SEDIMENTATION SYSTEM OF THE ANGARA RIVER AFTER REGULATION OF ITS FLOW

Abstract

Construction of reservoirs changes natural features of channel processes and depositional conditions in rivers. Based on the variation degree of these processes within reservoirs, we can distinguish the regressive accumulation, alternating backwater, and permanent backwater zones (areas). Zones of alternating back-water represent reservoir areas with river to lake-reservoir transitional conditions and are regarded as areas of the regulated river mouth, where mechanical deposition of most suspended material and active accumulation of sedimentary material take place due to a decrease in the transport capacity of water flow. According to Lisitsyn, the combination of interrelated processes in river mouths and accumulation of enormous masses of sediments with specific composition and properties can be qualified as a marginal filter phenomenon.