Pokrovsko-Yakutsky Reach of the Lena River: Transformation of Complex Conjugated Channel, Recent Deformations and Management of Channel Changes

• Published in: Izvestiya Rossiiskoi akademii nauk. Seriya geograficheskaya
• Main Authors: R. S. Chalov, A. S. Zavadsky, D. V. Botavi, P. P. Golovle, E. A. Morozova, V. V. Surkov, Р. С. Чалов, А. С. Завадcкий, Д. В. Ботавин, П. П. Головлев, Е. А. Морозова, В. В. Сурков
• Other Authors: The study was carried out according to the scientific research plan of the Department of Land Hydrology and Makkaveev Research Laboratory of Soil Erosion and Fluvial Processes, within the projects of the Russian Science Foundation (field observations and analysis of branching, no. 18-17-00086, environmental impact assessment, no. 14-17-00155) and the Russian Foundation for Basic Research (prediction of catastrophic manifestations, no. 18-05-00487), as well as within the framework of state contracts and contracts with the Academy of Sciences of the Republic of Sakha (Yakutia), Federal Agency for Maritime and River Transport and Lena River basin inland waterways administration., Работа выполнена по НИР (ГЗ) кафедры гидрологии суши и научно-исследовательской лаборатории эрозии почв и русловых процессов МГУ им. М.В. Ломоносова, проектам РНФ (18-17-00086 – натурные исследования и анализ разветвлений, 14-17-00155 – оценка экологических последствий) и РФФИ (18-05-00487 – прогнозирование катастрофических проявлений), госконтрактам и договорам с Академией наук Республики Саха (Якутия), Росморречфлотом и Администрацией “Ленводпути”.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Izvestiya Rossiiskoi Akademii Nauk. Seriya Geograficheskaya 2019
• Subjects: управление; channel transformation; parallel-sleeve branching; permafrost; deformation; erosion of banks; accumulation of sediments; control; трансформация русла; параллельно-рукавные разветвления; мерзлота; деформации; размывы берегов; аккумуляция наносов; lena river
• Online Access: https://izvestia.igras.ru/jour/article/view/972; https://doi.org/10.31857/S2587-55662019683-96

The article considers the conditions of conjugate branches’ system transformation into parallel-branched channel, which are the most complex morphologically (by the mode of deformations and management) on the example of the Pokrovsko-Yakutsky section of the middle Lena River basin in the 21st century. It may arise from the general increase in the Lena River’s water content and thawing frozen soils (composing shallow waters and near-shore shallows), as well as from the development of sleeves with unstable channel. At the same time, local conditions encouraged to the formation of a complex single (three-arm) branching at the beginning of the expansion of the valley bottom and the channel below city of Pokrovsk, the preservation of a straight unbranched channel upstream, the channel of the same type below the Tabaga Cape and alternating one-side branching at the end of the site. The modern riverbed reformation after the changes occurred consists in the transgressive displacement of floodplainisland massifs, intensive banks’ erosion, and the sediment accumulation zones’ formation. This has led to the significant complications in the river water usage (including water intake and port water areas’ sedimentation, creation an unfavorable environment in the port approaches area, berths and industrial infrastructure) and to creation of an emergency situation at the coastal infrastructure facilities. The revealed channel deformations’ regularities on the basis of long-term and modern researches and hydrodynamic modeling allowed to develop and justify the complex scheme of channel processes’ management, which implementation will allow to reduce or neutralize their adverse or dangerous manifestations. В статье на примере Покровско-Якутского участка Средней Лены рассматриваются условия трансформации в XX в. единой системы сопряженных разветвлений в сложные по режиму деформаций и управлению русловыми процессами параллельно-рукавные разветвления. Показано, что это связано с общим увеличением водности р. Лены и оттаиванием ...