SWAT模型在黑河中上游流域的改进与应用

Improvement and Applications of SWAT Model in the Upper-middle Heihe River Basin

基于物理机制的分布式水文模型是定量化研究人类活动影响下流域水文过程非常有效的工具。使用SWAT(Soil and Water Assessment Tool)对黑河中上游流域2000—2009年的月平均径流过程进行模拟的结果表明,SWAT模型很好地模拟了黑河上游自然状态下的径流过程,但对中游地区冬季径流模拟明显偏低。分析表明,黑河中游地形和农业生产高强度、反复的地下水抽取灌溉—渗透—地下水补给过程可能是导致模拟偏低的主要原因。基于此机制,论文提出了增加地下水下渗过程的模型修改方案,来间接模拟黑河中游的这一特定过程。对比模型修改前后的黑河中游的径流过程模拟结果表明,验证期的模型效率系数ENS和决定系数R2分别从0.53、0.61提高到了0.70、0.75,取得了较好的模拟结果。结果还表明,加强对黑河中游人工灌溉过程的模拟研究对于研究黑河中游水资源管理和水循环过程至关重要。

Heihe river basin （HRB） is the second largest inland river basin in China, and it also is a typical water shortage region. In this study, the Soil and Water Assessment Tool （SWAT） model is applied to simulate the monthly average runoff in the upper and middle reaches of HRB from 2000 to 2009. The results show that the SWAT model can simulate the runoff processes well in the upper reaches of HRB. The Nash-Sutcliffe coefficient （ENS） and coefficient of determina- tion （ R2 ） during the calibration period of 2005 to 2009 were 0. 81 and 0. 85, respectively. But the monthly runoff in the middle reaches of HRB was underestimated in winter. The complex to- pography and high intensity repeated groundwater irrigation - infiltration - replenishment in the middle reaches of HRB are suggested to be the primary cause. Based on the analyses of hydrologi- cal situation in middle reaches of HRB, a empirical method was proposed to simulate the runoff process by increasing the soil water infiltration of the SWAT model. The Nash-Sutcliffe coefficient （ENS） and the coefficient of determination （R2） of monthly average runoff simulation for middle reach of HRB during the calibration period increased from 0.53 to 0. 70 and 0.61 to 0. 75 after the modification of the SWAT model. The results indicated that the simulation of the irrigation processes was important to study the water resource management and the water cycle processes in the middle reaches of HRB.