In this paper, new formulae are presented to estimate the wave overtopping rate of mass-armoured berm breakwaters. In addition to the effects of dimensionless crest freeboard and crest width, the formulae consider the influences of water depth at the toe of the structure and structure slope on the overtopping rate through simple dimensionless parameters. The performances of the new formulae were then compared with those of the existing empirical prediction formulae. Statistical indicators such as Root Mean Square Error (RMSE) showed that the new formulae are better predictors than the existing ones.
Breakwaters are built to protect coastal region from wave action and consequently flooding and erosion (Lara et al., 2008). Safety in a harbour can depend on the wave overtopping rate at breakwaters and therefore their appropriate design is critical (Van der Meer and Bruce, 2014). The mean wave overtopping must be less than the allowable rate under the design and operating conditions to ensure the safety of people, land and property behind the breakwater (Goda, 2009). Additionally, Zviely et al. (2015) reported that excessive wave overtopping can lead to extensive damage in port infrastructure and moored vessels. Thus a reliable estimation of wave overtopping rate is essential to reduce the risk associated with the failure of the breakwaters.