Vital Caspian Graphics - Challenges Beyond Caviar



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infrastructure on land and offshore, and destruc- tion of beaches. Several tens of thousands of people in the lowlands of Azerbaijan, Daghestan and the Volga delta had to move. In Azerbaijan alone, dam- age resulting from the rise in sea level is estimated at $2bn. In Kazakhstan the encroaching sea has di- rectly affected some 20,000 square kilometres of land, including the abandoned oil wells. The factors behind the changes in the level of the Caspian are still the focus of debate. Scientists have not ruled out the involvement of tectonic (move- ment of the Earth’s crust below the sea) or geomor- phologic causes (rate of sedimentation). However these would appear to have a minor impact in com- parison to changing climatic factors, combined with the effects of human management of surface water in the Caspian basin. Most of the water flow- ing into the sea comes from coastal rivers. The quantity and quality of this water, particularly that of the Volga, are key variables in the balance of the Caspian. To this must be added rainfall over the sea itself. Water may be also be lost through infiltration into the ground and flow into the Kara Bogaz Gulf, but these factors are insignificant compared with natural evaporation from the sea.



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Figure: Most of the water flowing into the sea comes from coastal rivers – currently supplying 300 to 310 cubic km a year. The Volga alone accounts for 80% of inflow. But it has dropped substantially during the 20th century, declining from about 400 cubic km in the 1920-30s to between 260 cubic km and 270 cubic km at present, due to various climatic factors and human activities such as dams built for hydroelectric energy production. Rainfall over the sea itself is estimated to input 130 cubic km a year. Water loss through infiltration into the ground ac- counts for less than 5 cubic km and flow into the Kara Bogaz Gulf for about 18 cubic km, since the de- struction of the dyke. Natural evaporation from the sea is estimated to produce a loss of between 350 cubic km and 375 cubic km a year. The combination of these water input (around 440 cubic km) and wa- ter loss (around 373 cubic km) estimates suggest that at present the water level in the Caspian Sea should be continuing to rise.

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