Creation of System “Delta-Sea” as a Basis of Ecosystem Approach to the Management of Large Aral Sea’s Coastal Zone

Abstract

Aral Sea region is referred to be the ecological disaster zone of global scale (Gerasimov et al., 1983; Mikhlin, 1988, 2007). Intensive irrigation development in Amu Darya and Syr Darya rivers’ basins (RBs) in 1970–1980s have caused sharp decrease of sea level, and hope for water reception from outside (from Siberian rivers) was not justified. (Amu Darya and Syr Darya are two great rivers of Central Asia, which run into the Aral Sea.) In 1911–1960 average multiyear river flow of the Aral Sea Basin equalled about 117 km³/year, including Amu Darya RB — 80 km³, and Syr Darya RB — 37 km³. During this period, sea received the water in volume 56 km³/year, on average, including 42 km³ from Amu Darya River and 14 km³ from Syr Darya River. In the subsequent period a sharp decrease of inflow to the sea was observed. So, in 1961–1970 inflow to the sea was reduced to 30.0 km³/year, 1971–1980 — 16.7 km³, 1981–1990 — 3.45 km³, 1991–1999 — 7.55 km³/year, on average. In 1980–2001 years Amu Darya and Syr Darya rivers’ flow did not reach Aral Sea. Accordingly, sea level has decreased from 53 m (beginning of 1960s) up to 41 m (1985–1986), and 30 m (2001). Therefore, since 1960 the Aral Sea coastal line has receded to 130 km. In 1980s Aral Sea was divided into the Large and Small Aral Seas (LAS and SAS). Now the LAS was divided in two parts i.e. Western and East Aral Seas (WAS and EAS). Dynamics of the basic parameters of the Aral Sea for 1960–2000 is given in Tables 1 and 2.