Assessment of the Existing and Future Needs for River Water in the Kazakhstan Sector of the Ural River

Based on stationary and expeditionary hydrological data and information about the water management complex and volumes of water use, we have calculated for the first time the minimum permissible, average, and optimal hydrographs (in monthly increments) of the influx of Ural waters from Russia to the West Kazakhstan and Atyrau regions, which would not limit the functioning of the main participants of the Kazakhstan water management complex, would not deteriorate the quality of life of the population and existence conditions for aquatic and near-water biocenoses, and would preserve the river as a hydrographic object. The resulting hydrographs summarize (1) the values of current and future water consumption in the cities of Uralsk and Atyrau and numerous rural settlements, as well as water intake by irrigation and water supply canals, including the Kushum Canal; (2) the needs of river navigation for controlling depths and continuous navigation from May to October; (3) the environmental flow necessary for the reproduction of sturgeon fish species and the preservation of the bioproductivity and biodiversity of floodplain ecosystems. The latter element required nonstandard solutions, including those based on the existing domestic approaches to determining critical and optimal values (with respect to floodplain-channel ecosystems) values. Another and completely new result of this research is analysis of the long-term dynamics of maximum and minimum levels in the lower reaches of the Ural River and the frequency, duration, and depth of floodplain flooding.