The Loss of the Aral Sea

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Robert Hicks

Contemporary Geographical Issues

The Loss of the Aral Sea

Introduction

There are two major environmental disasters in the recent history of the former Soviet Union; Chernobyl and the Aral Sea.  In 1960 the Aral Sea was the world’s fourth largest lake, but now due to irrigation demands the sea is only half its original size, it’s predicted that by 2010 it will only be a third of its original size, also three times as salty.  This has devastated millions and millions of people who have depended upon the lake for its fish, water, reed beds and transport. Since 1960 the level has decreased from 68,000 km² to a predicted level of 21,058 km² in 2010. The Aral Sea is situated among the deserts of central Asia, in south western Kazakhstan and north western Uzbekistan, near the Caspian Sea.

 

The loss of the Aral Sea is both an amazing and tragic story, which has resulted in many people becoming ill, impoverished or in fact both.  The causes of the loss of volume within this sea are mainly man made and it’s only recently that scientists and doctors are beginning to realise the implications of those earlier actions.  It has now become widely accepted as one of the planets most serious environmental and human tragedies to have ever occurred.

This doesn’t just have implications upon the sea and its surrounding land. The knock on effect of this over the last forty years has seen the people of this region contract various diseases, such as cancer, kidney and liver diseases, arthritic problems, chronic bronchitis as well as a sharp increase in infectious diseases such as typhoid and hepatitis. The maternal and infant death rates have also sharply risen due to the contaminated drinking water. The renowned strong north easterly winds in the region blow the lying salt and chemical residues, from the now arid sea bed across the surrounding areas.

The Vanishing Sea

The Aral Seas tributary rivers are the Syr Darya in the north and the Amu Darya in the south.  These two feeders have been heavily tapped for irrigation purposes in recent decades, mainly for cotton fields and rice paddies. Therefore the seas levels have been dramatically decreasing and not being replenished.  

The irrigation system being used in the 1960’s was not up to date and it required more water per hectare than it would do now.  The long canals being built into the desert were unlined and this resulted in much loss of water and infiltration into the soil, which in turn made the soil became more saline.  These more saline soils were irrigated, which required heavier water volumes to flush away the salts; huge levels of water were used to fill pore spaces in dry soils; large reservoirs were built that needed filling and in turn this increased the evaporation and filtration losses.  Perhaps most surprisingly these new irrigation systems flushed the water straight into the desert instead of back into the rivers or the Aral Sea itself.  The result has been an increasingly large difference between the river inflow and the evaporation sides of the seas balance.  This has accelerated during the last four decades with disastrous effects.  The water has gone but the salt levels or salinity has remained virtually the same, resulting in the salinity level actually rising within the seas because of the lower volume of water and the saline residues being left to settle upon the old and now arid sea bed.

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In 1987, because of the continuing loss of water, the sea then divided into two water bodies; the smaller sea in the north and the larger one in the south.  Each sea was fed by each respective river and because of this they developed their own water balances.  A channel used to exist between the two seas, but in 1992 a dyke was built to stop the water from the smaller sea flowing into the larger one.

The two river deltas have also experienced much change, resulting in changes to the harvesting of the numerous types of reeds ...

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