三峡工程对鄱阳湖水资源生态效应的影响

在三峡工程现有调度规则的前提下,建立了反映水文情势变化的人工神经网络模型、鄱阳湖区间分布式水文模型、湖区二维水量水质模拟模型,并利用这些模型对三峡工程运行后对鄱阳湖防洪、水资源与水质生态等方面的效应进行了定量分析.分析结果表明:在防洪影响方面,三峡水库预泄期鄱阳湖水位抬升,低水增幅大于高水增幅,而三峡水库蓄水期鄱阳湖水位降低,低水降幅大于高水降幅,总体上对鄱阳湖防洪影响有限;在水质影响方面,鄱阳湖区水质浓度与五河来水的流量及其污染物浓度关系密切,受长江流量影响的关系并不大;在供水影响方面,三峡工程运行将对鄱阳湖枯水期供水形势产生较大影响;在生态影响方面,三峡工程运行后对鄱阳湖植被面积变化有一定的影响,影响大小与月份的不同有关,并将导致鄱阳湖不同区域湖滩草洲显露日期提前和显露时间有所增加,这将对鄱阳湖珍稀候鸟栖息地环境造成不利影响.

Influences of Three Gorges Project on water resources and ecological effects in Poyang Lake

On the premise of the existing operating rules of the Three Gorges Project,quantitative analysis of the effects of the project on the flood control,water resources,water quality,and ecosystem in Poyang Lake was conducted by establishing a BP artificial neural network model that can reflect the changes of hydrological situations,a distributed hydrological model for Poyang Lake,and a two-dimensional water quality and water quantity simulation model for the lake.The results show the following: In terms of the effects on flood control,the water level in Poyang Lake increased in the pre-discharge period of the Three Gorges Project,and the increase rate of the low water level was higher than that of the high water level,while in the storage period of the project,the water level in Poyang Lake decreased,and the decrease rate of the low water level was higher than that of the high water level.The project had limited effects on flood control on the whole.In terms of the effects on water quality,the water quality in Poyang Lake was in close relation with the inflow and concentration of pollutants of the Wuhe River,and was not significantly affected by the discharge of the Yangtze River.In terms of the effects on the water supply,the operation of the Three Gorges Project will have great influence on the water supply in dry seasons in Poyang Lake.In terms of the effects on ecology,the project will have an effect on the changes in vegetation area in the lake,and the degree of effect will differ in different months.Besides,the lake beach and grass moor in different lake areas will appear in advance and for a longer duration,negatively affecting the environment of the habitat of rare migratory birds in the lake area.