三峡库区干支流水体营养状态评价

Evaluation of Nutrient Status in the Mainstream and Tributaries of Three Gorges Reservoir

为反映三峡水库175 m蓄水以来干支流水体营养状态的总体情况,根据近几年的水环境监测数据,采用综合营养状态指数(TLI)法,对长江干流和主要支流进行富营养化状态评价。结果表明,三峡库区干流整体处于中营养状态;上游支流富营养化水平偏高,总体上以富营养为主;中下游支流营养水平总体上以中营养为主。4条典型支流中,香溪河综合营养状态指数总体较高,大部分时间处于富营养化状态;神农溪综合营养状态指数有增高趋势,达到富营养化的临界状态;大宁河综合营养状态指数小于50,处于中营养状态;小江综合营养状态指数偶尔达到富营养化标准,但有小幅下降趋势。

show that the nutritional status of mainstream of Three Gorges Reservoir is mesotropher, the TLI of upstream tributaries is overall high and the eutrophication level is eutropher, and the eutrophication level of downstream tributaries is mesotropher. Among four typical tributaries, the TLI of Xiangxi River is generally high and the eutrophication level is eutropher in most of year, the TLI of Shennongxi River is increasing and reaches a critical state of eutrophication, the TLI of Daning River is less than 50 and the utrophication level is mesotropher, and the TLI of Xiaojiang River reaches mesotropher occasionally but there is a slight decreasing trend.