子流域划分对SWAT模型模拟结果的影响研究

基于分布式水文模型SWAT,选择三峡库区支流大宁河为研究区域,在不同的子流域划分数量条件下,进行流域径流、泥沙以及营养物模拟计算,进而分析子流域划分对模拟结果的影响。研究结果表明:1不同子流划分方案对SWAT模型模拟结果存在直接影响。对于所研究流域,径流、TN和TP受到的影响较小,泥沙受到的影响较大。2为体现流域的真实河网水系特征,保证模拟效果,子流域划分个数不宜过少或过多。3在不同流域,子流域划分数目对径流、泥沙和营养物的变化趋势影响不同,不可同一而论。4推荐大宁河的子流域划分个数为37~121个。

Influence of different sub-watershed division schemes on simulation results of SWAT model

The distributed hydrological model-SWAT (Soil and Water Assessment Tool) is applied to analyze the influence of different sub-watershed division schemes on runoff yield, sediment yield and nutrient load in the Daning River watershed, a tributary of the Three Gorges Reservoir area. The results show that: ① The simulation results are directly affected by the division of sub-watershed in SWAT model. For the object area, the runoff yield, TN and TP load are slightly affected while the sediment yield is heavily affected. ② In order to reflect the real characteristics of the drainage network, sub-watershed division number should not be too little or too much. ③ The changing trend of simulation results are differently influenced by the subdivision level in different watershed. ④ The sub-watershed division number of Daning River is suggested to range from 37 to 121.