A new model for cross-shore surf and swash zone morphology evolution induced by nonlinear waves

Abstract

Nonlinear wave transformation in the surf and swash zone is computed by a nonlinear breaking wave model based on the numerical solution of the Boussinesq-type equations. Instead of classical equations, higher-order equations in dispersion as well as in nonlinearity are derived and used inside and outside the surf zone. The Dibajnia and Watanabe transport rate formula involving unsteady aspects of the sand transport phenomenon is adopted for estimating sheet flow sediment transport rates as well as the bed load and suspended load over ripples. For the calculation of the suspended load induced by wave breaking, the Bailard formula is used after the consideration that the only dissipation mechanism is the wave breaking. Runup and rundown as well as sediment transport in the swash zone are incorporated in the model. The model is able to reproduce beach accretion and erosion without the use of an erosion/accretion criterion. The model is validated against large-scale experimental data.