Geomorphological process development under the impact of man-made reservoir operation, a case study: Bratsk reservoir, Baikal-Angara hydroengineering system, Russia

The Bratsk reservoir is one of the constituents of the Baikal-Angara hydroengineering system. Large hydropower reservoirs created worldwide produce anthropogenic pressure that provokes substantial changes in the environment and land use practice, as well as different natural hazards, such as induced seismicity, activation of landslides, karst, and shore and bluff erosion processes. Creation of the Bratsk reservoir was followed by a burst activation of shore erosion, karst, aeolian processes, gully, and landslide formation. We monitored the short- and medium-term dynamics of process development in the context of reservoir water level change, which involved the comparative analysis of large-scale aerial photos and field measurements at four key sites. A complex (interaction) of processes can be observed in the shore zone. Based on the monitoring data, models of the geomorphological process evolution in the next years are presented. By investigations, we identified the mechanisms of karst-erosional, aeolian-erosional, and shore- and gully-erosional processes. The case study has shown that the response of dynamics of the processes, their interaction, and environment change are characterized by a certain cyclicity corresponding to water level fluctuations.