Conditions for Ice Jam Formation in Tailwaters (Usloviia Obrazovaniia Zatorov L'Da V Nizhnikh B'Efakh)

• Main Author: Donchenko,R V
• Other Authors: COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H
• Format: Text
• Language: English
• Published: 1978
• Subjects: Hydrology; Limnology and Potamology; Snow; Ice and Permafrost; *ICE; USSR; MATHEMATICAL ANALYSIS; TRANSLATIONS; RIVERS; ELECTRIC POWER PLANTS; HYDROELECTRICITY; DAMS; HYDRODYNAMIC CONFIGURATIONS; *Ice jams; Tail waters; Ice; permafrost
• Online Access: http://www.dtic.mil/docs/citations/ADA052396; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA052396

On the basis of studies on the dynamics of the ice cover edge the following peculiarities were found in the formation of jams in tailwaters. Formation of ice jams in tailwaters is a consequence of the dynamic destruction and separation of the edge with increased discharges. The process of dynamic destruction of the edge evolves by the formation of cracks along the shore, debacles, and hummocking on the section within which during discharges the size of fluctuation in the water level is 3-4 times greater than the thickness of ice on the edge during its formation. Jams are formed at the jointing of the intact ice cover and the shattered field under the influence of the forces of the flow and pressure of the ice field which exceeds the resistance of the ice. The amount of the greatest jam level is in direct dependence on the amount of maximum water consumption in the period of jam formation. An increase in discharges during the formation of ice jams promotes the increase in capacity of the jam, and as a consequence a reduction in the winter coefficients occurs. Regulation of the GES routine depending on the conditions for ice cover edge formation on the section within the diurnal lag time is a necessary condition for the movement of the edge in the tailwater without jam formation. (Author) Trans. of Gosudarstvennyi Gidrologicheskii Institut. Trudy (USSR) v227 p31-45 1975.