Bank erosion processes within the fluvial corridor of the St. Lawrence River: causes, drivers and future challenges.

<p>The St. Lawrence River is one of the largest river affected by seasonal ice formation outside the periglacial domain. It is also a major socio-economical axis in eastern North America where human activities and facilities are numerous within its fluvial corridor, upstream Quebec City (QC, Canada). Recent flooding episodes in 2017 and 2019 have shown that the sustainability of the St. Lawrence River and thus its socio-economic and ecological services will likely be altered in a near future. Bank erosion today represents a major hazard for land owners, infrastructures and riverine ecosystems. Consequently, there is a growing need to integrate bank erosion hazard in order to ensure sustainable management of riparian areas and to adapt land-use planning strategies.</p><p>Literature review and field surveys allowed us to conceptualize a scientific framework about bank erosion dynamics in large rivers characterized by the formation of river ice. We used this framework within the fluvial corridor of the St. Lawrence River to identify bank erosion processes and their drivers, with a focus on the role of river ice and the impacts of anthropogenic stressors such as urbanization, riverbank concreting, large-scale damming, and maritime traffic. We illustrate erosion processes and their impacts through several case studies representing different ecosystems from the fluvial section of the St. Lawrence River. We then discuss the future changes in the nature, the timing, the frequency and the magnitude of bank erosion processes to address the challenges caused by climate change and increased human activities in the St. Lawrence, and more generally in large rivers affected by seasonal ice formation.</p>