Hydrochemistry and quality of irrigation water in the middle reach of the Syr Darya River in the territory of the Republic of Tajikistan

Authors: NORMATOV, INOM - Tajik National University; GONCHARUK, VLADYSLAV - National Academy Of Sciences Of Ukraine; BOROZOVA, NIGORA - Tajikistan Academy Of Sciences; QURBONALI, KAROMATULLO - Tajik National University; BOBOKALONOV, JAMOLIDDIN - Tajik National University; Anderson, Raymond

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2025
Publication Date: 5/26/2025
Citation: Normatov, I.S., Goncharuk, V.V., Borozova, N., Qurbonali, K., Bobokalonov, J.M., Anderson, R.G. 2025. Hydrochemistry and quality of irrigation water in the middle reach of the Syr Darya River in the territory of the Republic of Tajikistan. Agricultural Water Management. 47:204-211. https://doi.org/10.3103/S1063455X25020079.
DOI: https://doi.org/10.3103/S1063455X25020079

Interpretive Summary: Irrigation is the major consumer of water in Tajikistan, with the Syr Darya River being a primary source. Water availability is expected to decrease in the future while demand is expected to increase with a growing population. This will increase use of return irrigation flows that have higher water salinity. To understand how irrigation water quality may change in the future, it is important to have a good baseline of existing water quality along the Syr Darya River. In this study, we sampled and analyzed water along a transect on the Syr Darya River. Currently, water along the entirety of the Syr Darya River is of adequate quality, but reservoirs may alter water chemistry significantly. These results are of interest to American agricultural and security analysts who are interested in food security in Tajikistan and elsewhere in Central Asia.

Technical Abstract: The main consumer of water in the region is irrigated agriculture. Approximately 97% (93800 million m3/year) are consumed by irrigated agriculture, whereas the other sectors, such as urban utilities and industry consume ~2700 million m3/year. Climatic changes towards warming will not only reduce the available water sources, but also increase the demand for them from agricultural crops, as higher temperatures increase the evaporation rate. It is expected that the total deficit of water in the two main rivers of Central Asia (Syr Darya and Amu Darya) in 2050 will attain 43 km3/year. Moreover, the monthly runoff regimes will essentially change. The total irrigated area of the Syr Darya River basin is 3.4 million ha, and the total use of the natural Syr Darya basin runoff is 30–150%. According to preliminary forecasts, the population in the Central Asia region is expected to grow by 30% to 2050 as compared to 2015 to attain >88 millions of people, so the areas of irrigated lands are planned to expand to solve the problem of food security in each country of this region. By 2025, the area of irrigated lands in the region must attain 11.8 million ha. This means that a lack of water will lead to the extended use of backwater for irrigation. This paper is devoted to studying the dynamics of the chemical composition of the Syr Darya River from the point of crossing the Tajikistan border to the point of passing to the neighboring Uzbekistan territory. Using the results of the chemical analyses of water samples, an attempt to estimate the utilization of water from the Syr Darya River for irrigation has been made. It has been established that, according top the principal indicators, just the content of adsorbed, soluble, and exchangeable sodium in the Syr Darya River fully meets the requirements to irrigation water.