Abstract:
The river network flow concentration parameter
Cs of the Xin'anjiang model is mainly controlled by topological and geomorphological characteristics of the river network. In order to address the issues of Predictions in Ungauged Basins (PUB), we developed a physically based method to estimate the values of
Cs in ungauged basins from the numerical solutions of the partial differential equations with proper definite solution conditions, which describe the dynamic changes of flow concentration processes of the river network. This method can be easily applied to the ungauged basins. To evaluate the robustness and effectiveness of this method, we applied it to derive the
Cs values of the Xin'anjiang model and calibrated the
Cs parameter directly in 25 humid and semi-humid basins in China. The results show that both derived and calibrated values were comparable to each other in general. Regardless of whether the catchment was divided into sub-catchments, the proposed estimation method was applicable. Although the model simulations using the estimated
Cs values were slightly poorer than those using calibrated
Cs values, these simulations were within the range of acceptable errors and satisfied the flood forecasting standard. Additionally, using the estimated
Cs and recalibrating the other parameters further improved the accuracy of resultant simulations. By adopting this method, the
Cs value can be obtained in the ungauged basins and makes it easier to apply the Xin'anjiang model in the ungauged basins.