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For Much of the World, Demand For Water Outstrips Supply 318

Posted by timothy
from the moisture-farming-has-a-future dept.
ananyo writes "Almost one-quarter of the world's population lives in regions where groundwater is being used up faster than it can be replenished, concludes a comprehensive global analysis of groundwater depletion (abstract). Across the world, human civilizations depend largely on tapping vast reservoirs of water that have been stored for up to thousands of years in sand, clay and rock deep underground. These massive aquifers — which in some cases stretch across multiple states and country borders — provide water for drinking and crop irrigation, as well as to support ecosystems such as forests and fisheries. Yet in most of the world's major agricultural regions, including the Central Valley in California, the Nile delta region of Egypt, and the Upper Ganges in India and Pakistan, demand exceeds these reservoirs' capacity for renewal."
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For Much of the World, Demand For Water Outstrips Supply

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  • "People back then would use fresh groundwater for bathing and flushing their waste!"
    • "People back then would use fresh groundwater for bathing and flushing their waste!"

      "Really Grandpa?" "That's right, all we had to do is turn the faucet and water just gushed out! You didn't have to go to the store and pay for it then, not like today, though some people did."

  • by ichthus (72442)
    Thanks for that, National Geographic. ...d' I mean... Slashdot? Hey, waitaminute.
  • by Tastecicles (1153671) on Thursday August 09, 2012 @01:46PM (#40934281)

    Physics 101.

    When you pump water out of the ground, it leaves a void. When you don't backfill, the void eventually collapses. The oil industry is aware of this problem (that and oil doesn't tend to want to just lift itself out of the ground once the initial pressure does its thing), which is why they use seawater to displace the oil: seawater is pumped in, oil flows out or is pumped out leaving the void which is then backfilled under gravity through a strategically placed hole or two.

    Back to the topic: the stable system of rain=>aquifer is disrupted to greater or lesser degrees by human activity. That's obvious. The amount of rain remains constant (more or less), which means the amount of water removed from the aquifer is gone. Simple as. The global water industry has a few options to try and deal with this problem before we start seeing entire cities disappearing into sinkholes:

    1. Backfilling. Something not currently done, but it begs the question as to what to backfill with?
    2. Alternative sources. We have viable desalination technology (geothermal, solar stills, seat salt extraction plants(!))... we have made great strides in atmospheric water extraction to the point where a plant in the middle of a desert can turn sand into golf course. One option that I don't think has been properly explored is a wide area water grid, possibly national or international in scale. We have the technology, we have the capability, the chock under that wheel is politics.

    • by Fned (43219) on Thursday August 09, 2012 @01:50PM (#40934349) Journal

      1. Backfilling. Something not currently done, but it begs the question as to what to backfill with?

      Oil, obviously.

    • by dkleinsc (563838)

      Alternately, the chock under the wheel is that it's much cheaper to use the groundwater. Of course, this might be disastrous in the long run, but it's easy to show that economics pays pretty much no attention at all to the long run.

    • by BenJury (977929)
      I know this is /. where everyone is an expert on everything, so I'll buck the trend and ask a honest question; wouldn't desalination be the perfect use for the power supplied by sources such as wind and solar? (Solar especially I guess.) As it appears to the be perfectly suited to the variable power output that these generate?
    • by Lumpy (12016)

      "Back to the topic: the stable system of rain=>aquifer is disrupted to greater or lesser degrees by human activity. That's obvious. The amount of rain remains constant (more or less), which means the amount of water removed from the aquifer is gone. "

      Because all that water is shot into space when we are done with it. it's gone forever....

      Please learn about water and what a watershed is. when you do watershed management and wastewater treatment your FUD does not exist.

      Only in poorly designed systems wh

      • by azadrozny (576352)
        I think that is what he is trying to say, that many of these systems are poorly designed. Water is being removed from an area of "ample" supply to areas with little or no supply. We are attempting to take the same volume of water and spread it out over a larger area, on a global scale.
    • by jamstar7 (694492)
      From a a friendly website [thehindu.com]:

      With these machines, the best water output is obtained at 50 to 70 per cent relative humidity and between 28-42 degrees Celsius. A lesser water output is produced even at 25 per cent relative humidity. Atmospheric water extractor units can be kept anywhere, but need access to fresh air, so they work best when placed by a window, or in the balcony or terrace.

      Sounds to me like they'd be way expensive to run in a desert to me. Desert air rarely hits 50 percent humidity.

  • Most of this planet is covered by water. We simply need to learn how to use it instead of our ground water. There are plenty of reasonable nascent [mit.edu] technologies to provide that ability. There just needs to be an economic incentive to invest. Either it comes earlier through government/corporate sponsorship through policy and investment, or it comes later when ground water becomes economically unviable relative to the alternatives.
  • Just as important (Score:5, Interesting)

    by Grayhand (2610049) on Thursday August 09, 2012 @02:05PM (#40934757)
    We're also polluting ground water at an alarming rate. With more droughts likely ground water is critical to agriculture in the US as well as drinking water. I used to live in LA and a disturbing number of wells were contaminated some even with radioactive waste, none from power plants it was industrial pollution. I'm in Phoenix now and the city is sinking due to the aquifer collapsing as the water is drained. That's capacity that is perminately lost. For every foot of settling that's the city a foot deep in water that's lost. The city has lost 74.5 million acre-feet in the last 70 years to give an idea what Phoenix is facing.
  • Put a price on it (Score:4, Insightful)

    by TheSync (5291) on Thursday August 09, 2012 @02:13PM (#40934981) Journal

    If water has a market price on it, people will use it efficiently.

    Unfortunately, most fresh water supplies are owned by governments that price is far below what a private owner would.

  • The Water Cycle (Score:5, Insightful)

    by Sputnik77 (2697769) on Thursday August 09, 2012 @02:18PM (#40935109)

    The issue, of course, is not "water"; it's freshwater. We have a lot of water on this planet. Generally it can exist in 5 states: seawater, clouds, freshwater (or what I like to call "drinkable land water"), aquifer water (underground water), and snow/ice.

    Around the world aquifers are being depleted. This is a problem because this is one of the most low-energy (and technologically well understood) ways to harvest drinkable land water. And humans are not the only living creatures that use aquifer water! If there is not aquifer water for plants then the plants are completely dependent on rainwater or flowing drinkable land water (rivers, creeks, etc., which are all on their way to becoming seawater again ASAP). This is a precarious state to be in, because on a macro scale, once plants start to be incapable of doing their job (providing ground shade, ecosystems for biomass, improving and retaining soil structure, etc.) a landscape can be on the road to desertification. What does this mean? That means that it's going to stop raining. This has happened, many times, because of human modification of the landscape and has led to the total collapse of multiple powerful civilizations (Jared Diamond's book "Collapse" talks about things like this).

    So what are we supposed to do? Say you are an ecological steward (or policy maker) for a couple hundred acres of land that are on their way to desertification or that are already in a stable, but arid, water cycle. It is easy to think of water in terms of accounting and cash-flow, what is the big picture that will make the landscape profitable and growing in "financial" reserves?

    The big picture is very simple: we are trying to make seawater into permanent land water. The more net land water the Earth has, the more stable and abundant the existence of terrestrial life on this planet, in general, will be.

    (Just remember we're practicing for Mars!)

    How do you do this? The input of "free" water we have (meaning no energy cost for the conversion from seawater to potential land water) is rain. We need to make sure that as much rain as possible stays as underground water... or the *sixth* form of water that I haven't mentioned yet: biomass! There is a lot of water in biomass. And it is a relatively closed loop (meaning that once some water becomes biomass it will stay in the biomass cycle for a long time). Insects, plants and *especially* soil biology are some of the greatest resources we have for storing water on land instead of losing it to the ocean.

    And then of course, we are all technologists, so I think it is also worthwhile suggesting that we should be using renewable energy resources to desalinate saltwater and just pump it back (I don't know if these techniques have even been invented yet) into our aquifers and ecologies.

  • How dare these people hoard this water and remove it from the ecosystem. I'd also like to know where all these vast reservoirs of water are hidden, so we can raid them, and return our water to us. Oh wait - perhaps it's a case of... ahh yes, the USABLE, water, the potable water, the water that can be drunk by people and animals and crops, yeah that's in short supply. And it costs lots of money to turn all that urine - be it human or animal, or all that fertilizer and insecticide contaminated farm run-off -

  • by logicassasin (318009) on Thursday August 09, 2012 @03:08PM (#40936161)

    Seriously... How stupid are we as an "intelligent" species that we don't rely on the massive oceans for our water supplies? Desalinate it, pump it, drink it. I'm really surprised that a multi-billion dollar industry hasn't popped up to make this happen all over to planet.

  • by TheSkepticalOptimist (898384) on Thursday August 09, 2012 @03:10PM (#40936181)

    Thankfully Global Warming will increase evaporation of the oceans causing more cloud cover and rain.

    Of course then the rain comes in the form of Category 5 hurricanes, but farmers will always find something to bitch about why their crops won't grow.

  • Aquifers, pssshhh. The best place to store water is in the body.
  • by mrand (147739) on Thursday August 09, 2012 @03:56PM (#40936931)

    Talk about a waste of water: parts of north Texas (and many other areas obviously), have clay soil which moves in crazy ways if allowed to dry out too much. This moves you house in crazy ways, causing cracks inside and out. The solution? We're encouraged to water our foundations. Huge amounts of water go to this, which results in our lake levels getting low, which puts us into water restrictions where we can't water the lawn.

    Better solutions would be (1) build the foundations to withstand the soil moving, (2) and/or use a different method to keep the soil stable. I'm skipping (3) move elsewhere because DFW is not going to sprout legs and go take over Oklahoma. Unfortunately (2) likely suffers the same problem as the current solution of watering the foundation with soaker hoses: it's basically impossible to do it evenly... so you end up with overmoist areas, and other areas that still move some.

            Marc

The economy depends about as much on economists as the weather does on weather forecasters. -- Jean-Paul Kauffmann

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