Water in Central Asia - Reservoir Monitoring with Radar Altimetry along the Naryn and Syr Darya River

Abstract

Water is a scarce resource in many regions of the world. In all Central Asian countries, the society depends on the availability of water either for hydro-power generation or irrigation. Since the collapse of the Soviet Union and the separation into independent countries, water management became a political issue. Public information on water resources is now unavailable for many lakes and reservoirs and the data exchange about in- and outflow or actual storage capacity between the national hydrometeorological services is limited. While the initial purpose of radar altimetry has been to measure heights over the open ocean, it proved to be a suitable tool for inland water body monitoring and to partially provide data about lake and reservoir level and volume changes. By using this technology, the water heights of the Toktogul, Kairakum and Shardara Reservoirs and Lake Aydarkol have been extracted from 1995 onward. Using additional, external information like remote sensing, the derived heights have been converted into water volume changes, the primary desired information. This study demonstrates that since 2011 the available water volume decreased and the water from the Toktogul and Shardara Reservoirs are overused. Merely the Kairakum Reservoir with a relatively small storage capacity is replenished every year. Likewise, a decrease of water level and volume of Lake Aydarkol is clearly visible