Amudarya natural flow

The values of natural flow of the Amudarya for every year in the period 1932-2006 have been determined as a sum of annual volumes of natural flow of rivers whose flow reaches the Amudarya stream. The fluctuation of this flow for the 75-year period is given in Table 7. 

The long-term fluctuations of annual volumes of the natural flow of the Amudarya and Syrdarya rivers (water resources), total inflow to the deltas and to the Aral Sea and main annual water levels of the Large and Small Sea are shown in Fig. 6. 

Table 7 Natural flow of the Amudarya and the Syrdarya in the catchment area...

Fig. 6 Total natural flow of the Amudarya and the Syrdarya rivers, inflow to the deltas and to the Aral Sea, water levels in the Aral Sea 1 natural flow 2 and 3 inflow to the deltas and to the Sea 4 water level in the Large Sea 5 water level in the Small Sea...

Variation of natural water resources forming on the Aral Sea watershed are characterized by moderate variability both during the stable period of the Sea and in the last 45 years. The average volume of the Amudarya annual flow in 1932-1960 and 1961-2006 is equal to 70.3 and 69.4 km per year and Cy = 0.15. The analogous Syrdarya flow is 36.2 and 36.8 km per year with Cy = 0.18 and 0.20. 

Herein is described the natural fluctuatirms of the Amudarya and Syrdarya annual flow, the variatiOTis in the river inflow to the deltas and to the Aral Sea that occurred (and are still in progress) as a result of economic activities in the drainage basins of the abovementioned rivers. This process is a crucial factor leading to the shallowing and division of the Aral Sea into two parts the Large Sea and Small Sea. 

The average values (of natural river flow) before and after 1960 coincide practically (101 and 100 km per year), in separate decades of the 75-year period the mean values deviate from the average in the Amudarya by +6% and —12%, in the Syrdarya by 20%, the total water resources of the Aral Sea watershed ... 

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