SWAT模型在三川河流域的应用

Application of SWAT Model in the Sanchuan River Catchment

利用黄河中游干旱半干旱区三川河流域20世纪80年代的降雨径流资料,构建了三川河流域的分布式水文模型SWAT(Soil and Water Assessment Tool),并对三川河流域的月平均流量过程进行了模拟,分析了月径流量的变化特征。模拟结果表明,月平均流量较实测的结果偏大,模型率定期和验证期的Nash-Sutticliffe效率系数分别为0.711和0.725。虽然Nash-Sutticliffe效率系数基本符合精度要求,但是模型中一些参数已经达到模型设置的临界值,进一步分析得出,由于流域上雨量站的数据不够,以及中国与美国土壤、土地利用数据库编码的差异,使得模型模拟结果受到影响,并且三川河流域自70年代以来水土保持措施蓄水效益较为显著,在一定程度上使得径流量减少,使得模拟结果偏大。

In this study, a physically based distributed hydrological model, SWAT（Soil and Water Assessment Tool）, is applied to the Sanchuan River Catchment based on the precipitation and discharge data in the 1980s. Sanchuan River Catchment is located in the middle reaches of the Yellow River Basin with arid and semi-arid climate. The variation of monthly discharge from 1980 to 1985 were analyzed on the basis of the simulation for monthly discharges in the study area. The results shown that the relative error of water budget is about 10%, while the Nash-- Sutcliffe efficiency coefficient is 0. 711 in the calibration period and 0. 725 in the validation period. Although the Nash- Sutcliffe efficiency coefficient meets the demand of precision, some parameters＇ values are reached the threshold points which has been set in the model. Thus the parameters can not be consistent with their physical meaning. There are no enough precipitation data and some differents of soil and landuse database between China and Amercia. Since the 1970s, some measures have been taken in soil and water conservation, which resulted in the reduction of runoff to some extent. All these elements may result in larger simulation result than the observed one.