Concave-bank benches on the Squamish River, British Columbia, Canada

Abstract

The form, sediments, and possible origin of two concave-bank benches on the Squamish River, British Columbia, are briefly described. They contain the only fine-grained within-channel deposits in this gravel-bed stream and are generally similar to features on the Barwon River in Australia.One concave-bank bench on the Squamish River is a mature feature and the other is currently being formed. Evidence from the latter example indicates that the features, like those on the Barwon River, are deposited in the separation zones developed at the concave bank of very sharp bends. Sediments appear to be supplied from suspensions in dissipating vortices advected into the separation zone. Two processes of vortex advection are briefly discussed.