Framework for Control of Dynamic Ice Breakup by River Regulation

摘要

This report describes and classifies the entire range of ice breakup behavior, from the thermal to dynamic, to provide order to this complex process. The theory and model of the authors are refined, building on the concept of an intrinsic relationship between river waves and dynamic ice breakup. A force balance is developed for a common dynamic breakup behavior. Empirical criteria that quantify the resistance to breakup of an ice cover are obtained from a case study and compared with published values. Sensitivity studies of ice breakup with the completed model demonstrate insights that follow from the theory presented and the intuitive nature of the results. This framework for understanding river ice processes provides the option for ice management by river regulation, and we focus on the potential for control of ice breakup. The concept of controlled breakup involves a release of water from a dam that moves the ice downstream of locations with a high potential for damage during uncontrolled breakup. The abrupt, short-duration characteristics of the controlled release, patterned after those of unregulated river breakup, minimize both the volume of water required to cause breakup and the water levels at breakup. The open water created by the breakup collects heat that increases the rate of melting of the ice. The benefits of successful regulation include flooding prevention, minimum erosion, and decreased potential for ice damage to structures during breakup, with out adverse effects on the environment. keywords: Flood control; Ice jams; Ice management; River ice; Unsteady flow. (edc)