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Comment by hugh3 | Hacker News Reader

there are some significant differences between petroleum and water. For oil, using it involves a chemical transformation that won't be reversed except on geological time scales. Using water often leaves it in its native state, with a cycle that returns it to the environment in a geologic blink of an eye. Still, the authors make a compelling argument that, not only can there be a peak water, but the US passed this point around 1970, apparently without anyone noticing.

Indeed, but since (as mentioned) water is nothing like oil, the concept of Peak Water hardly matters. I hear the US also passed Peak Rubik's Cube in about 1983 and nobody noticed that either.

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It hardly matters until we pump all the aquifers dry. At that point a majority of US crops will be reliant upon rain water, which won't be enough to sustain the farms in the west. Much of Oklahoma, Kansas, California will revert back into the Great American Desert (as it was known before).

For a great book on the subject, check out http://www.amazon.com/Cadillac-Desert-American-Disappearing-...

Most of California's agriculture is the Central Valley. Surely that was never desert? It's got rain all winter and runoff from the mountains all summer.

From Wikipedia[1]: "The northern Central Valley has a hot Mediterranean climate (Koppen climate classification Csa); the more southerly parts in rainshadow zones are dry enough to be Mediterranean steppe (BShs, as around Fresno) or even low-latitude desert (BWh, as in areas southeast of Bakersfield)."

Central Valley farms and the coastal cities are mostly fed by water from the Sierra's, via either rivers or one of California's many aquifers (e.g. Hetch Hetchy, Los Angeles, Colorado, California).

[1]http://en.wikipedia.org/wiki/Central_Valley_(California)#Cli...

The vast majority of water for California farms comes from Sierra Nevada snow-melt runoff, not aquafers.

>the concept of Peak Water hardly matters

It matters if we're using water faster than the hydrologic cycle can process it.

It doesn't really, the peak water argument was a busted flush when people realised there's constant water trade going on at rock bottom prices all around the world.

A few years ago it was fashionable to predict water wars. And then they didn't happen and people realised that when you buy any food from any other country, you import water. D'oh.

Given that the US is apparently a net exporter of food, seems to me they have plenty of water. All it might mean is that if water becomes scarcer in America, water intensive crops will become more expensive, thus their exports will drop.

On a side note, there are already many countries that are way past their own sustainable water use, but they buy food from countries which have excess water, so no ill ever comes of it.

Realistically, for the majority of human civilization desalination is a prime (and also becoming a much less-expensive) alternative.

Considering Israel and Singapore have already deployed desalinated water at lower costs than regular water in many parts of western countries, it really is a moot point.

Again, considering technological advances the prices will drop and once it hits a tipping point, every coastal city in the world will be able to switch as increased usage of the technology will not only mean lower construction costs of existing designs, but also lead to huge increases in research budgets. Since countries are already deploying it, it's really just a matter of time.

As mattmanser is pointing out, a lot of our water is exported through food. With desalination saving river water, there's a potential to greatly increase our exportation of water-intensive crops without damaging our waterways.

Desalination of water costs energy. If the energy costs are more than just pumping it out of an aquifer (or other fresh water source), then you're increasing your reliance on energy to get the amount of water that you need. This then increases the amount of reliance that we have on energy sources like oil just to get a basic necessity like water.

> With desalination saving river water, there's a potential to greatly increase our exportation of water-intensive crops without damaging our waterways.

Well, we still need waste treatment to keep those waterways clean. Let's just hope that someone doesn't come with the 'bright' idea that since we no longer rely on the waterways for drinking water, that we don't need to care about waste treatment.

with BP's recent successes in the gulf, water and oil will soon be one commodity, making this distinction academic

Luckily oil and water don't mix. They're like... wait, wait, there's some kind of analogy here...

Except as an emulsion...

So we add a bunch of oregano and call it the great gulf salad dressing?

is that what this dispersant they're using does? I think I heard its keeping from surfacing, which I think is what happens when oil and water don't mix.

So I've been wondering ... given that, why doesn't someone tootle around with a flamethrower on a boat and burn off the oil slick?

They are doing that for some of it.

I was wondering if someone had a great way to suck up the oil and separate it from the water, would you have to give the oil back to BP or could you keep it?

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