone can find actual numbers, sorry I can't right now.)

I bet this is the first use of large scale desalination. It already takes huge amounts of power to pump the water over the mountains to L.A. so reducing that load could make the desalination power requirements more palatable.

You cannot use the desalinated water in this way, because the excess salt will build up in and destroy the soils fertility. Sounds just like the kind of thing government would mandate, further destroying the environment.

I been seein' a lotta little blurbs in my various science feeds about recent fairly shocking improvements in both cost and effectiveness of some really interesting new desalination methods, so it's absolutely a space to keep an eye on for interesting developments. Improvements also in solar power and battery tech, clean fuels, safe/clean(ish?) nuclear, and a bunch of other really exciting stuff invented lately. Leaps and bounds… Still, much of that is all still "in the lab" as it were, so we can't expect to see the benefits of some of that for years (or even decades?) maybe. Still. All of that good stuff happening in science should not be ignored. At least some humans are still working toward the goal of trying to avoid total disaster.

California has huge desalinization plants.[1] 11 in operation now, more being built. Water price at output is US$0.005/gal. But that's $1630 for an acre/foot, very expensive for agriculture.

[1] https://www.carlsbaddesal.com/

If you wanted to replace all of California's water consumption with desal you'd need thousands of plants.

But even 10% of thousands of plants is a lot.

Have California farmers expressed interest in funding such projects?

Given how many of them receive absurdly subsidized water from the Bureau of Reclamation, I'm going to say no. Take Arizona, where the already subsidized (though not nearly as much as some BOR water projects) cost is ~$200 per Acre-foot from the Colorado River (via the Central Arizona Project) compared to the $2200 per Acre-foot price of Desalination water.

Farms in the Central Valley Project are paying < $20 per acre foot because the contracts were negotiated sixty years ago and not indexed to inflation.

Yeah and on top of that many of them had their loan interest federally subsidized to build out their private infrastructure. The original 160 acre limit per farm of the 1902 Reclamation Act at least made sense in this context. Despite that, many of the multi-millionaire farmers flaunt that rule entirely even with it being raised to 960 acres in 1982.

How much power is required to pump so much water from sea level to the elevation and distance of the Central Valley?

Just as one example, Tulare is at 300 ft, ~100 mi from the ocean.

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