Author(s): Laurence Charbonneau; Catherine Blouin; Tadros Ghobrial
Linked Author(s): Tadros Ghobrial
Keywords: Ice jams; River confluences; River breakup; Flood
Abstract: Tributaries can play a significant role in river winter hydraulics, especially during the breakup season. They can contribute to ice jam formation, increasing the risk of sudden floods for nearby populations. However, knowledge about tributary behavior during breakup and their effects on downstream ice jam formation is still limited. The main objective of this study is therefore to quantify breakup processes at a confluence to understand the interaction between tributary ice and downstream river ice in a real-world context. To achieve this goal, a 3-years field campaign was conducted on the confluence of the Sainte-Anne River and the Bras-du-Nord River in Quebec, Canada. Field measurements included water levels and temperature, as well as surface ice concentration and state on three locations along the confluence: one on each branch upstream of the confluence, and one downstream of the confluence. The field data were then analyzed to identify important ice processes at the confluence. Results showed that the morphology of this confluence represents a discordant-bed type and that under different hydro-environmental conditions, the same ice-jam formation process can form. When compared to processes defined in laboratory experiments, ice jam formation at this confluence can be associated with the impact of ice-free tributary flow constraining the main river’s ice.
Year: 2024