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采用水文学、泥沙运动力学与数理统计学相结合的研究方法 ,对宜昌和大通两个测站近五十年的实测水文、泥沙资料进行分析 ,以探究长江中下游水沙通量的变化规律。研究表明 ,水量由中游向下游沿程递增 ,但各测站的年均增幅不明显 ;长江中下游泥沙主要来源于长江上游地区的金沙江和嘉陵江 ,其次是汉江、洞庭湖和鄱阳湖等水系 ;长江流域来沙主要以悬移质形式下泄 ,悬沙通量由中游向下游沿程递减 ,同时各测站悬移质输沙量也逐年呈阶梯性递减趋势 ;长江中下游水沙通量有明显的季节性变化 ,洪季通量值明显高于枯季 ;悬沙颗粒主要由极细砂和粉砂组成 ,自中游向下游 ,泥沙颗粒逐渐细化 ;由于江阴河段附近边界条件的限制 ,该区域的悬沙粒径明显小于其上下游河段
Based on the research methods of hydrology, sediment movement mechanics and mathematical statistics, the measured hydrological and sediment data of two stations in Yichang and Datong over the past 50 years were analyzed to explore the water and sediment flux in the middle and lower reaches of the Yangtze River The law of change. The research shows that the amount of water increases from the middle reaches to the lower reaches, but the annual average increase of each station is not obvious. The sediment in the middle and lower reaches of the Yangtze River mainly comes from the Jinsha River and Jialing River in the upper reaches of the Yangtze River, followed by the Hanjiang River, Dongting Lake and Poyang Lake The sediment flux of suspended sediment decreased gradually from the middle reaches to the lower reaches, meanwhile the suspended sediment load at each station also showed a decreasing trend stepwise year by year. In the middle and lower reaches of the Yangtze River, The amount of suspended sediment is mainly composed of very fine sand and silt, and from the middle reaches to the downstream, sediment particles are gradually refined. Due to the boundary conditions near Jiangyin reach The size of suspended sediment in this area is obviously smaller than that of its upper and lower reaches