Author(s): Richard M. Vogel; Morris J. Root
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Keywords: No Keywords
Abstract: There is a documented history of flooding due to ice jams at several locations along the Missisquoi River. Floods caused by these ice jams are localized phenomena and occur independently of the more regionalized storm-induced floods. However, when the probability distributions of storm-induced floods are compared with the probability distributions of ice jam floods, it is shown that the ice jam events dominate the extremal distribution. These results have far-reaching implications within the context of estimating the frequency and magnitude of floods. A theoretical model of a floating ice jam is utilized to develop the water surface profiles along the reach for various ice jam recurrence intervals. The results are validated utilizing field surveys of actual ice jam flood events. Excellent agreement can be obtained between observed and computed flood stages. This paper in part compares the theory to field conditions and examines the theory in a practical application. Use of the quasi-theoretical expressions for the hydraulics of an ice cover requires information regarding the resistance to flow caused by the ice cover, as well as width, thickness and type of cover. A sensitivity analysis results in a description of conditions for which the expressions utilized are both accurate and meaningful.
Year: 1981