Modeling the Input of Suspended Solids’ Runoff from the River Don into Taganrog Bay in the Azov Sea

Abstract

Using a mathematical model of wind currents, supplemented by a module for the suspended sediment silt transfer and sedimentation, the spatiotemporal features of the accumulation of river sediments in the Don avandelta in different wind conditions (east and west wind surges and light winds of variable directions) are identified. It is shown that the exposure to an east wind of 6 to 8 m/s during the entire settlement period (6–7 calendar days) makes the water movement in Taganrog Bay progressive, and under the action of a southwest wind of the same speed, the pattern of current lines changes over time from progressive movements on the first day to the formation of two circulation zones in the area of the city of Taganrog and in the central part of the Don avandelta. It is also shown that the fields of suspended matter concentration are similar for different fractions of solids. Under the action of the east wind, they stretch along the extension of the axis of the main delta arms at the bay; under the action of the southwest wind, they are pressed to the arms’ mouths. During the east wind surges, the heavy fractions of sediment settle in the area of the Azov-Don navigable canal, and the light ones are carried off by the stream towards the bay. During the west wind surges, the sedimentation of the suspended solids occurs near the estuary, the heavy fractions form three areas of bottom deformation near the mouths of the main delta arms and the light ones, only two areas.