The Aral Sea, Before the Streams Ran Dry

It was once the fourth largest lake in the world. Fed primarily by snowmelt and precipitation from faraway mountains, the Aral Sea supported extensive fishing communities and a temperate oasis in a mostly arid region of Kazakhstan and Uzbekistan.

But in the 1950s and 60s, the government of the Soviet Union launched projects that diverted the region's two major rivers-the Syr Darya and the Amu Darya. The dams, canals, and other water works were built in order to transform the desert into agricultural fields for cotton and other crops. The Aral Sea has been slowly disappearing ever since.

An Argon reconnaissance satellite acquired this image of the Aral Sea on August 22, 1964, before the drop in water levels altered the shoreline and devastated surrounding communities. This inland "Sea of Islands" was home to more than a thousand of them. Vozrozhdeniye, translated as "renaissance" or "rebirth" island, was the home of biological weapons lab in 1966. That island is now part of a peninsula, having been reconnected to the mainland in 2001. (A U.S.-Uzbek team decontaminated the former island in 2002.)

Although irrigation made the desert bloom, it devastated the Aral Sea. As the lake dried up, fisheries and the communities that depended on them collapsed. The increasingly salty water became polluted with fertilizer and pesticides. Blowing, salty dust from the exposed lakebed became a public health hazard and degraded the soil. Croplands had to be flushed with larger and larger volumes of river water. The loss of the moderating influence of the Aral Sea made winters colder and summers hotter and drier.

Fifty years after its water sources were diverted, the Aral Sea is virtually gone. Some estimates suggest that the lake is just 10 percent of its original size.

iPad users can view more images of the Aral Sea by downloading the free NASA Visualization Explorer app. Those images are also available on the Web. For a time-series of the past decade on the Aral Sea, see World of Change: Shrinking Aral Sea on the Earth Observatory.

Source: NASA