The accumulated precipitation in the form of snow and ice in mountains is the sources of feed for the most of the rivers that form the runoff of the Amudarya and the Syrdarya, flowing into the Aral Sea. The runoff of the Amudarya is founded by drainage basins of its tributaries such as the Pyandje, Vahsh, Kunduz, Kafirnighan, Surhandarya, Sherabad rivers, and also the rivers of Turkmenistan and Afghanistan. The runoff of the Syrdarya is founded by drainage basins of the Narin, Karadarya, Chirchic, Ahangaran, Keles, Aris rivers and the rivers of the Fergana valley. The average annual runoff forming within the republic is 10 cubic km , and from the adjacent territories - 89 cubic km.
No far ago the Aral Sea was one of the largest inland lakes in the world. Its balance is determined by runoff from the Amudarya and the Syrdarya, groundwater, precipitation and evaporation. In conditions of balanced water regime of the Aral Sea the annual inflow from the Amudarya and the Syrdarya reaches 56 cubic km, precipitations - 9,1 cubic km, groundwater - 1 cubic km, and evaporation - 66,1 cubic km.
Source:
1. Shultz V.L. Rivers of the Central Asia. Gidrometeoizdat, 1965.
2. National report. Environment protection and use of the natural recources,Tashkent "Ukituvchi", 1993.
