DYNAMICS OF CHANGES IN THE RESOURCES OF THE RIVER FLOW OF THE TOBYL -TORGAI WATER BASIN

The study presents results of assessing the resources of the river flow of the Tobyl - Torgai water management basin. The purpose of the work is to update the previously developed methodology for assessing the annual runoff resources of individual rivers and river runoff resources of the considered water management basin of the Republic of Kazakhstan. The calculations used the average monthly and average annual water discharge of the main rivers. Methods have been developed for determining and restoring the observed and natural runoff, long-term statistical characteristics and its values of probability of exceeding. The equations for determining the water resources of local runoff and water resources coming from other regions are obtained. As a result of the work done on the preliminary calculation, the total surface water resources for the Tobyl – Torgai water management basin, formed in Kazakhstan and coming from the territory of the Russian Federation for a long-term period from 1931 to 2019, on average amount to 1,67 km3, of which: resources formed within Kazakhstan - 1,33 km3, inflow – 0,34 km3. The runoff formed in the territory of the basin, for the disturbed period, relative to the conditionally natural period, decreased by 8%, the runoff coming from the Russian Federation decreased by 12%, and the total water resources by 9%