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Aral Sea Disappearing
W33dz writes "The BBC is reporting today that the Aral Sea on the border of the former Soviet republics of Uzbekistan and Kazakhstan has lost half its size and 75% of its volume in the last 15 years. The article includes some stunning pictures from both NASA and the new European Space Agency's Envisat satellite.
This seems especially poignant since the US Government is hosting a summit on a proposed International Earth Observation System in Washington this month (BBC article). The meeting is intended to defend much of the Bush Administration's environmental policy and has an amazing guest list filled with the Who's Who of US politics."
I remember seeing stories about this back in 1985, for fuqs sake. Back then, more than half of the sea had already dissapeared because of mismanagement by the Soviet government. I've seen several referneces to it since then. If I recall correctly, that first story was from National Geographic, but that was a looong time ago, so don't hold me to that.
Life is hard, and the world is cruel
Have you ever seen the mouth of the Colorado river near Baja California?
In case you haven't, it's a small stream in a salt-flat. Irrigation projects siphon all of the water out.
The Soviets built massive irrigation projects that drew off of the Volga and other rivers. They were and probaly continue to grow everything from rice to cotton on land that was once parched steppe.
What ends up happening is that since you are spreading billions of cubic feet of water across hundreds or thousands of square miles, the water is used, evaporated (probaly about 75%) or added to the watertable.
Large-scale irrigation causes all sorts of problems. There has been reasearch that hypothised that the added moisture in western states increases the number of thunderstorms and forest fires in the Sierras and Rockies.
Conformity is the jailer of freedom and enemy of growth. -JFK
> The article says that it's more likely to be due to the excessive and wasteful irrigation systems in the area which take water from the rivers that supply the sea.
Doesn't our own Colorado River now disappear in the sand rather than flowing into the Gulf of California as it once did, as a result of so many people tapping its water?
Sheesh, evil *and* a jerk. -- Jade
That, and the flow is very reduced by that lil thing we call the Hoover Dam.
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> Is the irrigation surrounding the rivers taking the water out of the sea's watershed? Seems unlikely. The water would just eventually run back into the river and the sea.
No, much irrigation water is lost to evaporation or to incorporation into the crops.
Remember that crops, like most other life-forms, are mostly water. So for those little seeds turn into railcar-loads of consumables, all that water has to come from somewhere. Irrigation converts flowing water into money.
Also, some kinds of irrigation are extremely wasteful in terms of evaporation. Next time you drive through Texas under a blazing sun and see all those endless acres of rice shoots submerged under 6" of water, ask yourself what the evaporation rate must be. The lakes behind big dams also greatly increase the evaporation rate in a drainage system.
And though what goes up eventually comes down, it might come down half a continent away.
> I mean, how is water leaking from a poorly-built irrigation system different from the rain that falls right next to it and feeds the rivers and the sea to begin with?
In general terms, it is distributed differently, which means it can behave differently w.r.t. evaporation etc.
To make up an illustrative example, suppose you water your lawn to a total of 10" over 10 months, just a little bit every night. Not much runs off, right? But if you get a 10" rain over a couple of days it stacks up faster than it can be absorbed or evaporate, so most of it runs downhill into streams that feed the sea.
Surely that's not precisely what's happening in Central Asia, but it should call attention to the fact that the way water is distributed in space and time can have a big effect on where it ends up.
Sheesh, evil *and* a jerk. -- Jade
How did they make the desert bloom?
The most important innovation in coping with scarce water supplies has been drip irrigation. This method of irrigation applies water and nutrients directly to the root of the plant at a controlled rate. See the drip irrigation pipelines. With traditional irrigation, most of the water evaporates from the ditch and is wasted. Drip irrigation uses less water, works with saline water, requires less fertilizer, and produces more crops.
It was invented in 1965 and has been used all over the world. If those former Soviet republics aren't using it, I suspect the reason is that they don't think they can afford to pay for the equipment. I would say that perhaps they can't afford not to pay for it.
The Aral sea used to be the 4th largest lake in the world. (Quick quiz: name the top 3.) It's now the 12th largest. (Slower quiz: name the intervening 8.)
Not only has it lost half its surface area since 1985, it seems to have lost two thirds since 1960. outlines are interesting. I wonder what it's like on that island that's almost a peninsula.
And while this has little to do with global warming, it's a prescient example of significant human-caused environmental change.
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Having written the oringal post, I need to clarify that I was only pointing out the irony of Mr. Bush hosting an environmental summitt while his government's policies are so obviously ambivalent to the environment. Remember, this is the man who refused to even consider the Kyoto treaty and has opened up MILLIONS of acres of federal land to oil and timber companies. He and many in his administration are ex-oil executives. They made their livelihoods in petrochemicals and are not going to stop now. This is not saying that he is evil. . .it is saying that we need to pay attention to what he does not what he says.
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