Hydrodynamic modelling for mangrove reforestation at Tanjung Piai, west coast peninsular Malaysia

Abstract

Coastal erosion is greatly accelerated by the presence of agriculture and aquaculture activities (oil palm plantation or shrimp farming involving the construction of earth bunds) in the natural process. Earth bunds or dykes are constructed to prevent entrainment of seawater into the agriculture area behind the bunds so as to protect these valuable crops and plantings. Coastal erosion and mangrove belt depletion have exposed the earth bunds to direct wave impact. To prevent earth bund breaching and flooding of the area behind the bunds, the requirement arises to strengthen the earth bunds along the eroding coastline. Projects are carried out to replant the mangrove on the mud flats in front of the newly constructed earth bunds for its effective wave dissipating capability and environmental values. The replanting of mangroves on the mud flats in an open coast area requires protection from waves attack during the initial stage when the mangrove seedlings are still young and weak. In view of rather calm wave conditions along the west coast of Peninsular Malaysia, a settlement field made out of soil for mangrove seedling planting and temporary breakwaters built out of bamboo poles with stone filling as a line of protection is one of the possible methods to be studied for its possibility to be applied on the study area. This study aims to analyse the severity of coastal erosion and the hydrological aspects of Tanjung Piai; to identify the causal factors contributing to coastal erosion issue using numerical hydrodynamic modelling tool Delft3D; to identify existing or on-going restoration effort on site; and to explore restoration options that fit in the local condition. This report acts as a hypothesis analysis of erosion/sedimentation pattern at the study area.