Comparison of Models TOPSIS, SAW, ELECTRE and VIKOR in order to the prioritization of sedimentation and flood hazard of watersheds

To determine and zonation of flood prone hazardous area and prioritization the sub-basins in terms of flood potential can have great contributions in promising watershed management. The present research aims to prioritize flood and sedimentation potential in the sub-basins of the Bonekooh watershed using TOPSIS, SAW, ELECTRE and VIKOR methods.

In this present study, we used area estimation indices, drainage density, gravel coefficient, basin average height, basin average slope, curve number, sediment yield, cover percentage, sediment delivery ratio, runoff height and concentration time as an important indicators affecting water permeability, runoff production and, consequently, the potential for flooding and sedimentation. Then, using the Analytic Hierarchy Process (AHP) method, the weight of each index is met. Following the formation of decision matrix with 18 options (sub-basins) and 11 criteria (evaluation index), Technique for order Preference by Similarity to ideal Solution (TOPSIS), Simple Additive Weighting (SAW), Elimination Et Choice Translation Reality (ELECTRE) and Vise Kriterijumska Optimizacija Kompromisno Resenje (VIKOR) techniques were used to prioritize sub-basins. Borda and Copland methods were used to combine the rank of proposed techniques. The residual sum of squares (RSS) method was used to determine the closest method to the final result. Also, in order to validate the models, we estimated the percentage change and the intensity of the changes.

The results showed that the highest runoff height index (0.18) and the gravel coefficient had the lowest weight (0.028), according to experts. Prioritization results showed that in SAW, TOPSIS and VIKOR methods, sub-zones 9, 4, and 2 ranked first to third priorities respectively and are in a more critical situation, but in the ELECTRE approach sub-basins 9, 4, 2 and 7, respectively, have the first to third priorities. Considering the results of the combined ranking of the proposed techniques, sub-basins 9, 4 and 2 are in first to third priority, respectively, and have a more critical situation than the rest of the sub-basins. Also, zones with flood and sedimentation potential in the area showed that 32% of the area in high and very high risk. The results of the sum squared error showed that the VIKOR method had the least error and the ELECTRE method had the most error than the final ranking. Also, the TOPSIS and VIKOR methods with the lowest percentage of change (59.72%) were ranked first and the ELECTRE method with the highest percentage change (65.27%) is the last rank. The lowest intensity was also observed in the VIKOR method (4.59) and the highest intensity variation was observed in ELECTRE method (5.61).

Therefore, it can be said that multi-criteria decision-making techniques are a practical and appropriate approach for better decision-making based on mathematical sciences and optimization. Therefore, these types of low-cost and fast-track research can be prioritized to protect watersheds.