Development of a time-dependent Boussinesq model for nearshore hydrodynamics

A time-dependent wave transformation model is developed which is capable of representing the processes of refraction, diffraction, shoaling, energy loss due to bed friction, breaking and reforming on a complex bathymetry. The model is based on the Boussinesq equations, and wave breaking is included through the adoption of an energy-based 'roller' formulation. The model has been extended to include a time-varying shoreline by merging an additional swash zone formulation with the Boussinesq model. The resulting model is capable of reproducing a broad range of hydrodynamic phenomena, and is readily adaptable to many coastal hydrodynamic systems.; In a one-dimensional form, the model is compared to the flume experiments of Hansen and Svendsen (1984), and Okayasu (1986) with generally favorable results. The fully two-dimensional model is then applied to the ebb shoal region in the vicinity of Sebastian Inlet, Fl. Model results suggest a complex wave and current environment with significant transformation of the incident wave field. The estimation of mean currents indicates a return flow from the shoal that is driven primarily by gradients in mean water level.