The safety of dikes during flood waves : analysis of the failure probability of dike ring areas in flood wave situations

The objective of this research is to develop a model, which determines failure probabilities of dike rink areas given a certan (predicted) flood wave. This model can be used as a support tool for decision makers, providing real-time information on the failure probability of a dike ring area given a certain flood wave. In this research the failure probability given a certain flood wave is considered for various failure mechanisms. Attention is paid to all dike characteristics that determine the strength of the dike and (predicted) loads. First, a conceptual approach for the calculation of the failure probability in flood wave situations is developed. This has been applied on an example dike section. Afterwards, a case study is performed, calculating the failure probability in the 1995 flood wave situation for a dike ring area in the Netherlands. The calculation of the failure probability of a dike ring area given a certain flood wave can be based on a water level observation or a water level prediction. The water level predictions are based on model Lobith, a linear regression model with a maximum prediction lead-time of 4 days. The prediction lead-time is defined as the time interval between the moment t of prediction and the moment of occurance of a certain water level. A water level observation can be made when the water level actually occurs (t=0 days).