Author(s): H. Kalke; C. Schneck; V. Mcfarlane; M. Loewen; M. Jasek
Linked Author(s): Mark R. Loewen
Keywords: No Keywords
Abstract: Frazil ice production occurs in many northern rivers when turbulent water is cooled to below0°C. These frazil particles are adhesive in nature and can freeze to the riverbed where they form large accumulations of anchor ice (Tremblay et al. 2014). Anchor ice release has been observed in the field to lift bed material and transport or “raft” it downstream (Kempema and Ettema2011; Tremblay et al. 2014; Kalke et al. 2015). Kalke et al. (2015) sampled two anchor ice pans rafting sediment and found sediment concentrations of 13 and 29on the Peace River in December 2014. These measurements were consistent with previously recorded sediment concentrations in the field of 22±25 (Kempema and Ettema 2011). Sediment mass fluxes by anchor ice rafting on the Peace River were estimated to account for up to approximately 3% of the annual suspended sediment transport (Kalke et al. 2015). These sediment mass fluxes were calculated using surface ice concentrations and pan thicknesses predicted by the CRISSP1D river ice processes model. In this study, digital images and grab samples of released anchor ice were collected on the North Saskatchewan and Peace Rivers in Alberta. High-resolution images acquired with an unmanned aerial vehicle (UAV) were used to estimate surface ice pan concentrations, the percentage of released anchor ice pans and the properties of the rafted coarse sediment. These measurements were used to predict the sediment mass fluxes and to evaluate the impact anchor ice rafting has on the annual sediment budget.