Abstract
Climate change and intensive economic activity in the river basins lead to a restructuring of the water regime. Therefore, this study aims to study the current intra-annual flow distribution in the plain rivers of the Yesil river basin, and to determine the estimated intra-annual distribution for different time periods. The results showed that the decrease in spring runoff is most noticeable in the upper stream of the Yesil river, in the lower stream of the river the spring runoff for the period with the disturbed regime is much higher than the spring runoff for the natural period, there is an increase in seasonal runoff. These findings indicate that as a result of an increase in the coefficient of natural flow regulation, the winter runoff of the Yesil river in the middle stream has increased by two or three times.