INFLUENCE OF EOLIAN PROCESSES (WIND FACTOR) ON THE FORMATION AND MORPHOLOGY OF CHANNELS AND FLOODPLAINS OF PLAIN RIVERS

Abstract

The paper provides a generalized description of the influence of the eolian factor on channel processes in mouth areas of large and largest rivers. It is shown that the impact of wind manifests itself, firstly, in a change in the hydraulic structure of the flow, which leads to an increase or decrease in the surface velocity, transverse distortions of water surface, and level derivations due to up and down surges, causing flow backwater or an increase in slopes (level drop). Accordingly, this affects the development of erosion processes in the windward parts of the channel, accumulation of sediments and shallowing of the leeward parts, including channel branches located here, and the strengthening or weakening of bank erosion depending on the ratio of the vectors of the river flow and wind directions. Secondly, when channel sandy side-bars dry out in a low water period, the eolian process causes a deficit of sediments in the leeward part of the channel and their accumulation in the windward part, leading to its shallowing, as well as intensifying erosion of the island heads or accumulation of sediments in their tails. Thirdly, sand transported from the shoals is accumulated on the floodplain along its edge, forming dunes. The formation of dunes creates new conditions for the interaction of channel and floodplain flows during the flood period. Hydroclimatic changes in the late 20th - early 21st centuries contributed to the overgrowth of riverine shallows and dunes on the floodplain. Other forms of influence of eolian processes on river channels are also shown.