Comment by cwal37 | Hacker News Reader

Comment by cwal37 | Hacker News Reader

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That's the sort of thing that sounds like you're closing the loop, but has some serious flaws the deeper you go. First off, where is that water coming from? You mention desert, so is it an incredibly saline salt lake or briny fossil aquifers? If you're pumping out mass quantities of fossil water, be prepared for an eventual end, and localized subsidence, depending on the depth/structure of the formation.

Then there's the salt. Salt's actually kind of on the downslope in terms of its use in de-icing. You're literally salting the earth around roadways. Places that see a lot of snow and have a lot of waterways (from personal experience, like Northern Wisconsin and the UP), actually use sand instead. You expect there to be snow on the roads for a number of months regardless, so you're just offering some traction. Certain places in the Northeast are the same as far as I'm aware. Here's a resource on road salt from New Hampshire[1]. Pickle brine[2] and beet juice[3] are also beginning to get some play. Not to say the rock salt market couldn't absorb some additional supply, but I don't know where the limit is if we're talking mass desalinization.

[1] http://des.nh.gov/organization/divisions/water/wmb/was/salt-...

[2] http://news.nationalgeographic.com/news/2014/02/140204-melt-...

[3] http://time.com/5761/salt-shortage-triggers-beet-juice-chees...

The Salton Sea is below ocean level. If you dug a canal out to Laguna Salada and into the Gulf of California, the ocean water would flow, by gravity, into the depression.

If nothing else, you could probably truck the salt to Coyote Dry Lake and just dump it on the existing salt flats there.

Reminds me of the Qattara Depression Project:

https://en.wikipedia.org/wiki/Qattara_Depression_Project

Build a canal/channel/etc to a below sea level place, harvest the hydro power, and get a nice new (saline) lake to boot.

Anyway, I don't think that the salt is totally worthless. Don't they have salt ponds in the bay around San Jose?

The energy input is the bigger problem; you can only get so much water from a glorified solar still.

The Salton Sea is 230 feet below sea-level. Locks would be necessary to negotiate the difference. Obtaining a "right-of-way" for the 68 miles from the Border would be lengthy & expensive. The salt, however, can be mined for Lithium! Visit the salton sea on facebook and see what a lot of us are doing. All the best, John Mackey

If someone were to buy out the residents of Mexicali, Imperial, Indio, Brawley, El Centro, Coachella, etc. the area could nearly fill to the ancient extent of Blake Sea/Lake Cahuilla, and a canal would need no locks. Aside from the buyout compensation, actual construction of a canal suitable for international shipping vessels would probably be only about $5 billion.

As most people every remotely familiar with politics might guess, the technical challenges are not even remotely the most difficult obstacles to be overcome for such a project.

If you situated it somewhere like the atacama desert, then you'd be right on the ocean, and that's where you could source the water from.

I'm from Canada & the reason they don't use salt in places like Edmonton & Winnipeg is that it just gets too cold and salt no longer works at that temperature. In Ontario where they get the lake effects they use salt everywhere.

> If you situated it somewhere like the atacama desert, then you'd be right on the ocean

Well, the Atacama is 8000ft above the ocean, so the energy required to pump the water up there would be significant.

In fact, about the same as the energy to desalinate it via reverse osmosis ...

8000 feet? I'm going to have to ask for a source on that one. For reference, Whistler & Blackcomb are both under 8000ft, and I sincerely doubt there'd be drop offs that size right into the ocean.

Googling for "atacama elevation" yields 7K-13K feet for me depending on the result.

To be more accurate, sodium chloride salt doesn't work. The freezing point depression effect depends on the total number of ions/molecules in solution. A dissolved mole of NaCl produces one mole of Na+ and one mole of Cl-. A mole of urea would be half as effective, while a mole of CaCl2 would be 50% more effective.

CaCl2 works down to about -32C (-25F).

But at some point, you just can't dissolve enough stuff into the water to stop it from freezing. Fortunately, that is also about the point where ice stops being quite so slippery when you drive or walk on it. So you just throw down white sand for better traction instead, put on the winter tires, and you're good until it melts in the spring.

In Minnesota, Wisconsin, Ontario, Michigan, and New York, the temperatures are such that snow and ice could go through multiple freeze-thaw cycles. If they just left it, snow would melt and re-freeze into smooth, slippery ice. Ice would melt and seep into the roads, then refreeze and pop out big chunks of pavement each time. That's why they salt and plow. It's too cold for it to safely drain away, and too warm to just leave it alone.

If there were a substance that allowed snow and ice to stay frozen at higher pressures or higher temperatures, that might be useful there, too.

There are startups working on energy storage using molten salt. I don't know if it requires a special kind of salt, though.

http://www.technologyreview.com/news/525121/molten-salts-mig...

I really meant pull it from the ocean then to a desert where land is cheap and sun is plentiful.

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