Simulating 2DH coastal morphodynamics with a Boussinesq-type model

A recently developed compound 1DH numerical model for simulating coastal sediment transport and bed morphology evolution is extended and validated in two horizontal dimensions. The wave module is a higher-order Boussinesq-type model. The bed load in the surf zone is computed from an advanced semi-empirical formula while the suspended load can be calculated through the solution of the advection-diffusion equation for the sediment or alternatively from a simplified formula. The estimation of the sediment transport in the swash zone is based on the ballistic theory. Extended simulation time is achieved through the application of the morphological accelerator factor technique. The validation tests showed a good response of the model with regard to longshore sediment transport under the combined action of waves and currents. A similarly good behaviour of the said model in the cross-shore direction was presented in a previous paper. In addition, the formation of a tombolo behind a detached breakwater is adequately predicted. A sensitivity analysis is also performed studying the equivalence between regular and irregular waves, as well as the effect of various parameters involved in sediment transport and morphological models.