Author(s): Martin Jasek; Joel Evans
Linked Author(s):
Keywords: River Ice; Ice Formation; Growth and Dynamics
Abstract: BC Hydro owns and operates the W.A.C. Bennett and Peace Canyon dams on the Peace River in northern British Columbia and manages flow releases in consultation with Alberta Environment and Parks to reduce the potential for freeze-up ice jam flooding at the Town of Peace River, AB. BC Hydro goes on “ice control flow” operations where the discharge is held relatively constant from several days before the leading edge of the ice cover (ice front) reaches the Town of Peace River, to when the thermal ice cover upstream of the town reaches a thickness that is sufficient for ice cover stability. Regulated or natural flow fluctuations can mobilize an unstable ice cover and produce thick freeze-up ice jams that can cause high water levels. CRISSP, a one-dimensional river ice hydraulic model, and PRTGM, an air-snow surface-ice surface energy exchange model, are used during daily operations planning to model ice front location and thermal ice growth respectively. These two factors determine the duration and timing of the control flow period. This study uses these models, along with inputs of air temperature and snowfall from future climate prediction models, to determine how the timing and duration of future ice control flow periods could change over the remainder of this century. Generally, the study found that the start of ice control would be delayed, and the best performing climate model indicated that the duration of the ice control flow period would shorten over the remainder of this century, including many years towards the end of this century when no ice control operation would be required. The other climate models indicated that the average duration of the ice control period would initially increase before decreasing after about the year 2060.
Year: 2022