Regional patterns in recent trends in sediment yields of Eurasian and Siberian rivers

Abstract

A multipurpose hydrological and statistical analysis of long-term changes in suspended sediment yield has been made for large Russian rivers discharging to the Arctic Ocean. Factors affecting sediment yield formation, e.g., snow pack duration, mean air temperature and mean water discharge, have been analyzed as well. The duration of observations at 13 selected meteorological stations varies from 56 to 113 years and covers the period from 1883 to 1995. The duration of water discharge measurements at 22 hydrological stations varies from 20 to 120 years; measurements were made from 1881 to 2000. The duration of sediment yield observations is shorter (from 1936 to 2000) and varies from 14 to 62 years. The air temperature rise is evident for 10 stations while temperature fall is observed at 3 stations (Dickson Island, Narjan Mar, Kiusiur). These three stations are established in the coastal area of the Arctic Ocean. The most impressive coincidence of trends towards an increase of mean air temperature and mean annual water discharge is observed in the Pechora, Angara, Lena, Aldan, Yana and Indugirka river basins, and in the lower reaches of the Ob and Yenisei river basins. A decrease of water discharge is observed in the Severnaya Dvina river, probably refracting by the effect of cut forest on water availability in the river. The decrease of water discharges in the upper parts of the Ob and Yenisei river basins refracts reservoirs. Changes in suspended sediment yield depend more on man's activity than on climate change. Construction of reservoirs in the upper reaches of the Ob and Yenisei rivers explains the decreased sediment yield. An increase of sediment yield in the Kolyma river basin has been observed due to the gold mining there.