The role of morphodynamics in predicting coastal flooding from storms on a dissipative beach with sea level rise conditions

Abstract

Abstract. We investigate the role of morphodynamic changes in the flooding of a micro-tidal dissipative beach for both current and sea level rise scenarios. By considering beach morphodynamics and flood processes associated with highly energetic waves, the study allows one to evaluate threats to coastal zones. Coupling of SWAN and XBeach models is employed to propagate offshore wave conditions to the swash zone, estimating morphological changes and flooding associated with wave conditions during cold fronts and hurricanes that affected Cartagena de Indias (Colombia). The numerical models were calibrated from previous research in the study area. The results indicate that numerical modeling of flooding on microtidal dissipative beaches under extreme wave conditions should be approached by considering beach morphodynamics, because ignoring them can underestimate flooding by ∼ 15 %. Moreover, model results suggest that beach erosion and flooding are intensified by sea level rise, resulting in the most unfavorable condition when extreme events are contemporaneous with high tides. In this case, the increase in erosion and flooding is ∼ 69 % and ∼ 65 %, respectively, when compared with the present conditions of sea level.