In
the 1960s, the Soviet Union undertook a major water diversion project on the
arid plains of Kazakhstan, Uzbekistan, and Turkmenistan. The region’s two major
rivers, fed by snowmelt and precipitation in faraway mountains, were used to
transform the desert into farms for cotton and other crops. Before the project,
the Syr Darya and the Amu Darya rivers flowed down from the mountains, cut
northwest through the Kyzylkum Desert, and finally pooled together in the
lowest part of the basin. The lake they made, the Aral Sea, was once the fourth
largest in the world.
Although
irrigation made the desert bloom, it devastated the Aral Sea. This series of
images from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s
Terra satellite documents the changes. At the start of the series in 2000, the
lake was already a fraction of its 1960 extent (black line). The Northern Aral
Sea (sometimes called the Small Aral Sea) had separated from the Southern (Large)
Aral Sea. The Southern Aral Sea had split into eastern and western lobes that
remained tenuously connected at both ends.
By
2001, the southern connection had been severed, and the shallower eastern part
retreated rapidly over the next several years. Especially large retreats in the
eastern lobe of the Southern Sea appear to have occurred between 2005 and 2009,
when drought limited and then cut off the flow of the Amu Darya. Water levels
then fluctuated annually between 2009 and 2014 in alternately dry and wet
years. Dry conditions in 2014 caused the Southern Sea’s eastern lobe to
completely dry up for the first time in modern times.
As
the lake dried up, fisheries and the communities that depended on them
collapsed. The increasingly salty water became polluted with fertilizer and
pesticides. The blowing dust from the exposed lakebed, contaminated with
agricultural chemicals, became a public health hazard. The salty dust blew off
the lakebed and settled onto fields, degrading the soil. Croplands had to be flushed
with larger and larger volumes of river water. The loss of the moderating
influence of such a large body of water made winters colder and summers hotter
and drier.
In
a last-ditch effort to save some of the lake, Kazakhstan built a dam between
the northern and southern parts of the Aral Sea. Completed in 2005, the dam was
basically a death sentence for the southern Aral Sea, which was judged to be
beyond saving. All of the water flowing into the desert basin from the Syr
Darya now stays in the Northern Aral Sea. Between 2005 and 2006, the water
levels in that part of the lake rebounded significantly and very small
increases are visible throughout the rest of the time period. The differences
in water color are due to changes in sediment.
