| Ice formation in river channels interacts with river flow, affects operations of water resources projects, and changes fluvial processes such as sediment transport and river channel morphology. This thesis includes the application and extension of a two-dimensional numerical model for coupled hydro-thermo-ice-sediment dynamics river ice, with sediment transport and bed change. The study consists of four parts. In the first part, the existing river ice model is used to study the measures for mitigating the ice stoppages at the intakes of the Niagara Power Project during lake ice run events. This shows the applicability of the river ice dynamic model in assisting operations of hydropower projects to improve wintertime power production. In the second part, a unified formulation on border ice formation is developed and implemented to allow the simulation of the entire river freeze up process, and validated with field data. This clarifies the understanding on the border ice formation, which was a subject of many field studies that resulted in no consistent usable formulations. In the third part, the model is applied to examine several key phenomena of ice effects on the bed changes during the winter ice season. This sheds light on the effect of ice on bed changes during and after freeze up and breakup, as well as the interaction between ice jam evolution and bed change in alluvial channels. In the fourth part, the model is extended to include the secondary current attributed to the channel curvature to study the effect of ice cover on flow and sediment processes in river bends. This advances the understanding on the secondary current under ice cover and related sediment transport and bed changes, and paves the way for studying the mechanics of many river ice processes in curved alluvial channels and their interaction with channel morphology, including ice jam formation, channel migration, and evolution of frazil jams in river bends. |
