长江倒灌对鄱阳湖水文水动力影响的数值模拟

发布时间：2018-01-19 12:30

  本文关键词： 倒灌 水动力-粒子示踪模型 流量比 水文水动力 鄱阳湖 长江　出处：《湖泊科学》2017年05期 　论文类型：期刊论文

【摘要】：倒灌是发生在湖泊与周围水体交汇处的一个重要物理过程,对湖泊水文水动力与水环境带来严重影响或干扰,进而对湖泊水质产生重要的影响或控制作用.本文采用统计方法和二维水动力-粒子示踪耦合模型来分析倒灌物理成因、倒灌发生判别与指示以及倒灌对鄱阳湖水文水动力的影响.统计表明,流域"五河"入湖径流、长江干流径流情势以及两者叠加作用均是倒灌的影响因素,但长江干流径流情势是影响或者控制倒灌频次与倒灌强度的主要因素."五河"来水与长江干流的流量比可用来判别与指示倒灌发生与否.当流量比低于约5%时,倒灌可能发生且最大发生概率可达25%;当流量比高于10%时,倒灌发生概率则低于2%.水动力模拟结果表明,倒灌对湖区水位与流速的影响向湖区中上游逐渐减弱,湖泊水位和流速受影响最为显著的区域主要分布在贯穿整个湖区的主河道,而浅水洪泛区的水位和流速则受倒灌影响相对较小.倒灌使得湖泊空间水位提高约0.2~1.5 m,湖泊主河道的流速增加幅度可达0.3 m/s.粒子示踪结果表明,倒灌导致湖区水流流向转变约90°~180°,倒灌导致的水流流向变化能够使湖区大部分粒子或物质向上游迁移约几千米至20 km,且粒子在下游主河道的迁移距离要明显大于中上游洪泛区.
[Abstract]:Inverted irrigation is an important physical process that occurs at the intersection of lakes and surrounding water bodies, which has serious influence or interference on the hydrohydrodynamics and water environment of lakes. In this paper, statistical method and two-dimensional hydrodynamic particle tracer coupling model are used to analyze the physical origin of backwater irrigation. The statistics show that the runoff of "five rivers" into the lake, the runoff situation of the main stream of the Yangtze River and the superposition of the two factors are the influencing factors of the inverted irrigation. However, the runoff situation of the Yangtze River main stream is the main factor that affects or controls the frequency and intensity of the inverted irrigation. The flow ratio of the incoming water to the main stream of the Yangtze River can be used to judge and indicate the occurrence or not of the backwater irrigation, when the flow ratio is lower than about 5. The maximum probability of reflux may be up to 25. When the discharge ratio is higher than 10, the probability of inverted irrigation is lower than 2. The hydrodynamic simulation results show that the effect of inverted irrigation on the water level and velocity of lake area is gradually weakened to the upper and middle reaches of lake area. The area where the water level and velocity of the lake are most affected is mainly distributed in the main river course which runs through the whole lake area. However, the water level and velocity of water in shallow floodplain area are relatively less affected by backwater irrigation, which increases the water level of lake space by about 0.2 ~ 1.5 m. The flow velocity of the main channel of the lake can increase by 0.3 m / s. The results of particle tracing show that the flow direction of the lake is changed by 90 掳~ 180 掳. The change of flow direction caused by backwater can make most particles or matter move upstream from several kilometers to 20 km, and the migration distance of particles in the downstream main channel is obviously larger than that in the middle and upper reaches of floodplain.
【作者单位】： 中国科学院南京地理与湖泊研究所流域地理学重点实验室;江西师范大学鄱阳湖湿地与流域研究教育部重点实验室;
【基金】：江西省重大生态安全问题监控协同创新中心项目(JXS-EW-00) 国家自然科学基金项目(41401031,41371062,41301023)联合资助
【分类号】：P343.3;X143
【正文快照】： 湖泊是全球陆地水系统中极为重要的组分,因其具有丰富的地表水资源和高度的生态价值,湖泊是人们休闲娱乐、工农业用水和发展渔业的重要场所,也是众多生物群赖以生存的必需环境[1].世界上很多大型湖泊通过自然或者人工连通与其周围水体(例如河流、海洋等)存在复杂的水力联系[2]，

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