Comparison of Runoff Parameterization Schemes with Spatial Heterogeneity across Different Temporal Scales in Semihumid and Semiarid Regions

Due to the spatial variability of precipitation, topography, soil properties, and antecedent soil moisture, runoff is generated by more than one kind of mechanism. Based upon digital elevation model-derived subcatchments and river network, the Xinanjiang Model (XAJ, saturation excess mechanism of rainfall-runoff partitioning), the Shaanbei Model (SAB, infiltration excess mechanism), and the Hybrid Model (HYB, two mixed runoff mechanisms by combining spatial distribution curves of soil tension water storage capacity and infiltration capacity) were applied for streamflow modeling at four hydrological observational stations in the Laohahe River basin, and compared at different time intervals ranging from 1 to 24 h. The results show that the daily (24 h) HYB Model or XAJ Model performs better than the SAB Model over semihumid and semiarid areas. It is revealed that there is less possibility that rain intensity is larger than infiltration rate in semihumid and semiarid regions within a duration of 24 h. Uniform distribution of precipitation within a duration of 24 h makes the physical concept of infiltration excess fuzzy. In the event-based flood modeling at time intervals of 1, 2, 3, 4, 6, and 12 h, HYB is superior to XAJ and SAB in semiarid areas where the mean annual precipitation is less than 400 mm. It is concluded that it is more meaningful to use infiltration excess mechanisms for shorter-duration flood modeling than for daily streamflow simulation in semihumid and semiarid regions.