气候和土地利用变化对大汶河流域径流的影响

Impact of Climate Change and Land Use on Runoff in the Dawen River Basin

为了分析气候与土地利用变化背景下大汶河流域径流的响应,利用土壤与水评价(SWAT)模型,设置5类情景,分别采用情景模拟分析方法进行定量分析,采用极端土地利用情景设计模拟流域内不同土地利用类型的径流响应。结果表明:上、下游的戴村坝和莱芜2个水文站率定和验证阶段决定系数R2分别为0.83和0.80、0.73和0.69,Nash-Suttclife模拟系数EN-S值分别为0.79和0.76、0.71和0.72。与基准期(1980—1990年)相比,1991—2004年流域土地利用变化使年径流量增加0.288亿m^3,而气候变化导致年径流减少1.32亿m^3;受土地利用变化影响,2005—2015年年径流量增加0.132亿m3,而受气候变化影响,年径流量减少0.61亿m^3。与2000年土地利用模拟径流量相比,耕地情景下径流量减少38.3%,林地情景下的径流量减少19.8%,草地情景下的径流量增加4.3%,证明草地具有涵养水源的作用。该流域的降雨量和流域年径流之间呈正相关关系,而流域年总径流量与气温呈负相关关系,并且流域年径流量受降雨量影响更大、更明显。

The soil and water assessment tool(SWAT)model widely used at home and abroad was selected to quantitatively analyze the impact of land use and climate change on runoff in the Dawen River basin.There are five scenarios,and the scenario simulation analysis method is used for quantitative analysis and the extreme land use scenario design was used to simulate the runoff response of different land use types in the basin.The calibration and validation results at hydrological stations of Daicunba and Laiwu show that the coefficients of determination(R 2)are 0.83 and 0.80,0.73 and 0.69,and the Nash-Suttclife coefficients are 0.79 and 0.76,0.71 and 0.72 respectively.Taking 1980-1990 as the r eference period,during the period from 1991 to 2004 the annual runoff increases by 2.88×10^7m^3 caused by the changes of basin’s land use,while the annual runoff decreases by 1.32×10^8 m^3 due to climate change.Land use changes duringthe period from 2005 to 2015 result in an increase in annual runoff of 1.32×10^7 m^3,and annual changes in climate cause a decrease in annual runoff of 6.1×10^7 m^3.Compared with the current land use simulation in 2000,the runoff of cultivated land scenarios and forest land scenarios are reduced by 38.3%and 19.8%,and the runoff of grassland scenarios increases by 4.3%,and proves that grassland has the role of conserving water sources.There is a positive correlation between runoff changes and precipitation changes in the river basin.Annual total runoff in the basin decreases with rising temperaturesand decreased with declining temperatures,which shows that the impact of precipitation variability is stronger than that of air temperature change.