Abstract
The results of chemical analyses of the Vakhsh river and its tributaries and the calculations of the main criteria for the water applicability for irrigation purposes are presented: the proportion of sodium cations capable of absorption, dissolution, ion exchange, and the proportion of magnesium. It was found that the waters of the Vakhsh river and its tributaries (Kyzylsu, Muksu, Obikhingou and Surkhob) are favorable for irrigation of agricultural land. On the values of the magnesium cations ratio to calcium cations the Vakhsh river and tributaries water correspond to the first class of «soft waters». It is shown that due to the surface and underground water exchange, underground water reservoirs are enriched by cations of alkaline and alkaline earth elements. The underground water reservoirs of the Vakhsh tributaries basin on the water quality terms are also suitable for irrigation purposes.