“一带一路”区域水电站工程生态环境影响遥感监测

为实现“一带一路”区域可持续发展,我国倡导绿色、低碳、循环、可持续的生产生活方式,建设绿色“一带一路”。遥感技术在生态环境监测与评价方面具有重要作用。本文以“一带一路”区域中国援建的水电站工程为研究对象,基于陆地系列卫星(Landsat)、哨兵2号（Sentinel-2）等遥感对地观测数据,利用决策树与缓冲区分析等方法,从水电站库区概况、水电站对植被生长状况与生态资源影响等方面,开展“一带一路”区域水电站项目建设对当地经济发展和生态环境影响的遥感监测及分析。本文首先根据遥感影像与DEM确定库区及库容,结合最小外接正方形面积比及平均宽度等指标确定各水电站缓冲区类型和范围。利用NDWI及NDVI构建决策树模型,提取各缓冲区土地利用类型,分为水体、林地、草地、耕地和其它5类;结合区域植被覆盖度,估算库区生态占用并对水电站建成前后的土地利用类型和植被变化进行分析。研究结果表明：① “一带一路”沿线10座水电站造成的生态损失与库区面积呈正相关,不同工程间,在水体、林地、草地、耕地和其它方面的损失面积大小存在较大差异;② 土地利用类型与植被覆盖度年均变化幅度约为0.35%、1.27%,水电站修建对周边生态资源与植被生长状况影响较小,同时在植被覆盖度较低的地区水电站的修建会明显改善周边环境;③ 各水电站周边的植被覆盖度差异较大,大部分水电站周边植被生长状况良好;④ 水电站建设始终坚持工程建设与环境保护并重,从施工设计到水电站后期维护期间,积极采取环保措施,减少占用,保护生物多样性,生态风险防范得当;⑤ 水电站提供了优质的清洁能源,促进了当地经济和社会发展。

Monitoring and Analyzing Ecosystem Impact on Hydropower Projects by Remote Sensing in the Belt and Road Region

China has advocated a green, low-carbon, recyclable, and sustainable lifestyle for the sustainable development of regions along the green "belt and road". Remote sensing plays an important role in monitoring and evaluating ecological environment. This study focuses on the ecological impacts of hydropower projects in the "belt and road" region supported by China. The ecological impacts of hydropower projects on reservior area, vegetation growth, and ecological resources are analyzed based on decision trees and buffer area analysis methods using Landsat and Sentinel-2 images. In our study, first, the DEM and satellite images are used to obtain reservoir area and storage capacity of each hydropower station. Then, through buffer area analysis, buffer area type and its distance to reservior area of each hydropower station are determined by the area of reservior area, the ratio of reservior area to the smallest circumscribed square, and the average width of reservior area. Decision trees of each buffer area are further built to classify water, forest, grassland, cultivated land, and other land use types based on NDWI and NDVI. The ecological footprint and changes of each land use type before and after the hydropower construction are also analyzed. The Fraction of Vegetation Coverage (FVC) is used to evaluate the status and changes of vegetation growth for each hydropower station. Results reveal that the ecological loss caused by hydropower projects has a positive correlation with the area of reservior area. Generally, the construction of hydropower station has small impact on land use types and vegetation growth of surrounding areas as the annual average variation of land use type and FVC are about 0.35% and 1.27%, respectively. However, there is a significant difference in the lost area of land use types and FVC between hydropower stations. FVC is improved in areas with low FVC after the construction of hydropower station. Furthermore, the hydropower project in areas with low vegetation coverage significantly promotes local ecological environment. During the construction, from design, building to later maintenance of hydropower stations, experts actively take environmental protection measures to reduce reservior area, protect biodiversity, and control ecological risks. Hydropower stations can provide high-quality clean energy and promote local economic and social development.