Swirls of turquoise and cream colored the waters of beautiful Lake Balkhash in late April 2021. The Moderate Resolution Imaging Spectroradiometer (MODIS) on board NASA’s Terra satellite acquired this true-color image of the lake and surrounding countryside on April 28.
Lake Balkhash, spanning about 17,000 square kilometers (6,600 square miles) in southeastern Kazakhstan, is one of Asia’s largest lakes. Despite the lake’s large size, winters are harsh enough to keep the lake frozen over from November through March or early April, when the ice covering rapidly melts over a period of about two weeks. According to satellite imagery, Lake Balkhash was entirely frozen as late as April 2 this year and by April 16 had become ice-free. The swirling colors are primarily suspended sediment, raised from the shallow lake bottom by inflow from river water, melting snow and ice, and near-constant wind in the region.
Roughly 70 to 80 percent of Lake Balkhash’s water comes from the Ili River, which flows into the southeastern section of the lake. As it nears Lake Balkhash, the river expands into a wide delta, which is one of the largest wetlands in Central Asia. The Ili River Delta is a Ramsar Site and recognized as an Important Bird Area (IBA) by BirdLife International. Southern Lake Balkhash and the delta support 10 inland wetland types, with a rich variety of desert flora (427 species) and fauna (345 species), according to the Ramsar description. It also supports many threatened species, including 25 bird, 1 fish and 3 mammal species. The Ili River can be seen in this image coursing to the lake and widening into the deep green delta.
While Balkhash and the Ili Delta currently support an abundance of species, the lake and delta are important fisheries, and the floodplains are heavily used for agriculture and pasture. As the population increases along the long Ili River, which courses across Kazakhstan and China, so does the demand for diverting water for use upstream. Reduction of water flow through the Ili River may threaten both the delta and Lake Balkhash itself in years to come.