DYNAMICS OF SPRING RUNOFF FLUCTUATIONS FOR THE RIVERS OF THE DON AND DNIEPER BASINS IN THE BELGOROD REGION

This article is based on the results of studying the dynamics of long-term fluctuations in the flow of spring floods of the Don and Dnieper river basins in the territory of the Belgorod Region in the period 1968–2018. The object of the study are the maximum water discharges during the spring flood on the Tikhaya Sosna river near the town of Alekseevka (right tributary of the Don river) and Vorskla river near the village of Kozinka (left tributary of the Dnieper river). These rivers were chosen as objects of study due to the fact, that the analysis of the zonal and azonal distribution of runoff over the territory of the Belgorod region allows us to correlate their main characteristics as close in values. The flow dynamics during the flood period for the rivers of the Don and Dnieper basins has a negative trend. The decrease in the river flow of the flood, which is typical for the most part of The Russian plain, occurs mainly under the influence of climatic factors, whose contribution to the decrease in the value of modern runoff is estimated at 80%. The values of the maximum flow rates of the Tykhaya Sosna river and the Vorskla river have pronounced fluctuations over the years depending on meteorological conditions. The main factors influencing them, are: water storage in snow before snowmelt, the intensity of the snowmelt and rainfall period, high water, humidity and the degree of freezing of soils and the presence of an ice crust on the soil surface. Thus, the determining factors affecting the nature of the formation of the maximum costs of the spring flood of the Tikhaya Sosna and Vorskla rivers are the growth of average annual temperatures in the catchment area of these basins. This factor also causes a decrease in the depth of soil freezing. This causes large losses of water for infiltration and leads to a pronounced shortage of river flow.