基于SWAT模型的半城子水库流域径流模拟

SWAT model-based runoff simulation in Banchengzi Reservoir Catchment,Beijing

该文应用分布式水文模型(SWAT模型)对半城子水库流域的径流状况进行模拟研究,并重点探讨森林植被变化对水文生态响应的影响。对半城子水库流域1990—1999年期间年、月径流进行模拟,以月径流模拟的效率系数、相对误差和相关系数3个指标为标准,对模型的敏感参数进行率定,并对2000—2006年的月径流进行验证模拟。结果表明,该模型适用于半城子水库流域的径流模拟,且精度较高。然后基于SWAT模型的模拟分析结果,应用GIS的空间分析功能,分析了半城子水库流域在1990、1995、2000和2005年的径流分布以及不同土地利用类型对水文响应影响的贡献。结果表明,降雨和土地利用变化对径流产生了较大的影响。降雨较多的月份,产生的径流也较大;降雨较少的月份,产生的径流也较小。土地利用的变化主要表现在灌木林和针叶林面积的减少和阔叶林面积的增加,相应的水文变化表现为径流量的减少。其中,针叶林和针阔混交林产生的径流量最大。

The runoff in the Banchengzi Reservoir Catchment,Beijing,was simulated using a SWAT(the Soil and Water Assessment Tool)model,and our emphasis was placed on impacts of vegetation changes on the hydrological responses.The monthly and yearly runoff was simulated during the period of 1990--1999,and the sensitivity of the model was calibrated with three indices,i.e.,efficiency coefficient,relative error,and correlation coefficient of monthly runoff.Then the monthly runoff during the period of 2000--2006 was also validated.Results show that SWAT model was fit for the runoff simulation in the Banchengzi reservoir catchment with a high accuracy.Based on the simulation with SWAT model,we applied the spatial analysis functions of GIS and analyzed the runoff distribution in the year of 1990,1995,2000 and 2005 as well as the impacts of different landuse types on hydrological responses.Results indicate that precipitation and landuse changes had considerable impacts on the runoff.The months of more rainfall produced more runoff and vice versa.The landuse changes were mainly characterized by the decrease of shrub and coniferous forest areas and increase of broad-leaved forest areas.The corresponding hydrological changes were represented by the decline of runoff volume,of which,the runoff volume produced was the largest in coniferous forests and broadleaf-conifer mixed forests.