Author(s): M. B. Samarakoon; Norio Tanaka
Linked Author(s): Norio Tanaka
Keywords: No Keywords
Abstract: The construction of hard infrastructures for mitigation of tsunami is not a feasible solution because of high capital cost and also establishment of a hard infrastructure for tsunami mitigation has adverse effects on the ecology and aesthetics of a beachfront. Coastal vegetation can play a significant role in reducing the severity of a tsunami because the energy associated with the tsunami is dissipated when it passes through a coastal forest. The objectives of this study were to study the role of mangroves in dissipating energy associated with tsunami, situation of mangrove forests in coastal areas and future challenges of mangrove forests in Sri Lanka. The available primary data was used to collect required information for the research. The results of the study revealed that the water flowing within mangrove swamps is resisted by the drag force due to mangrove trees and their roots, by the bottom friction on the uneven mud floor, and by the eddy viscosity due to turbulent motions of water through narrow openings between trees/roots. Coastal areas with dense mangrove forests suffered fewer losses and less damage to property than those areas in which coastal forest ecosystems had been degraded or converted to other land use in Sri Lanka. However, the mangrove area is rapidly decreasing even after the 2004 tsunami in Sri Lanka. Finally, it can be concluded that there is a necessity for conserving mangrove forests in Sri Lanka for protecting from future natural hazards like tsunami.