Experimental data analysis of wave attenuation in mangroves

Abstract

The ability of mangrove forest to absorb wave energy was reported in several tsunami events. However, characteristics of mangrove trees that can often withstand the impact of tsunamis, as well as their ability to absorb wave energy, are still an interesting area of research. Based on the experiments conducted in a wave flume at Balai Penelitian dan Pengembangan Pantai, Buleleng, Bali, the effectiveness of mangrove swamps in reducing wave energy was studied. In the wave flume, paddles were put in motion in order to produce monochromatic wave influx. These waves propagate into the domain, then passing through mangrove forest, and further up till the wave was reflected back by the right hard wall boundary. In this article, the Mansard-Funke 3-point method was implemented to decompose the recorded wave signal into incident and reflection waves. Furthermore, the reflection and transmission coefficients were calculated. From sensitivity analysis of experimental data using various water depth and wave period, we found that in a 3 meter length of mangrove, the wave energy was dissipated up to 64%.