Sediment Transport in Ice-Covered Rivers: A Prospect Research Project

The process of sediment transport in rivers can be linked to both open channel hydraulics and sediment supplies. Compared to its open channel version, a limited amount of research has been directed to sediment transport in ice-covered rivers. In northern regions, the presence of an ice cover modifies channel hydraulics and the availability of sediment during a significant portion of the year, thus adding to the complexity of this process and affecting the distribution of the carried sediments over a year cycle. Few flume studies have investigated the effects of a modeled ice cover on channel hydraulics and sediment transport while a limited number of under-ice sediment transport measurements (mostly suspended) have been performed in the field. A general consensus however exists on a significant reduction of sediment transport capacity once the ice cover is present. An ideal free-floating ice cover increases channel roughness and water depth, thus directly affecting water velocities and sediment transport capacity. Meanwhile, sediment availability in winter conditions has mostly been addressed only qualitatively (Beltaos and Prowse, 2009; Ettema, 2002; Milburn and Prowse, 1996). Yet, it is believed that the reduction in sediment transport could be promoted by a decline in sediment supplies during winter. Nevertheless, a number of known ice-related transient processes are likely to increase sediment transport. These ice cover processes are commonly observed in most ice affected rivers and could counter-balance the expected decrease in sediment transport rates in winter. Ice jams, during the freeze-up and break-up periods, are probably the most documented phenomena locally affecting sediment transport. However, limited hydraulic and sediment transport measurements have understandably been obtained during these events. Frazil, in the form of anchor ice o