Improved prediction of wave overtopping rates at vertical seawalls with recurve retrofitting

Abstract

This study investigates the reduction in overtopping discharge along a vertical seawall through the implementation of a recurve retrofitting. A comprehensive set of physical modelling experiments were undertaken in a laboratory-scale wave flume at the University of Warwick, to investigate the wave overtopping processes under both swell and storm wave conditions. The tests measured overtopping discharges for impulsive and non-impulsive wave conditions. The effects of geometrical design of recurve retrofitting on overtopping reduction are examined by four configurations with varying overhang length and recurve hight. The study revealed that the reduction in overtopping is primarily determined by the length of the overhang in the recurve wall, while the influence of the recurve height is limited. A longer overhang length results in a more substantial decrease in overtopping discharges on the seawall crest. The results also highlight the role of incident wave steepness and the crest freeboard on the overtopping mitigation performance of the recurve walls. A new enhanced methodology is proposed to predict the wave overtopping from vertical seawalls with recurve retrofitting., considering the effects of freeboard and wave steepness. The findings of this study provide new important insight in the role of retrofitting as a robust intervention to improve the wave overtopping mitigation performance of seawalls. The predictive empirical formulae proposed by this study facilitate readily and accurate estimation of overtopping rates as a function of retrofitting geometrical design, allowing for wider application of retrofitting solutions.