Changjiang Delta in the Anthropocene: Multi-scale hydro-morphodynamics and management challenges

Guo, Leicheng; Zhu, Chunyan; Xie, Weimin; Xu, Fan; Wu, Hui; Wan, Yang; Wang, Zhanghua; Zhang, Weiguo; Shen, Jian; Wang, Zheng Bing; He, Qing

doi:10.1016/j.earscirev.2021.103850

Cited by 25 publications

(10 citation statements)

References 181 publications

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“…The actual reservoir capacity is 3.8 × 10 8 m 3 , and the water supply capacity exceeds 7.19 × 10 6 m 3 /day, accounting for more than 50% of Shanghai's total raw water supply and benefiting more than 13 million people. Since its full operation in June 2011, the reservoir has played a vital role in Shanghai's drinking water supply, fundamentally altering the historical reliance on the Huangpu River as the primary water source [12,45]. As of early 2022, based on our information, the reservoir's water level had been consistently normal and well regulated until it was disrupted by extreme drought (Figure 1), resulting in a significant decrease in water levels (Figure 3B,C).…”

Section: Study Areamentioning

confidence: 88%

Satellite-Derived Indicators of Drought Severity and Water Storage in Estuarine Reservoirs: A Case Study of Qingcaosha Reservoir, China

Yuan,

Xu,

Zhang

et al. 2024

Remote Sensing

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Estuarine reservoirs are critical for freshwater supply and security, especially for regions facing water scarcity challenges due to climate change and population growth. Conventional methods for assessing drought severity or monitoring reservoir water level and storage are often limited by data availability, accessibility and quality. We present an approach for monitoring estuarine reservoir water levels, storage and extreme drought via satellite remote sensing and waterline detection. Based on the CoastSat algorithm, Landsat-8 and Sentinel-2 images from 2013 to 2022 were adopted to extract the waterline of Qingcaosha Reservoir, the largest estuarine reservoir in the world and a key source of freshwater for Shanghai, China. This study confirmed the accuracy of the satellite-extracted results through two main methods: (1) calculating the angle of the central shoal slope in the reservoir using the extracted waterline data and measured water levels and (2) inverting the time series of water levels for comparison with measured data. The correlation coefficient of the estimated water level reached ~0.86, and the root mean square error (RMSE) of the estimated shoal slope was ~0.2°, indicating that the approach had high accuracy and reliability. We analyzed the temporal and spatial patterns of waterline changes and identified two dates (21 February 2014 and 15 October 2022) when the reservoir reached the lowest water levels, coinciding with periods of severe saltwater intrusions in the estuary. The extreme drought occurrences in the Qingcaosha Reservoir were firstly documented through the utilization of remote sensing data. The results also indicate a strong resilience of the Qingcaosha Reservoir and demonstrate that the feasibility and utility of using satellite remote sensing and waterline detection for estuarine reservoir storage can provide timely and accurate information for water resource assessment, management and planning.

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Section: Study Areamentioning

confidence: 88%

Satellite-Derived Indicators of Drought Severity and Water Storage in Estuarine Reservoirs: A Case Study of Qingcaosha Reservoir, China

Yuan,

Xu,

Zhang

et al. 2024

Remote Sensing

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“…Such a delayed response is illustrated by the construction of dams such as in the Yangtze. The construction of reservoirs leads to a pronounced reduction of the sediment load immediately downstream of the dam, but this reduction becomes less pronounced in the downstream direction by erosion in the river bed (L. Guo et al., 2021a; X. Guo et al., 2021b; Yuan et al., 2020). Further downstream, the morphological change in the mouth zone of the Yangtze Estuary is suggested to show a time lag of 30 years in response to the reduced sediment supply (C. Zhu et al., 2019).…”

Section: Discussionmentioning

confidence: 99%

Impact of Reduced Fluvial Sediment Supply on Saltwater Intrusion in the Yangtze Estuary

Zhu,

van Maren,

Guo

et al. 2023

Earth's Future

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A decline of the fluvial sediment supply leads to coastal erosion and land loss. However, the fluvial sediment load may influence not only coastal morphodynamics but also estuarine hydrodynamics and associated saltwater intrusion. Previous studies revealed that suspended sediments influence estuarine hydrodynamics through various flow–sediment interactions. In this contribution, we systematically investigate how changes in fluvial sediment load and other climate‐change‐induced environmental change influence estuarine hydrodynamics and sediment dynamics. For this purpose, we utilize a well‐calibrated fully coupled model in which hydrodynamics, saltwater intrusion, and sediment transport interact with each other, to explore saltwater intrusion in the Yangtze Estuary in response to a decline in the sediment load, modified discharge, and sea‐level rise. Model results suggest that a 70% decline in the suspended sediment load weakens the impact of sediments on salinity‐induced stratification and thereby reducing saltwater intrusion. Sea‐level rise or discharge peak reduction increases saltwater intrusion. However, a fully coupled model accounting for sediment effects predicts a much larger increase in saltwater intrusion compared to noncoupled models. Whether this effect is important depends on estuarine sediment concentrations and therefore the potential role of sediments should be carefully investigated before applying a noncoupled model. This work highlights not only the relevance of a suspended sediment decline but also the use of fully coupled models for predicting saltwater intrusion in turbid estuaries and has broad implications for freshwater resource management in turbid estuarine systems influenced by human interventions and climate change.

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“…It has also been observed in existing studies that the Jiuduansha at the mouth of the Yangtze River is experiencing siltation, but scouring has not occurred because of the reduction in suspended sediment in the basin, which is inextricably linked to the scouring of the tidal reach (Wei et al, 2016(Wei et al, , 2017. Sediment transport in the Yangtze River Basin forms a good "source-sink" relationship with the scouring and deposition of the estuarine delta (Guo et al, 2019(Guo et al, , 2021a(Guo et al, , 2021b(Guo et al, , 2022d, and the evolution of scouring and deposition in the foreshore and submerged delta of the Yangtze estuary is closely related to the upstream sediment supply.…”

Section: Impacts Of Channel Evolution Of Tidal Reach On Sediment Supp...mentioning

confidence: 94%

“…Notably, a portion of the fine sediment scoured from the riverbed replenishes the suspended sediment, entering the estuary via water flow (Yang et al, , 2014(Yang et al, , 2015. The remaining portion of coarse-grained sediment scoured from the riverbed spreads to the estuary through the tidal reach in the form of bottom sediment (Guo et al, 2019(Guo et al, , 2021a. Studies have shown that the bottom sediment transport in the lower tidal reaches of the Yangtze River is relatively active (Chen, 2014;Yang et al, 2020), with sediment shifting occurring primarily in the form of sand wave movement (Zheng et al, 2016(Zheng et al, , 2018.…”

Section: Distribution Relationship Of Sediment Among Branch Channelsmentioning

confidence: 99%

Critical threshold of periodic point bar scour and sediment body transport path in tidal reaches: A case study of Fujiangsha reach, Yangtze River

et al. 2023

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The evolution of point bars in changing sections of a downstream tidal current limit is periodic. Accordingly, assessing the critical morphology and hydrodynamic characteristics of point bar scour and the sediment transport process of scour sediment bodies can support river regulation and waterway maintenance. The frequent scour of point bars in changing sections of tidal current limits within the Yangtze River directly restricts waterway stability. This study examined the Fujiangsha reach of the Yangtze River, hydrological data on sediment transport, and riverbed topography from 1950. The Jingjiang bank tail exhibited an evolutionary cycle (siltation>scour>siltation), with a primary period ranging from 3-6 years. Additionally, certain morphological and dynamic conditions were necessary for scour. The Datong station flow (Q) ranged from 20,000-40,000 m 3 •s -1 for ≥180 days•yr -1 , enabling the bank silt layers to widen. Scour occurred during flooding and was concentrated in areas 5.0-7.5 km downstream from Ebizui. When Q≥40,000 m 3 •s -1 , scouring occurred in the bank middle and lower reaches, whereas Q≥50,000 m 3 •s -1 for >50 consecutive days, scour occurred at the tail as well. Moreover, the volume of the scour shoals increased with the number of high-flow days (≥60,000 m 3 •s -1 ). Bottom sand transport mainly occurred in the low-bank zone. Before the project's second phase, the longitudinal transport of the scouring sand bodies occurred as follows: Jingjiang bank > low bank on the north side of Shuangjiansha > Fubei anabranch. During the second phase, the longitudinal transport route changed to Jingjiang bank > Fubei anabranch. The Jingjiang bank volume was also reduced; thus, its development was controlled. Owing to changes in the longitudinal transport routes, dredging should be conducted in areas where scouring sand bodies are separately transported from the tail, thereby reducing the load of dredging and maintenance for the Fubei anabranch

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Changjiang Delta in the Anthropocene: Multi-scale hydro-morphodynamics and management challenges

Cited by 25 publications

References 181 publications

Satellite-Derived Indicators of Drought Severity and Water Storage in Estuarine Reservoirs: A Case Study of Qingcaosha Reservoir, China

Satellite-Derived Indicators of Drought Severity and Water Storage in Estuarine Reservoirs: A Case Study of Qingcaosha Reservoir, China

Impact of Reduced Fluvial Sediment Supply on Saltwater Intrusion in the Yangtze Estuary

Critical threshold of periodic point bar scour and sediment body transport path in tidal reaches: A case study of Fujiangsha reach, Yangtze River

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