Morphological characteristics and changes of two meandering rivers in the Qinghai-Tibet Plateau, China

Guo Xiwei; Gao Peng; Li Zhiwei

摘要

This study investigated bend morphology and dynamic changes of two highly convoluted meandering rivers, the Black River and the White River, in the Upper Yellow River Watershed of the Qinghai-Tibet Plateau (QTP), China. Using remotely sensed data, we characterized channel morphology and lateral changes of 290 meander bends in the two rivers. These bends exhibited extensive development of compound structures with each involving multiple sub-bends. Their migration patterns were dominated by extension, translation, and the combination of both, with the average migration rate higher in bends that changed by translation than that of bends by other modes. These morphological changes led to a longitudinal erosion-to-deposition pattern along the two studied rivers. Our analyses showed that the White River migrated much faster with more frequent cutoffs but fewer compound bends than the Black River, which may be attributed to the greater stream power of the former. We found a similar single-mode relationship between migration rate and bend curvature, commonly reported in previous studies, indicating that the largest migration rate occurred in bends with medium curvatures. This relationship, however, was altered to a quasi-monotonic inverse one when the average migration rates of bends were calculated for each class interval of bend curvatures, suggesting the complexity of bend morphodynamics. In general, the two studied meandering rivers migrated slower than many other meandering rivers worldwide, which allowed their bends to evolve into complex planform structures. (c) 2021 Elsevier B.V. All rights reserved.

机译：本研究研究了中国青藏高原（QTP）上黄河流域两大逆向蜿蜒河流，黑河和白河的弯曲形态和动态变化。使用远程感测数据，我们在两条河流中表征了290曲刃弯曲的通道形态和横向变化。这些弯曲表现出广泛的复合结构的发展，每个涉及多个子弯曲。它们的迁移模式由扩展，翻译和两者的组合为主，弯曲的平均迁移率高于翻译的弯曲率高于其他模式的弯曲。这些形态变化导致沿两个研究河流的纵向腐蚀图案。我们的分析表明，白河迁移得更快，更频繁的截止值比黑河更频繁的截止值，这可能归因于前者的较大流动力。我们发现迁移率和弯曲曲率之间的类似单模关系，常见于先前的研究中报告，表明在弯曲中发生最大的迁移率，具有中曲线。然而，当为弯曲曲率的每个阶级间隔计算弯曲的平均迁移率时，这种关系被改变为准单调逆一个，表明弯曲形态学性的复杂性。一般来说，这两个学习的蜿蜒河流迁移慢于全球许多其他蜿蜒的河流，这允许他们的弯道进入复杂的平面形状结构。（c）2021 Elsevier B.v.保留所有权利。

Morphological characteristics and changes of two meandering rivers in the Qinghai-Tibet Plateau, China

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