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channel evolution under changing hydrological regimes in anabranching reaches downstream of the Three Gorges Dam

Frontiers of Earth Science 2018年第3期12卷 640-648页

作者： Jianqiao HAN Wei ZHANG Jing YUAN Yongyang FAN Institute of Soil and Water Conservation Northwest A&F University Yangling 712100 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China Bureau of Hydrology Changjiang Water Resources Commission Wuhan 430010 China Changjiang Institute of Survey Planning Design and Research Wuhan 430010 China

Elucidating the influence of dams on fluvial processes can benefit river protection and basin management. Based on hydrological and topographical data, we analyzed channel evolution in anabranching reaches under changing hydrological regimes influenced by the Three Gorges Dam. The main conclusions are as follows： 1） the channels of specific anabranching reaches were defined as flood trend channels or low-flow trend channels according to the distribution of their flow characteristics. The anabranching reaches were classified as T1 or T2. The former is characterized by the correspondence between the flood trend and branch channels, and the latter is characterized by the correspondence between the flood trend and main channels; 2） on the basis of the new classification, the discrepant patterns of channel evolution seen in anabranching reaches were unified into a pattem that showed flood trend channels shrinking and low-flow trend channels expanding; 3） flood abatement and the increased duration of moderate flow discharges are the main factors that affect channel adjustments in anabranching reaches after dam construction; and 4） in the next few decades, the pattern of channel evolution will remain the same as that of the Three Gorges Dam operation. That is, the morphology will fully adapt to a flow with a low coefficient of variation. Our results are of interest in the management of the Yangtze River and other rivers influenced by dams.

关键词： anabranching river channel evolution Three Gorges Dam Yangtze River

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Experiments on channel evolution due to Dam Removal in Taiwan

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Journal of Mountain Science 2014年第6期11卷 1396-1405页

作者： WANG Hsiao-Wen CHENG Ying-Che LIN Chung-Yi Department of Hydraulic and Ocean Engineering National Cheng Kung University

Due to safety concerns and habitat restoration for landlocked salmon,a 13-m high check dam on Chijiawan Creek was removed in late May 2011 in *** conducted experiments to understand channel evolution of different *** further compared our experimental results of riverbed elevation changes with the analytical solutions derived from the diffusion equation and field dynamics as well after the creek experienced the first flood *** results indicated that magnitude of discharges and notch size are dominant factors in resulting channel *** the largest differences between grain size distribution are associated with discharge,the largest differences in net change in upstream volume are associated with notch *** the theoretical equation could help understand the channel change after dam removal,it only explained the evolution closer to the *** physical experiments,on the other hand,provided insights especially with regard to comparing alternative proposed management *** discrepancies between predicted and actual outcome highlight more needed inputs for future dam-removal assessments.

关键词： Dam removal Physical Experiments channel evolution Grain size distribution Riverbed elevation

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Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works

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International Journal of Sediment Research 2022年第4期37卷 424-434页

作者： Meirong Zhou Junqiang Xia Shanshan Deng Zhiwei Li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

In the middle and lower reaches of alluvial rivers, various kinds of river regulation projects affecting natural channel evolution often are distributed due to the requirements of flood control, navigation,and channel stability. However, the influence of large-scale river regulation works on fluvial processes is not fully known. Therefore, a two-dimensional(2D) morphodynamic model has been improved to address this problem. The new detailed procedure is presented in this paper:(i) First, each node in the study domain was labeled using a specified point code to distinguish the zones with or without regulation works; and(ii) second, a 2D model was improved to consider the effect of river regulation works. In the refined model, the modules of sediment transport and bed deformation were treated separately in different zones. In the unprotected zones, both bed deposition and erosion were likely to occur. In the protected zones, bed erosion could not occur owing to the protection provided by the river regulation works, unless there was a deposition layer newly formed over the previous simulation periods. The observed data of the years 2004 and 2008 were used to calibrate and verify the improved 2D morphodynamic model which was applied in a 68-km-long reach of the Middle Yangtze River. Satisfactory results were obtained indicating that the improved model can better simulate the process of sediment transport and the morphology adjustment in three central bars in the study reach.

关键词： Two-dimensional model River regulation works channel evolution Central bar Middle Yangtze River

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channel evolution AFTER THE CONSTRUCTION OF THE 1ST PHASE OF THE DEEPWATER channel PROJECT OF THE YANGTZE ESTUARY

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International Journal of Sediment Research 2006年第2期21卷 158-165页

作者： Hualin WU1,2, Huanting SHEN3 and Yonghong WANG41 Res. Assoc. Prof., Hohai University, College of Traffic and Ocean, Nanjing, 210098, China2 Res. Assoc. Prof., Shanghai Estuarine and Coastal Science Research Center, Shanghai, 201201, China 3 Prof. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China 4 Res. Assoc. Prof., Ocean University of China, Qingdao, 266003, China Hohai University College of Traffic and OceanNanjing210098China Shanghai Estuarine and Coastal Science Research Center Shanghai201201China State Key Laboratory of Estuarine and Coastal Research East China Normal UniversityShanghai200062China Ocean University of China Qingdao266003China

In order to deepen the navigation channel, the Chinese government authorized the construction of the Yangtze Estuary Deepwater channel Project in 1997. The project is divided into three phases, increasing the navigation channel depth to 8.5, 10.0, and 12.5 m stage by stage. The evolution of the North Passage after the construction of the first phase of the deepwater channel project is analyzed, based on surveyed topographic data. Then, the paper summarizes the comprehensive effect of the first phase of the project. Regarding hydrologic data monitored during the constructing process, the effects of the training dikes and groins on the riverbed erosion of the North Passage is studied. Finally, the evolution mechanism is analyzed and summarized. The evolution mechanism found can be helpful for regulation of other braided rivers or estuaries.

关键词： Yangtze Estuary Training dike Groin channel evolution

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GEOMORPHIC THRESHOLDS FOR channel evolution IN THE LOWER YELLOW RIVER

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International Journal of Sediment Research 2004年第3期19卷 191-201页

作者： Zhongyan LI and Zhongchen LU Associate professor, Computing Institute of Science and Engineering, North China Electric Power University, Beijing 102206, E-mail: lizhongyan11@sina.comProfessor, Research Center for Eco-Environment Sciences, Chinese Academy of Sciences, Beijing 100085 Associate professor Computing Institute of Science and Engineering North China Electric Power University Beijing 102206 Professor Research Center for Eco-Environment Sciences Chinese Academy of Sciences Beijing 100085

channel evolution refers to boundary changes of rivers affected by fluvial actions. This paper provides an analysis of the development and formation of stream patterns in the lower Yellow River and presents intensive studies of several critical problems relating to channel evolution, including thresholds of channel gradient and longitudinal profile adjustment, channel surface morphology, response of channel pattern to boundary conditions, critical discrimination of cross sections and the discrimination of channel pattern changes using hydrologic parameters.

关键词： channel evolution Geomorphic thresholds the Lower Yellow River

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Genesis, evolution and reservoir identification of a Neogene submarine channel in the southwestern Qiongdongnan Basin, South China Sea

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Acta Oceanologica Sinica 2023年第5期42卷 57-78页

作者： Shuo Chen Donghui Jiang Renhai Pu Yunwen Guan Xiaochuan Wu Tianyu Ji Chuang Liu State Key Laboratory of Continental Dynamics(Northwest University) Xi’an 710069China Institute of Shanghai Offshore Petroleum Branch China Petroleum&Chemical CorporationShanghai 200120China Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China

A rarely reported middle-late Miocene-Pliocene channel(incised valley fill),the Huaguang channel(HGC),has been found in the deep-water area of the southwestern Qiongdongnan Basin(QDNB).This channel is almost perpendicular to the orientation of another well-known,large,and nearly coeval submarine channel in this *** on the interpretation of high-resolution 3D seismic data,this study describes and analyzes the stratigraphy,tectonics,sedimentation,morphology,structure and evolution of HGC by means of well-seismic synthetic calibration,one-and two-dimensional forward modeling,attribute interpretation,tectonic interpretation,and gas *** HGC is located on the downthrown side of an earlier activated normal fault and grew northwestward along the fault *** channel is part of a slope that extends from the western Huaguang Sag to the eastern Beijiao *** HGC underwent four developmental stages:the(1)incubation(late Sanya Formation,20.4–15.5 Ma),(2)embryonic(Meishan Formation,15.5–10.5 Ma),(3)peak(Huangliu Formation,10.5–5.5 Ma)and(4)decline(Yinggehai Formation,5.5–1.9 Ma)*** channel sandstones have a provenance from the southern Yongle Uplift and filled the channel via multistage vertical amalgamation and lateral *** channel extended 42.5 km in an approximately straight pattern in the peak *** 10.5 Ma,sea level fell relative to its lowest level,and three oblique progradation turbidite sand bodies filled the channel from south to north.A channel sandstone isopach map demonstrated a narrow distribution in the early stages and a fan-shaped distribution in the late *** formation and evolution of the HGC were controlled mainly by background tectonics,fault strike,relative sea level change,and mass supply from the Yongle *** HGC sandstone reservoir is near the Huaguangjiao Sag,where hydrocarbons were ***-bounding faults and underlying faults link the source rock with the reservoir.A regionally extensive m

关键词： South China Sea Qiongdongnan Basin submarine channel channel evolution reservoir identification

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Prediction of recent bank retreat processes at typical sections in the Jingjiang Reach

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Science China(Technological Sciences) 2014年第8期57卷 1490-1499页

作者： XIA JunQiang ZONG QuanLi ZHANG Yi XU QuanXi LI XiaoJuan State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Bureau of Hydrology Changjiang Water Resources Commission

The Jingjiang Reach is experiencing continuous channel degradation owing to operation of the Three Gorges Project （TGP） in 2003. Significant retreat processes at composite riverbanks have occurred at local sites of this reach, which may influence the stability of the fiver regime and the effect of existing river training works. Therefore, bank retreat plays a key role in fluvial processes of the Jingjiang Reach, and it is necessary to predict the long-term processes of bank retreat at typical sections in the reach. In this study, various factors influencing bank retreat in the Jingjiang Reach are investigated, based on bank erosion processes at four sections and the corresponding flow and sediment conditions. It is discovered that fluvial erosion intensity is a dominant factor in controlling the processes of bank retreat in the reach, although other factors, such as bank soil properties, can also influence bank retreat. The bankfull width at a section with severe bank erosion since 2002 is defined as being equal to the sum of the bankfull width in 2002 and the accumulated bank retreat distance after 2002. The magnitude of the bankfull width can be expressed as an exponential function of the previous 5-year average fluvial erosion intensity during flood seasons. The accumulated distances of bank retreat at four sections over the period 2002-2012 are predicted using the proposed empirical relationships, with the calculated bank retreat processes agreeing well with observed data.

关键词： composite riverbank channel evolution bank retreat fluvial erosion intensity Jingjiang Reach Three Gorges Project

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Gravel excavation and geomorphic evolution of the mining affected river in the upstream reach of the Yangtze River,China

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International Journal of Sediment Research 2022年第2期37卷 272-286页

作者： Yi Xiao Wenjie Li Shengfa Yang National Inland Waterway Regulation Engineering Research Center Chongqing Jiaotong University

As economic development upstream in the Yangtze River basin has progressed in recent decades,the demand for sediment has rapidly increased and contributed to an expansion in sediment excavation that may affect the river's stability and navigation *** the current study,the distribution of gravel mining in the upstream reach of the Yangtze River was investigated using field measurements obtained from2008 to *** experimental investigation was then done to analyze the bed load behavior in a typical mined channel using a physical river ***,a two-dimensional hydrodynamic-sediment transport numerical model was developed to predict the evolution of the mined *** results indicate that gravel mining was mainly distributed among the following nine river sections:Tongluoxia-Yibin,Erlong-Xianglutan,Naxi-Jinkou,Binpangqi-Hongyanqi,Chayuqi-Shenbeizui,Yangshipan-Shangbaisha,Dongxikou,Baisha-Wenzhongba,and *** gravel shoals near the riverbank have been destroyed,and the bed topography has been altered by up to 1.65 × 10～9 m3over the past 10 years.A bed load velocity formula was proposed to describe bed load transport in the mined channel based on dimensional *** recovery process of the excavation pits was slow in both the experiments and simulations,with only 0.12% and 1.39%,respectively,of the mined amounts of gravel being ***,the recovery rate of the mining pits gradually slowed as the sediment supply from upstream decreased,suggesting that the destroyed gravel shoals rarely returned to their original forms due to the combined operation of hydro-projects in upstream areas and limited sediment storage in the channel.

关键词： Gravel mining Bed load transport channel evolution Yangtze River upstream 2D numerical model

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Simulating bed evolution following the Barlin Dam(Taiwan,China)failure with implications for sediment dynamics modeling of dam removal

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International Journal of Sediment Research 2016年第4期31卷 299-310页

作者： Hsiao-Wen Wang Desiree Tullos Wei-Cheng Kuo Department of Hydraulic and Ocean Engineering National Cheng Kung University Department of Biological and Ecological Engineering Oregon State University

The failure of the Barlin Dam in Taiwan,China offers an important case study for evaluating concepts in modeling the rapid erosion and channel recovery following intentional and unplanned dam *** present a modeling effort that applied a 1D and quasi-2D uncoupled hydraulics and sediment model(NETSTARS) to evaluate how discretization and parameterization influence thefitofbed elevationpredictions to observations following dam *** analysis evaluated the model sensitivity to sediment transport function,active layer thickness,and number of stream tubes used to define the *** indicate that a) the model is more sensitive to active layer thickness and sediment transport function than to the number of stream tubes,b) development of dam removal models are likely to benefit from varying the active layer thickness in time,and c) increased lateral discretization does not appear to improve model fit in the steep and rapidly changing river environment at our *** conclude with discussion on differences between,identifying the need for,and general use of 1D,quasi-2D,and fully 2D models in dam removal and failure analysis.

关键词： Dam removal Modeling Sediment dynamics channel evolution Taiwan,China

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PREDICTING THE DEPTH OF EROSION IN RESERVOIRS FOLLOWING DAM REMOVAL USING BANK STABILITY ANALYSIS

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International Journal of Sediment Research 2003年第2期18卷 115-121页

作者： Martin W. DOYLE,Emily H. STANLEY,Andy R. SELLE,John M. STOFLETH,Jon M. HARBOR Department of Geography University of North Carolina Center for Limnology University of Wisconsin Madison Department of Earth and Atmospheric Sciences Purdue University West Lafayette Department of Earth and Atmospheric Sciences Purdue University West Lafayette Department of Earth and Atmospheric Sciences Purdue University West Lafayette Chapel Hill NC 27599 WI 53706 IN 47907 IN 47907 IN 47907

Dam removal has emerged in the U.S. as a critical concern for river management. Of particular interest is predicting the quantity of sediment that will be eroded from a reservoir following dam removal, which necessitates predicting the geometry a channel will approach as it forms in the reservoir. The geometry and sediment characteristics of the Koshkonong River were measured as it adjusted to the removal of the Rockdale Dam. Bank stability modeling was used as a tool for predicting the maximum depth of the evolving channel and general agreement was found between depths predicted with the model and those observed up to one year following dam removal. Model sensitivity analysis showed strong control of bank heights by groundwater levels in the reservoir sediment, as well as some control by vegetation established on the sediment surface. Long-term monitoring is needed to assess the accuracy of the model, but preliminary agreement is encouraging for applying this model and similar models to future dam removals.

关键词： Dam removal Bank stability model channel evolution Reservoir sediment

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