Wave overtopping is typically measured in the field using overtopping tanks. In this paper, an alternative system is developed that uses two laser scanners. The system also measures wave run-up, as well as run-up depths and velocities, both during perpendicular and oblique waves on a dike in the field. The paper considers the first calibration tests with the system in the field, with perpendicular and oblique waves generated by the wave run-up simulator on a grass dike slope. Furthermore, simulations are performed with the numerical wave model SWASH, to gain more insight in the potential performance of the system during actual oblique wave attack during a storm. The run-up is determined from the measured elevation and reflection intensity, which agrees well with the visually observed run-up. Run-up depths and front velocities can be determined accurately as well. The (virtual) wave overtopping discharge can be calculated from the data, which agrees well with the most commonly used overtopping equations for perpendicularly incident waves. Finally, from the simulated run-up data of obliquely incident waves, it is concluded that an estimate can be obtained of the incident wave period and wave angle of incidence at the toe of the structure.@en

Wave overtopping is commonly measured using overtopping tanks. In this paper, an alternative system is developed by using two laser scanners. It measures wave run-up, as well as layer thicknesses and front velocities, both during normally and obliquely incident waves on a dike in the field. The paper considers the first field validation tests with the system, with normal and oblique waves generated by the wave run-up simulator on a grass dike slope. Furthermore, a range of environmental conditions are simulated, to determine the robustness of the system. From the measured distance and reflection, the run-up is determined, which corresponds well to the observed run-up. From the data, the layer thickness and front velocity are determined as well. Layer thicknesses and front velocities are determined reliably with the laser scanners. Also, the (virtual) wave overtopping discharge can be calculated, which corresponds well with the most commonly used overtopping equations.@en

Oosterlo et al. (2019) developed a system using two terrestrial laser scanners, which can measure run-up heights, depths and velocities of waves on a dike in field situations. The system has now been placed next to two overtopping tanks on a dike in the Eems-Dollard estuary in the Netherlands to measure during actual severe winter storms. The goal of the present paper is to further validate this innovative system with data obtained during storm Ciara (10 - 12 February 2020), a severe winter storm with very oblique wave attack. Furthermore, the data gathered during storm Ciara will be compared to the current knowledge on wave overtopping, to possibly gain new insights in the influence of very oblique wave attack on wave overtopping.@en

This paper presents the first field measurements with an innovative laser scanner system, during an actual severe winter storm with very oblique wave attack. The goal of this paper is to validate this innovative system for measuring wave run-up and wave overtopping parameters during storms with very oblique wave attack. The paper describes the analysis of the run-up and overtopping data obtained during storm Ciara (10 - 12 February 2020) and validates the results with data from overtopping tanks and video recordings. Storm Ciara was a highly unique and complex storm, with offshore-directed wind and alongshore-directed waves at the dike. This posed large challenges for measuring the front velocities. The wave run-up heights and the overtopping discharges could be measured accurately with the laser scanners. Reasonable results were achieved for the run-up depths. This has led to several new insights into the probability distribution of oblique wave run-up and the run-up depths of up-rushing oblique waves. Larger deviations were found for the 2D front velocities and wave angle of incidence, which could not be determined as well for storm Ciara. This arose from the highly complex conditions during Ciara with very oblique wave attack. The mobile system is now ready to be used at several different locations in the measurement campaign in this area over the coming years.@en