土地利用和气候变化对王家桥小流域径流的影响

Impacts of Land Use and Climate Change on Runoff in Wangjiaqiao Watershed

以三峡库区内典型小流域王家桥为例,利用SWAT模型模拟土地利用和气候变化及两者共同作用对径流的影响。结果表明:扩大耕地、退耕还林、发展经济林的土地利用情景下,年均径流量较基准年变化率分别为15.13%、-13.99%、23.22%,退耕还林能有效调节和减少流域径流量;浓度路径为RCP2.6、RCP4.5、RCP8.5的气候变化情景下,径流量变化率分别为7.13%、7.78%、8.91%,径流量随未来温室气体和硫酸盐气溶胶排放情况增大而增加;两者综合情景下年均径流量均增加,2030年左右增幅较显著;对影响径流的因素进行方差分析,发现土地利用变化对径流的影响比气候变化的影响更显著。在未来气候变化背景下,可通过合理配置流域的土地利用类型,实现对流域水量平衡的调节。

The typical Wangjiaqiao watershed within the Three Gorges Reservoir area was selected as case study to investigate the variation of runoff under the changes of land use, climate and the combination of them by using the soil and water assessment tool(SWAT) for simulation. The results show that the rates of annual average runoff change by 15.13%,-13.99% and 23.22% under the scenarios of arable land expansion, returning farmland to forest and economic forest development respectively. Furthermore,returning farmland to forest can regulate and reduce runoff. Under the climate scenarios of RCP 2.6, RCP 4.5 and RCP 8.5, the change rates of runoff are 7.13%, 7.78% and 8.91% respectively,and the runoff increase with the future emission of greenhouse gases and sulphate aerosols. The annual average runoff increase greatly under the scenario of the combination of them,especially around 2030. In addition,the variance analysis has found that the influence of land use are more significant than that of climate change on runoff. It is advisable that land use in the watershed can be allocated reasonably to control water balance in the future.