ИСТИНА

Climate change together with water use generates changes in the runoff, morphological processes, hydro-ecological conditions, hydrological hazards, etc. Large-scale changes in the runoff of large rivers may affect the regime of the seas, and possibly the processes in the atmosphere. Runoff of the Arctic rivers is particularly prone to the current changes. Long-term fluctuations of annual runoff of such rivers in Russia have been established to contain alternation of periods with different runoff, upward trends. The trend exists due to increased runoff since the late 1980's - mid 1990's. As a result, the average runoff of most of the major rivers increased by 5–10% in 1976–2013, in comparison with 1935–1975. In the rivers of the North European part and Yakutia (except Kolyma), runoff increase is observed in all seasons. The volume of runoff in spring-summer flood increased on average by 2.5–7%. In the Ob and Yenisei, regulated by reservoirs, runoff reduction is observed over the entire period of open channel, in the Kolyma – only in the flood season. All the rivers demonstrates positive winter runoff dynamics, especially Ob (+17.9), Yenisei (+68.4), Lena (+46.3) and Kolyma (+169%). Water consumption in the Arctic rive rbasins does not affect the fluctuations of river inflow in the Arctic seas, whereas the operation of large reservoirs has changed the regime of the rivers in the Kola Peninsula and in Karelia, as well as of the Ob, Yenisei, Lena and Kolyma rivers. The studies were performed due to RSF (No.14-37-0038).