TSUNAMI HAZARDS: FLOW RESISTANCE AND IMPACT MITIGATION BY COASTAL GREEN BELTS

Abstract

In the aftermath of the Indian Ocean Tsunami, the protection offered by coastal vegetation became evident in many countries affected and the role of coastal green belts in mitigating tsunami impacts has now been clearly recognized. Coastal green belts also attract attention as an environmental friendly and cost effective measure of impact mitigation. In this research, attention was concentrated on expanding the preliminary experimental on the resistance offered by coastal vegetation to tsunami overland flow, to determine the energy dissipation characteristics in detail,  and to assess the effectiveness of coastal green belts in tsunami impact mitigation. Detailed experimental studies were conducted in which the vegetation was represented by geometrically similar small scale models. The effectiveness of coastal green belts was assessed by the percentage energy reduction for various forms of vegetation. Reduction levels in the range up to 30 % were obtained in the experiments indicating the possibility of achieving significant levels of energy reduction of tsunami inundation by coastal green belts. The reliance of the level of inundation reduction on the level of energy dissipation was also investigated.