On the contribution of climatic and anthropogenic factors to changes in the flow of large rivers of the Russian plain and Siberia

Changes of annual and seasonal flow of Volga, Don, Yenisei and Lena are estimated by two methods. One of them is to restore the natural flow of recent decades, during which there were observed its significant anthropogenic changes. For these purposes, we used data on the runoff of rivers (tributaries of the considered rivers and their upper parts), the water regime of which is relatively weakly changed by the anthropogenic impact. Another uses the data of water management statistics. Subsequently, the data on the naturalized river flow were compared with the anthropogenic-modified runoff for this and for the previous base period, when anthropogenic impact can be neglected. It is shown that climatic and anthropogenic factors perform either unidirectionally, increasing or decreasing the flow, or in opposite directions. Moreover, the impact of anthropogenic factors, mainly of reservoirs and water consumption, is of the same scale as the influence of climatic factors, while in many cases exceeds it.