A comparison of three multi-criteria decision-making models in mapping flood hazard areas of Northeast Penang, Malaysia

Flooding is a major and recurring natural disaster in Northeast Penang, Malaysia. The ability to effectively identify flood hazard areas represents an important part of flood risk analysis and management. There is a need for a structured study that incorporates stakeholders' inputs such as the multi-criteria decision-making (MCDM) model to delineate flood-prone locations to support the management and mitigation measures of flooding in this area. Previous studies have compared the analytic hierarchy process (AHP) and fuzzy AHP methods in flood hazard mapping. Therefore, this study proposes to test the predicting capability of three MCDM models in the determination of flood-prone areas: the AHP, triangular fuzzy AHP (TF-AHP), and trapezoidal fuzzy AHP (TZF-AHP) in this area. The methodology applies nine flood-causative factors (FCFs) which include drainage density, elevation, land use, slope, rainfall, flood depth, distance from rivers, lithology, and distance from inundation. The resulting flood hazard maps showed a closer similarity between the TF-AHP and TZ-AHP methods compared to the AHP method for flood hazard mapping. The sensitivity analysis indicated that the AHP was more accurate than the fuzzy AHP models based on the weight estimation. The validation results showed that 100%, 93%, and 93% of the actual flood events occurred in the 'moderate' to 'very high' flood hazard areas for the AHP, TF-AHP, and TZF-AHP, respectively. Overall results showed the accuracy of all three models in modeling flood hazard areas. Therefore, the findings can be adopted as a tool in making informed and accurate policies about flood management for effective climate mitigation decision making.