Theory of the sedimentation of suspended particles from fluvial plumes



A two-layer model for the flow and sedimentation within a salt wedge or highly stratified hypopycnal fluvial plume emptying into a fiord is developed from basic principles. From this model, it is found that the amount of suspended sediment of a particular grain size decreases as an exponential function of distance, and that the velocity and depth of the plume converge to constant values. The model is consistent with measurements from the plume of the Homathko River in Bute Inlet, British Columbia, Canada, and suggests that certain aspects of current empirical models of plume sedimentation are based upon sound principles.