The impacts of the Three Gorges Dam upon dynamic adjustment mode alterations in the Jingjiang reach of the Yangtze River, China

Li, Sixuan; Li, Yitian; Yuan, Jinliang; Zhang, Wei; Chai, Yuanfang; Ren, Jinqiu

doi:10.1016/j.geomorph.2018.06.020

Cited by 36 publications

(20 citation statements)

References 35 publications

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“…Spur dikes had been constructed along both upper and lower sub‐reaches of the North Passage during this period (Dai et al, 2013), causing the blockage effect of the North Passage on the ebb tidal current to become enhanced, and the ebb tide in the South Passage strengthen, as evidenced by the decrease/increase in ebb partition ratio in the North/South Passage (Table I). This in turn promoted a stronger ebb tidal current in the deep area of the South Passage due to water retention in the deep channel (Li et al, 2018), eroding the thalweg of the upper sub‐reach and transporting eroded sediment into the thalweg of the lower sub‐reach of the South Passage (Figure 8), causing remarkable deposition to occur in the lower sub‐reach (Table I).…”

Section: Discussionmentioning

confidence: 99%

“…The spur dikes hindered the ebb tidal current in the North Passage while intensifying the strength of the ebb tide in the South Passage, exacerbating erosion in the upper sub-reach of the South Passage (Table I). Erosion of both the upper and lower sub-reaches of the South Passage mainly occurred in the deeper regions during this period (Figure 8), indicating an obvious effect of water retention in the deep channel (Li et al, 2018) of the South Passage due to the strengthened ebb tide in the South Passage.…”

Section: Impact Of the Deepwater Channel Projectmentioning

confidence: 94%

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Decadal link between longitudinal morphological changes in branching channels of Yangtze estuary and movement of the offshore depo‐center

Zhu

Yao

Borthwick

et al. 2020

Earth Surf Processes Landf

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In estuaries, the morphology of inland and offshore areas usually evolves synergistically. This study examines the decadal link between longitudinal changes in morphology of branching channels and movement of the offshore depo‐center (where sediment deposition rate is maximum) of the Yangtze River estuary, under intense human interference. Integrated data analysis is provided on morphology, runoff discharge, and ebb partition ratio from 1950 to 2017. Channel‐volume reductions and change rates between isobaths in branching channels reflect the impact of estuarine engineering projects. Ebb partition ratio and duration of discharge ≥ 60 000 m3 s‐1 act as proxies for the water excavating force in branching channels and runoff intensity. It is found that deposition occurs in the lower/upper sub‐reaches (or further downstream/upstream channels) of the inland north/south branching channels, and the offshore depo‐center moves southward or southeastward, as runoff intensity grows; the reverse occurs as runoff intensity declines. This is because the horizontal circumfluence in the Yangtze estuary rotates clockwise as ebb partition ratios of the north/south branching channels increase/decrease for increasing runoff, and conversely rotates anticlockwise for decreasing runoff. Land reclamation activities, the Deepwater Channel Project, and the Qingcaosha Reservoir have impacted greatly on longitudinal changes of morphology in the North Branch and the South Passage and on ebb partition ratio variations in the North/South Channel and the North/South Passage. Dam‐induced runoff flattening has enhanced deposition in the upper/lower sub‐reaches of the north/south branching channels and caused northward movement of the offshore depo‐center, except in areas affected by estuarine engineering projects. Dam‐induced longitudinal evolution of branching channel morphology and offshore depo‐center movement will likely persist in the future, given the ongoing construction of large cascade dams in the upper Yangtze and the completion of major projects in the Yangtze estuary. © 2020 John Wiley & Sons, Ltd.

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Section: Discussionmentioning

confidence: 99%

Section: Impact Of the Deepwater Channel Projectmentioning

confidence: 94%

Decadal link between longitudinal morphological changes in branching channels of Yangtze estuary and movement of the offshore depo‐center

Zhu

Yao

Borthwick

et al. 2020

Earth Surf Processes Landf

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“…In this study, we select floods with distinct rise and recession of the river flow and with a peak Q above 15 000 m 3 s −1 , which represents the dominant discharge in the medium‐flow channels in the YCR (CWRC, 2017; Li et al ., 2018). Therefore, the terms ‘flood’ or ‘flood wave’ do not necessarily suggest a discharge that overflows the channel banks and inundates the floodplain, since this event rarely occurs after the TGD construction.…”

Section: Methodsmentioning

confidence: 99%

Enhanced hysteresis of suspended sediment transport in response to upstream damming: An example of the middle Yangtze River downstream of the Three Gorges Dam

Lyu

Fagherazzi

Shan

et al. 2020

Earth Surf Processes Landf

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The peak in sediment transport in alluvial rivers generally lags behind the peak in discharge. It is thus not clear how the hysteresis in the sediment/discharge relationship may be impacted by damming, which can fundamentally alter the water and sediment regimes in the downstream reaches of the river. In this study, a total of 500 flood events in the Yichang–Chenglingji Reach (YCR) of the Middle Yangtze River immediately downstream of the Three Gorges Dam (TGD) are analysed to study the impacts of dam operations on the hysteresis of suspended sediment transport. Sediment rating curves, hysteresis patterns, as well as lag times, are investigated to determine the relationship between suspended sediment concentration (SSC) and flow discharge (Q) at different temporal scales, from inter‐annual to individual flood events, for the pre‐ and post‐TGD period from 1992 to 2002 and from 2003 to 2017, respectively. The results showed that the TGD operation decreased the frequency and magnitude of floods. The decrease in peak flow and increase in base flow weakened the flood contribution to the annual discharge by nearly 20%. However, the relative suspended sediment load contribution during flood events was much higher than the discharge contribution, and was little impacted by the dam. At seasonal and monthly scales, more than 80% of the suspended sediment was transported by ~65% of the water discharge in the summer and early autumn. The monthly SSC–Q relationship changed from a figure‐eight to an anti‐clockwise pattern after the construction of the TGD. For single flood events, the TGD operations significantly modified the downstream SSC–Q hysteresis patterns, increasing the frequency of anti‐clockwise loops and the lag time between peak Q and peak SSC. These adjustments were mainly caused by differences in the propagation velocities of flood and sediment waves and the sediment ‘storage–mobilization–depletion’ process, whereas the influence of lateral diversions was small. © 2020 John Wiley & Sons, Ltd.

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“…The construction of large dams and reservoirs has many and complex environmental, economic, and social impacts (Hohensinner et al 2011;Zhang et al 2016). Among the major consequences are alterations of hydrosedimentary flows and geomorphic changes, both upstream and downstream from the dam (Brandt 2000;Zhou et al 2011;Čanjevac and Orešić 2018;Li et al 2018). Therefore, as a result of the transition from a fluvial to a fluvial-lacustrine flow regime upstream from the dam, sediment retention and shore abrasion processes become dominant (Petkovic, Dragovic and Markovic 1999;Repnik Mah, Mikoš and Bizjak 2010;Vukovic, Vukovic and Stankovic 2014).…”

Section: Introductionmentioning

confidence: 99%

The impact of large dams on fluvial sedimentation: The Iron Gates Reservoir on the Danube River

Nistor¹,

Săvulescu²,

Mihai³

et al. 2021

AGS

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Dam construction is one of the major human pressures impacting fluvial processes, including topography and hydro-sedimentary flows, as a result of the change in flow regime from fluvial to fluvial-lacustrine. This article investigates geomorphic changes at Iron Gates I, the largest reservoir on the Danube River, completed in 1972 for hydropower and navigation. The study focuses on a gulf area that emerged at the mouth of the Cerna River into the reservoir, highlighting spatial changes in topography and sediment distribution, based on a diachronic analysis of two datasets before and after the dam was built: one extracted from historical topographic maps and the other obtained from a bathymetric echo sounding survey, integrated within a GIS analysis. The results reveal the dominance of the sedimentation process, with an alluvium layer thickness up to 14 m. The current sediment pattern has changed the submerged morphology, leading to the formation of an alluvial fan at the mouth of the Cerna River and of a sedimentary bar between the Cerna Gulf and the Danube River’s channel. The siltation process together with the current underwater morphology limits ship traffic and the storage capacity of the reservoir.

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The impacts of the Three Gorges Dam upon dynamic adjustment mode alterations in the Jingjiang reach of the Yangtze River, China

Cited by 36 publications

References 35 publications

Decadal link between longitudinal morphological changes in branching channels of Yangtze estuary and movement of the offshore depo‐center

Decadal link between longitudinal morphological changes in branching channels of Yangtze estuary and movement of the offshore depo‐center

Enhanced hysteresis of suspended sediment transport in response to upstream damming: An example of the middle Yangtze River downstream of the Three Gorges Dam

The impact of large dams on fluvial sedimentation: The Iron Gates Reservoir on the Danube River

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