Wave Runup on Dikes with Shallow Foreshores

TLDR

Shallow foreshores significantly alter wave height distributions and energy spectra between deep water and the toe of coastal structures. The study combined prototype measurements, physical model tests, and numerical simulations to investigate how wave energy spectra affect runup and overtopping on dikes with shallow foreshores, and compared model results with prototype data. The integrated data identified a characteristic wave period for runup and overtopping that depends on wave energy spectra, was confirmed by tests across diverse foreshores and structures, accurately reproduced six prototype storm conditions, and led to a prediction method applicable to both deep‑water and shallow‑foreshores.

Abstract

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.