ИСТИНА

The theoretical base of the proposed technique founds on the mechanics of interaction of the flow inside quasi-stable banks with cohesionless bed. Bed forms are symptomatic of local variations in the sediment transport capacity, which can give rise to sequences of erosions and depositions. The strategy of modeling consisted in the following: for the initial time moment the channel outlines of the simulated river reach correspond to bankfull conditions and the bottom is flat; depth and sediment particle size are taken typical for the chosen river; bed deformations under dominant discharge passing are simulated until a quasi-stable condition of bed configuration is achieved. The approach based on 2D hydrodynamic modeling of flow with moving bed appeared to be fruitful for large lowland rivers of various channel patterns. Side and mid-channel bars, riffle-pool sequences, confluence scours and other larger-scale features typical for meandering and braided channels, as well as river junctions were reproduced rather authentically.