A comparison of single- and multi-gauge based calibrations for hydrological modeling of the Upper Daning River Watershed in China's Three Gorges Reservoir Region

Many parameters in hydrological models cannot be measured directly and should be estimated through calibration. In this study, four separate calibration schemes, including a multi-gauge and three single-gauge ones, were conducted to simulate the daily stream flow of the Upper Daning River in China's Three Gorges Reservoir Region using the Soil and Water Assessment Tool (SWAT). A highly efficient calibration technique – the Sequential Uncertainty Fitting version-2 (SUFI-2) procedure – was utilized in the calibration and validation. Results indicated that all four schemes could obtain satisfactory parameter sets, and there were no obvious differences between the simulation results obtained by the multi- and single-gauge calibration schemes in terms of Nash–Sutcliffe efficiency value (E_NS). This might be attributed to the uniformly distributed land uses, similar topography variations and the low resolution of soil type map of the study area.