Application Comparison of three Hydrological models in Semi-arid Region

Three models, Xinanjiang, HEC and TOPMODEL, are used in flood simulation of the Gaoli basin. Gaoli basin is a sub-basin of the Yihe basin and it is located in the semi-arid region. Although the structures of runoff-formation of the three models are of the saturation runoff type, the simulated results are good. Because the time step is two hours for the hydrological data, the mechanism of runoff-formation through rainfall-excess could not be distinguished from the historic hydrological data. In semi-arid watershed, stable infiltration can usually be obtained in one hour. Therefore, in order to distinguish the mechanism of runoff-formation from the historical hydrological data, the step-time of the data should be less than 0.5 hour.