Estimation of the sediment yield from the drainage basin of the Lena River

The assessment of sediment runoff from the territory of two key catchments located in the Lena River basin was carried out within the framework of this study. The Lena River basin is located within the Russian Federation and belongs to the Arctic catchment. The study sites are located within very different natural conditions. The first section of the Chara river is located within the mountainous part of the catchment with coordinates of the section are 57° n.l, 118° e.l. The second site is located in the area of ​​Yakutsk, in the flat part of the Lena river basin with coordinates of the site are 62° n.l., 131° e.l.

The assessment of sediment yield from the catchment area was performed using the WaTEM / Sedem. The following values ​​of sediment runoff entering the catchment of the Chara and rivers in the area of ​​Yakutsk were obtained. The catchment area of ​​the Chara River is characterized by an average long-term modulus of sediment equal to 149 t / km² per year (1961-1984), 172 t / km² per year (1985-2020). The obtained values ​​do not agree with the data on sediment runoff measured in the river at the hydrographic station in the village of Chara. The sediment runoff measured in the river decreased from 28 to 15 t / km² per year (Magritsky, Banshchikov, 2021). Comparison of data from modeling sediment runoff from the catchment area and measured data at Tabaga station in the area of Yakutsk indicates a greater consistency of the results. The modeling data give an estimate of 3.5 t / km2 per year, and the measurement data - 5 t / km² 1980-x (1961 - 1984) and 9 t / km² per year (1956-2019).

 Funding: The work was supported by the Russian Science Foundation (project № 21-17-00181)