Practical derivation of operational dike failure probabilities

Probability forecasts for natural loads, such as river discharge or wind speed, allow deriving predictive dike failure probabilities within a future time interval, the so-called operational dike failure probabilities. The operational dike failure probabilities can be used to assess the safety of dikes and can support decision making in the face of flooding. In this article, a practical framework for deriving the operational dike failure probabilities is introduced. The framework is based on a presently applied technique that is used to estimate the annual dike failure probabilities in the Netherlands. The framework is applied to a dike located in the delta of the river Vecht, providing probability forecasts for water levels and waves at the dike and the operational dike failure probabilities. Several aspects of the framework are also analysed, giving insight into the properties and accuracy of the method.