EVALUATION OF THE REDUCTION EFFECT OF WAVE ABSORBING WORKS ON WAVE RUNUP

Abstract

 Quantitative knowledge on effect of wave absorbing works to mitigate wave runup height on coastal dikes and revetments is limited, and the height of coastal dikes and revetments with wave absorbing works is usually set by using the reduction rate of required revetment height based on acceptable wave overtopping discharge proposed by Goda. This study evaluates the effect of wave absorbing works on wave runup height, by comparing with the measured wave runup heights by hydraulic model experiments on revetments with wave absorbing works by Matsushita et al. and the estimated ones by Integrated Formula of Overtopping and Runup Modeling (IFORM) by Mase et al. The results show that the reduction rate of wave runup height by wave absorbing works is in the range of 40-80% and increases with wave steepness. Additionally, the results imply that using the reduction rate of required revetment height by Goda may underestimate the wave runup height by wave absorbing works when wave steepness is 0.02 or less and the ratio of water depth to wave height at the toe of revetment is 1 or more.