SWAT模型流域划分方法在平原灌区的改进及应用

Improvement and application of SWAT model watershed delineation method in plain irrigation districts

不准确的子流域定义会影响土壤和水评估工具(SWAT)模型在平原灌区的模拟结果。针对SWAT模型流域划分,提出基于数字高程模型(DEM)预处理和SWAT模型自动与自定义划分方法联用的改进方法,并以内蒙古河套灌区九排域为例进行应用。结果表明:相较于SWAT原有自动划分方法,改进方法能够生成案例区域特定级别排沟对应的所有子流域,子流域边界识别率、河网识别率、总流域覆盖率分别提升61%、4%、4%;基于改进划分方法构建的SWAT模型水文模拟结果与实际情况吻合良好。改进方法能够有效提升SWAT模型在平原灌区特定级别的水文管理中的适用性。

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.