Flood Risk Map Based on GIS, and Multi Criteria Techniques (Case Study Terengganu Malaysia)

The heavy floods in the Terengganu have showed an increasing trend in recent years. Terrain characteristics of land and meteorological properties of the region are main natural factors for this disaster. In this paper, Terengganu was selected as the case study for flood risk analysis. Geographical Information System (GIS) is integrated with Multicriteria Decision Analysis (MCDA) to evaluate the potential flood risk areas. Some of the causative factors for flooding in watershed are taken into account as annual rainfall, basin slope, drainage network and the type of soil. The spatial multi-criteria analysis was used to rank and display potential locations, while the analytical hierarchy process method was used to compute the priority weights of each criterion. Using AHP, the percentages derived from the factors were Rainfall 38.7%, Drainage network 27.5%, Slope of the river basin 19.8% and Soil type 14%. At the end of the study, a map of flood risk areas was generated and validated with a view to assisting decision makers on the menace posed by the disaster.