Numerical modeling of wave overtopping of damaged and upgraded rubble-mound breakwaters

Upgrade of aging harbor breakwaters is a worldwide problem, whose urgency is enhanced by the effects of climate change on coastal areas. In this context, the present work contributes to improve current understanding of the hydraulic response of damaged and upgraded rubble-mound breakwaters, providing also a methodology for the implementation of an ad-hoc prediction tool based on numerical simulations. The numerical model IH2VOF, which was calibrated using experimental data, proved to be a valid tool for the study of wave overtopping phenomena of structures with irregular armor slope or additional armor layers. The results confirmed that also for the non-conventional tested structures the wave sequence significantly affects the uncertainty of wave overtopping estimates when low-energy sea states are considered, more than the time series length. Site-specific formulas for the assessment of both mean wave overtopping discharge and probability were defined to overcome the limits of state-of-the-art formulations. Finally, traditional formulations for the description of the individual wave overtopping volumes based on the two-parameters Weibull distribution can be applied also to damaged and upgraded breakwaters.