Wave runup on dikes with shallow foreshores

Prototype measurements, physical model tests, and numerical model computations have been performed and combined to study wave runup on dikes with shallow foreshores. Shallow foreshores considerably affect the evolution of wave height distributions and wave energy spectra between deep water and the toe of coastal structures. The numerical model investigations were performed to study the influence of wave energy spectra on wave runup and wave overtopping. This resulted in a characteristic wave period for wave runup and wave overtopping, which takes the effects of wave energy spectra into account. This was confirmed in a series of physical model tests with different types of foreshores and different types of structures. Also, results from physical model tests were compared with results from measurements in prototype. The six storm conditions that were measured in prototype were accurately reproduced in the physical model tests. The results of each of the three data sources were combined, and led to a prediction method that can be used for conditions with deep water and for conditions with shallow foreshores.