Author(s): Wael Taha; Andree-Sylvie Carbonneau; Marie-Eve Larouche; Ahmad Shakibaeinia; Clement Billy; Iurii Lokhmanets
Linked Author(s): Ahmad Shakibaeinia
Keywords: River Ice; River Ice Breakup and Jamming
Abstract: Ice jam initiation caused by river morphological features has been investigated in the past using geospatial tools. Physical and numerical modelling have also been used to assess jamming by arching at low Froude numbers as a result of channel restrictions. It is well understood that ice jam initiation occurs in rivers when ice runs pass through channel restrictions, meandering channels, shallows and slope reduction. However, it’s not well understood how these morphological features interact with the characteristics of an ice run and the channel hydraulics leading to the formation of an ice jam, and particularly for gorging ice jams which cause the highest increases in water levels. The channel morphology of 24 rivers in the Québec City area has been characterized using geospatial tools to obtain the spatial variations of channel slopes, widths, depths and curvatures. Using this data, parametric laboratory testing in a flume has been carried out to assess the limits of ice jam initiation for channel width restrictions, depth reductions and slope reductions for ice runs of different concentrations and characteristic ice floe sizes. In addition, numerical modelling using a 3D meshless Lagrangian model has been calibrated using laboratory test results in a rectilinear channel and then used to evaluate ice jam initiation in curved channels. Results from physical and numerical modelling have allowed us to develop ice run concentration thresholds for ice jam initiation as a function of channel slope, width restriction, depth reduction, slope reduction, channel curvature and ice floe characteristic size. Such results can be used by advecting an ice run through a river and then checking if the advected ice floe concentration exceeds the threshold concentration for jam initiation at a specific location with a set of morphological features.
Year: 2022