Wind induced sediment resuspension: a lake-wide model

A lake-wide suspended sediment model has been developed and subsequently coupled with a horizontal circulation model to predict depth-averaged suspended sediment concentrations throughout a lake. Resuspension is induced by shear stresses at the sediment-water interface which are considered to be a result of wave action. These shear stresses are calculated using linear wave theory. The model allows for winds from any direction to generate the waves and associated stresses. Sediment deposition is characterised by a formulation which describes the change in suspended sediment concentration with time rather than relying on one or more representative settling velocities. Sediment resuspension is modelled as being independent of deposition. The processes of advection and diffusion in redistributing resuspended sediments horizontally are accounted for in the hydrodynamic model. The result is a general, process based model for predicting depth-averaged suspended sediment concentrations throughout a shallow lake. The model was tested against data collected during 1993 and 1994 from Thomsons Lake, Western Australia.