IMPLICATIONS OF YEDOMA BANK OUTCROPS ON THE ARCTIC RIVERS SEDIMENT RUNOFF

• Main Authors: Sergey R. Chalov, Vsevolod M. Moreydo, Kristina N. Prokopeva, Vasily A. Efimov
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Для почтовых отправлений: 199155 Санкт-Петербург, а/я 136, Редакция журнала «Гидросфера. Опасные процессы и явления» / For mail: 199155 St. Petersburg, PO Box 136 Editorial Board of the «Hydrosphere. Hazardous processes and phenomena». 2023
• Subjects: sediment runoff; permafrost; rivers of the Russian Arctic; Duvanny Yar; Kolyma River; acoustic doppler discharge measurement; river channel processes; сток наносов; многолетнемерзлые отложения; реки арктического побережья России; Дуванный Яр; Колыма; допплеровская расходометрия; русловые процессы; Arctic; Arctic Ocean; Indigirka; Kolyma; Yar; Ice; kolyma river
• Online Access: https://hydro-sphere.ru/index.php/hydrosphere/article/view/157; https://doi.org/10.34753/HS.2022.4.2.165

The erosion of permafrost outcrops (yedoma) in the valleys of large Arctic rivers is considered as an important source of suspended sediment and carbon inflow into the natural waters of the Lena, Kolyma, Yana, Indigirka Rivers and further into the Arctic Ocean. In the course of expeditionary studies of the Duvanny Yar Yedoma ice complex, the largest inland outcrop of permafrost, located in the lower reaches of the Kolyma river in 2019–2021 the assessments of its influence on the suspended sediments’ runoff were carried out. To analyze the scale of the turbidity plume from the ice complex and suspended sediments’ balance on the adjacent river reach we used remote sensing methods, and field measurements of turbidity, including using an acoustic Doppler current profiler. An increase of around 20% in the turbidity of the Kolyma River was revealed during the summer low-flows in the reach downstream of the yedoma. The influx of suspended matter due to the melting of the slopes of the ice complex on hot summer days in the emerging network of turbidity streams was estimated at a value of more than 5 kg/s. The effect of thermal destruction of the ice complex is confirmed by a statistically significant relationship between the length of the turbidity plume propagating from Duvanny Yar Yedoma downstream the Kolyma river and the air temperature in this area. Thus, for the first time, quantitative data have been obtained confirming the role of activation of destruction of permafrost in the formation of sediment runoff. Размыв обнажений многолетнемерзлых пород (едома) в бортах долин крупных рек Арктики рассматривается как важный источник поступления взвешенных наносов и углерода в природные воды рек Лена, Колыма, Яна, Индигирка и далее в Северный ледовитый океан. В ходе экспедиционных исследований ледового комплекса едомы Дуванный Яр – крупнейшего внутри­материкового обнажения многолетнемерзлых пород, расположенного в нижнем течении реки Колыма – в период с 2019 по 2021 год проведены оценки его влияния на сток речных ...