Quantitative analysis on the ecological impact of large-scale water transfer project on water resource area in a changing environment
Abstract. The interbasin long-distance water transfer project is a key support for the reasonable allocation of water resources in a large-scale area, which can optimize the spatiotemporal change of water resources to reinforce the guarantee of the access of water resources. And large-scale water transfer projects have a deep influence on ecosystems; besides, global climate change causes the uncertainty and additive effect of the ecological impact of water transfer projects. Therefore, how to assess the ecological and environmental impact of large-scale water transfer projects in both construction and operation has triggered a lot of attention. The water-output area of the western route of China's South-North Water Transfer Project was taken as the study area of the present article. According to relevant evaluation principles and on the basis of background analysis on the eco-environment of the study area, the influence factors were identified and evaluation indexes were established. The climate-hydrology-ecology coupled simulation model was used to imitate the laws of ecological and environmental change of the water resource area in a changing climate. The emphasis of influence analysis and quantitative evaluation was placed on the reservoir construction and operation scheduling, representative river corridors and wetlands, natural reserves and the water environment of river basins below the dam sites. In the end, an overall influence evaluation of the impact of the project on the water circulation and ecological evolution of the water resource area was conducted. The research results were as follows: the environmental impacts of the western route project in the water resource area were concentrated on two aspects, i.e. the permanent destruction of vegetation during the phase of dam construction and river impoundment, and the significant influence on the hydrological situation of natural river corridor after the implementation of water transfer. Its impact on local climate, vegetation ecology, typical wetlands, natural reserves and the water environment of river basins below the dam sites was small.