南水北调西线调水工程区的自然生态环境评价

Natural Eco-environmental Evaluation of West Route Area of Interbasin Water Transfer Project

应用遥感与地理信息系统方法，对南水北调西线调水工程区遥感数据、地理信息数据进行一系列的信息识别、信息提取，获取了工程区地形地势、土地覆盖、植被覆盖度、植被净初级生产力、年均温度和年降雨量等主要的自然环境因子。用海拔高度反映地势状况，土地覆盖类型反映地表覆盖状况，植被覆盖度反映抗侵蚀能力，植被净生产力反映物质能量的循环状况，年均温度反映热量状况，年降水量反映降水状况，建立综合自然环境指数，对调水工程区的自然生态环境现状进行定量评价。按计算结果将调水工程区分为四级区域，并对这四级区域进行空间统计，分析了它们的自然生态环境，为全面深入进行南水北调西线工程区环境影响评价提供可供借鉴的新思路和新方法。

The impact of interbasin water transfer on environment is very significant. The affected area of the west route scheme of South to North Water Transfer Project in China(SNWT) is located in the southeasten part of the Tibetan Plateau, where the altitude is high with fragil eco-environment. Therefore, it is necesary for SNWT to analyze the natural eco-environment. In the article, we apply the remote sensing and 015 to analyze the natural environment of the study area which lies in the range of 31°27′-33°58′N and 96°57′-102°30′E, covering an area of 91 200 km2. The materials we used include 8 images of TM, 1:1 000 000 basic geographic data of China, the meteorologic data from 631 stations in China(1958-4998), statistic data and natural resources maps of Qinghai and Sichuan provinces. We obtained natural environmental factors such as land cover, vegetation cover, NPP(Net Primary Productivity), temperature, precipitation and topographic terrain by remote sensing and 015 method. We use the natural environment index which contains natural factor index and the total number of natural factor analyzed to express the natural conditions of the study area. The natural factor index of land cover, vegetation cover, NPP, temperature, precipitation and altitude are calculated and the natural environment index is divided into four grades or four level sub-areas. According to the calculation result, we analyze the features of each grade of the natural environment index or the natural eco-environment of the four sub-areas, so as to provide new trajectories and new methods that can be used for reference in environmental impact assessment of the affected area of the west route of South-to-North Water Transfer Project in China.