Study on ecological environment change of water source area of the middle route of South-to-North Water Diversion Project in the past 20 years

Abstract The South-to-North Water Diversion Project (SNWDP), which began operation in 2013, is an important step in China’s water resources development, and the middle route of SNWDP is one of the most important parts. However, this project has caused a certain negative impact on the ecological environment of Danjiangkou reservoir, the water source area of this project. This study uses DEM data and Landsat data for different years to analyze land-use changes in QGIS software and discusses the causes and impacts of the middle route of SNWDP. The results show that the present area of water and vegetation increased significantly, while the cultivated land and human area (including urban, rural and other areas of human activity) decreased obviously compared with 1999. The reasons for this change include natural conditions, engineering construction and policies, but policies such as raising the Danjiangkou dam and returning farmland to forests have played a bigger role. The impacts of SNWDP include water quality deterioration, soil erosion, changes in vegetation area, changes in biodiversity and changes in the lives of residents in the area. These impacts have positive reference significance for the construction of water conservancy undertakings in China in the future.