Abstract: In order to discuss the applicability of storm water management model for flood peak discharge simulation in mountainous area,in this paper the Qinghe River Basin in Xi’an was taken to carry out a case study on flood peak discharge using the traditional lumped model and the semi-distribution model. The semi-distribution model was based on DEM and drainage basin system to develop the SWMM model.Two different modes of hydrological models could be validated by the peak discharge during several typical rainfall episodes in 2016.The results showed that the lumped pattern was in good fitting with the measured values,the relative error was only 6%,and the deterministic coefficient was 0.871.In order to further test the applicability of the lumped model,the results were satisfactory from the perspective of runoff process.The relative errors of the two rainfalls were 11%,and the certainty coefficient and Nash coefficient of the two rainfalls were higher than 0.8,which revealed that the good results were achieved in the simulation.Therefore,the lumped hydrological model based on SWMM is suitable for simulating the runoff discharge in the Qinghe River Basin.At last,the runoff processes in the drainage basin under different recurrence periods were simulated.The flood peak discharge occurred about 1.5 hours after starting rainfall,and the change of runoff discharge will be relatively stable during the following decade.This model has a certain application value to the local water conservancy department in assessing extreme rainfall events.

Key words: storm water management model, runoff simulation, rainstorm, Qinghe River Basin, Xi’an