Study On Eco-Environmental Vulnerability In Water Source Area Of The Middle Route South-to-North Water Transfer Project

The Middle Route of the South-to-North Water Transfer Project plays an important role in alleviating the shortage of water resources in Beijing,Tianjin,Hebei and North China Plain,and solving the spatial structural imbalance of water resources in China.The ecological environment of the water source area directly affects the quality and safety of the water environment of each water use city.Therefore,we carry out the research on the coupling and coordination of the ecological environment and the natural conditions and the human activities in the water source area of The Middle Route of the South-to-North Water Transfer Project.it reveals the influence of driving factors and evolution mechanism of vulnerability,assessing the vulnerability of the ecological environment in the water source area,predicting the vulnerability of ecological environment in extreme water diversion case.It provides a theoretical basis for the protection of the ecological environment and the sustainable utilization of water resources in the water source area,which has important value and significance.Based on in-depth analysis of the water and soil resources and ecological environment in the water source area of The Middle Route of the South-to-North Water Transfer Project,the assessment index system of 4 levels of ecological environment vulnerability is established,such as the total target layer,the standard layer,the index layer and the factor layer.Using RS and ArcGIS technology to process multi temporal and multi platform TM remote sensing image and DEM,select 1987,1996,2006 and 2016 as the typical years to evaluate the eco-environmental vulnerability of water source area in The Middle Route of the South-to-North Water Transfer Project.This paper analyzes the pattern of vulnerability evolution,Studying on the driving mechanism based on principal component analysis and Levenberg-Marquart method,reveals the main driving factor.Finally,the ecological environment vulnerability of the water source area of The Middle Route of the South-to-North Water Transfer Project.The results of the study show that: The ecological environment vulnerability of the water source area of The Middle Route of the South-to-North Water Transfer Project is not high,and the degree of vulnerability belongs to preference.Ecologically vulnerability areas are mainly concentrated in the central region of research areas with densely populated and more concentrated in bare land,with relatively low vulnerability in the northern and southern regions.From 1987 to 2016,the vulnerability of ecological environment is decreasing gradually.It is concluded that the main driving factors that affect the vulnerability of eco-environment in water source area are total water resources,sunshine percentage,water consumption for 10000 yuan GDP,tertiary industry proportion,water production coefficient,slope and land use type,and the simulation model of ecological environment evolution is established.There is a functional relationship between water yield modulus and erosion modulus and vegetation coverage in the study area.In the case of extreme water diversion,water diversion will have a certain impact on the ecological environment of the water source area,but the influence is relatively small.