Geography of Kazakhstan the water in Kazakhstan is polluted by industrial effluents, pesticide and fertilizer residue, and, in some places, radioactive elements. The most visible damage has been to the Aral Sea, which as recently as the 1970s was larger than any of the Great Lakes of North America save Lake Superior. The sea began to shrink rapidly when sharply increased irrigation and other demands on the only significant tributaries, the Syr Darya and the Amu Darya (the latter reaching the Aral from neighboring Uzbekistan), all but eliminated inflow. During the Soviet Era, Kazakhstan received water from Tajikistan and Kyrgyzstan, and Uzbekistan, Turkmenistan,
Geography of Uzbekistan ridges on the periphery of the valley. Water resources, which are unevenly distributed, are in short supply in most of Uzbekistan. The vast plains that occupy two-thirds of Uzbekistan's territory have little water, and there are few lakes. The two largest rivers feeding Uzbekistan are the Amu Darya and the Syr Darya, which originate in the mountains of Tajikistan and Kyrgyzstan, respectively. These rivers form the two main river basins of Central Asia; they are used primarily for irrigation, and several artificial canals have been built to expand the supply of arable land in the Fergana Valley and elsewhere. During