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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."
It's not necessarily a red herring. If the problem is that a large amount of water is evaporating, it wouldn't necessarily make it back into the watershed, but could be lost through airborne transmission.
It probably depends a lot on the air currents and geography of the region. But it's very surprising how much water can be moved through the air.
Irrigation can also move water from one watershed to another (it does not respect watershed boundaries like rivers tend to).
For a really interesting technical analysis on the Aral sea issue, check out this google cache of a paper by the Land and Water Development Division, Food and Agriculture Organization of the United Nations.
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
"ust to clarify and emphasize why this is a big deal: Aral is not really a sea - it's a lake. A sea is a body of water that has direct exit into an ocean. A lake - doesn't connect to any ocean"
huh? It is a sea, primarily because it is salty.
The vast majority of what is called lakes do connect to the ocean: from Lake Superior to Lake Placid.
See dictionary.com concerning sea " A relatively large body of salt water completely or partially enclosed by land." This applies to the Caspian Sea as well. Lake Superior is the largest lake in the world, not the Caspian Sea.
Don't blame Durga. I voted for Centauri.
> 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.
Ceci n'est pas une signature.
I was taught this in school 7 years ago.
Nevada's share of the Colorado River water is 1% set in the 1930's. Nevada has never used its entire allotment -- inefficient irrigation of California's Imperial Valley has been using (wasting) the excess. Nevada (and the Las Vegas Valley) has been experiencing the greatest rate of population increase of anywhere in the US. As Nevada's population grows, the allocation must be changed.
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As for the "wasting of water" by the casinos, there is an aquifer (underground river) running under the Las Vegas strip. The aquifer water is quite hard and not very good for drinking.
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Las Vegas means "The Meadows" and was settled because of its natural springs and underground water, a green oasis in the middle of the Mohave Desert.
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Next time, learn the facts before you start blathering.
There is a lot of American involvement in this problem, but it is actually positive. American RFS (river forecast system) technology that is being utilized to manage the flows of the Columbia, the Mississippi, and other large rivers in the states is being utilized to control the flows of the rivers that are draining the Aral. I read a great article about it in the dead tree version of Wired a while ago, the text is available online here.
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Reading over the original post, the only link made between the lake's drying up and the Bush administration is that its "especially poignant" considering the recent debate over Bush's environmental policy. That's hardly trying to pin the blame on Bush, and people who reach this conclusion are reading far more than what's really there.
The Aral Sea's disappearance serves as warning to how much damage poor farming techniques and industry can do to the environment. As previous posts have stated, water resources are still being squandered at an alarming rate all over the world, and governments and industry should start taking precautions.
This isn't really a trade off between "natural ecosystems" and supporting the population; if the farmers around the Aral Sea are poor now, just wait until the watershed is depleted beyond use.
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.
We are Pentium of Borg. Division is futile. You will be approximated.
A couple of points-- in dammed rivers, the water temperature is warmer, not colder, than in the free flowing river pre-dam (except maybe in the immediate vicinitity of the dam). See this report on the columbia river warming as an example. Dams slow the river, slow==warm. The warmer water has a dramatic effect on the wildlife, just in another direction.
As far as the water loss, the dams make it possible to use the water from the seasonal floods year round for irrigation. If you take water from a large single channel (i.e. a river) and spread it out over a vast area (i.e. millions of acres of farmland), your loss due to evaporation is going to be hellacious. That's why the colorado is a trickle when it hits the sea of cortez, and the area around it is an incredible salt desert.
1984 was supposed to be a warning, not an instruction manual.
There's a long section in the Economist about two weeks ago on the Central Asian Republics with one article that talks about the politics of water there. The Aral Sea is drying up because the irrigations systems of the countries along the rivers that feed it are horrendously inefficient, and because the water system as a whole in the region is poorly managed. Unfortunately, with one megalomaniacal ruler in Turkmenistan, and a whole host of other political solipsists in the region, this isn't likely to change in the near future.