LOCATED IN eastern KAZAKHSTAN, Lake Balkhash is the world's sixteenth-largest lake, covering a surface area of about 7,000 square mi (18,000 square km); however, its size is being reduced by overutilization of streams that flow into the lake. Closed, with no outflow, Lake Balkhash, like the ARAL SEA at the opposite end of Kazakhstan, has suffered from misuse of water resources. Both have been slowly shrinking for years in area, depth, and volume. Now, in independent Kazakhstan, the lake has fared little better than it did in Soviet times.
Within a complex mountainous drainage basin, Lake Balkhash is fed mainly by the Ili River, as well as by the Karatal and Aqsu rivers. While these streams have long been used for a variety of needs in this arid and seasonally cold watershed, in recent decades developments have caused reductions of stream flow into Lake Balkhash. One major withdrawal has been the filling of the Kapchagay (Qapshaghay) Reservoir on the Ili River. More broadly, the growing population in western CHINA has placed additional demands on the headwaters of the Ili River. The mountainous location of the source of the Ili River in western China instead of in eastern Kazakhstan has significantly complicated any potential resolution of environmental woes of Lake Balkhash. This negative externality requiring international negotiations over water flows includes about 15 percent of the watershed for Lake Balkhash.
With these and other concerns about water supply, officials at the United Nations Development Program have issued warnings that the lake could dry up to an extent similar to that of the Aral Sea. Kazakh statistics indicate that a surface area reduction occurred by 2003.
On the Kazakh side of the border, water from the lake and its tributaries long has been withdrawn for municipal, agricultural, and industrial uses. Irrigation in Kazakhstan continues to be prominent in this rural region. Ironically, agricultural production has fallen significantly since the 1990s, but water usage remains at the same levels because of artificially set nominal prices for water.
A major example of industrial use has been the copper mining, smelting, and refining industries in and near the city of Balkhash, along the northern shores of the lake. The third-largest copper producer of the Soviet Union, the city, through its smelting plants, annually emits some 80,000 tons of particulate matter. This effluent, in addition to the natural sediments carried in the river inflows, has caused considerable sedimentation of the lake, which now is separated into eastern and western parts, divided by a sandbar. The western portion of the lake is slightly larger by surface area (58 percent), but shallower (only 46 percent of volume).
While Lake Balkhash generally is considered a saline lake, though mildly so, the eastern portion of the lake has increased in salinity more than the western side. With greater freshwater inputs to the west and with limited exchange of water between sides, the eastern waters have progressively differed more and more from the western portion. Environmental damage to the lake's waters also has reduced fish catch, so that amelioration of the problem was sought by introduction of exotic fish species from other parts of the former Soviet Union. This tactic has had mixed results.