Simulating the effects of climate change on the ice regime of the Peace River

Winter can be a critical time on many rivers, during which ice conditions and a number of environmental factors can lead to rapidly developing and damaging flood events. Also, in northern Canada, rivers are important for both summer (ferry) and winter (ice bridge) transportation; however, during periods of variable ice conditions these transportation links are temporarily interrupted. As a result, northern communities can become isolated for periods of time. With climate warming becoming an increasing concern, it is important to know how elevated temperatures might affect river ice covers so that we can assess the implications for ice jam events, hydropower dam operation, and winter transportation. The Peace River in northern British Columbia and Alberta was used as a case study in this paper to assess the validity of a newly developed, public domain, thermo-hydraulic river ice model, River1D. The Canadian second-generation coupled global climate model (CGCM2) provided an offset for the historical air temperature input, and a future climate analogue for the mid-21st century ice regime was generated. The historical and future climate simulation results indicated significant potential reductions in the duration and extent of ice cover on the Peace River and a longer period over which the river will be impassible by ferry or ice bridge. Specifically, the number of days an ice bridge could be sustained at the Shaftes-bury Ferry site was shown to decrease by 60% to 78%.