Automatic incorporation of circular riverbank failures in two-dimensional flood modeling

Riverbanks undergo changes caused by river hydraulics and by the possible landslides that change the channel bank profiles. Those failures are an important form of alluvial channel adjustments but are usually difficult to include during morphodynamic modeling. This paper proposes a novel approach combining a 2D depth-averaged hydrodynamic, sediment transport and mobile-bed model, a limit equilibrium slope-stability model, and a bank failure sediment redistribution submodule, into a fully automatic and continuous dynamic simulation to predict morphological changes for a river reach undergoing exceptional flooding. All mesh nodes located within the mass wasting zone will be automatically updated, allowing a new bank face form. The failed materials is redistributed in the transect according to the geometry of the landslides observed at the study site. The Outaouais River at Notre-Dame-Du Nord, Quebec, is used to test the coupling procedure. Typical results showing the effectiveness of the developed framework are presented and discussed.

Mots clés

Streambank erosion; Riverbank failure; Two-dimensional modeling; SRH-2D; BISHOP; Automatic coupling; Sediment redistribution