Assessment of vertical channel deformations on the rivers of the Angara region based on hydrometric measurements data

Abstract

The article presents the vertical channel deformations assessment (erosion of the riverbed bottom or accumulation of sediment) on the rivers of the Angara region. Channel processes are wide-spread here due to geomorphological and hydrological features of the territory. Vertical channel deformations are a change in the river bottom altitude under the water flow, sediment transport and accumulation. An important indicator of the dynamics of channel deformations is the changes of the water level and discharge. The Q = f (H) curve is one of the most important characteristics of the river’s water regime and bed morphometry. The direction and speed of the vertical channel deformations were determined by analysing the curves of the water level changes at a fixed discharge. The average of the annual maxima discharge is chosen as the fixed discharge. As a result, the sections of the rivers with erosion of the riverbed bottom, sections with a predominance of sediment accumulation, as well astable sections of the riverbed have been identified. The identified trends of the vertical channel deformations were verified by constructing of cross-section channel profiles according to depth measurements for the period 1997-2017.Moreover, the imposition of multi-temporal cross-section channel pro-files revealed not only vertical, but also horizontal deformations.