土地利用变化对云龙水库流域径流的影响

Effects of Land Use Change on Runoff in Yunlong Reservoir Basin

人类对不同土地的利用方式导致下垫面发生变化,进而影响流域的水文循环。以云龙水库流域为研究对象,结合ArcGIS构建了SWAT模型(soil and water assessment tool,SWAT),并设置6种不同的土地利用情景模式研究不同的土地利用变化对径流的响应。结果表明:率定期R^(2)=0.80,E_(ns)=0.75,验证期R^(2)=0.82,E_(ns)=0.88,模型适合研究区的径流模拟。2000—2020年,林地、耕地和草地的土地利用面积之和占总面积的97%以上,占比较大。不同土地利用情景模式下,2000—2020年,年平均径流量增加了0.03%;极端土地利用情景S_(1)、S_(2)和S_(3)的年平均径流量分别变化了-0.96%、-5.83%、5.98%,说明耕地有增加径流的作用,林地和草地有减少径流的作用。与2020年的水文要素相比,S_(1)、S_(2)和S_(3)各水文要素都发生改变,其中蒸发变化不大,土壤水渗透量、地表径流、地下径流、产水量变化显著。

Different land use patterns lead to the change of underlying surface,which affects the hydrological cycle of the watershed.Taking Yunlong Reservoir Basin as the research object,we constructed SWAT model(soil and water assessment tool,SWAT)based on ArcGIS and set up six different land use scenarios to study the response of different land use changes to runoff.The results show that:the periodic R^(2)=0.80,E_(ns)=0.75,the validation R^(2)=0.82,E_(ns)=0.88,the model is suitable for runoff simulation in the study area.From 2000 through 2020,the land use types in the study area are mainly forestry land,farmland and grassland,the sum of three kinds of land use area accounted for more than 97%of the total area,which was relatively large.The different situation of land use patterns showed that the annual runoff increased by 0.03%from 2000 to 2020;The annual runoff of extreme land use scenarios S_(1),S_(2) and S_(3)changed by-0.96%,-5.83%and 5.98%,respectively,illustrating the farmland has the effect of increasing runoff,while forestry land and grassland have the effect of reducing runoff.Compared with the hydrological factors in 2020,each hydrological factor S_(1),S_(2) and S_(3) has changed.Evaporation has little change,but soil permeability,surface runoff,underground runoffand water yield have significant changes.