North Aral Sea levels further were due to begin in 2010. The Aral Sea began shrinking in the 1960s, when the Soviet Union decided that the two rivers feeding it, the Amu Darya and the Syr Darya, would be diverted to irrigate cotton and food crops in Kazakhstan and Uzbekistan. In 1986, due to an accelerated loss of water, the Aral Sea split into northern and southern parts; the southern part is the current South Aral Sea. There is now an ongoing effort in Kazakhstan to save and replenish the North Aral Sea. As part of this effort, a dam project was completed
Kazakhstan–Uzbekistan border sparsely populated and traverse largely desert areas, in stark contrast to the western third which is densely populated, containing some of the largest towns in Uzbekistan and southern Kazakhstan. The eastern-most section is mountainous and contains a series of national parks (Sayram-Ugam National Park and Aksu-Zhabagly Nature Reserve in Kazakhstan and Ugam-Chatkal National Park in Uzbekistan. Uzbekistan’s Jizzakh to Sirdaryo railway crosses through Kazakhstan briefly, a legacy of the Soviet era where infrastructure was built without regard to what were then internal boundaries. Russia had conquered Central Asia in the 19th century by annexing the formerly independent Khanates of Kokand