Wave reflection on natural beaches: an equilibrium beach profile model

Waves are the most energetic phenomena that control beach morphology. The beach profile mostly depends on the way in which the incident wave energy distributes along the profile, dissipation and reflection being the main mechanisms. While the dissipation phenomena have been widely studied, the effect of wave reflection on the beach profile has attracted much less attention and is still poorly known. In order to evaluate its importance, a new equilibrium profile model that includes reflection is proposed. The model is based on a two-section profile scheme, largely corresponding to the surf and shoaling-dominated zones of the beach profile. The obtained formulations are represented by the expression of two terms. One of the terms accounts for the dissipation effect and coincides with the Dean profile. The other term integrates the reflection process. The model and its coefficients have been calibrated using measured profiles along the Spanish coast. The validation shows a significant improvement of the fitting parameters with respect to the most popular equilibrium profiles model. Moreover, additional empirical expressions that relate morphology and hydrodynamic in the equilibrium profile model are also presented in this study as a novel contribution to this topic.