Based on a Fourier analysis of a continuous series of observations (188 years) of the water discharge of the Dnieper River, the study has identified qualitatively distinct periods of the discharge formation and a cyclicity constituent of 12.5 years. By means of the piece regression models, which make it possible to define the contribution of annual sums of precipitation and air temperature to the riverine discharge, the study has established the climatic dependence of the hydrological processes. It has also demonstrated that an essential increase in the annual precipitation sums since the 1940s did not result in an increase in the water volume in the Dnieper. This suggests that the declining sensitivity of the hydrological cycles to the climatic rhythms is the effect of a strong anthropogenic impact. Accordingly, the Dnieper water-volume formation period (1900–1946) optimal for simulation has been defined, which most accurately reflects the impact of natural climatic factors on the riverine discharge. The regression model for the conditions when the water discharge is over 1686 m3/s can be used for prognosis (and retrognosis) of extreme hydrological events in the south of the East-European Plain based on the thickness of the bottom sediments of Lake Saki.
Regional Environmental Issues, 2013, Issue 4, p. 19-25