Integration of bathymetric and topographic data for partial assessment of coastal vulnerability index in Malaysia

Abstract

Coastal area is a dynamic area of interaction between land and water. Seamless coastal mapping allows coastal management authorities to identify the characteristics and the transition process from land to sea. Recently, researchers have developed the Coastal Vulnerability Index (CVI) to determine the vulnerability of coastal areas to coastal hazards such as coastal erosion. Malaysia implemented its pilot project of CVI at Tanjung Piai, Johor and Pulau Langkawi, Kedah in 2007. However, the analysis of CVI parameters was carried out separately and a large scale of coastal mapping has not been carried out yet. There are six physical parameters of CVI, namely shoreline change rate, coastal slope, relative sea-level change, tidal range, geomorphology and mean wave height. In this study, two parameters which are shoreline change rate and coastal slope were analyzed to determine the coastal vulnerability of study area. At present, in Malaysia there is no single technology that can measure both terrain height and water depth to a suitable level of accuracy and density to develop a seamless coastal mapping. LiDAR (Light Detection and Ranging) technology has the ability for measuring terrain heights, but, it does not have the ability to penetrate water to yield bathymetric result. In this study, the bathymetry data and LiDAR data were integrated to develop a seamless coastal mapping by standardizing the vertical datum and the coordinate system. Additional information of water level was added into coastal mapping to delineate the shoreline positions and to determine the shoreline change rate. The results show that the area of Minyak Beku, Batu Pahat, Johor is located at low lying region and eroded at a magnitude of more than 6m per year. In conclusion, integration of bathymetric and topographic data could generate a seamless coastal mapping as a support for CVI analysis.