土地利用和气候变化对流溪河水库流域径流的影响

Effect of Land Use and Climate Change on Runoff in Liuxi River Reservoir Basin

[目的]探究径流对土地利用与土地覆被变化(LUCC)和气候变化的响应,为华南地区流溪河水库流域未来水资源的合理利用开发及社会经济可持续发展提供依据。[方法]通过构建分布式生态水文模型CHESS和设置情景模式,定量分析了土地利用和气候变化对径流的影响,同时结合CA-Markov模型,对流域未来径流变化进行了预测。[结果]CHESS模型在流溪河水库流域径流模拟中有很好的适用性,率定期的纳什系数(NS)为0.82,R 2为0.91,验证期的NS为0.74,R 2为0.86;土地利用变化方面,耕地转化为林地或草地会导致年均径流量减少,林地或草地转化为耕地会导致年均径流量的增大,耕地、林地、草地对径流形成的贡献能力为耕地>草地>林地;气候变化方面,年均径流量与降水量成正比,与温度成反比;2000—2020年,流域年均径流量逐渐增大,气候变化促进了径流的形成,土地利用变化抑制了径流的形成,且气候变化的影响占主要地位;未来预估情景下,2030年、2050年流域内建筑用地面积会增大,林地、草地面积会减小,耕地、水体面积变化不大,且在2040—2050年,流域年均径流量呈现增大趋势。[结论]土地利用和气候变化分别抑制和促进了流溪河水库流域径流的产生,且气候变化的影响较大,未来流域年均径流量呈现增大趋势,应加强对洪涝灾害的预警。

[Objective]The objective of this study is to explore the response of runoff to land use and land cover change(LUCC)as well as climate change,provide a basis for the rational utilization and development of water resources and the sustainable development of social economy in Liuxi River Reservoir Basin.[Methods]We analyzed the impacts of land use and climate change under several scenarios on river runoff in the Liuxi River Reservoir Basin using a distributed eco-hydrologic CHESS model.Meanwhile,we used the CA-Markov model to predict the future changes of land use change on river runoff.[Results]The CHESS model had a good performance in simulating river runoff in the Liuxi River Reservoir Basin.The calibration and validation results showed that NS was 0.82 and 0.74,and R 2 was 0.91 and 0.86,respectively.Under the land use change scenarios,the conversion of farmland into forest or grassland would reduce runoff,and the conversion of forest or grassland into farmland would lead to the increase of runoff.The descending order of contribution to runoff was farmland,grassland,and forest.Under the climate change scenarios,changes in runoff were proportional to precipitation and inversely proportional to temperature.From 2000 to 2020,the basin runoff increased gradually.Climate change promoted the generation of runoff during this time,while land use change inhibited it,and the impact of climate change was greater.Under the future land use change scenarios,the area of building land in the basin will increase in 2030 and 2050,while the area of forest and grassland will decrease,and the area of farmland and water will change little.Moreover,the runoff of the basin will increase in the period from 2040 to 2050.[Conclusion]Land use and climate change have respectively suppressed and promoted the generation of runoff in the Liuxi River Reservoir Basin,and the impact of climate change is greater.In the future,the runoff in this basin will show an increasing trend,and early warning of flood disasters should be strengthened.