THE COMBINATION OF LOW CRESTED BREAKWATER WITH MANGROVES TO REDUCE THE VULNERABILITY OF THE COAST DUE TO CLIMATE CHANGE

The potential impacts of climate change on existing coastal hazards are likely to increase. During this century our coastline is likely to be impacted by climate change. Impacts such as sea level rise and an increase in frequency and severity of storm events are likely to lead to a greater coastal inundation and erosion. Hard approach protection has been used despite the expensive cost and less environmentally friendly. It is necessary to develop an eco-protection concept using vegetation or combination of vegetation with civil structures. Combined model is likely to be cheaper and is environmentally sounder. This paper presents the results of experimental research on the performance of mangroves as shore protection (Thaha, 2003) combined with a low crested rubble mount breakwater by Seabrook & Hall (1998) in Pilarczyk KW et al. (2003). The results showed a maximum wave transmission can be reduce 48% up to 85% for tidal ranges of 2.00 m for a 50 m width of composite structures with mangrove relative roots density in the range of 0.009 to 0.073. The increase of transmitted wave height throught the LB-BW (without mangroves) due to the sea level rise can be reduced by combining it with mangrove forests where the mangrove wave damping capacity will increase by the growing of mangrove roots density. The combined equation of wave transmission coefficients consisting of both mangrove roots and low crest breakwater parameter is presented at the end of this paper