Effect of coastal vegetation on attenuation of non-breaking solitary wave force in sloping coast lines

Wave attack is the main source of irreparable damages to the sea coast line. The coastal protection techniques are now improved from structural protection to biological ones. This includes plantation of trees and development of vegetation canopy (called green belt) along the shorelines and protection of coastal structures against the waves created by tsunami. For this¡ the application of green belt has been studied and effect of vegetation density and wave height on wave force is evaluated for waves in broken condition. Experiments were conducted in a flume with 8.3m length¡ 0.8m width¡ and 0.55m height. Experimental variables include four bed slopes¡ four vegetation densities¡ and 110 wave heights. The results show that absorption of wave force increase with increase of wave height and density of vegetation. At the highest vegetation density the wave force effect was reduced by about 75% compared to the case without vegetation.