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长江-鄱阳湖顶托作用评价指标研究

人民长江 2024年第1期55卷 1-5,20页

作者：陈璐邓金运长江勘测规划设计研究有限责任公司湖北武汉430010 流域水安全保障湖北省重点实验室湖北武汉430010 武汉大学水资源工程与调度全国重点实验室湖北武汉430072 湖北省交通规划设计院股份有限公司湖北武汉430051

长江与鄱阳湖形成的江湖交汇系统存在复杂的河床演变与物质能量交换,江湖顶托关系是影响江湖水量交换的重要因素,同时对整个区域的水资源、防洪、灌溉、航运、生态有着重要影响。以长江与鄱阳湖的交汇区为研究对象,从动量基本方程出发,... 详细信息

长江与鄱阳湖形成的江湖交汇系统存在复杂的河床演变与物质能量交换,江湖顶托关系是影响江湖水量交换的重要因素,同时对整个区域的水资源、防洪、灌溉、航运、生态有着重要影响。以长江与鄱阳湖的交汇区为研究对象,从动量基本方程出发,建立了一套评估长江与鄱阳湖顶托强度的指标体系,提出了顶托强度指标——顶托角。研究结果表明:自20世纪80年代以来,顶托角整体上没有发生趋势性变化,说明长江对鄱阳湖的顶托作用在三峡水库蓄水后变化不明显。但从年内变化来看,在枯水期,由于三峡水库的补水作用,长江对鄱阳湖的顶托作用明显增强;在汛期,由于三峡水库的削减洪峰以及汛末蓄水,长江对鄱阳湖的顶托作用减弱。长江对鄱阳湖的顶托作用变化会在4~6月使湖水滞留湖区,易发生流域性洪水;在7~10月加速湖水的入江,使鄱阳湖的低水位形势持续恶化。研究成果可为长江和鄱阳湖的治理与保护提供参考。

关键词：江湖关系顶托作用顶托角三峡水库鄱阳湖长江

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长江中游通江湖泊对干流顶托作用变化规律

水科学进展 2024年第1期35卷 98-111页

作者：杨春瑞邓金运陈立郑柠辉赵晋武汉大学水资源工程与调度全国重点实验室湖北武汉430072

长江中游通江湖泊(洞庭湖和鄱阳湖)对干流的顶托作用直接关系到区域防洪安全。通过构造支流顶托强度指标并结合Copula函数,分析三峡水库蓄水前后两湖出流对长江干流顶托强度的变化和异同,讨论干支流流量分布和地形变化对两湖顶托强度变... 详细信息

长江中游通江湖泊(洞庭湖和鄱阳湖)对干流的顶托作用直接关系到区域防洪安全。通过构造支流顶托强度指标并结合Copula函数,分析三峡水库蓄水前后两湖出流对长江干流顶托强度的变化和异同,讨论干支流流量分布和地形变化对两湖顶托强度变化的贡献。研究结果表明:①三峡水库蓄水后,对干流顶托强度变化方面,汛期洞庭湖变化不大、鄱阳湖明显减弱;枯水期洞庭湖略有增强、鄱阳湖变化不大。②干支流流量分布导致的汇流比变化和江湖交汇区地形调整综合影响导致了两湖蓄水后顶托强度变化的差异;三峡水库蓄水后,干支流流量分布变化使洞庭湖、鄱阳湖对干流平均顶托强度分别减弱5.11%和13.45%;干流河床冲刷加剧导致的交汇区干支流河床高程差增大使洞庭湖、鄱阳湖对干流平均顶托强度分别增强6%和0.9%。

关键词：顶托作用汇流比 Copula函数长江中游洞庭湖鄱阳湖

Relationship between the equilibrium morphology of river islands and flow-sediment dynamics based on the theory of minimum energy dissipation

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International Journal of Sediment Research 2022年第4期37卷 514-521页

作者： Xuhai Yang Zhaohua Sun jinyun deng Dongfeng Li Yitian Li State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Department of Geography National University of Singapore

River islands are vital geomorphic units in alluvial rivers, and the variation of their morphology and position plays a significant role in regulating flow-sediment transport and channel stability. Based on the theories of minimum energy dissipation theory of fluid movement and river morphodynamics, this study uses the river islands in anabranching channels to analyze the relationship between the shape coefficient of river island and the flow-sediment dynamics under stable equilibrium conditions. Results indicate that the river islands could adjust their lengths and widths to reach an appropriate allocation of flow diversion ratio and sediment separation ratio in the two anabranching channels to ensure flow-sediment being smoothly transported downstream and achieve the minimum energy dissipation. Under the minimum energy dissipation condition of flow-sediment transport balance, the ratio of “sediment separation ratio” to “flow diversion ratio” in short and straight branching channels is between 1 and *** the proportion of flow-sediment transport reaches its maximum, the steady island morphology coefficient is approximately 0.2; that is, the island length is five times the width. We verify the steady island morphology coefficients using two typical islands in the middle and lower reaches of the Yangtze River and find the relative error is within ±3%.

关键词： Equilibrium morphology of islands Flow-sediment dynamics Minimum energy dissipation theory Sediment separation ratio Flow diversion ratio

The barrier river reach identification and classification in the Middle Yangtze River

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Frontiers of Earth Science 2019年第3期13卷 596-613页

作者： Jinwu TANG Chunyan HU Xingying YOU Yunping YANG Xiaofeng ZHANG jinyun deng Meng CHEN Changjiang Institute of Survey Planning Design and Research Wuhan 430010China Hubei Institute of Survey & Design for Water Resources & Water Power Engineering Wuhan 430064China State Key Laboratory of Water Resource and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport EngineeringMinistry of TransportTianjin 300456China

Adjustments of upstream river regimes are one of the main factors affecting downstream fluvial processes. However, not all adjustments of river regimes will propagate downstream. There are some distinctive river reaches where upstream and downstream adjustments have no relevance. However, the irrelevance is neither caused by different river types nor by the different conditions of water and sediment;but rather, the channel boundaries and riverbed morphologies block the propagation effect. These are referred to here as the barrier river reach phenomena. The migration of the thalweg line is the essential reason for causing the propagation effect. Numerous influencing factors for thalweg migration exist, including 1) the average flow rate above the critical bankfull discharge, the average flow rate below the critical bankfull discharge, and their ratio, 2) the ratio of the duration of the aforementioned two periods, 3) the thalweg displacement at the entrance of the river reach, 4) the deflecting flow intensity of the node, 5) the ratio of the river width to water depth, 6) the relative width of the floodplain, and 7) the Shields number. In this study, the correlativity between the measured distances and the restricting indicators of thalweg migration in the Middle Yangtze River over the years was established. The barrier degree of 27 singlethread river reaches was subsequently assessed. These reaches included 4 barrier river reaches;5 transitional reaches transforming from barrier to non-barrier;10 transitional reaches transforming from non-barrier to barrier;and 8 non-barrier river reaches. Barrier river reaches were found to be important for maintaining the stability of the river regime and the transverse equilibrium of sediment transport in the downstream reaches. To some extent, the barrier river reaches may protect the natural dynamical properties from being destroyed by artificial river regulation works. Thus, they are of great significance for river management.

关键词： the barrier river reach Yangtze River channel adjustment thalweg migration identification and classification

Flow resistance adjustments of channel and bars in the middle reaches of the Yangtze River in response to the operation of the Three Gorges Dam

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Journal of Geographical Sciences 2022年第10期32卷 2013-2035页

作者： HU Yong deng jinyun LI Yitian LIU Congcong HE Zican State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China CCCC Second Harbour Engineering Co Ltd Wuhan 430040China

Since the Three Gorges Dam(TGD)was put into operation,the flood water level at an identical discharge rate has not displayed a decreasing trend along the middle reaches of the Yangtze River(MYR).The flow resistance variations of the channel and bars in response to the operation of the TGD remain poorly understood,despite the importance of understanding these for water disaster mitigation and water environment ***,the impacts of the TGD on the downstream flow resistance of the channel and bars in the MYR were analyzed using systematic surveys of hydrological datasets,cross-sectional profiles,sediment datasets,and remote sensing images,during different *** the actual natural conditions in the MYR,a modified semi-empirical formula,which considered the grain,dune resistance,as well as the topographic features of the riverbed,was proposed to predict the channel ***,the effect of various dam-control flow and sediment elements on the variation in different flow resistance components,and the corresponding relationships among them were *** showed a decline in the comprehensive,channel,and bar resistances as the discharge increased,whereas there was a slight increase when reaching the bank-full ***,the bar resistance occupied 65%,while the channel resistance,in which dune resistance was much larger than grain resistance,contributed 35%to the comprehensive *** addition,while flow resistance rose over time,there was a decline as the distance from the TGD *** conclusion,the increased dune and bar resistances,interpreted by the fluctuated channel longitudinal profile and growing vegetated area on bars,were the dominant factors preventing the flood water level from dropping.

关键词： flow resistance water level channel geomorphology bar Three Gorges Dam Middle Yangtze River

Erosion-deposition patterns and depo-center movements in branching channels at the near-estuary reach of the Yangtze River

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Frontiers of Earth Science 2020年第3期14卷 537-552页

作者： Boyuan Zhu jinyun deng Jinwu Tang Wenjun Yu Alistair G.L.Borthwick Yuanfang Chai Zhaohua Sun Yitian Li School of Hydraulic Engineering Changsha University of Science&TechnologyChangsha410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha410114China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China Changjiang Institute of Survey PlanningDesign and ResearchWuhan430010China Changjiang Waterway Institute of Planning Design&ResearchWuhan430040China School of Engineering The University of EdinburghThe King’s BuildingsEdinburghEH93JLUK Department of Earth Sciences Vrije Universiteit AmsterdamBoelelaan 10851081 HVAmsterdamThe Netherlands

Channel evolution and depo-center migrations in braided reaches are significantly influenced by variations in *** study examines the effect of runoff variations on the erosion-deposition patterns and depocenter movements within branching channels of the near-estuary reach of the Yangtze *** assume that variations in annual mean duration days of runoff discharges,ebb partition ratios in branching channels,and the erosional/depositional rates of entire channels and sub-reaches are representative of variations in runoff intensity,flow dynamics in branching channels,and morphological features in the *** results show that the north region of Fujiangsha Waterway,the Liuhaisha branch of Rugaosha Waterway,the west branch of Tongzhousha Waterway,and the west branch of Langshansha Waterway experience deposition or reduced erosion under low runoff intensity,and erosion or reduced deposition under high runoff intensity,with the depocenters moving upstream and downstream,*** waterway branches undergo opposite trends in erosion-deposition patterns and depo-center movements as the runoff *** morphological changes may be associated with trends in ebb partition ratio as the runoff discharge rises and *** flattening the intra-annual distribution of runoff discharge,dam construction in the Yangtze Basin has altered the ebb partition ratios in waterway branches,affecting their erosion-deposition patterns and depo-center *** trends are likely to continue into the future due to the succession of large cascade dams under construction along the upper Yangtze and ongoing climate change.

关键词： near-estuary reach Yangtze River runoff discharge ebb partition ratio erosion-deposition pattern depo-center movement

A STUDY ON THE EQUILIBRIUM PROFILE FOR THE LUOSHAN-HANKOU REACH IN THE MIDDLE YANGTZE RIVER

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International Journal of Sediment Research 2003年第2期18卷 107-114页

作者： jinyun deng ,Yitian LI Wuhan University Key Lab of Water and Sediment Sciences Ministry of Education 430072 Wuhan

Based on the morphology of the Luoshan-Hankou reach in the middle Yangtze River, the one dimensional (1-D), unsteady flow and sediment transport model was applied to study the river channel equilibrium profile. Meanwhile, a simple theoretical model relating the equilibrium profile and the incoming flow and sediment from the upper reach was developed. The numerical simulation results of the 1-D model were compared with the corresponding results of the theoretical model with reasonable agreement found between the two models. Finally, the equilibrium slope variations and their effects on flood control in response to the changes in the sediment transport process because of the Three Gorges Reservoir were analyzed using the 1-D model.

关键词： Equilibrium profile Incoming flow and sediment Slope Flood level 1-D mathematical model

Evolution characteristics and drivers of the water level at an identical discharge in the Jingjiang reaches of the Yangtze River

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Journal of Geographical Sciences 2020年第10期30卷 1633-1648页

作者： CHAI Yuanfang YANG Yunping deng jinyun SUN Zhaohua LI Yitian ZHU Lingling 无 Department of Earth Sciences Vrije Universiteit AmsterdamBoelelaan 10851081 HV AmsterdamThe Netherlands State Key Laboratory of Water Resources and Hydropower Engineering Science School of Water Resources and Hydropower EngineeringWuhan UniversityWuhan 430072China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China Key Laboratory of Engineering Sediment Tianjin Research Institutes for Water Transport EngineeringMinistry of TransportTianjin 300456China Bureau of Hydrology Changjiang Water Resources Commission Wuhan430010China

The operation of large-scale reservoirs have modified water and sediment transport processes,resulting in adjustments to the river topography and water *** polynomial fitting method was applied to analyze the variation characteristics of water levels under different water discharge values in the Jingjiang reach of the Yangtze River from 1991–*** segregation variable method was used to estimate the contributions of the varied riverbed evaluation,the downstream-controlled water level,and the comprehensive roughness on the altered water level at an identical *** find that low water levels in the Jingjiang reach of the Yangtze River from 1991–2016 are characterized by a significant downward trend,which has intensified since *** scouring has been the dominate factor causing the reduced low water level while increased roughness alleviated this *** 1991–2016,there was first a decrease followed by an increase in the high water *** variation characteristic in terms of the'high flood discharge at a high water level'before 2003 transformed into a'middle flood discharge at a high water level'since *** increased comprehensive roughness was the main reason for the increased high water level,where river scouring alleviated this *** navigation conditions and flood control,intensified riverbed scouring of the sandy reaches downstream from dams enhanced the effects that the downstream water level has on the upstream water *** has led to an insufficient water depth in the reaches below the dams,which should receive immediate *** alteredvariation characteristics of the high water level have also increased the flood pressure in the middle reaches of the Yangtze River.

关键词： water level at identical flow spatio-temporal evolution channel geomorphology middle reaches of the Yangtze River

The synchronicity and difference in the change of suspended sediment concentration in the Yangtze River Estuary

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Journal of Geographical Sciences 2015年第4期25卷 399-416页

作者： YANG Yunping deng jinyun ZHANG Mingjin LI Yitian LIU Wanli Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport Engineering Min- istry of Transport Tianjin 300456 China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan 430072 China

The sediment discharge from the Yangtze River Basin has a stepwise decreasing trend in recent years. The impounding of the Three Gorges Reservoir exacerbated this de- creasing trend and affected the change of the suspended sediment concentration （SSC） in the Yangtze River Estuary through the transmission effect. The SSC data of the Yangtze River Estuary during 1959-2012 showed that：（1） The SSC in the South Branch of the Yang- tze River in the estuary and in the off-shore sea area displayed decreasing trends and de- creased less towards the sea. At the same time, the difference in decreasing magnitude be- tween SSC and sediment discharge became bigger towards the sea. （2） For the North Branch the preferential flow did not change much but the SSC tended to decrease, which was mainly caused by the decrease of SSC in the South Branch and China East Sea. （3） Due to the de- creased runoff and the relatively strengthened tide, the peak area of the SSC in the bar shoal section in 2003-2012 moved inward for about 1/6 longitude unit compared with that in 1984-2002, and the inward-moving distance was in the order of flood season 〉 annual average 〉 dry season. （4） In the inlet of the South Passage, the SSC decreased mainly because the increase caused by resuspension and shore-groove exchange was less than the decrease caused by the sharp SSC decrease in the basin and the sea areas. The reverse was true in the middle section, where the SSC showed an increasing trend. （5） In the inlet of the North Passage, under the combined influence of decreased flow split and sediment split ratios, the decreased SSC in the basin and the sea area and decreased amount of resuspension, the SSC displayed a decreasing trend. In the middle section, because the increased amount caused by sediment going over the dyke was markedly more than the decreased amount caused by external environments, the SSC tended to increase. Holistically, the sharp decrease in sediment discharge caused synchronized SSC de

关键词： suspended sediment concentration synchronicity difference sediment discharge Yangtze River Es-tuary