Migration and cutoff of meanders in the hyperarid environment of the middle Tarim River, northwestern China.
Migration and cutoff of meanders in the hyperarid environment of the middle Tarim River, northwestern China.
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DOI：
10.1016/j.geomorph.2016.10.018
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
Zhiwei Li;Guoan Yu;G. Brierley;Zhaoyin Wang;Y. Jia
中科院分区：
文献类型：
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作者：
Zhiwei Li;Guoan Yu;G. Brierley;Zhaoyin Wang;Y. Jia
塔里木河中游是我国西北部最长的内陆河，在极端干旱的环境中发育了一条曲流河道。虽然塔里木河流域面积超过100万平方公里，但下游的流量主要限于夏季，灌溉压力使汛期越来越短。利用多期遥感图像和河道河床、河岸特性及河岸植被覆盖的实地调查分析，分析了105条河曲的平面形态、横向迁移率和截止线。结果表明，塔里木河曲流区的地貌特征与其它环境相似。河曲的中心线长度与颈槽宽度之比在1.2 ~ 8.1之间，弯曲曲率（弯曲半径与槽宽之比）在0.30 ~ 2.8之间，弯曲顶点的平均偏转角为79.9°。曲流的迁移速率为1.4 ~ 96.7 m y− 1。从2000年到2013年，400公里长的河段发生了45次沿着断流。由于降水量有限，河岸植被覆盖稀疏，且河岸由密集的根系、细砂和粉砂材料组成，但缺乏粘土，因此河岸强度有限，对弯曲运动的约束有限。
A meandering channel has developed in the middle Tarim River, the longest inland river flowing through a hyperarid environment in northwestern China. Although the drainage basin of the Tarim River extends over 1 million km2, flow in downstream reaches is largely restricted to summer months, and irrigation pressures have made the flood season increasingly short. The planform morphology, lateral migration rate, and cutoffs of 105 meanders were analysed using multiperiod remote sensing images and field survey analyses of channel bed and bank properties and of riparian vegetation cover. Results show that planform attributes of the meandering Tarim River are similar to those found in other environments. The ratio of the channel centreline length to the neck channel width of meanders ranges between 1.2 and 8.1, the bend curvature (ratio of bend radius to channel width) ranges between 0.30 and 2.8, and the average deflection angle of the bend apexes is 79.9°. Meander migration rates range from 1.4 to 96.7 m y− 1. From 2000 to 2013, 45 cutoffs occurred along the 400-km-long reach. As the riparian vegetation cover is sparse because of limited precipitation and because banks are comprised of dense roots, fine sand and silt materials, but lack clay, bank strength is limited and presents limited constraints upon bend movement.