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Lake Location:
Russia | Lake Area:
24,904 sq. miles | Lake Depth:
220 feet |
Aral Sea
The Aral Sea is a landlocked endorheic sea in Central Asia; it lies between Kazakhstan in the north and Karakalpakstan, an autonomous region of Uzbekistan, in the south. The name roughly translates as "Sea of Islands", referring to more than 1,000 islands of one hectare or more that dotted its waters.
Since the 1960s the Aral Sea has been shrinking, as the rivers that feed it (the Amu Darya and the Syr Darya) were diverted by the then Soviet Union for irrigation. The Aral Sea is heavily polluted, largely as the result of weapons testing, industrial projects, and fertilizer runoff.
The major ecological problem is that diversion of the Amu Darya and Syr Darya rivers for irrigation has shrunk the Aral Sea dramatically; the Aral Sea has been drying up for about 50 years. This has brought about a number of ecological and economic problems for the sea and the area. One of the greatest misuses of the Aral is that for the past forty years it has been a dumping ground for raw sewage runoff, resulting in the extermination of many native fish.
The sea's surface area shrank by approximately 60%, and its volume by 80%. In 1960, the Aral Sea was the world's fourth-largest lake, with an area of approximately 68,000 km2 and a volume of 1100 km3; by 1998, it had dropped to 28,687 km2, and eighth-largest. Over the same time period its salinity has increased from about 10 g/l to about 45 g/l. As of 2004, the Aral Sea's surface area was only 17,160 km2, 25% of its original size, and still contracting.
Even the recently discovered inflow of submarine groundwater discharge into the Aral Sea will not in itself be able to stop the desiccation. This inflow of about 4 billion cubic metres per year is larger than previously estimated. This groundwater would originate in the Pamirs and Tian Shan mountains and seek its way through geological layers to a fracture zone at the bottom of the Aral Sea.
In 1987, the continuing shrinkage split the lake into two separate bodies of water, the North Aral Sea (the Lesser Sea, or Small Aral Sea) and the South Aral Sea (the Greater Sea, or Large Aral Sea); an artificial channel was dug to connect them, but that connection was gone by 1999 as the two seas continued to shrink. In 2003, the South Aral further divided into eastern and western basins; the evaporation of the North Aral has since been partially reversed.
As of summer 2003, the South Aral Sea was vanishing faster than predicted. In the deepest parts of the sea, the bottom waters are saltier than the top, and not mixing. Thus, only the top of the sea is heated in the summer, and it evaporates faster than would otherwise be expected. Based on the recent data, the western part of the South Aral Sea is expected to be gone within 15 years; the eastern part could last indefinitely.
Possible solutions
Many different solutions to the different problems have been suggested over the years, ranging in feasibility and cost, including the following:
- Improving the quality of irrigation canals;
- Installing desalination plants;
- Charging farmers to use the water from the rivers;
- Using alternative cotton species that require less water;
- Using fewer chemicals on the cotton
- Redirecting water from the Volga, Ob and Irtysh rivers. This would restore the Aral Sea to its former size in 20-30 years at a cost of $30-50 billion.
In January 1994, the countries of Kazakhstan, Uzbekistan, Turkmenistan, Tajikistan and Kyrgyzstan signed a deal to pledge 1% of their budgets to helping the sea recover. By 2006, the World Bank's restoration projects especially in the North Aral were giving rise to some unexpected, tentative relief in what had been an extremely pessimistic picture. (Source)
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