Author(s): B. Michel
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Keywords: No Keywords
Abstract: Various mechanisms of ice cover formation in rivers are known and have been extensively studied. They include frontal progression by juxtaposition of single ice plates, frontal progression with an ice accumulation, shoving and the formation of hanging dams. There is another mechanism which has been identified by analyzing the records of extensive measurements made by Hydro-Quebec on ice cover formation on the St. Lawrence River and on the Beauharnois Canal. This is the mechanism of packing of slush at the frontal edge of the cover. As the name implies, the incoming ice pieces are then packed at the edge by successive compression and accumulation and they form ice covers that are thicker than those formed by the known process of frontal progression but thinner than those formed by general shoving over long distances. The general equation of packing is derived in the paper and the results of the analysis are compared with field data. Contrary to shoving, the ice cover thicknesses that result are independent of river width. They explain much better the field measurements in most rivers that show thicker ice covers than those predicted by frontal progression when no general shoving occurs.
Year: 1986