Comparison of weighting methods of multi-criteria decision analysis (MCDA) in evaluation of flood hazard index

Abstract

AbstractPreparing a map of flood hazard susceptibility is an important step in flood risk management. Therefore, it is necessary to use methods that reduce errors and increase accuracy in identifying flood hazard areas. This study was conducted with the aim of preparing a map of the flood hazard index (FHI) and evaluating subjective and objective multi-criteria decision analysis (MCDA) weighting methods. Talar basin on the north of Iran has been investigated as a case study for this research. Seven flood-influencing factors including elevation, slope, flow accumulation, distance from the river, rainfall intensity, land cover, and geology were used to create a flood hazard map. The weighting of these factors has been performed by Analytical Hierarchy Process (AHP), sensitivity analysis of AHP (AHPS), Shannon Entropy (SE), and Entropy-AHP. The maps created with the data of past floods were validated with ROC and Kappa index methods. The results showed that the FHI-SE method was more accurate than other methods with an accuracy value of 0.979. FHI-SEA, FHIS, and FHI methods were placed in the next priorities, respectively. Based on the SE method, the factors of distance from the river, elevation, and slope respectively have obtained the highest weight value in creating the flood hazard index map. Different classifications of distance from river variables separately for mountains and plains can reduce the overestimation of flood hazard areas in mountainous areas. The objective weighting method has provided more accuracy than the subjective weighting method such as AHP.