Automatic calibration of SWAT model in the head region of the Yellow River

This paper describes the application of Soil and Water Assessment Tool(SWAT) to the head region of the Yellow River, which is located in the eastern part of Tibetan plateau. Available weather data from 17 weather stations in and around the focus area and stream flow data from Tangnaihai stream gauge station for the period 1984-1997 were used in the flow calibration and validation. LH-OAT(Latin Hypercube one-factor-At-a-time) method was firstly employed to decide 12 most sensitive parameters. Subsequently, the Shuffled Complex Evolution algorithm(SCE-UA) was applied to SWAT model to get a group of optimized parameters. Three quantitative statistics, Nash-Sutcliffe efficiency, percent bias and coefficient of determination, in addition to the graphical techniques, were used in model evaluation. Nash-Sutcliffe efficiency for calibration and validation respectively, are greater than 0.7, implying good performance of SWAT model in the head region of the Yellow River.