Author(s): Wojciech Majewski
Linked Author(s): Wojciech Majewski
Keywords: No Keywords
Abstract: In many countries of the northern hemisphere rivers and channels are covered with ice during periods varying from few days to several months. Process of river ice formation is a set of complex phenomena that are affected by many factors including meteorological conditions, thermal regime, hydraulic conditions and channel morphology. Ice which appears in various forms impedes seriously utilization of rivers for power generation, navigation, water supply, municipal and industrial use. Extent, thickness and forms of ice cover may change considerably in space and time thus causing changes in flow conditions. These problems are present at various intensities during periods of ice formation, ice cover duration, and during break-up and ice run. Ice jams which may be considered as an extreme case of ice cover may result in very high water stages and even dangerous flooding. In recent years much attention has been directed to control and mitigate negative consequences of ice on flow conditions and hydraulic engineering projects. The paper presents general aspects of ice cover formation on the flowing water and its influence on hydraulic conditions (velocity distribution, flow resistance, water depth). A very important parameter in estimating hydraulic conditions is the coefficient of the resistance of the underside of ice cover. Its variation and methods of assessment are presented. Models for calculation of water surface profiles with ice cover for steady nonuniform and unsteady flow are described.
Year: 1990