基于EFDC模型的鄱阳湖水利枢纽工程对湖泊流场的影响分析

发布时间：2018-11-10 19:25

【摘要】：鄱阳湖是我国最大的淡水湖,具有调蓄洪水和保护生物多样性等生态功能。但近年来,鄱阳湖出现水量不足、湿地退化、水质恶化、等生态问题,引起了各方高度重视,鄱阳湖水利枢纽的构建则再次引起热议。然而构建水利枢纽工程势必影响自然状态下鄱阳湖的水文、水动力。其中,湖流是重要的动力学指标,它决定着湖中各类物质输移和扩散,影响着一系列的人类活动。所以本文通过构建鄱阳湖二维水动力模型,在鄱阳湖水利枢纽拟定的调度方案下,通过模拟对丰、平、枯典型年份的流速、流向、基本湖流格局及局部湖流进行了有枢纽与无枢纽状态下的比较,由此分析出鄱阳湖水利枢纽工程对湖泊流场的影响,为枢纽的建立可供科学依据。研究结果如下:(1)通过对2010(丰水)年、2000(平水)年和2004(枯水)年三个年份重要区域有无枢纽平均流速的模拟发现,丰水年,枢纽工程对湖泊流速的影响最小,对入江河道与主湖区的影响作用大于两个国家级自然保护区。平水年,枢纽工程对鄱阳湖流速的影响强于对丰水年型流速的影响,入江河道流速减小,鄱阳湖南矶山湿地国家级自然保护区流速增大。枯水年,枢纽对鄱阳湖流速的影响是最大的,各调度期不同地方的流速变化不同。(2)为了研究鄱阳湖水利枢纽工程对流向的影响,分析了不同调度期三个典型年份有无枢纽的平均流向。结果显示,在各个调度期中,三峡蓄水期、补偿期和低枯水期的流向变化较明显。鄱阳湖水利枢纽对流向影响最大的年型是2004年,其次为2000年,对2010年的影响最小。另外,选取了调度期的开始日期进行有无枢纽的对比,发现枢纽蓄水期与低枯水期流向变化最明显。(3)鄱阳湖水利枢纽工程水位调度的实施,会改变湖泊的基本湖流特征。自然状态下的倒灌型湖流和顶托型湖流由回流型湖流和排水型湖流代替。无枢纽状态下鄱阳湖湖流以重力型为主,其次为顶托型,倒灌型最少;有枢纽状态下,重力型+排水型湖流有所减少,其中以枯水年为最;顶托型+蓄水型湖流有所增加,也以枯水年为最;枯水年型的倒灌由无枢纽的14d减少到8d。由于蓄水,有枢纽时2000年和2010年分别发生了11d和12d回流。(4)在基本湖流特征受到鄱阳湖水利枢纽工程影响的同时,局部湖流也发生了相应的变化。通过对丰、平、枯年型下鄱阳湖不同湖区的局部流场中的5种特征进行统计分析,得出:在无枢纽状态下,松门山南部的顺时针环流场、汉池湖附近的回流场和汉池湖附近的反时针半环流场发生的次数相对较多,其中以汉池湖附近的反时针半环流场为最多;在有枢纽状态下,松门山南部的顺时针环流场和汉池湖附近的回流场均有所减少,其中以枯水年2004年减少比较明显;而松门山南部的反时针环流场、主湖区的局部回流场和汉池湖附近的反时针半环流场则有所增加,尤其是在枯水年份的2004年。
[Abstract]:Poyang Lake is the largest freshwater lake in China with ecological functions such as flood regulation and biodiversity conservation. However, in recent years, ecological problems such as water shortage, wetland degradation, water quality deterioration, and so on have aroused great attention, and the construction of Poyang Lake water conservancy project has once again aroused heated discussion. However, the construction of water conservancy project will affect the hydrology and hydrodynamics of Poyang Lake. Among them, lake flow is an important dynamic index, which determines the transport and diffusion of all kinds of matter in the lake, and affects a series of human activities. In this paper, by constructing the two-dimensional hydrodynamic model of Poyang Lake, under the dispatching scheme developed by Poyang Lake Water Conservancy Project, the velocity and direction of flow in typical years of Fengping, Ping and dry are simulated. The basic lake flow pattern and local lake flow are compared between those with or without a hub, and the influence of Poyang Lake water conservancy project on lake flow field is analyzed, which can be used as a scientific basis for the establishment of the project. The results are as follows: (1) through the simulation of the average velocity of the three important regions in 2010, 2000 and 2004 (low water) years, it is found that the key projects have the least influence on the lake velocity in the high water year. The influence on the river channel and the main lake area is greater than that on the two national nature reserves. In the year of plain water, the influence of the junction project on the velocity of Poyang Lake is stronger than that on the type of annual velocity of abundant water. The velocity of river flow into the river decreases, and the velocity of velocity increases in the National Nature Reserve of Nanji Mountain Wetland in Poyang Lake. In the dry year, the impact of the project on the flow velocity of Poyang Lake is the biggest, and the velocity changes are different in different places during the operation period. (2) in order to study the influence of Poyang Lake water conservancy project on the flow direction, The average flow direction of three typical years with different scheduling periods is analyzed. The results show that the flow direction of the three Gorges water storage period, compensation period and low dry water period is obvious. The year type of Poyang Lake Water Control Project which has the greatest influence on the flow direction is 2004, followed by 2000, and the least impact on 2010. In addition, the starting date of the dispatching period is selected to compare whether there is a hub or not, and it is found that the change of the flow direction in the storage period and the low dry period is the most obvious. (3) the implementation of the water level regulation of the Poyang Lake Water Conservancy Project will change the basic lake flow characteristics of the lake. In the natural state, the backflow and topside flow are replaced by the backflow and drainage. Under the condition of no pivot, the gravity type is the main type, the top support type is the second, the inverted irrigation type is the least, and the gravity drainage type lake flow decreases under the condition of the junction, especially in the dry year. The upper-support type of water storage type lake flow increased, and the dry year was the most, and the dry year type of backwater irrigation decreased from 14 days to 8 days. Due to water storage, 11 days and 12 days of backflow occurred in 2000 and 2010 respectively. (4) while the basic lake flow characteristics were affected by Poyang Lake water conservancy project, the local lake flow also changed correspondingly. Based on the statistical analysis of five characteristics of local flow fields in different lakes of Poyang Lake in Fengping and dry years, it is concluded that the clockwise circulation field in the south of Songmen Mountain is in the condition of no junction. The frequency of backflow field near Hanchi Lake and counter-clockwise half-circulation field near Hanchi Lake is relatively high, and the counter-clockwise half-circulation field near Hanchi Lake is the most frequent. The clockwise circulation field in the south of Songmen Mountain and the reflux field near Hanchi Lake have been decreased under the condition of hub, especially in the dry year of 2004. However, the counter-clockwise circulation field in the south of Songmen Mountain, the local backflow field in the main lake area and the counter-clockwise half-circulation field near the Hanchi Lake increased, especially in the dry year of 2004.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV61;P343.3

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