Comparison of different objective weighting methods in a multi‐criteria model for watershed prioritization for flood risk assessment using morphometric analysis

Abstract

AbstractMorphometric analysis of watersheds coupled with multi‐criteria decision making (MCDM) techniques is a widely used approach in identifying and prioritizing subwatersheds for flood risk assessment. Finding the appropriate weight for each morphometric parameter is one of the most important steps in MCDM methods. The present research focuses on analyzing the effect of using objective weighting methods in watershed prioritization in Daroungar Watershed in Northeast of Iran. To this aim, the weights of morphometric parameters were determined using six objective weighting methods and were used for ranking subwatersheds based on flood generation by a multi‐criteria model. Study results show that the highest weight in various methods belonged to different parameters. Comparison of flood susceptibility ranking maps indicated, except standard deviation method, there is a significant correlation among WM, preference selection index, criteria importance through intercriteria correlation, entropy, and method based on the removal effects of criteria methods; however, the distribution of flood susceptibility classes is not the same in the six weighting methods. The flood hazard ranking map using aggregation methods depicts that subwatersheds 6, 74, 27, and 67 which have high priority for flood hazard, have the same rank in all aggregation methods. Overall, in the present study, the importance of choosing the appropriate weighting method in prioritizing watersheds was emphasized.