University of Tehran Press Journal of Ecohydrology 2423-6098 6 4 2019 12 22 Flood Reduction in Urban Basins Using LID- BMPs IN SWMM Model and Selecting The Best Option With AHP- TOPSIS (Case Study: Golestan Area in Semnan) Flood Reduction in Urban Basins Using LID- BMPs IN SWMM Model and Selecting The Best Option With AHP- TOPSIS (Case Study: Golestan Area in Semnan) 1003 1013 74199 10.22059/ije.2019.284215.1148 FA Seyedeh Zahra Miremadi M.Sc Student, Department of Water Engineering and Hydraulic Structures, Faculty of Civil Engineering, Semnan University, Semnan, Iran Hojat Karami Assistant Professor, Department of Water Engineering and Hydraulic Structures, Faculty of Civil Engineering, Semnan University, Semnan, Iran Khosrow Hosseini Associate Professor, Department of Water Engineering and Hydraulic Structures, Faculty of Civil Engineering, Semnan University, Semnan, Iran Sayed Ali Asghar Hashemi Assistant Professor, Agriculture and Natural Resources Research and Education Center of Semnan, Semnan, Iran Journal Article 2019 05 22 With the passage of time and progress of civilizations, access to sufficient and high-quality water resources in order to provide the needs of human societies, becomes ever more important. With increasing impenetrable surfaces in urban areas and its resulting flood hazards, the new prespective of management methods of LID- BMPS has been considered in order to use surface run-off, decreasing peak discharge and preventing floods in urban areas on developed or developing parts. In this research, the effect of correction of channel dimensions, reservoir design for flood control and provision of required water for the green area and the use of LID facilities including implementation 100% of  permeable pavement for sidewalk areas and rain barrels in two conditions (using 100% of the surface of the roof) and (using 50% of the surface of the roof) on decreasing peak discharge and the volume of flooding 12 sub-basing in the study area of Golestan settlement in Semnan city was evaluated using SWMM model. Finally, by using AHP- TOPSIS methods, rain barrels (using 50% of the surface of the roof) with about 81% reduction of peak discharge flood for the return period of deasining 5 year and 78% reduction of peak discharge flood for the return period of designing 10 years have been allocated themselves the first and the last rank of correction of channel dimensions. With the passage of time and progress of civilizations, access to sufficient and high-quality water resources in order to provide the needs of human societies, becomes ever more important. With increasing impenetrable surfaces in urban areas and its resulting flood hazards, the new prespective of management methods of LID- BMPS has been considered in order to use surface run-off, decreasing peak discharge and preventing floods in urban areas on developed or developing parts. In this research, the effect of correction of channel dimensions, reservoir design for flood control and provision of required water for the green area and the use of LID facilities including implementation 100% of  permeable pavement for sidewalk areas and rain barrels in two conditions (using 100% of the surface of the roof) and (using 50% of the surface of the roof) on decreasing peak discharge and the volume of flooding 12 sub-basing in the study area of Golestan settlement in Semnan city was evaluated using SWMM model. Finally, by using AHP- TOPSIS methods, rain barrels (using 50% of the surface of the roof) with about 81% reduction of peak discharge flood for the return period of deasining 5 year and 78% reduction of peak discharge flood for the return period of designing 10 years have been allocated themselves the first and the last rank of correction of channel dimensions. https://ije.ut.ac.ir/article_74199_53443051d718cfe40b02af9f12991335.pdf