基于3S技术的青藏公路改建工程环境影响评价方法

Application of 3S technologies in Qinghai-Tibetan highway environmental impact assessment

通过青藏公路格尔木至拉萨段改建完善工程的环境影响评价实践,凝练出以Landsat7 ETM＋、Landsat5 TM、Geoeye等遥感影像为数据源,采用数据融合、GIS空间分析、光谱差值法和目视判读法等方法,对施工前后公路沿线土地利用变化信息进行提取,并构建干扰斑块数量、干扰强度和干扰幅度等评价大型线性工程施工期干扰强度的新指标和新思路.结果表明,研究区域内土地利用类型的变化主要是高寒草甸向裸地或建筑的转变,同时也提取出少量植被恢复斑块.变化斑块集中分布在公路两侧10~50m范围内,对区域干扰幅度较小.通过工程监理与实地考察数据的验证,该方法能准确提取评价区域土地利用变化斑块,提出的干扰指标能有效提高变化信息的分析精度.

A new approach of environmental impact assessment using RS and GIS was presented by the case study of Qinghai-Tibet highway.Satellite images with different resolutions from Landsat7 ETM＋,Landsat5 TM,and Geoeye-1 were used as data sources.Techniques such as data fusion for multi-sources remotely sensed imagery,spatial analysis and overlay analysis of GIS,and visual interpretation were used to detect land use/ land cover change along Qinghai-Tibetan highway after the construction.Characteristics of the environmental impacts were identified with index including number,intensity and range of changed patches.Results showed that most of the land use/land cover type in study areas changed from grass to construction land or bare land.An increase of grass patches caused by vegetation restoration measures was also detected.Detected patches were mainly located between 10~50m from the highway,which showed that the construction caused only a minor disturbance distance.The accuracy of change detection was verified highly by field investigation and construction log,which indicated that this method could effectively and accurately detect land use and land cover changes and help to assess the environmental impact of the highway construction.