Calculation of the Overtopping Probability for a Coastal Dike in the Extreme Storm Surge Condition

A probabilistic model for analysis of the extreme wave run-up on a coastal dike during extreme storm surges is presented. The model is based on crossing theory, and it is used to estimate the overtopping probability for the dike in such extreme storm surges. The application of the model is demonstrated by calculations for an example dike in the most severe storm surge during its lifetime. Uncertainties in environmental conditions as well as in topographical properties are included. The probability calculations are carried out by means of a first-order reliability method. A sensitivity study is included, and the influence of climate changes is considered. An example of reliability-based optimization of the dike profile is given.