Estimation of transformation of flood runoff hydrographs and water stages in the Lower Volga and its delta

A system of hydrographs’ quantitative parameters for the flood discharges and stages in the Lower Volga River and its delta was developed. Water releases from the Volzhskaya Hydropower Plant and floods in the upper sections of the Volga River delta caused by those releases were identified and grouped in accordance with their water content; their parameters were computed for the entire period of the runoff managing (i.e., since 1961). In addition, parameters of typical hydrographs, which were averaged for different categories of water content, were computed and their graphical models were plotted. Quantitative and qualitative estimates of changes in shape of the discharge hydrographs in the Lower Volga were obtained for different flood types, while for the water stage hydrographs in the Lower Volga and its delta, only quantitative estimation was carried out.