Impact of hydro power plant operation on the fluvial processes of the Ob river at the reach from the Novsibirsk dam to the Tomi river estuary

Abstract

The article seeks to analyse the impact exerted by the hydro power plant (GES) on fluvial processes, using the example of a reach of the Ob river. The reach selected for the purpose of the study was regulated in 1959 and is located below the Novosibirsk dam. The most significant consequences of  dam operation include: deepening of  the channel as a result of bed erosions, decrease of bed and water surface slope, as well as channel transformation from braided-anastomosing to straight. Due to the changes in morphology, navigation conditions below the dam clearly deteriorated, while local 12 m deep pools were formed. The process of bed erosion was further strengthened by dredging, which was markedly limited after 1990. Navigation conditions are adversely affected by the morphological conditions resulting from the operation of the hydro power plant. Moreover, the article attempts to explain why reservoirs are poorly planned, the most important factor being insufficient knowledge of fluvial processes, in particular of dredging consequences. Such works should be conducted bearing in mind hydrological security and exert possibly minimal influence on the environment.