Probabilistic Assessment of Wave Overtopping of Nampo Dikein the West Coast of Korea

The Nampo dike,which is located at the west coast of Korea, was destroyed by wave overtopping during the storms on 30 August and 17 September in 1989. In this paper, is performed the probabilistic assessment of wave overtopping of Nampo dike by use of Owen model, Van der Meer & Janssen model and Hedges & Reis model for wave overtopping of seawall. Based on the available tidal and wave data for storm surges in 1989, the risk assessment of wave overtopping of the Nampo dike has been carried out by both Level II and Level III reliability methods. The calculated results show the general agreement of failure probability between the two methods. By utilizing the rehabilitated cross section of Nampo dike, the failure probability of wave overtopping for the Nampo dike after rehabilitation will be rapidly reduced to that of initial design at crest level of 9.0 m with the improved slope from 1:2 to 1:4 at seaside. Since the sea level may only rise 1.0 m in the next few decades, the failure probability of Nampo dike will be still in the safe range.