Central Asia's second-largest lake, Balkhash may be drying out, as announced by the United Nations in January 2004. The lake lies in Eastern Kazakhstan and is fed principally by the Ili River, but has no outlet. Experts believe that in becoming more shallow and saline, Balkhash may have repercussions comparable to the tragedy of the Aral Sea.
Lake Balkhash, in Kazakhstan, is the largest moderately saline lake of Central Asia. The lake has a surface area of over 16 000 km2, a length of 600 km and its width varies from five to 70 km. Its drainage basin of approximately 413.000 km2 is situated in southeastern Kazakhstan (85%) and northwestern China (15%). The western half of the Lake is freshwater, while the eastern half is salt water. The average depth of the lake is six metres, though its maximum depth reaches 26 metres. Lake Balkhash is usually frozen from November through March.
North of Lake Balkhash are the southern semi-arid Kazakh Uplands, and south, the Saryesik-Atryan Desert. Three major streams feed Lake Balkhash, all from the south or southeast: the Ili River, with a large delta, the Karatal River, with a smaller delta, and the Aqsu River. Since 1960, water levels in Lake Balkhash have been declining, mostly due to evaporation and increased water usage for irrigation along the Ili and Karatal Rivers.
The Ili River flows from northwestern China's Xinjiang province to Kazakhstan, through the city of Almaty, to Lake Balkhash. Cotton production that consumes large amount of water is well-developed in the Xinjiang region, that currently uses 40% of the region's arable land.
Lake Balkhash plays a significant role in maintaining the natural and climatic balance in the region. The gradual degradation of the lake ecosystems is being hastened by the construction of hydroelectric installations in China to the southeast.
The population of the basin is over 3.2 million people, most of them in the Ili basin, including the Almaty region.
Decrease of the Lake's Level
The western part of the lake is very shallow, and thus a decrease in the inflow of the Ili River has repercussions for the Lake's level. Several differences between the satellite images of 1972 and 2001 can be described.
The most obvious is the near-complete drying out of the reservoir on the southern part of Lake Balkhash. Only a small part of it remains, that is likely to disappear in the near future unless remedial action is taken. From 1972 to 2001, the southern part of the Lake's surface decreased by ap-proximately 15.000 ha.
Another sign of the disminish-ing water level is the newly-formed island (next to the southeastern bank of the Lake). In other parts of the lake, some islands have seen their surface area enlarging.
On these images, the drying out of many wetlands and ponds can be observed on the east bank of the Lake. Another part of the Ili River delta is visible on the upper left part of the image. The delta's vegetation is gaining ground on the lake, and the upstream part has seen the vegetation completely dried out, leaving bare soil.
The Ili River
The Ili River, which provides 80 % of the water flowing into Lake Balkhash, has its source in China in the northern ranges of the Tien Shan, and is 1 400 km long. The river flows through the sandy Sarysesik-Atyran Desert on its way to Lake Balkhash.
Flowing into Lake Balkhash it forms a delta of 8 000 km2, supporting the ecological balance of the ecosystem, which consititutes the habitat of wild animals and birds.
The Kapchagai reservoir, built along the middle reaches of the Ili River in 1966, and used for water storage since 1970, allowed the development of irrigation agriculture along the lower reaches of the river. The reservoir serves for hydroelectric power generation and for irrigation water supply. Since its inauguration, water use has increased along the lower reaches of the Ili River. The decrease in the River's inflow deeply affected the Lake's environment and water system.
The Chinese government is settling many people from central China in the western Xinjiang Uyghur Autonomous Region. This population will need new industrial facilities and agriculture complexes, that will also consume water and thus put pressure on the riverine ecosystem.
The Karatal River
The Karatal River is also one ot the most important tributaries of Lake Balkhash. The river rises in the Dzungarsk-Alatau Mountains, near the border with China. Its length is approximatively 390 km and its catchment area 19 100 km2. Because of the irrigation in the river valley, little water reaches Lake Balkhash. The River, after travaersing the Sary-Ishikotrau Desert, finishes its course in a wide delta of a hundred metres width, house for large sheat-fish and birds.
Lake Balkhash Pollution
The Balkhash system is heavily polluted by non-ferrous metallurgy and agriculture. The main water polluters are industrial, mining and refinery enterprises, animal farms and irrigated farming. The Balkhash copper smelter heavily pollutes lake Balkhash with heavy metals and sulphites. Municipal wastewater treatment facilities are frequently overloaded or out of order.
The over-exploitation of the Ili River contributed to an increase in the salinity of water in the west of the country.
Although, Kazakhstan has strengthened its water management efforts in recent years, experts beleive that with the population growth curve, agriculture, industry and urbanization in the western areas of China, there is going to be more water use in the future, and therefore urgent measure have to be taken.
Authors: Guillaume Le Sourd, Diana Rizzolio (2004)
Assessment based on Landsat Satellite Images
Sources: UNDP, UNECE, Regional Environment Centre for Central Asia.