鄱阳湖枯水期水位变化及其影响因素量化分析

Quantitative assessment of water stage changes of Poyang Lake in dry period and its influencing factors

湖泊湿地在维系生物多样性、陆地表层物流平衡与生态平衡等方面有着不可替代的作用。鄱阳湖是长江中下游重要的水源地和调洪场所,独特的水文条件创造了湖区丰富的生境和生物多样性。自三峡水库运行以来,鄱阳湖水位变化显著,枯水期提前且持续时间延长,10月份水位异常偏低,严重影响了越冬候鸟的栖息地。本文采用模糊划分聚类模型,围绕天然径流变化、三峡水库汛末蓄水、地形变化对鄱阳湖枯水期10月份水位变化的影响展开研究,并量化各因素的影响大小。结果表明,湖区及长江干流径流减少是造成鄱阳湖10月水位降低的主要原因,三峡水库汛末蓄水则进一步加快了鄱阳湖水位的消落,研究成果可为鄱阳湖管理及改善枯水期湖区生态环境提供依据。

Lake wetlands play an irreplaceable role in maintaining biodiversity,ecological balance,and land surface mass balance.Poyang Lake is important for flood control and water source of the middle and lower Yangtze River and provides a unique hydrological condition for its rich habitats and biodiversity.Since the Three Gorges reservoir was put into operation,Poyang Lake has experienced an earlier and longer dry period,especially its abnormally low water stage in October that greatly imperils its function as an habitat for wintering birds.This paper presents a quantitative analysis of the water stage changes of Poyang Lake in October using a fuzzy division clustering model;and examines its influencing factors such as the river runoff,the Three Gorges reservoir’s water storage after flood period,and the corresponding change in the river and lake geography.Results show that a significant decrease in the Poyang inflow and the Yangtze mainstream runoff is the main cause for the lake’s stage falling,and that the reservoir impounding after flood season has further accelerated this falling.These results can provide a basis for lake management and improving the lake ecosystem and environment during the dry period of Poyang Lake.