基于SWAT模型的岷江上游流域土地利用变化对径流的影响

Effects of Land Use Change on Runoff in the Upper Reaches of Minjiang River Basin Based on SWAT Model

定量评估土地利用对水文过程的影响,对水资源规划和管理具有重要意义。本研究的主要目的是定量评估成都岷江流域径流对土地利用变化的响应机制。以成都岷江流域作为研究对象,基于GIS技术构建CMADS驱动下的SWAT模型来展开逐月径流模拟,并结合情景设置法,分别模拟研究区内不同土地利用情景下的径流过程,定量分析不同土地利用变化对流域径流产生的影响。结果表明:(1)林地、草地、耕地是成都岷江河流域的主要土地利用类型,随时间推移,仅有林地呈少量下降,草地面积保持不变,其余土地利用类型均有少量提高,其中建设用地、未利用地的年变化速率最快;(2)构建了适用于成都岷江流域的SWAT模型,率定期和验证期R2和NSE系数均在0.7以上,经过参数率定后的SWAT模型径流模拟效果较好,适用性高;(3)以2020年的土地利用现状为基准年,排除其他干扰因素,采用极端土地利用情景法,结果表明耕地具有增加径流的作用,林地和草地均具有拦截径流的作用,其中林地的截流作用更为明显。本研究可为指导该流域和类似流域的管理决策提供参考。

Quantitative assessment of the impact of land use on hydrological processes is important for water resources planning and management.The main objective of this study was to quantitatively assess the response mechanism of runoff in the Minjiang River Basin to land use change in Chengdu.Taking the Minjiang River Basin in Chengdu as the research object,the CMADS-driven SWAP model was constructed based on GIS technology to carry out month-by-month runoff simulation,and combined with the scenario setting method,the runoff process under different land use scenarios in the study area was simulated,and the impact of different land use changes on the runoff of the basin was quantitatively analyzed.The results show that:(1)Woodland,grassland and cultivated land are the main land use types in the Minjiang River Basin of Chengdu,and with the passage of time,only the forest land shows a small amount of decline,the grassland area remains unchanged,and the remaining land use types have increased slightly,of which the annual change rate of construction land and unused land is the fastest.(2)A SWAT model suitable for the Minjiang River Basin in Chengdu was constructed,and the R2 and NSE coefficients of the regular and verification periods were above 0.7,and the runoff simulation effect of the SWAP model after the parameter rate was determined was good and the applicability was high.(3)Taking the land use status in 2020 as the base year,excluding other interference factors,and using the extreme land use scenario method,the results show that cultivated land has the effect of increasing runoff,and both woodland and grassland have the effect of intercepting runoff,of which the interception effect of woodland is more obvious.This study can provide a reference for guiding management decisions in this and similar basins.