Prioritization of Low-Impact Development Methods for Management of Urban Surface Runoff, Using the Fuzzy TOPSIS and TOPSIS Method (Case Study: Sepahan-Shahr Town, Isfahan)

In recent decades, the percentage of residential areas has increased due to the expansion of urbanization. This has led to an increase in the percentage of impermeable areas, thus increasing surface runoff in cities. Therefore, it is necessary to control surface runoff values using strategies such as low-impact development (LID) methods in cities. In this study, 6 LID methods have been used, namely permeable pavement, rain barrel, infiltration trench, bio-retention system, impermeable pavement-infiltration trench, and rain barrel-bio-retention system. These methods have been evaluated by 4 criteria which are: reduction of runoff volume, reduction of peak discharge of runoff, economic and social criteria. The SWMM model has been used to determine the values of hydrological criteria. To determine the values of the economic criteria (cost), the price analysis list, and the social criteria, a questionnaire has been used by experts in the field. To prioritize LID methods, the Fuzzy TOPSIS and TOPSIS multi-character decision-making criteria have been used, in terms of the weighted entropy of the fuzzy Shannon for the Fuzzy TOPSIS method and terms of the weighted entropy, equal, emphasis on hydrological criteria and emphasis on economic criteria, for TOPSIS method. The results showed that in the TOPSIS method in terms of the weighted equal, emphasis on economic criterion and emphasis on hydrological criterion, bio-retention system & rain barrel and, in terms of the weighted entropy, rain barrel, selected as the best scenario. In the Fuzzy TOPSIS method, the rain barrel scenario was selected as the most efficient scenario and ranked first in the study area.