祁连山张掖段水电开发对区域生态环境的影响

The impacts of hydropower development in Zhangye section of Qilian Mountains on regional eco-environment

2017年7月26日—8月13日,通过实地调研、样方调查、河水和土壤样品分析等方法,评估了祁连山张掖段水电站建设时间、占地面积、水电开发对水质、土壤及生态流量的影响。结果表明:祁连山自然保护区张掖段内水电站建设主要集中在2000—2008年;依据2017年统计数据计算26座水电站总占地面积为798.35 hm^2,占祁连山张掖段面积(188×10^4 hm^2)的0.042%,水电工程占地面积较小;祁连山张掖段水电站建设区域内植被盖度、生物量比原生植被分别低27.14%和236.8 g·m^-2;水电站建设区域内水质、土壤状况良好,水电开发对水质、土壤的影响较小;2017年前祁连山张掖段水电开发导致生态水量下降并形成了156.76 km的减水河段。

From July 26 to August 13,2017,by the methods of on-the-spot investigation,plot survey,and the analysis of river water and soil samples,we assessed the impacts of construction time,site area of hydropower stations,and hydropower development on water quality,soil and ecological flow in Zhangye section of Qilian Mountains Nature Reserve. The results showed that the construction of hydropower stations was mainly concentrated from 2000 to 2008. The total area for 26 hydropower stations was 798.35 hm2,accounting for 0.042% of total area in study region( 1.88 million hm2),which indicated that hydropower projects covered a small area. The vegetation coverage and biomass in the construction areas of the hydropower stations were 27.14% and236.8 g·m-2 lower than those of the original vegetation,respectively. The water quality and soil of the areas around hydropower stations were in good conditions,indicating that the water and soil were seldom affected by hydropower development. The hydropower development had led to the decrease of ecological water quantity,causing a water-reduction river section with a length of156.76 km.