Fluvial diversity in relation to valley setting in the source region of the Yangtze and Yellow Rivers  

作　　者：YU Guo-an LIU Le LI Zhiwei LI Yanfu HUANG Heqing Gary BRIERLEY Brendon BLUE WANG Zhaoyin PAN Baozhu 

机构地区：[1]Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China [2]State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China [3]School of Environment, University of Auckland, Private Bag 92019, Auckland, New Zealand [4]Changjiang River Scientific Research Institute, Wuhan 430010, China

出　　处：《Journal of Geographical Sciences》2013年第5期817-832,共16页地理学报（英文版）

基　　金：National Natural Science Foundation of China, No.41001008; No.51209010; International Science ＆ Technology Cooperation Program of China, No.2011DFA20820; No.2011DFG93160Acknowledgements Gary Brierley gratefully acknowledges support from a Visiting Professorship awarded by the Chinese Academy of Sciences.

摘　　要：The spatial distribution of valley setting （laterally-unconfined, partly-confined, or confined） and fluvial morphology in the source region of the Yangtze and Yellow Rivers is contrasted and analyzed. The source region of the Yangtze River is divided into 3 broad sections （I, II and III） based on valley setting and channel gradient, with the upstream and downstream sections being characterized by confined （some reaches partly-confined） valleys while the middle section is characterized with wide and shallow, laterally-unconfined valleys. Gorges are prominent in sections I and III, while braided channel patterns dominate section II. By contrast, the source region of the Yellow River is divided into 5 broad sections （sections I-V） based on valley characteristics and channel gradient. Sections I, II and IV are alluvial reaches with mainly laterally-unconfined （some short reaches partly-confined） valleys. Sections III and V are mainly confined or partly-confined. Greater morphological diversity is evident in the source region of the Yellow River relative to the upper Yangtze River. This includes braided, anabranching, anastomosing, meandering and straight alluvial patterns, with gorges in confined reaches. The macro-relief （elevation, gradient, aspect, valley alignment and confinement） of the region, linked directly to tectonic movement of the Qinghai-Tibet Plateau, tied to climatic, hydrologic and biotic considerations, are primary controls upon the patterns of river diversity in the region.The spatial distribution of valley setting （laterally-unconfined, partly-confined, or confined） and fluvial morphology in the source region of the Yangtze and Yellow Rivers is contrasted and analyzed. The source region of the Yangtze River is divided into 3 broad sections （I, II and III） based on valley setting and channel gradient, with the upstream and downstream sections being characterized by confined （some reaches partly-confined） valleys while the middle section is characterized with wide and shallow, laterally-unconfined valleys. Gorges are prominent in sections I and III, while braided channel patterns dominate section II. By contrast, the source region of the Yellow River is divided into 5 broad sections （sections I-V） based on valley characteristics and channel gradient. Sections I, II and IV are alluvial reaches with mainly laterally-unconfined （some short reaches partly-confined） valleys. Sections III and V are mainly confined or partly-confined. Greater morphological diversity is evident in the source region of the Yellow River relative to the upper Yangtze River. This includes braided, anabranching, anastomosing, meandering and straight alluvial patterns, with gorges in confined reaches. The macro-relief （elevation, gradient, aspect, valley alignment and confinement） of the region, linked directly to tectonic movement of the Qinghai-Tibet Plateau, tied to climatic, hydrologic and biotic considerations, are primary controls upon the patterns of river diversity in the region.

关 键 词：valley setting fluvial morphology river patterns spatial distribution source region of the Yangtze and Yellow Rivers 

分 类 号：X522[环境科学与工程—环境工程] X321