Are we running out of water?

Factual Questions
1

I hear that we are depleting the Oglala aquifer about 6 times as fast as it is being replenished. I also read the other day that if we had a particularly bad drought, Dallas could be in real trouble. To what extent are we running out of fresh water? What can we do about it? Is the bulk of fresh water used for irrigation? Would it be economically possible to desalinate water from the ocean and pipe it to crops in the Great Plains? Does the quality of our food supply depend on the Oglala, or are there other sources of water? Is American agriculture efficiently using water?

Thanks,
Rob

2

To respond to a couple of your half dozen or so questions here.

Yes, pretty much every study shows we are using up water from this aquifer (and most others) faster than it is being replenished. And the water level in Lake Superior has fallen quite a bit in recent years (an inch a month drop is what I recall). There is a massive amount of fresh water in the polar ice caps, but they seem to be melting now. And global warming results in a reduction in available water – warmer air means more humidity is retained in the air rather than falling as rain. So in several ways, we seem to be using up fresh water faster than it can be replaced.

Economical desalination? Depends on how badly we need the water, and thus how much we are willing to pay for it. Getting oil from the Alberta, Canada oil sands was once considered economically infeasible, but that was before oil approached $100/barrel. But rather than desalinate, it might be easier to take already fresh water from the great lakes or the Mississippi or Missouri rivers. Though that might cause some problems for the states down at the end of those rivers.

3

Some old threads on groundwater use and depletion:

[thread=402890]Great column on ground water today.[/thread]
[thread=446685]What does it mean to “use” water?[/thread]
[thread=363400]Things people do with water but don’t need to…[/thread]

Regarding the o.p.'s questions, yes, freshwater aquifer depletion is a significant and serious issue, and it is occurring in many regions of the world where high density population, agriculture, or industry has significant fresh water demands that cannot be serviced by natural fresh water sources that are regularly replenished. The Ogallala Aquifer supports a not inconsiderable section of “America’s Breadbasket”, making semi-arid southern Great Plains states into bountiful agricultural regions yielding water-hungry crops like bread wheat, short grain rice, and cotton. Some aquifers are naturally replenished from glacial or runoff sources, but many, like the Ogallala, have a cycle recharge time of hundreds or thousands of years; furthermore, excessive depletion may cause subsidence, in which the matrix of the aquifer, no longer supported by hydraulic pressure, starts to collapse upon itself and suffers from reduced capacity. In other areas, like the Indus River Valley in Pakistan, while the water source is renewable large scale irrigation projects and increased industrial demand upstream resulting in pollution and silted of water for downstream users causes major disruptions.

How big of a problem is this? The ultimate impact of freshwater depletion and overuse is potentially catastrophic, likely even greater than the impact of global climate changes (although the two issues are intertwined). The “Green Revolution” that permitted unchecked population growth and industrial development in Asia was predicated on access to free or highly subsidized water. Pakistan has the largest irrigation project on the planet; without this, the country could not come close to providing for its own burgeoning population, much less the exports that allow the nation hard currency. And yet, water availability and resulting crop yields are decreasing in recent years in Pakistan and India. The issue isn’t localized, either; because of the export of water-intensive crops, the populations of developed nations that import these crops are using “virtual water”; i.e. they share in the depletion of available water by large scale consumption of goods and grains. Never mind turning off the tap while brushing your teeth; that Egyptian cotton shirt you’re wearing cost several hundred–maybe even thousands, depending on conditions–gallons of water from the progressively silted and dry-running Nile Delta. A significant drop in water availability may cause an unavoidable waive of crop failures across a region, which would then require importation of crops from elsewhere to avoid famine. This may also result in warfare over access to water resources, a likely future conflict between Pakistan and India, or Israel and its neighbors.

Remediating the problem is far more difficult than most people really appreciate. Setting aside the energy problems with mass desalination of water (and what to do with the resultant wastes), physically moving the water from coastal regions inland and upward is an enormous logistical challenge. Large scale projects to move water from available underground and surface water sources to arid regions for agriculture and personal use, like Libya’s Great Manmade River Project (a.k.a. Col. Quadaffi’s “Eight Great Wonder of the World”) have cost billions of dollars (~US$25B for the GMRP), have resulted in enormous losses–more than was pumped from the aquifer and lost into the desert), and have only served to redirect the problem. Ditto for water from the Metropolitan Water District of Southern California from the open-top California and Colorado River aquiducts; a substantial portion is lost to evaporation. Even large surface catchments and reservoirs interfere with the hydrological cycle which supports the aquifers, ultimately reducing the throughput of those systems with concomitant effects on other ecological systems.

And this is a deliverly system that is mostly downhill, with only occasional pumping stations. Most of the “free” inland water we get from natural is “pumped” by the enormous amount of “waste” energy from the Sun which drives the hydrologic cycle, which is powered at ~1kW per square meter. Although the reality is that we only use a small fraction of the water that goes through this cycle, it is still an amount of energy that serves to relocate, distill, purify, and mineralize the water we ultimately use for drinking, bathing, and agriculture.

Because water it is a common resource–and one that is ultimately almost completely renewable–we take it for granted, but in fact there are limits on how quickly even a planetary-size system can process water, and we are in many ways exceeding that with current demand. Short of a nearly-limitless, pollution-free energy source and a massive hydroengineering infrastructure to pump water uphill–which is kind of like pushing string–we’re going to need to learn to conserve, treat, and recycle water on a more local scale. Given the additional cost, and current lack of incentive to do so, it’ll probably take a few famines before it becomes the same sort of issue that global climate change is now, despite far more definitive drawbacks and limits.

Stranger

4

The main problem is that the water is being used by mega farms.
This brings two problems. 1) They (like that Archer Daniels Midland Company (ADM)) tend to have bought every politician in Washington and all the statehouses. 2) When you try to appeal directly to the voters, the farm states turn out to have all the cards in terms of early primary states and longest-enshrined congressmen.
What’s needed is someone like FDR, who with his TVA project just swept aside local influence peddlers.

5

Do you have a cite for this? In North Mississippi, where there are no mega-farms, Tupelo switched from using well water to using water from the Tenn-Tom Waterway because the aquifer they had previously been using was becoming depleted. Are you saying that was somehow caused by “mega farms”?

6

The big problem in Wisconsin is the small area one of the qualifiers can charge from. The reservoir is large, but the input is small due to the way the glaciers deposited material. The housing developments are draining it like thousands of mosquitoes on a person. Central Wisconsin is porous sand so the problem there is chemical contamination. Madison lakes used to get water from the underground aquifer. The aquifer now is getting water from the lakes.

7

That, and also the fact that in most of the Southwestern U.S., not enough people question the notion that as long as you can fit another housing tract in someplace, you should build it.

8

The wiki article on desalination says that desalination of seawater costs roughly $0.50 per cubic meter. That’s not too bad if you’re living on the coast, but if you have to pipe the water significantly inland, that’s going to be costly (especially since, as the article notes, inland = higher elevation, in most cases). But again, whether something is too expensive or not depends a lot on how badly you need it.

9

I remember hearing years ago a story on NPR about water conservation in Las Vegas, and they were interviewing an enforcement officer about a water shortage situation they had. He had issued a citation to a homeowner for excessive water use, and the homeowner shouted at him, “You people are trying to turn this place into a desert!” :rolleyes:

10

Well, Stranger, the trouble with using water hungry crops is that they use a lot of water. So how about we stop doing that?

The solution is to switch to less water hungry crops, and stop providing subsidized water so farmers can grow rice in the desert. I don’t think we need famines before we can change, charging farmers the real cost of the water they consume would just about address the whole issue.

When water is cheap farmers waste a lot of it. When water is expensive, farmers will conserve it. Not hard to figure out.

11

The last statement is the crux of the problem; water has either been free for pumping, or provided by government-subsidized, which has supported mass agriculture in regions that are otherwise ill-suited to large scale farming. The use of water by industry or high-density populations has general come without ramifications for downstream use, or often (as with the MWDSC) has bypassed normal users without cost. Water used by industry is typically either full of wastes making it non-potable and often nonusable for agriculture, and water that goes to or falls upon the impermeable surface of cities rarely gets the chance to absorb back into the ground, and is instead carried away by the sewage system and dumped into channels that run out to the ocean, removing the water from the hydrologic cycle until it is evaporated and redeposit on land. A few cities make a genuine effort to reprocess and reuse water, but it is very costly in comparison to the “free” water that is readily available and requires much less processing to achieve potable levels. And then the use of water reservoirs to provide spare water and power load balancing also removes water from the natural hydrologic cycle (where it would normally seep into the ground and into an aquifer), instead evaporating.

The “simple” solution is to stop trying to grow crops in desert climes, minimize stop pumping water from non-renewable aquifers, eliminate industries that pollute, and demolish dam and irrigation systems which divert water out of the normal water cycle in such a way to as to interfere with normal replenishment of ground table water. Of course, this would be both massively expensive and, for many areas, untenable; the Green Revolution which has permitted large scale population growth in the latter half of the 20th Century has also pronounced as much of a dependence on free (or very cheap) water as it has on cheap petroleum and coal, and unlike fossil fuel use there aren’t really any alternatives to water. The realistic result is to reorganize crop growth so that water-thirsty crops are grown in areas where replenishable water is available and use water-conserving irrigation techniques and systems (drip irrigation, lined and covered canals) to minimize redirection and use of water. This will also cause larger imports (or at least shipping) of foodstuffs or mass relocation of agrarian populations, so the ramifications are more than just changing what you grow.

While this doesn’t have to result in famines, reliance on market pressures to adapt to reduction or loss of “free” water (harkening back to the socio-economic problem of “the tragedy of the commons”) is probably insufficient; the decline of available water is already showing a steep drop, and will only become worse as “ice age” aquifers bottom out. Note that this isn’t a knock on laissez faire marketism so much as a recognition of how dramatic such an uncontrolled correction would be; the problem has been exacerbated by artificially subsidized water, and the most striking examples of the problem are actually occuring or have their genesis in (nominally) authoritarian socialist nations like the Peoples Republic of China and the former Soviet Union. One need only look at the former and current boundaries of the Aral Sea (once a major producer of fish protein which has declined by about 80% in volume, with proportional increase in salinity, in the past forty years due to irrigation and diversion of river feeds) to see the effects of planned but ill-considered large scale irrigation and water redirection.

Mega-farming is a problem in terms of the intensity of usage, and even more in terms of how much untreated wastes are dumped back into the effluvia. But the problem of water usage from unsustainable sources is going to occur whether it is from large scale corporate farming or a bunch of smaller farms. In some ways it is actually easier to implement water saving technology and monitor water usage with larger farms than it is small holdings.

Ultimately, all the water we “lose” is still on Earth, and still available for reclamation. But the cost of doing this by our own hand is masked by how much energy, streaming freely from the Sun, is actually used to drive the normal hydrologic cycle. Trying to build systems to accelerate or replace this is an enormous and failure-prone engineering exercise.

Stranger

12

Well said, Stranger.

Also:

is what I was getting at. It is “a” problem, not the “main” problem.

13

Are we running out of water?

No, yes, and who is “we?” The planet has the same water it had when Julius Caesar was walking around in a bedsheet. Well, except for a few billion more people, who are mostly water. It is distributed in a way that’s fine for some people, and really inconvenient for some others.

The rain falls on the rich and poor alike, but the rich are better at profiting from it.

14

You didn’t even read previous responses, did you?

Stranger

15

Heh … that reminds me: the Water District around here has been airing some bizarre commercials showing old ladies kicking water-wasters in the crotch. Maybe that will help!

16

Oh, keep your shirt on, Stranger. Yeah, that Egyptian cotton shirt that cost the Nile hundreds, maybe thousands of gallons of water. I did read the previous responses, including your 71 lines of tightly packed information, chiding, and philosophy.

I spent quite a bit of time writing and rewriting a longer post, and I kept getting more tired and more depressed. Finally, I deleted everything except one harmless, noncommittal little piece. Then I went to cook a pork stew. I still managed to get you peeved, because you thought I ignored all your hard work. The stew was wonderful. I did not intend to get your dander up. Sorry.

17

At that rate, in 30 years…uhm, add the 2, carry the 1…we will have a desert where Lake Superior used to be, and the citizens of Canada will walk across to Upper Michigan and shake hands without getting their feet wet, thereby proving Mark Twain right…

It’s pretty dangerous to take a few years of lake level changes and extrapolate to a crisis. While I am less familiar with Superior levels than Lake Michigan levels, I know that in 1964, Michigan was at a 100-year low and people were worried. What hath man wrought? But 12 years later, people were stacking large rocks on the shore to prevent the high waves from flooding their houses as the same lake reached a 100-year high. So which was the long-term trend? Down or up?

Probably neither, and if man didn’t cause the 1964 draught after 100 years of industrialization, it’s not too likely that man caused the 1986 floods, either.

So even though Lake Michigan is now close to the 1964 low doesn’t mean that it is because we are using water too fast (we’re not – Lake Michigan shoreline communities have severe limitations). It might mean Mother Nature has other ideas and is merely laughing at us.

18

At an average depth of 482 feet, at an inch a month it would take, um, carry the… wait, wtf? An inch a month is a foot a year. Duh. 482 years to drop the basin to where it’s average depth is used up.

And it’s max depth is over 1300 feet. That’s gonna take a while longer than 30 years. :wink:

19

Math ain’t my strong suit. Much stronger is my irony suit. At least if it’s ironed. :slight_smile:

20

When you consider that many estimates of world population during Caesar’s time were in the same ballpark as the U.S. population today, that is not very comforting.

“Mostly water” is right. We can’t drink each other to quench our thirst. Instead we’re like water-intensive garden plants.