Performance Of Mangrove� Forest In Coastal Protection

This study aims to analyze the parameters of mangrove vegetation and wave that influence the ability of mangrove forest in dissipating surface wave. Surprisingly, in December 2004, mangrove trees have shown impressing resistant to the forceful impacts of the Indian Ocean Tsunami. It is reported that approximately 200,000 people dead in the countries around the Indian Ocean and scientist observed that the mangrove forests protected villages from the worst destruction. With the urge for mangrove protection and replanting, questions were raised about the degree to which the mangrove forests are able to reduce damages to the property and loss of human life. In recent years, mangroves have been studied extensively but they still remain poorly understood. This research focus on performance of mangrove trees Rhizophora spp, of age ten years old. This research comprises of site visits, field measurements as well as laboratory experiments. The site visits were conducted to observe the behaviour of waves propagating through mangrove forests and to obtain the dimensions of mangrove trees, specifically Rhizophora spp. The dimension were then scaled down to 1:10 and modelled in the wave flume in laboratory. The parameters tested include forest density, tree arrangement, age, incident wave height and water depth, in a narrow wave flume by using artificial mangrove models. It is found that wave height reduction in the area of 100 m mangroves of age 10 years old was 2.5 times larger than area without mangroves whereas for area with mangrove of age 20 years old is 4 times greater compared to area without mangrove. The difference of wave reduction between tandem and staggered arrangement was less than 3 %, which was not significant. For a 200 m mangrove forest width, a density of 0.11 trees/m² is sufficient to reduce wave height over 77 %. Significant wave reduction was shown when water level was within the height of the roots. At this shallow water depth, the higher the wave heights, the more wave reduction occurred. The experimental results were also compatible with the results of field observation at Pantai Teluk Tiga, Perak.