2020 Volume 76 Issue 1 Pages 7-19
When high waves and surge occur simultaneously, the flooding regime changes from overtopping by waves, combined overtopping-overflow by waves and surge, and to overflow dominated by surge. However, the modeling of combined wave overtopping and overflow, or, transient overtopping-overflow has not been well established yet. Accordingly, the present study proposed such modeling based on the full scale experimental results. The estimation of wave overtopping discharge is based on the model for seawalls installed at deep water to very shallow water including on land. The overflow discharge is estimated by a formula for weir. In the transient regime, the combined overtopping-overflow discharge is computed by properly accounting for the relative importance of wave overtopping to surge overflow. The present model was applied to idealized cases of seawall, wave and surge conditions to indicate the typical characteristics of time history of flooding discharge. In addition, the present model was implemented into a wave-surge coupling simulation model for simple conditions of bathymetry and typhoon. The results clearly demonstrated that it is very important to account for the transient phenomena in inundation simulations.