Field measurements of very oblique wave run-up and overtopping with laser scanners

Abstract

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.