三峡水库运行对长江荆南三口生态系统健康的影响

Impacts of the Operation of the Three Gorges Reservoirs on the Ecosystem Health of the Three Outlets

根据荆南三口河系五个代表性水文监测站1981—2015年的水文资料,运用层次分析法对水沙、水质和生物多样性3个方面的7个指标建立指标体系,并得出权重.根据评价标准对每个指标进行评分,加权相加得到总分值对三峡水库影响下的荆南三口河系生态系统健康程度进行综合评价.结果表明:(1)河流生态系统健康状态与水沙特性息息相关,因此三峡水库对荆南三口河流生态系统健康的影响主要体现在水沙、水温、水质和生物多样性等方面;(2)三峡水库运行前荆南三口河流生态系统健康程度为"健康"程度,且各个指标都基本达到健康河流标准;(3)三峡水库运行后荆南三口河流生态系统健康程度为"亚健康"程度,相较于三峡水库运行前,各指标的分值下降较大.研究三峡水库对三口河流生态系统健康影响,对优化三峡水库调度方案和维护荆南三口河系生态健康具有重要的意义.

In this work, an evaluation index and its weight are constructed by analytic hierarchy process （ AHP） , according to the hydrological data from five representative hydrological monitoring stations of the Three Outlets river system from 1981 to 2015. Our evaluation system includes three kinds of index （water and sediment, water quality and biodiversity） and seven indicators. The ecosystem health of the Three Outlets under the impacts of the operation of the Three Gorges Reservoirs is assessed comprehensively. Our results show that the ecosystem health is closely related with the characters of water and sediment. So the impact of the Three Gorges Reservoirs on the ecosystem health is mainly embodied with water and sediment, water temperature, water quality and biodiversi-ty. Before the operation of the Three Gorges Reservoirs, the ecosystem of the Three Outlets was healthy and all in-dexes were near standard. After the operation of the Three Gorges Reservoirs, the ecosystem of the Three Outlets has been sub-health and all indexes decreased significantly. This study should be of great significance to optimize the operation plan of the Three Gorges Reservoirs and to maintain the ecological health of the Three Outslets.