COAST GEOMORPHOSYSTEMS OF THE RIGHT BANK OF THE VOTKINSK RESERVOIR

Methods and results of field studies of the complex of coastal processes on the right Bank of the Votkinsk reservoir are presented. They include observations of the rate of destruction and retreat of the walls of landslide-scree slopes, cut by abrasion, and processes that develop on the emerging shallows. For the first time, the processes of slow mass displacement of material entering the shallows due to the destruction of the banks were established and quantified within the shallow coastal waters. The main morphological types of coastal geomorphosystems are identified and the rates of re-formation are determined for their surface and underwater parts. It is noted that the most productive processes in relation to the flow of loose material into the reservoir bowl are the processes of shedding. Accordingly, weathering, as a source of loose material formation, acquires the importance of the most important shore-forming factor in the surface part of coastal geomorphosystems in the reservoir conditions. Among the most important lithodynamic flows of underwater sections of the coastal zone, the underwater "creep" is singled out. It was found that the layer of loose sediment lining the bench with a layer of 20-25 cm by the beginning of ice formation completely slides in the drying zone at a distance of 15-20 meters by the beginning of spring water discharge. Mass displacement of fine-grained earth occurs in the summer, but the slid material is actively replenished with abrasive products in the summer. Banks are destroyed by parallel retreat of the underwater and surface parts of the coast. At present, the rate of coastal destruction often increases rather than decreases, which makes it necessary to review some theoretical provisions concerning the laws of coastal development and forecast estimates. The results obtained can be used to estimate the rate of siltation of the reservoir basin.