The study focused on the question of how the natural and human forcing has affected the morphodynamic evolution of bars in the middle Yangtze River. A large channel bar was investigated using satellite remote sensing data during 1986–2017. A novel algorithm was proposed to select images acquired at the similar river stage. The bar was delineated from selected images and surface area, volume and centroid were quantified to examine bar morphodynamics. The results indicated a four-stage evolution process, including a steady extension (1986–1998), a quick shrinkage (1998–2002), a fluctuated shrinkage (2002–2012), and a fluctuated extension (2012–2017). The first stage was characterized by the steady growth at a rate of 0.087 km²/a, and a centroid translation towards the inner bend by 400 m. The second stage was the most dynamic episode, with the bar degradation at a rate of 0.71 km²/a, and a downstream migration by 850 m. In the third stage, the bar was eroded at a rate of 0.05 km²/a, and migrated towards the inner bend by about 80 m. In the fourth stage, the bar was deposited at a rate of 0.12 km²/a, and traveled upstream by around 400 m. The bar volume exhibited the similar trend. The analysis showed that the four stages were separated by the consecutive floods, the closure of Three Gorges Dam and the installation of two river engineering works. The results suggested that the bar evolved much more dynamic under the natural flow (1985–2003) than that of the regulated (2003–2012). The findings revealed that the evolution was largely governed by the flow and sediment supply while the human forcing can affect the process by altering these regimes. This study also demonstrated the great usefulness of combining multi-temporal imagery and river stage records in the assessment of bar morphodynamics.

该研究的重点是自然和人类强迫如何影响长江中游水坝的形态动力学演化。在1986-2017年期间，使用卫星遥感数据调查了一个大型频道栏。提出了一种新颖的算法来选择在相似河流阶段采集的图像。从选定的图像描绘出条形，并对表面积，体积和质心进行定量，以检查条形的动力学。结果表明，演化过程分为四个阶段，包括稳定扩展（1986–1998），快速收缩（1998–2002），波动收缩（2002–2012）和波动扩展（2012–2017）。第一阶段的特征是以0.087 km ²的速度稳定增长/ a，向内弯曲的质心平移400 m。第二阶段是最活跃的阶段，棒材退化速度为0.71 km ² / a，下游迁移为850 m。在第三阶段，钢筋以0.05 km ² / a的速度腐蚀，并向内弯曲处迁移约80 m。在第四阶段，以0.12 km ²的速率沉积钢筋/ a，向上游移动约400 m。棒材体积表现出相似的趋势。分析表明，这四个阶段被连续的洪水，三峡大坝的关闭和两个河道工程的安装分隔开。结果表明，自然流量（1985-2003年）下酒吧的动态变化比受监管的自然条件下（2003-2012年）动态得多。研究结果表明，演化主要受流量和沉积物供应的控制，而人类强迫可以通过改变这些机制来影响过程。这项研究还证明了将多时相图像和河段记录相结合对酒吧形态动力学的评估具有很大的帮助。