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Geodiversity in the Yellow River source zone

Journal of Geographical Sciences 2013年第5期23卷 775-792页

作者： brendon blue Gary BRIERLEY YU Guo-an School of Environment University of Auckland Private Bag 92019 Auckland New Zealand Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China

It is a key premise of ＇ecosystem approaches＇ to natural resources management that we must have an appropriate understanding of biodiversity values, and controls upon them, if we wish to manage them effectively. These biodiversity values, and associated ecosystem functionality, vary with space and time and are tied directly to landscape-scale relationships and evolutionary traits. In riverine systems, nested hierarchical principles provide a useful platform to assess relationships between landscape components across a range of scales. These understandings are most instructively synthesized through catchment-scale analyses. This paper outlines a rationale for systematic catchment-wide appraisals of river geodiversity. An initial application of these principles is presented for the Yellow River source zone in Qinghai Province, western China. Geo-ecological relationships are outlined for five broad sections of the trunk stream, highlighting implications for the management of these individual landscape compartments and for the system as a whole.

关键词： geodiversity river classification anabranching Qinghai-Tibet Plateau Sanjiangynan Yellow River source zone

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Analysis of controls upon channel planform at the First Great Bend of the Upper Yellow River, Qinghai-Tibet Plateau

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Journal of Geographical Sciences 2013年第5期23卷 833-848页

作者： LI Zhiwei WANG Zhaoyin PAN Baozhu DU Jun Gary BRIERLEY YU Guo-an brendon blue State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China Changjiang River Scientific Research Institute Wuhan 430010 China School of Environment University of Auckland Private Bag 92019 Auckland New Zealand Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China

The 270 km long section of the Upper Yellow River at the First Great Bend is comprised of single channel and multiple channel systems that alternate among anastomosing, anabranching, meandering and braided reaches. The sequence of downstream pattern changes is characterized as： anastomosing-anabranching, anabranching-meandering, meandering-braided and braided-meandering. Remote sensing images, DEM data and field investigations are used to assess ahd interpret controls on these reach transitions. Channel slope and bed sediment size are key determinants of transitions in channel planform. Anas- tomosing reaches have a relatively high bed slope （0.86‰） and coarser sediment bed material （d50 = 3.5 mm）. In contrast, meandering reaches have a low slope （0.30‰） and fine sediment bed material （d50 = 0.036 mm）. The transition from a meandering to braided pattern is characterized by an increase in channel width-depth ratio, indicating the important role of bank strength （i.e. cohesive versus non-cohesive versus channel boundaries）. Interestingly, the braided-meandering and meandering-braided transitions are coincident with variable flow inputs from tributary rivers （Baihe and Heihe rivers respectively）. Theoretical analysis of the meandering-braided transition highlights the key control of channel width-depth ratio as a determinant of channel planform.

关键词： Yellow River Source river pattern diversity river pattern transition anastomosing river ana- branching river meandering river braided river

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维普期刊数据库

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

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Journal of Geographical Sciences 2013年第5期23卷 817-832页

作者： YU Guo-an LIU Le LI Zhiwei LI Yanfu HUANG Heqing Gary BRIERLEY brendon blue WANG Zhaoyin PAN Baozhu Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China State Key Laboratory of Hydroscience and Engineering Tsinghua University Beijing 100084 China School of Environment University of Auckland Private Bag 92019 Auckland New Zealand Changjiang River Scientific Research Institute Wuhan 430010 China

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

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维普期刊数据库

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Bed load transport under different streambed conditions-a field experimental study in a mountain stream

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International Journal of Sediment Research 2012年第4期27卷 426-438页

作者： Guo-an YU Zhao-yin WANG He Qing HUANG Huai-xiang LIU brendon blue Kang ZHANG Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences State Key Laboratory of Hydroscience and Engineering Tsinghua University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Nanjing Hydraulic Research Institute School of Environment The University of Auckland Pearl River Hydraulic Research Institute

Bed load transport in mountain streams is closely linked to streambed *** structures are arrangements of boulders and cobbles deposited during extreme floods,in a stable configuration exhibiting high dissipation of *** experiments were carried out in a mountain stream in Yunnan,southwestern China,studying bed load movement on three typical streambeds,i.e.,with well developed,partially developed,and no *** underwater observation and video-capturing system was designed to observe and measure the movement of bed load *** initiation mode, trajectory,velocity,and acceleration of bed load particles under the three conditions were observed and *** showed that the bed load movement was highly associated with streambed *** well-developed structures,bed load particles moved intermittently through saltation and the bed load transport rate was very *** partially-developed structures most bed load particles moved through saltation but a portion of sediment moved in sliding and *** the case with no streambed structure(plane bed) contact load motion(sliding and rolling) gradually became ***,laminated load motion occurred and became the main component of bed load transport when the flow discharge and incoming sediment load were very *** load motion was a special form of bed load motion with an extremely high *** load transport and streambed structure both acted to dissipate flow energy and were mutually *** rates of bed load transport occurred in the streams with no or poor bed structures,and low bed load transport was associated with well developed *** bed load transport rate was inversely correlated to the degree of streambed development.

关键词： Bed load transport Streambed structure Mountain stream Underwater observation and Video capturing system

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