River ice breakup and associated flooding are realities for many northern communities. This is certainly the case in Hay River, NWT, which is located at the junction of the Hay River and Great Slave Lake. Hay River experiences a wide range of spring river ice scenarios; from docile thermal melt outs, to severe ice jams resulting in life-threatening, disastrous flooding. This study involved the analysis of five seasons of aerial and time-lapse photographs, water level measurements and hydrometeorologic data. This work also compiled an extended historical record of breakup in the Hay River delta, which was compared against the field data gathered for this study; combining local, experiential knowledge with scientific observation into a cohesive description of breakup. This will be used to advise the non-technical flood watch community on the patterns of timing and sequencing of breakup, which is critical for evacuation planning. / Water Resources Engineering

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The Town of Hay River experiences significant threats to life and property each spring as ice jam release events from upstream bring waves of ice and water to the town. The development of a forecasting tool for ice jam release events has been limited by insufficient data, especially regarding the speed of ice runs associated with ice jam release events. The purpose of this research was to document and analyze ice jam release events to provide the town warning of their potential timing and magnitude, and to contribute to general knowledge on ice jam release. Comprehensive field programs were undertaken from 2007 to 2009, and this new data was used to assess the River1D ice jam release forecasting model. Although the model showed reasonable approximations for wave arrival times for flood forecasting purposes, the predicted speeds and arrival times of ice runs did not agree very well with field observations. / Water Resources Engineering