Effect of erosion scarp on wave attenuation ability of Rhizophora sp.

Abstract

Mangroves are trees and shrubs that grow in saline coastal habitats in the tropics and subtropics, mainly between latitudes 25 ° N and 25 ° S. The saline conditions tolerated by various species range from brackish water, through pure seawater (30 to 40 ppt), to water of over twice the salinity of ocean seawater, where the salt has become concentrated by evaporation. Mangrove forests cover large parts of the tropical and subtropical shores in the world. The forests are the breeding grounds for sea life as fish, shrimp, prawns, crabs, shellfish and snails and also nesting sites for many shore birds as well as a home to crab eating monkeys, fishing cats, lizards, and sea turtles. Mangroves protect the coastline and prevent erosion by collecting sediment from the rivers and streams and decelerating the flow of water. Moreover, the roots, stems and canopies attenuate and dissipate wave energy, acting as a natural sea defense. Erosion scarp is one of the shore morphology. It forms by the strong wave energy hit the river bank and make erosion. The erosion made the coastline vertical like a wall that it is approximately 90 degree. The wave that pass trough erosion scarp will increase in height and automatically the energy of the wave is also increase. This is because the wave propagates from deep water into shallow water. This study is to know the effect of erosion scarp on wave attenuation ability of mangrove forest. This is very important in order to identify the factors of coastal erosion to prevent the degradation of mangrove forest. From the result, the erosion scarp helping the wave increase in height. This is because the wave that propagates from the deep water into shallow water. Erosion scarp is one of the natural creation but it also give bad impact on shoreline.