清漳河流域土地利用方式变化对径流的影响研究

SWAT Model of Runoff Research under Different Land Use and Land Cover Scenarios in Source Regions of Qingzhang River

土地利用方式的变化是影响流域径流的重要因素,利用基于GIS技术的分布式水文模型SWAT,以清漳河流域为研究对象,分析了不同土地利用方式对流域径流的影响。结果表明:率定后的模型适用于清漳河流域,模型率定期和验证期径流模拟的Nash-Sutcliffe效率系数分别为0.88和0.78,相关系数R2分别为0.90和0.79,相对误差Re分别为1.92%和-4.79%。不同的土地利用方式对流域径流有较大的影响作用,同草地和林地相比,城市用地与耕地均有增加地表径流的作用,但耕地相对于城市用地作用较弱;林地与草地均具有涵养水源的作用,但同林地相比,草地涵养水源的作用较差。为减少流域水土流失,应注意采取退耕还林还草,退草还林政策。

Land use change is an important factor affecting runoff.By using GIS technology,SWAT hydrologically distributed model is established to study the runoff response of the Qingzhang River under the scenarios of different land uses.The results show that：after calibration,the SWAT model suitable for Qingzhang River,relative error of average annual discharges reach 1.92% and4.79%,Ens reaches 0.88 and 0.78 and R2 reaches 0.90 and 0.79 in the model calibration and verification period respectively.The different land use patterns have a great influence on runoff,urban land and farmland increase surface runoff.But compared with the city,farmland is weak.Woodland and grassland can reduce surface runoff and have water conservation function,but the grass water conservation function is relatively poor.In order to reduce soil erosion,we should return farmland to forest and grassland,and return grass to forestry.