Migration Patterns of an Asymmetric Meandering River: The Rouge River, Quebec

The migration patterns responsible for the asymmetry of highly sinuous Rouge River meanders are described and related to the hydraulic and sediment transport patterns controlling bank erosion in these bends. Two elements of the overall migration patterns play important roles in maintaining asymmetry, and raise fresh questions concerning our understanding of erosion processes: significant outer bank erosion starts remarkably early at bend entrances, well before crossover of the high velocity filament. In addition, such erosion extends far along the cross‐valley reaches, despite the very gentle channel curvatures between meander apices. Data on high‐flow suspended sediment transport and helix structure suggest how, beyond the control exerted by near‐bank shear stresses, the spatial patterns of near‐bed primary and secondary flows can also exert an influence on the distribution of bank erosion, by controlling the evacuation of the influxes of eroded bank materials.