中文摘要：

侧面的移植是在中间的长江(MYR ) 里的词法变化的一种重要形式，特别地为更低的 Jingjiang 活动范围。自从它的被坝所围住的水，三座峡水库(TGR ) 实质地在 2003 年 6 月把沉积供应归结为下游的河隧道。沉积的减少怎么影响河岸侵蚀和隧道调整的过程的科学理解复杂、有限。在现在的纸，在到充满 TGR 的典型蜿蜒地流和 MYR 的编织岛的河片断的词法回答被一个 3-D morphodynamic 模型调查。3-D 模型的潜力被观察数据表明了。在 Shishou 的词法进化在被坝所围住的水被预言的 TGR 的开始的 12 年期间弯曲。在学习活动范围的平面形状进化上的 TGR 操作的效果基于模仿的结果被分析。沉积负担被 75% 由于早 TGR 充满减少。有更少的沉积负担的病床降级的大小与预先建水坝状况相比由于 TGR 手术被增加。品质上，没有 TGR 操作，在在 TGR 操作以后的 Shishou 拐弯的全面平面形状进化趋势类似于那。侧面的移植的大小在隧道拐弯的一些部分被增加了，在 TGR 操作的词法反应展出更侧面的移植而非垂直降级的地方。在河岸脚趾搜索提高河岸失败。沉积负担和弱银行反搜索能力以及重要螺旋状的流动的减少能为在隧道拐弯的加强的银行侵蚀负责。

英文摘要：

Lateral migration is an important form of morphological changes on the Middle Yangtze River （MYR）, particularly for the lower Jingjiang reach. The Three Gorges Reservoir （TGR） has substantially reduced sediment supply to the downstream river channels since its impoundment in June 2003. The scientific understanding of how decrease of sediment influences the processes of bank erosion and channel adjustments is complex and limited. In the present paper, the morphological responses in a typical meandering and island-braided river segment of the MYR to the filling of the TGR were investigated by a 3-D morphodynamic model. The potential of the 3-D model has been demonstrated by the observed data. The morphological evolutions in the Shishou bend during the first 12 years of the TGR impound- ment were predicted, The effects of the TGR operation on the planform evolutions in the study reach were analyzed based on the simulated results. Sediment load is decreased by 75~ due to the early filling of the TGR. The magnitude of bed degradation with less sediment load due to the TGR operation is increased compared with the pre-dam situation. Qualitatively, the overall planform evolution trends in the Shishou bend after the TGR operation are similar to that without the TGR operation. The magnitude of lateral migration has been increased in some part of the channel bend, where the morphological response of the TGR operation exhibits more lateral migration rather than vertical degradation. Scouring at the bank toe enhances bank failure. Decrease of sediment load and weak bank anti-scour ability as well as the significant helical flow can be responsible for intensified bank erosion in the channel bend.