Assessing the effect of climatic and anthropogenic factors on the annual runoff of large rivers in European Russia and Siberia

Abstract

This study presents the analysis of variations in the annual runoff of large rivers in European Russia (the Volga and Don) and Siberia (the Yenisei and Lena). Two methods used in the study assess the runoff changes under the effect of climate and economic activity. One method uses the data on water management statistics, and another is based on the reconstruction of the natural runoff in recent decades, during which its considerable anthropogenic changes have been taking place. We compare the obtained runoff estimates with the anthropogenically affected runoff over this period and the runoff for the previous (reference) period, in which the anthropogenic impact was negligible. The study shows that, in the period of considerable anthropogenic impact, the annual runoff of the Volga and Don decreased, and that of the Yenisei and Lena increased. In the case of the Volga and Don, the effect of anthropogenic factors is comparable with that of the climatic factors, whereas in the Yenisei and Lena, the former is much less than the latter. Both impacts on the runoff in the Volga and Don are directed towards its decrease. In the Yenisei and Lena, the effects of these factors were differently directed with the predominant effect of climatic factors.