Author(s): Michael De Coste; Yuntong She; Julia Blackburn
Linked Author(s): Yuntong She
Keywords: No Keywords
Abstract: The Town of Hay River, located in the North West Territories, Canada, frequently falls victim to ice jam flooding occurring in the nearby multi-channel Hay River Delta (the Delta). These events can pose a great threat to the town. Studies have noted that the most extreme flooding events occurred when ice jams in the two major channels of the Delta, East and West, are pushed into the mouth of Great Slave Lake. It is currently believed that such movement is caused by ice jam release waves travelling into the Delta from upstream. It is vital to gain a better understanding of the effects of ice jam release waves in the Hay River on ice jam conditions in the Delta, in order to better predict flooding in the town. This study incorporates upstream ice jam release events into the prediction of flood levels within the Delta. Specifically, a model of the Hay River (developed using the River1D model and previously validated for simulating ice jam release waves upstream of the Delta) was used to route the ice jam release waves down to the inlet of the Delta. The River1D Network Model, selected for its capability of simulating dynamic wave propagation in multi-channel networks, was then used to simulate the propagation of these waves through the Delta. Flow splits in the individual channels were determined and peak discharges were used to predict new ‘post-wave’ice jam configuration and flood levels. This method was applied to breakup events from 2008 and 2009, where upstream ice jam release had magnified the severity of Delta ice jams. Good agreement with field measurements was achieved in terms of water levels before and after the arrival of ice jam release waves.