Author(s): Oleg F. Vasiliev
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Abstract: Since 1961 the Aral Sea water level has dropped by at least 23 m, its surface area was reduced by 75% and water volume–by 90% . By now it is divided into two unequal parts–Small Aral, supplied by waters of Syr-Darya river and Large Aral, supplied by waters of Amu-Darya river. While water level of the Small Aral has stabilized, the Large Aral continues to dry out. Its continuing degradation has led to formation of two water bodies–West and East parts, connected by a narrow straight. The West part is much deeper than the East one (now their maximum depths are about 45 m and 5 m respectively) and has much smaller surface area. What is especially important from ecological point of view the salinity of Aral waters has increased drastically from 10‰to 90‰since 1961 year (in the west part and even more in the East part). Thus it would be reasonable to concentrate efforts on rehabilitation of the West part by diverting to it a part of Amu-Darya runoff which totally goes to the east part now. The possibility of ecosystem rehabilitation in the deepest part of the Aral Sea has been studied in cooperation with the hydrologists from the Scientific-Information Center of the Interstate Coordination Water Commission of the Central Asia (SIC ICWC) and the hydrobiologists from the Academy of Sciences of Uzbekistan. The modeling of hydrological and hydrophysical processes in water bodies in terms of water mineralization was carried out using the hydrothermodynamical model developed. Possible hydrophysical changes in the deep part of the Aral Sea that might be expected under further sea degradation due to a lack freshwater inflow were estimated. It was shown that under sufficient freshwater transfer from Amu-Darya river water desalination in the sea site under study can be carried out (due to washing out the excess salt by the through-flow to the eastern part). The preliminary calculation shows that in 10-15 years (since freshwater delivery begins) water salinity in the deep part of the sea under study can be reduced up to the environmentally sound level.
Year: 2007