Abstract：Inaccurate subbasin definitions will affect soil and water assessment tool (SWAT) model results in plain irrigation districts. The SWAT model watershed delineation method was modified by preprocessing of digital elevation model (DEM) and joint use of automatic and pre-defined methods. This improved method was then applied to the Ninth Drainage Ditch Watershed of the Hetao Irrigation District in Inner Mongolia, China. The results show that the improved method generates specific subbasins corresponding with specific levels of the drainage ditches. This method increases the subbasin boundary agreement rate by 61% compared with the original automatic delineation method, improves the river agreement rate by 4% and improves the total watershed coverage rate by 4%. The hydrological simulation results of the improved SWAT model agree well with the measured data; thus, this method is more practical for the special management requirements of plain irrigation districts.
姜婧婧, 杜鹏飞. SWAT模型流域划分方法在平原灌区的改进及应用[J]. 清华大学学报（自然科学版）, 2019, 59(10): 866-872.
JIANG Jingjing, DU Pengfei. Improvement and application of SWAT model watershed delineation method in plain irrigation districts. Journal of Tsinghua University(Science and Technology), 2019, 59(10): 866-872.
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2019, Vol. 59 
