Why did the Syr Darya and Amu Darya often fail to reach the Aral Sea by the 1980s?

By the 1980s, the Syr Darya and Amu Darya rivers frequently failed to reach the Aral Sea primarily due to the Soviet Union’s large-scale economic policies, which diverted massive amounts of water from these rivers for agricultural irrigation.123

Beginning in the 1960s, the Soviet government converted vast acreages of pasture and untilled land in Central Asia into irrigated farmlands to support crops such as cotton. As these irrigation projects expanded, the volume of water extracted from the rivers and their tributaries increased significantly, leaving little to no water to reach the sea. By the 1980s, the rivers were so depleted that they virtually dried up before reaching the lake during the summer months. This diversion caused an ecological disaster, leading to the rapid shrinkage of the Aral Sea, increased salinity, and the collapse of local fishing industries.24315