西气东输管道沿线河西走廊地区生态系统评价与生态安全保障体系建设

Ecosystem Assessment and Ecological Security System Design for Hexi Corridor Region along the West-East Gas Pipeline Project (WEPP)

西气东输管道沿线河西走廊地区是典型的荒漠—绿洲—戈壁区 ,具有干湿交错带、农牧交错带、森林边缘带以及沙漠边缘带等多种环境脆弱带 ,管道施工造成地表土壤、植被的破坏 ,加剧荒漠化过程 ,还会诱发沙尘暴 ,使地区生态环境进一步恶化 ,直接影响到管道的安全运行 ,从区域生态安全和管道安全双重角度提出区域的生态安全保障体系具有重要意义。以西气东输管道沿线河西走廊地区为例 ,对管道沿线两侧各 10km内进行了生态系统制图分析 ,识别出该区的主要生态系统类型 ,并对其中主要的 3种生态系统进行了评价。在此基础上 ,针对几种典型生态系统区如裸地生态系统、绿洲生态系统、戈壁半灌木矮半灌木荒漠生态系统地区提出来了生态安全保障体系 ,具有保障区域生态安全和管道安全运行双重意义。

Because the Hexi Corridor Region along WEPP is typical of desert oasis Gobi region with vulnerable environment for all kinds of ecotones such as dry wet ecotone, agro pasture ecotone, forest edge region and desert edge region, WEPP will bring destruction to vegetation and soil of the region, aggravating desertification, inducing sandstorm, deteriorating the regional ecological environment and endangering the safety for the running of WEPP. So it is very important to build ecological security system for both ecological safety and pipeline safety. Based on the Arcview GIS platform, main ecosystems are identified along the pipeline within 10 km on each side, and ecosystem assessment is focused on the main 3 ecosystems: Gobi Gray brown desert soil semi and short shrub desert ecosystem taking account of 34.65% of the total assessing area, oasis ecosystem with 20.58%, and the barren land ecosystem with 19.43%,So the ecological security systems are aiming at these ecosystems, which is important to both ecological security for the region and the safety running for WEPP. The desert systems are divided into two kinds of transferring zone: middle low hill areas and desert area, and Straw lattice design (30m wide) is used in the desert area, but to the former, the main problem is the gravity erosion, and the gully detention project and fixation project of gully should be done. The oasis ecosystems are divided into three zones: small areas of sand land and sand dunes area, farmland area and ecotone area, and to the first one, gravels are used for pipe gully burying preventing sands from erosing, and two belts on the sand dunes are sand barrier and artificial bush belt and natural restoration belt; to the second one, the main measure is that soil be excavated and buried on layers; to the third one, three belts designed according to the distances away from the pipeline are sand barrier belt (0～5m), sand barrier and artificial bush forest belt (5～50m) and the closing belt for reservation (50～1000m) in the Gobi area, and the opposite three belt in the oasis are grass planted belt (0～50m), artificial bush forest belt (5～50m) and the closing belt for reservation. The Gobi Gray brown desert soil Semi and short shrub desert ecosystems are divided into two kinds: Gobi plain area and mountain front Gobi area, and to the former, on each side of the pipeline, three belt designed are gravel barrier belt (0～5m), artificial enclosed grass belt (5～50m) and natural restoration belt (50～500m), to the latter a ridge on the pipe built to reserve water for the recovery of vegetation, and three belts designed are current collector belt for restoration and project belt for restoration. Along the ridge, flood discharge passages be built every some distances.