基于SWAT模型的洞庭湖区间径流模拟研究

Modeling of Interval Runoff Based on the SWAT Model for the Dongting Lake Basin

在人类活动强烈的在平原湖区,由于DEM精度较低,很难反映围湖造田形成的大量堤垸,径流的汇流过程亦会受到人工排涝的影响。针对人类活动强烈的洞庭湖湖区,结合GoogleEarth遥感卫星数据,识别出堤垸区的边界,以此修改研究区域的DEM来实现子流域的划分。对于堤垸区的汇流计算,采用天然出流过程的过去n d平均,以此反映人工排涝过程,从而能更好地利用SWAT模型对洞庭湖未控区间进行模拟。利用修改的DEM和过去n d平均出流的模型对流量进行了模拟,结果表明,改进后模型率定期的效率系数从0.88提高到了0.9,验证期的效率系数从0.85提高到了0.88。提出的模型改进方法,可为于平原湖区的水文模拟提供参考。

In the plain lake area where human activities are frequent,many polders designed for reclaiming land from lakes cannot be reflected by DEM,and water conservancy project will produce an effect on concentration.In this paper,the boundary of the polders of the Dongting Lake area are identified by the remote sensing satellite data of Google Earth to modify DEM and guide sub-basin delineation.The concentration module of SWAT model is replaced by the n-days average of natural runoff process.SWAT model can therefore be better used to simulate the uncontrolled zone of Dongting Lake.By using the modified DEM and the past n-day average outflow model,the interval runoff is simulated,and the result shows that the efficiency coefficient increases from 0.88 to 0.9 in calibration period,and from 0.85 to 0.88 in validation period.The proposed model is helpful for the application and research on the distributed hydrological model in the plain lake area.