Integrating geospatial techniques and multi-criteria decision analysis for physical flood vulnerability assessment in Sibu, Sarawak

Abstract

Flooding is one of the most frequent and economically damaging natural disaster in Malaysia. Determining exposed elements vulnerable to flood is essential in flood risk management. This study aims to develop a micro-scale physical flood vulnerability assessment for buildings and roads in Sibu, Sarawak, Malaysia. Indicators of each element-at-risk were grouped into three clusters: (i) building or road characteristics (C), (ii) flood intensity (I) and (iii) surrounding environment (SE). The indicators were further refined and validated for relevance based on expert opinions. The analytical hierarchy process (AHP) and analytical network process (ANP) were applied to assign priority weights to selected indicators and the weighted linear combination (WLC) produced a flood vulnerability index (FVI). The outputs were validated against flood damage data obtained through field observations. The results provide the spatial distribution of physical flood vulnerability index in Sibu, Sarawak and the degree of expected vulnerability is expressed on a scale between 0 and 1 (very low vulnerability to very high vulnerability to flood). The contribution combines a geospatial-based approach with expert knowledge-driven methods to assess micro-scale physical flood vulnerability in Sibu, Sarawak. It extends prior Peninsular Malaysia work by testing indicator interdependencies in a low-lying East Malaysia setting. The models could contribute to local authorities and stakeholders to support more effective flood risk mitigation strategies.