长江干流九江段与鄱阳湖不同季节的同位素特征

为了分析不同时期鄱阳湖与长江及其他各条河流的关系,初步探讨三峡水库运行对鄱阳湖水量的影响,对九江段长江干流、鄱阳湖地区河水、湖水进行了采样和氘氧稳定同位素分析。结果表明:水体同位素存在明显的时间和空间变化,可用于揭示湖泊与河流之间的关系。三峡补水调度过程能有效减少鄱阳湖春季的水量流失,4月份鄱阳湖流域已进入雨季,大量内河来水导致鄱阳湖水以较大的流量向长江补给;调洪削峰调度阶段,较高的长江水位对鄱阳湖存在一定的顶托作用,导致湖水难以排泄;三峡蓄水过程引起的长江水位降低加速了枯水期鄱阳湖水的流失。三峡水库的调度需要考虑到鄱阳湖流域水情,以免加重该流域丰水期的洪涝灾害和枯水期的水资源短缺。

Stable isotope characteristics in the Poyang Lake region at Jiujiang section of the Yangtze River in different seasons

In order to find out the relationship between the Poyang lake and the Yangtze River and other inflowing rivers, and to objectively discuss the influence of the Three Gorges Reservoir''s operation on the lake, samples of river water and lake water in the Poyang Lake region at Jiujiang section of the Yangtze River were taken and analyzed for stable isotopic composition. The isotopic composition of rivers and lakes shows a great temporal and spatial variation, which can be used to reveal the relationship between the lake and rivers. The water-supply dispatch effectively reduces the water loss of the lake in spring. In April,the lake greatly recharges the Yangtze River because of the considerable flow volume of inflowing riv-ers which have just entered rainy season. During the flood storage dispatching period, the high water level of the Yangtze River restrains the discharge of lake water. The lower water level of the Yangtze River caused by the impoundment dispatch greatly accelerates the water discharge of the Poyang Lake during its dry season. Thus,the water regime of the Poyang Lake basin should be taken into consideration during the dispatches of the Three Gorges Reservoir,alleviating possible floods in wet season and droughts in dry sea-son.