Quantifying the actual sediment load flux into Lake Baikal: A case study of the main tributary - The Selenga River (Russia)

The significant reduction of sediment load flux into Lake Baikal from its main tributary - the Selenga River began in the mid-1970s, and can be explained by climate change and socio-economic activities. Integrated analysis was done of changes in hydro-meteorological parameters (water discharge, sediment load, air temperature, and precipitation) and their tendencies over periods of 1946-1975 (baseline) and 1976-2017 (warming). Changes in natural processes and human activity were negligible during the baseline period. In the warming period, against the background of an increase in temperature, the water discharge had a slight decreasing trend (-13%) whereas the sediment load has significantly decreased (-53%) these are consist with the precipitation change (-9.4%). Analysis of hydro-climatic data using statistical methods showed that in the warming period the greatest reduction in river sediment runoff occurred in the interval 1996-2017. In this period the sediment load was 768 x 10(3) t/yr, which is less than the average value during the warming period - 1048 x 10(3) t/yr. Considering sedimentation in the Selenga River delta, the actual sediment load flux from the Selenga River into Lake Baikal amounted to 515 x 10(3) t/yr, which is three times less than the average multiyear value 1535 x 10(3) t/yr for observation period (1946-2017). (C) 2021 International Research and Training Centre on Erosion and Sedimentation/the World Association for Sedimentation and Erosion Research. Published by Elsevier B.V. All rights reserved.

Automated summary

The sediment load flux from the Selenga River into Lake Baikal has significantly reduced since the mid-1970s, which can be attributed to climate change and socio-economic activities. The analysis reveals that during the warming period, there was a slight decrease in water discharge and a significant decrease in sediment load, which is consistent with the change in precipitation. The greatest reduction in sediment runoff from the river occurred between 1996 and 2017. This reduction has important implications for the ecosystem and water quality of Lake Baikal.