平原河网地区SWAT模型子流域概化方法

SUB-BASIN DELINEATION METHODS FOR SWAT MODEL IN PLAIN RIVER NETWORK REGION

针对平原河网地区SWAT模型子流域概化过程中存在的主要问题:1)基于DEM提取的河道和流域与实际不符;2)平原河网地区河道常分汊或呈网状,使SWAT模型无法识别;3)水利工程影响汇流过程,分别提出了相应的解决方案:1)基于高程值对原始DEM进行修正或人工绘制河道和子流域;2)将分汊河道处理成跨流域调水或对网状河流进行合理概化;3)人工划定子流域和增设虚拟水库.该方法在案例研究区的应用结果表明子流域概化结果比较符合平原河网地区实际水文过程,能够满足后续模型构建和应用的要求.

Sub-basin SWAT model applications in plain river networks face at least three difficulties. One difficulty is that sub-basins and rivers from DEM data do not agree well with practical situations. The divarieated or braided stream can not be identified by SWAT model. One further difficulty is that water-control projects affect seriously flow routing processes. Possible corresponding solutions were proposed. DEM could be corrected by modifying manually the elevation value and flow direction. Divaricated streams could be treated as trans-sub-basin water diversions, and river networks could be generalized rationally. Alternatively, sub-basin boundaries could be drawn manually and virtual reservoirs could be added. Watershed delineation results using these methods agreed well with the realistic hydrologic processes in plain river network region and would meet the demands of subsequent model setups and applications.