黄土高原地区西气东输工程沿线水土流失敏感性评价

西气东输管道的建设将直接破坏施工区范围内的地表植被,导致区域生态环境的恶化和水土流失的进一步加剧,加剧的水土流失反过来会对西气东输管道的安全运行形成较大的威胁,甚至在某些严重地区,由于崩塌、滑坡和泥石流的发生,可能会直接破坏管道,影响其安全运行.如何控制管道工程沿线地区的水土流失,加强区域友好环境的构建,不仅对于提高区域生态系统的功能具有重要意义,而且对于管道工程的安全运行具有重要的实际价值.本文在系统分析影响区域水土流失敏感性因子的基础上,在GIS的支持下,选取土壤、植被类型、坡度和坡向作为评价指标,采用图层权重-叠加模型和模糊分级模型,以专家经验打分法对各指标进行赋值,评价了黄土高原地区西气东输管道工程沿线10 km范围内水土流失的敏感性.根据研究结果将该区分为弱敏感、较敏感、敏感和高度敏感4类地区,并评价了水土流失敏感性的空间特征及其主要原因.在此基础上,从区域生态系统和管道工程的安全角度探讨了生态恢复和友好环境构建的基本措施.

Sensitivity Assessment of Water and Soil Loss Along West-East Pipeline Project in Loess Plateau, China

Vegetation within the working area would be completely destroyed and the adjacent areas would be affected by the construction of West-East Pipeline Project. This will result in further environmental deterioration and serious water and soil loss, that will in turn threaten the safety of the west-east pipeline (WEPP) from the long term. Thus it is of highly significance to improve the regional ecosystem function and practical for the safe operation of pipeline to control the water and soil loss along the pipeline with the purpose of establishing a friendly environmental system. In this paper, based on analysis of factors that affect ecosystem sensitivity to the water and soil loss, soil, vegetation, slope aspect and slope degree were selected as assessment indices to make an assessment of the water and soil loss sensitivity by assigning weight to each factor based on experts' knowledge under the support of GIS. Furthermore, according to overlay model of layer weightiness - classification marking and Fuzzy-classification, the study area within 10km of both sides along the pipeline was divided into four groups, which were the slightly sensitive area, the moderately-sensitive area, the sensitive area and the highly sensitive area. The spatial characteristic of sensitivity to water and soil loss was assessed and main reasons causing water and soil loss was then discussed. At last, basic measures of ecological recovery and friendly environment construction in term of the safety of both regional ecosystem and pipeline were discussed.