Long-term and Intraannual Changes in Run-off and Water Levels in the Volga River Delta

V. F. Polonskii and L. P. Ostroumova

Data of the State Observation Network on the water run-off for the whole observation period and on water levels in the delta of the Volga River for the period of regulated run-off regime (1961–2006) are analyzed. Periods of various water content are revealed and the current tendency of long-term run-off changes is established with the help of difference-integral curve of recovered natural annual run-off. Periods of various degree of man’s impact on the run-off, entering the delta of the Volga River, are marked out. The role of irretrievable anthropogenic loss and the influence of run-off regulation on its intraannual distribution are assessed. Regularities of seasonal and long-term water level changes in the delta of the Volga River are revealed. The run-off regulation effect on the intraannual distribution of water levels is assessed. The influence of the water divider on the redistribution of the run-off and water levels in the delta is shown. The effect of the current increase in the Caspian Sea level on the penetration of the backwater into the delta of the Volga River is revealed.