拟建鄱阳湖水利枢纽工程对水龄的影响模拟分析

Simulation of the impacts of the Poyang Lake hydraulic project on water age

鄱阳湖水利枢纽工程的建设运行必然会改变鄱阳湖的水情。本文利用EFDC水龄模块模拟了鄱阳湖的水龄分布,并分析研究拟建的水利枢纽工程在丰、平、枯等典型年份对水龄的影响,结果表明:受"五河"来流流量以及长江顶托倒灌作用的影响,鄱阳湖水龄在赣江入湖三角洲和入江水道较小,平均水龄分别是16.6 d和23.2 d,而在东北湖湾较大,平均水龄为119.4 d;水利枢纽工程的建设会减小鄱阳湖枯水期的流速,从而增大水龄,主要影响区域是北部过江水道区域以及中心湖区西侧的赣江入湖三角洲区域,尤其是过江水道的东侧,水体有明显滞留;水利枢纽工程增加了整个湖体的水力更换时间,在枢纽调控方案的补偿调节期和低枯水期水力更换时间增加了20%左右。研究结果可为鄱阳湖水利枢纽工程的建设提供参考。

The planned Poyang lake hydraulic project could lead new changes on water regime. By the water age module of the EFDC, the distribution of water age is simulated, the impacts of the Poyang lake hydraulic project on water age during high, normal and low flow years are studied respectively. The results show that the distribution of Poyang lake＇s water age is influenced by the inflow of five rivers and the reverse flow from Yangtze river. The water age is smaller on the area of the Ganjiang river delta and in the channel connecting to Yangtze river with an average age of 16.6 d and 23.2 d each, the northeast＇s zone has a greater age of 119.4 d. The hydraulic project reduces the velocity during dry reason increasing water age. The main influential area is river channel in the north of lake and the west side of central lake. The Poyang lake project increases the lake water replacement time, increasing by 20% during the low water season. The influence of Poyang lake hydraulic project on water age is analyzed in this paper, providing the necessary reference for the construction of project.