鄱阳湖水利调控对湖区典型丰枯水年水动力水质影响研究

鄱阳湖水利枢纽工程的修建会在一定程度上阻拦长江与鄱阳湖的江湖连通性,湖区水流情势将发生改变。本研究采用有限体积法求解非结构网格下的二维浅水水动力水质模型,根据初定的枢纽工程水位调度方案,研究典型丰枯水年湖区水动力与水质条件变化。结果表明,枢纽工程建成后,丰水年星子站年平均水位抬升1.49 m,枯水年星子站年平均水位抬升1.88 m,枯水年水利枢纽工程对湖泊水位抬升变幅值、流速变幅值和工程影响的持续时间均高于丰水年。工程后丰水年枯水期水面面积增加15.3%,水量增加29.2%,枯水年枯水期水面面积增加22.8%,水量增加54.1%。选用示踪剂模型研究工程后湖区物质输运条件的改变,发现湖区物质输运过程明显减慢。典型丰水年水力滞留时间增幅为1~2 d,典型枯水年水力滞留时间增幅2~9 d;典型丰水年示踪剂传输时间增加值1~9 d,典型枯水年示踪剂传输时间增加值1~20 d。

Study on the influence of Poyang Lake Hydraulic Project on hydrodynamics and water-quality in wet and dry year

The original relationship between the Yangtze River and the Poyang Lake will be hindered after the construction of Poyang Lake Hydraulic Project, which may have a great effect on water flow situation in the lake. A 2D well-balanced shallow water model for unstructured grids is established on the base of the Godunov-type finite volume method. According to the water level scheduling scheme by Poyang Lake Water Conservancy Project Construction Office,the variation of hydrodynamics and water quality in wet and dry year is researched. The results indicate that the annual average water level in Xingzi station increases by 1.49m in wet year and 1.88m in dry year after the construction. The water-level variation,velocity variation and the duration of the impact in dry year are all greater than those in wet year. The surface area will increase by 15.3% and the water quantity increase by 29.2% in the dry season of wet year, while that will be 22.8% and 54.1% in the dry year,respectively. The tracer model is applied in studying material transmission of the lake. The residence time increases by 1~2d in wet year and 2~9d in dry year. The tracer travel time increases by 1~9d in wet year and 1~20d in dry year. The material transport process in the lake is significantly slowed down after the construction. A simulation research of hydrodynamics and water quality in wet and dry year is applied in this paper, which lays the foundation of further study on migration and transformation of the contaminant and establishment of ecological model of lake-wetland.