Evaluation of Storm Water Management Model (SWMM5.0) in simulation of urban runoff (case study: urban catchment of Neyshabur)

The increasing of urbanization and the increase of impervious areas in cities has as a consequence extreme flooding events, with increase in citizens’ problems and economical losses. In order to be able to overcome mentioned problems, computer models are an appropriate solution. The use of hydrological- model to simulate the runoff necessitates the proper calibration of the different parameters involved in the routed hydrograph. Therefore, In the present study, the Storm Water Management Model (SWMM5.0) was chosen to simulate quantity of runoff of an urban subcatchment, located in Neyshabur. Data from nine rainfall events were collected. the model was calibrated using six rainfall events and validated using three new events.  The model performance was evaluated based on the Normalized Root Mean Squared Error (NRMSE), Coefficient of Residual Mass (CRM), and EFFiciency of model (EFF). The results showed that the SWMM model could simulate accurately the shape of the hydrograph, the peak discharge and the time of peak. For validation events, values of NRMSE, EFF and CRM were 29.4%, 80% and -0.16 m3/s, respectively. Overall SWMM model was found to be a very useful modelling tool, which can be used for the simulation of urban runoff hydrographs. finally, the evaluated model used to simulate 2, 5 and 10-year return period flood.