Numerical Simulations of Coastal Overwash Using A Phase-Averaged Wave—Current—Sediment Transport Model

Abstract

Coastal overwash is a natural phenomenon that commonly occurs during storm events and can cause considerable changes in nearshore morphology within a short time. In this study, a complete set of empirical overwash transport algorithms is developed and introduced into a phase-averaged wave-current-sediment transport coupling model that integrates the Finite-Volume Community Ocean Model (FVCOM) and the Simulating Waves Nearshore (SWAN) model. The resulting morphological evolution model can simulate coastal overwash. Validation against the data obtained from multiple sets of laboratory overwash experiments demonstrates that the model performs relatively well in simulating morphological changes caused by runup overwash and inundation overwash under different hydrodynamic and beach profile conditions. The sensitivity of each empirical coefficient in the overwash transport algorithms is comprehensively analyzed. The effects of each coefficient on the output of the model are discussed, and a recommended value range is provided for each coefficient.