Assessment of vulnerability for coastal erosion with GIS and AHP techniques case study: Southern coastline of Sri Lanka

Abstract

AbstractCoastal Vulnerability Index for erosion was introduced for southwestern coast of Sri Lanka in this study. Slope, geomorphology, erosion rate, dune width, tide direction, tidal range, wave height, protection methods and adjacent land use type were used as variables. Existing maps, Google Earth images, field observations, and questionnaire surveys were used as data sources and decision model was prepared using GIS technique. Weights for the model were determined through questionnaire surveys and analytical hierarchical process technique. It was revealed that 7.5% and 23.7% of coastline are very highly and highly vulnerable for coastal erosion, respectively. A total of 27.11% of study area was classified as moderately and 29.4% as lower vulnerable. Only 12.25% of the line is very low vulnerable for coastal erosion. Two hot spots were identified to be given immediate attention. Coastal slope was recognized as most influential factor for high vulnerability using Pearson product moment correlation coefficient values.Summary for Managers It can be concluded that the southern coastline of Sri Lanka is in risk and immediate attention of policy makers for mitigation process is highly recommended. It is recommended to construct artificial barriers after analyzing the characteristics and the profile of the coast. Special attention is highly required for hot spot areas in Kahawa and Hikkaduwa coastal areas. Furthermore, study recommends to introduce different buffer zones for various purposes and uses.