Studying the main factors and prioritizing the flooding potential of subwatersheds using fuzzy topsis and electre III, case study: Sarkhoon Watershed

Exact estimation of flood-water peak discharge and prioritizing the flooding potential in subwatersheds in main watersheds is necessary (because of cost, watershed restoring is not practicable in all subwatersheds), moreover flood may occur only in some specefic subwatersheds. This study was conducted in Sarkhoon watershed of Bandarabbas (South of Iran) with the aim of developing a flood prioritizing method in small catchments. The resarch was carried out using ElectreIII and Fuzzy Topsis methods belonging to multicriteria models. For the analysis, 7 criterions were selected that includes:  Basin mean weight slope, gravilus coefficient, permeability, runoff coefficient, shape coefficient, vegetation cover and rainfall intensity with 25, 50 and 100 years return periods. Then the criterion weights were determined using AHP method and for selecting the best hierarchy and function of electre III and Fuzzy Topsis, the spearman coefficient were utilized and the results showed a correlation coefficient of 0.8 between predicted and actual flood peak values. In the final step the combination method for the final prioritizing was adopted. Results showed that subwatersheds 18-1-1, 14 and 18-1-2 have more flooding peak. It was concluded that the combination method can promise as a suitable method for prioritizing the flooding potential in subwtersheds.