Downstream hydrochemistry and irrigation water quality of the Syr Darya, Aral Sea Basin, South Kazakhstan
Satybaldiyev B. Ismailov B. Nurpeisov N. Kenges K. Snow D.D. Malakar A. Taukebayev O. Uralbekov B.
1 May 2023IWA Publishing
Water Supply
2023#23Issue 52119 - 2134 pp.
New hydrochemical measurements from the Syr Darya provide insights into factors affecting the composition and quality of a major freshwater source replenishing the Aral Sea. This river is heavily used for power and irrigation and crosses territories of four Central Asia republics. It is intensely managed, draining several major tributaries, many reservoirs, and numerous irrigation distribution systems and canals. Analysis of seasonal changes in dissolved ion concentrations using geochemical diagrams, elemental ratios, statistical correlation, and equilibrium modeling allowed the characterization of mineral formation processes that control the dissolved chemical composition. Measured water hydrochemistry and composition type differs substantially from previous reports from the upper reaches of the Syr Darya in Kyrgyzstan. Element ratios, statistical correlation, and the presence of NO3- and NO2- suggest that the downstream trend of increasing total dissolved solids (TDS) from Zhetysay city to the Aral Sea in June is controlled by evaporation–crystallization processes, which contribute to the river dissolved load through soil runoff and return irrigation waters following leaching of secondary salts. Downstream sample composition during the growing season shows significant changes in magnesium-to-calcium ratios in the river water. Elevated magnesium levels in Syr Darya waters may pose a problem to sustainable uses for irrigation.
hydrochemistry , irrigation , magnesium , major ions , sodicity , water quality
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Center of Physical-Chemical Methods of Research and Analysis, Al-Farabi Kazakh National University, Almaty, Kazakhstan
LLP EcoRadSM, Almaty, Kazakhstan
School of Natural Resources, Nebraska Water Center, Part of the Robert B. Daugherty Water for Food Global Institute, University of Nebraska, Lincoln, 68583-0844, NE, United States
Department of Cartography and Geoinformatics, Al-Farabi Kazakh National University, Almaty, Kazakhstan
Cluster of Engineering and High Technology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
Center of Physical-Chemical Methods of Research and Analysis
LLP EcoRadSM
School of Natural Resources
Department of Cartography and Geoinformatics
Cluster of Engineering and High Technology
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