Lake Balkhash, spanning about 17,000 square kilometers (6,600 square miles) across southeastern Kazakhstan, is the largest lake in Central Asia and fifteenth largest in the world. Between 70 to 80 percent of the lake’s water comes from the Ili River, which enters Balkhash along the southeastern shoreline. The river’s delta, visible as a large mostly-green V, is one of the largest wetlands in Central Asia. The delta covers about 817,000 hectares (3,154 square miles), containing reedbed, river channels, scrub, lakes, and desert, and hosts colonies of breeding birds, including endangered species such as the Dalmatian Pelican and White-headed Ducks.
As NASA’s Aqua satellite passed over Kazakhstan on July 15, 2019, the Moderate Resolution Imaging Spectroradiometer (MODIS) on board acquired a true-color image of the crescent-shaped Lake Balkhash.
The western section of the lake appears a milky blue, while eastern waters are clear blue. The color difference is most likely due to sediments suspended in the water in the west. The lake is very shallow, so the near-constant winds can stir up sediment from the lowest parts, adding a milky sheen to the water. There’s also a difference in salinity between to two ends of the lake. The water in the western part of the lake is almost fresh, but the eastern side of the basin is brackish to salty.