Impact of Urbanization on Flood Regime in Gullied Loess Plateaus Based on HEC-HMS
In the process of urbanization of gullied loess plateaus,the hardening of underlying surface will affect the hydrological regime of rainstorm,increasing the difficulty of flood simulation and prediction.In order to realize the early warning of urban flood disasters in the wa-tershed,this study based on HEC-HMS hydrological model,calibrated the runoff yield and concentration parameters under different land use conditions before and after the urbanization process of Yanwachuan watershed,carried out extreme rainstorm flood scenario design and re-vealed the hydrological effect of basin urbanization on rainstorm floods in different recurrence periods.The results show that the HEC-HMS rainfall-runoff model can be used for flood forecasting in gullied loess plateaus,the comprehensive qualified rate of its simulation is 81.25%and the average Nash efficiency coefficient is 0.82.The basin urbanization has the greatest impact on the changes in flood elements during the low recurrence period,and the change of flood volume is greater than the change of flood peak.The increase of flood peak and flood volume of 100-year flood is 4.54%and 6.40%respectively and the increase of flood peak and flood volume of 5-year flood is 7.06%and 9.49%respec-tively.The spatial response distribution of design flood elements in each sub-basin has significant differences,with the strongest response in the northwest,followed by the south and the weakest in the northeast of Yanwachuan watershed.
万方数据
维普
