A statistical analysis of bank erosion and channel migration in western Canada

Abstract

Mean lateral-migration rates for 18 meandering river channels in western Canada are explained statistically in terms of hydraulic and sedimentological variables. The volume of sediment eroded from the outer bank of a meander bend is shown to be largely a function of river size and grain size of sediment at the base of the outer bank. These variables explain almost 70% of the volumetric migration rate for these relatively large, sand- and gravel-bed streams. It would appear that bank erosion and channel migration are essentially problems of sediment entrainment which is dependent on total stream power and sediment size. Vegetation on the outer bank is seen to have little significant effect in controlling channel migration. Further refinements of the type of data used here should permit the development of an accurate predictive model of regional channel migration. To this effect, it is most important to develop a precise relationship between bank resistance and the size of sediment at the base of the outer bank.