تحلیل حساسیت متغیرهای موثر بر سیلاب شهری با استفاده از مدل SWMM

Complex in hydrological and hydraulic processes are one of the distinguishing features of urban areas. Therefore, accurate determination of the input variables of urban models and their impact on model output is time consuming and difficult. Sensitivity analysis shows which parameters impact more severely the results and ranked model parameters according to their effect on model output which can be calculated using this method. In this study the sensitivity of affective variables that influence urban flood peak, was studied by using the SWMM model in Imam Ali town in Mashhad city. The initial value of the eight-parameter including percentage of impervious area (%Imperv), slope, width, N-Manning for impervious area, N-Manning for pervious area, depth of depression storage on impervious area, depth of depression storage on pervious area and percent of impervious area with no depression storage reduction (%Zero-Imperv) and increases in the range of acceptable change and flood peak discharge was selected as the dependent variable. Result showed that with 30% increase in the amount of impervious areas, peak discharge increases 3.38 percent and this parameter was recognized as the most effective parameter and percent of impervious area with no depression storage has the minimum impact on peak discharge. It is recommended to increasing in the amount of impervious areas that causes from land use change, urbanization, no doctrinaire infrastructures causes increases in peak discharge and flood risk hazard in urban area.