GIS平台下的重金属矿区生态敏感性可视化评价

Visual Evaluation of Ecological Sensitivity in Heavy Metal Mining Area Under GIS Platform

利用GIS平台,针对重金属锰矿区筛选出高程、坡度、坡向、植被覆盖率以及重金属空间分布5个生态敏感因子,运用层次分析法、判断矩阵以及生态敏感性综合指数对永州东湘桥锰矿区生态敏感强弱、分布进行可视化分析评价。从单因子生态敏感性分析发现,场地高低落差明显,214 m以上的高敏感区域占比19%,并主要集中在场地的中部;并涵盖了9个坡向且分布较为均匀,其中高度敏感的正南向占比13%;场地坡度较为平缓,坡度>15°的高度敏感区所占比例为11%;场地植被覆盖率较低,高敏感区域所占比为43%;重金属高敏感区域占比为9%,中度敏感以及高度敏感占据总场地的50%以上。综合生态敏感性评价发现,敏感度最高的区域山高坡陡、污染严重、无植被覆盖并呈散状分布,面积为0.306 4 km^2,占总面积的9.43%;中度敏感区主要分布在高敏感区域周边,面积为1.434 4 km^2,占场地的44.18%;低敏感区1.499 6 km^2占场地的46.39%,主要分布在场地北部和中下区域。

Using GIS platform, in terms of five ecological sensitive factors including elevation, gradient, slope direction,vegetation coverage and the spatial distribution of heavy metals selected for manganese ore area, the visual analysis and evaluation of ecological sensitivity and distribution in Dongxiangqiao Manganese Mine of Yongzhou were carried out by using AHP, judgment matrix and comprehensive index formula of ecological sensitivity. From the single factor ecological sensitivity analysis, it was found that the height difference of the site was obvious, and the high sensitive area above 214 m accounted for 19%, and mainly concentrated in the middle of the site. Nine slope directions were covered and distributed evenly, among which the highly sensitive due south direction accounted for 13%. The slope of the site was relatively gentle, and the proportion of highly sensitive areas with a gradient greater than 15° was 11%. The vegetation coverage rate of the site was low, and the proportion of the highly sensitive area was 43%. Heavy metal areas with high sensitivity accounted for 9%, while moderate sensitivity and high sensitivity accounted for more than 50% of the total site. The comprehensive ecological sensitivity evaluation found that the region with the highest sensitivity was characterized by steep mountain slopes, severe pollution, no vegetation coverage and scattered distribution, with an area of 0.306 4 km^2, accounting for 9.43% of the total area. Moderately sensitive areas were mainly distributed around highly sensitive areas, with an area of 1.434 4 km^2, accounting for 44.18%of the site. The low sensitive zone(1.499 6 km^2) occupies 46.39% of the site and is mainly distributed in the north, middle and lower areas of the site.