Current vector dispersion in a river of fluctuating discharge

Abstract

As water stage falls over a bedform covered sediment surface, local flow directions are increasingly controlled by the topography and if the bed material is still mobile, smaller surface features will reflect the control. Dispersion will increase as water stage falls. A bank in the bed of the Tana River, Norway, is used to illustrate this. Pebble features record high stage directions while sand features reflect falling stage modifications in direction of flow. Consideration of this effect might be important in using palaeocurrent distributions to specify channel type in fluviatile sandstones.