Wave-Current Interaction and its Influence on Sediment Transport

The interactions between waves and currents were evaluated and their potential influence on sediment transport assessed. To consider wave-current interactions, wave and current fields were individually examine and then combined. Flow fields were explored using an available hydrodynamic model, the Environmental Fluid Dynamics Code (Hamrick, 1996; Jin et al. 2000). Three flow fields were considered: a strong current (a river), a moderate current (a bay or harbor), and a weak current (small lake with wind-driven circulation). Wave fields were explored using small amplitude (linear) wave theory. The combined effect of wave-current interactions was explored using the approach of Grant and Madsen (1979). These analyses indicate that, in the presence of currents, waves dramatically enhance sediment transport. Even when a current is weak, the combined effect of waves and currents can resuspend and transport sediments. For the conditions explored, bottom shear stresses from wave-current interaction were greater than the shear stresses from currents alone by an order of magnitude or more