Morphological characteristics of an alpine highly-sinuous meandering river in Qinghai-Tibet Plateau, China

Authors: Xiwei Guo*, Syracuse University, Peng Gao, Syracuse University
Topics: Geomorphology
Keywords: Meandering channel, lateral migration, alpine environments, Qinghai-Tibet Plateau
Session Type: Poster
Day: 4/5/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

Meandering channels are vastly developed in a unique alpine setting within the upper Yellow River watershed in the northeastern margin of the Qinghai-Tibet Plateau of western China. This study investigates the morphological characteristics of the lower Black River (Heihe River), a major tributary of the upper Yellow River with meandering channels developed. The mean elevation is 3400 m. A 240-km channel segment with highly-convoluted meander bends, stretching from the first upstream confluence to the mouth of the Black River, was studied. Along the entire reach, there were 149 meander bends identified and analyzed by their spatiotemporal changes from 1986 to 2017. Among them, compound loops are extensively formed in clusters along the river, taking up nearly 1/3 of the total bends. Bend migration rates vary spatially that, based on types of morphological change, meander bends with downstream translation have nearly twice higher migration rate on average than that of the bends with transverse extension. The relation between bend curvature and migration rate agrees with previous findings that the channel bend is most active at the curvature of between 2 and 3, with mild differences of migration rates for curvatures greater or less than this critical range. Analysis of the temporal changes of the studied reach revealed that erosion is substantially higher than deposition in its upstream half, while the opposite trend prevailed in the downstream half. Also, it appears that drastic sedimentation processes at bend-scale are largely driven by the dynamics of fluvial bars.

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