Author(s): Vincent Mcfarlane; Johnson Kau; Nicolas Castro
Linked Author(s):
Keywords: Frazil ice; Supercooling; Energy budget; Freeze-up; Heat flux
Abstract: Ice formation on structures, especially water intakes, is a major concern in Northern rivers. The flow through freshwater intakes can be seriously reduced by the accumulation of frazil ice, to the point that downstream processes that rely on the water drawn by the intake must be completely shut down. This can be very costly for intake operators in many industries. The most effective strategy to mitigate the impacts of ice formation on intakes has been to predict when supercooling and ice formation will occur and take preventative actions. However, to accurately predict a supercooling event requires a detailed understanding of all the heat fluxes which contribute to the full energy budget of the river and can influence the water temperature. These include fluxes which occur not only at the air-water surface interface, but also at the water-riverbed interface. However, the heat fluxes occurring at the riverbed are not often measured or accounted for throughout the freeze-up, ice-covered, or breakup periods of a river. In this study, the full energy budget of the Pembina River, AB, was calculated by analysing water surface and riverbed heat flux data which were collected during the 2023 freeze-up season, including measurements of riverbed temperature and radiation reaching the riverbed. These data were used to determine the relative influence of bed heat fluxes on the supercooling and frazil ice production processes, which will be important for improving our understanding of the river freeze-up process and refining thermal ice process models.
Year: 2024