Coastal Flooding and Protection from Bio-Shields

Abstract

In addition to the flooding associated with heavy rainfall, coastal flooding can also be caused by storm surges, tidal waves and tsunamis. The potential of such hazards to cause severe damages in coastal regions and the protection offered by bio shields—coral reefs, coastal sand dunes and vegetation was evident in the aftermath of the Indian Ocean Tsunami in 2004. In this investigation, attention was focussed on the mitigation of tsunami induced flooding by coastal vegetation and results of small scale physical model studies carried out to assess the energy dissipation characteristics of selected forms of vegetation and the reduction in the extent of inundation due to the presence of vegetation are presented. The results indicate significant levels of energy dissipation and reduction in the extent of inundation. A vegetation may be characterized by the type of plants, density (spacing), extent, pattern and location and the relative influence of these characteristics on energy dissipation and reduction of inundation are also presented.