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长江中游宜昌-湖口河段分汊河型分布广泛,涵盖了顺直分汊、微弯分汊及鹅头型分汊3种类型.本文依据三峡水库蓄水以来大量原型观测资料,总结归纳了长江中游各分汊河段的演变特征及其内在机理,并初步预测了其发展趋势.研究结果表明,三峡水库蓄水后,沙量大幅减少,同时局部河床边界条件发生变化,长江中游分汊河段普遍出现支汊冲刷发展、中低滩冲刷变形、高滩滩缘崩退等演变现象.伴随着三峡水库调度方式的不断优化,加之河床冲刷下造床质输移水平的沿程恢复,以及大量航道整治工程的作用,城陵矶以下分汊河段稳定性将优于荆江河段.
The Yichang-Hukou reach of the middle reaches of the Yangtze River has a wide range of distributary river types, covering three types: straight divergence, slightly divergent divergence and goose divergence. Based on a large amount of prototype observation data since the Three Gorges Reservoir was impounded, The evolution characteristics and its internal mechanism of each section of the middle reaches of the Yangtze River and its preliminary prediction of its development trend show that after the Three Gorges Reservoir has been impounded, the amount of sediment decreases sharply while the boundary conditions of local river beds have changed. Along with the continuous optimization of the Three Gorges Reservoir’s dispatching method and the recovery of bed transportage under riverbed scouring, the evolution of branches and scouring, , As well as the role of a large number of waterway regulation works, the stability of the following Fenghuangcheng section of Chenglingji will be superior to Jingjiang section.