Sedimentary processes on an estuarine marsh island within the turbidity maximum zone of the Yangtze River mouth

2000 ◽  
Vol 20 (2) ◽  
pp. 87-92 ◽  
Author(s):  
S.-L. Yang ◽  
D. Eisma ◽  
P.-X. Ding
Keyword(s):  
Yangtze River ◽  
River Mouth ◽  
Turbidity Maximum ◽  
The Yangtze River ◽  
Sedimentary Processes ◽  
Turbidity Maximum Zone

Dynamic sedimentation process of the turbidity maximum zone in the Yangtze River Estuary under the influence of human activities

2020 ◽  
Author(s):  
Weihua Li ◽  
Xiaohe Zhang ◽  
Zhanhai Li ◽  
Jiufa Li
Keyword(s):  
River Estuary ◽  
River Mouth ◽  
Turbidity Maximum ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
The South ◽  
Turbidity Maximum Zone ◽  
The North ◽  
The Yangtze River Estuary ◽  
Mouth Bar

<p>Due to the impact of the Three Gorges Dam on water and sediment storage, the sediment flux into the Yangtze River Estuary has dropped sharply by 70%, and the suspended sediment concentration in the estuary has responded accordingly. From the comparison of the measured suspended sediment concentration data of the Yangtze River estuary for many years, it is known that the suspended sediment concentration in the South Passage has been reduced by about 60% recently, and that in the middle and upper reaches of the North Channel and the South Channel has been reduced by about 40%. On the other hand, A series of artificial engineering has been completed in the past 20 years, such as the 12.5m Deep-Waterway Regulation Engineering, the Nanhui Shoal Slush-enclosure Engineering, and the Hengsha Shoal Slush-enclosure Engineering, etc. These engineering have significantly changed the original water and sediment transport pattern of the Yangtze River Estuary. It resulted in a significant change of the estuarine turbidity maximum zone and the corresponding river mouth bar topography. This paper intends to discuss the impact of human activities on the dynamic sedimentation process of the maximum turbidity zone in the Yangtze River Estuary based on field measured data. Results are as follows:</p><p>(1) Compared to two decades ago, the suspended sediment concentration in the North Passage, the South Passage and the North Channel, and the middle and lower reaches of the North Branch is still high, which is related to the existence of the turbidity maximum zone and river mouth bar in these river sections.</p><p>(2) The implementation of man-made engineering such as the submerged diversion dike between the North Passage and the South Passage and the Nanhui Shoal Slush-enclosure Engineering changed the flow structure in the upper section of the South Passage, leading to the turbidity maximum zone and the corresponding river mouth bar have completely disappeared.</p><p>(3) Affected by the 12.5m Deep-Waterway Regulation Engineering, the turbidity maximum zone and the corresponding river mouth bar originally located at the upper section of the North Passage have also disappeared.</p><p>(4) The longitudinal circulation flow structure, salt water wedges, and stagnation points in the middle and lower sections of the North Passage and the South Passage still exist. The positions of the turbidity maximum zone and the corresponding river mouth bar topography are not significantly affected by the engineering. And the core area of ​​the obvious turbidity maximum zone and the river mouth bar (only in the South Passage) still exist. Due to the artificial dredging of the navigation channel in the North Passage, it actually appeared as an invisible river mouth bar that has been dredged by continuous dredging.</p><p> (5) The drastic reduction of sediment flux from the basin has caused seabed erosion adjacent to the Yangtze River Estuary, and the corresponding eroded sediment has become one of the main sediment budget sources of the turbidity maximum zone.</p>

scholarly journals Link between East Asian summer monsoon and sedimentation in river-mouth sandbars since the early Holocene preserved in the Yangtze River subaqueous delta front

2020 ◽  
Vol 95 ◽  
pp. 84-96
Author(s):  
Gang Xu ◽  
Jian Liu ◽  
Marcello Gugliotta ◽  
Yoshiki Saito ◽  
Lilei Chen ◽  
...  
Keyword(s):  
Yangtze River ◽  
Late Holocene ◽  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
River Mouth ◽  
Early Holocene ◽  
The Yangtze River ◽  
Delta Front ◽  
The Yangtze River Basin ◽  
Asian Summer

AbstractThis paper presents geochemical and grain-size records since the early Holocene in core ECS0702 with a fine chronology frame obtained from the Yangtze River subaqueous delta front. Since ~9500 cal yr BP, the proxy records of chemical weathering from the Yangtze River basin generally exhibit a Holocene optimum in the early Holocene, a weak East Asian summer monsoon (EASM) period during the middle Holocene, and a relatively strong EASM period in the late Holocene. The ~8.2 and ~4.4 cal ka BP cooling events are recorded in core ECS0702. The flooding events reconstructed by the grain-size parameters since the early Holocene suggest that the floods mainly occurred during strong EASM periods and the Yangtze River mouth sandbar caused by the floods mainly formed in the early and late Holocene. The Yangtze River-mouth sandbars since the early Holocene shifted from north to south, affected by tidal currents and the Coriolis force, and more importantly, controlled by the EASM. Our results are of great significance for enriching both the record of Holocene climate change in the Yangtze River basin and knowledge about the formation and evolution progress of the deltas located in monsoon regions.

Variation in sedimentary 210Pb over the last 60 years in the Yangtze River Estuary: New insight to the sedimentary processes

2020 ◽  
Vol 427 ◽  
pp. 106240
Author(s):  
Xueshi Sun ◽  
Dejiang Fan ◽  
Huijie Liao ◽  
Ming Liu ◽  
Yuan Tian ◽  
...  
Keyword(s):  
Yangtze River ◽  
River Estuary ◽  
Yangtze River Estuary ◽  
The Yangtze River ◽  
Sedimentary Processes ◽  
The Yangtze River Estuary

Study on the Yangtze River Estuarine Turbidity Maximum

2011 ◽  
Vol 90-93 ◽  
pp. 2774-2777 ◽  
Author(s):  
Xin Li ◽  
De An Wu
Keyword(s):  
Yangtze River ◽  
Turbidity Maximum ◽  
Estuarine Turbidity Maximum ◽  
The Yangtze River ◽  
Definition Of ◽  
River Estuarine

This paper presents the definition of the estuarine turbidity maximum, its formation reasons and the factors of variety. According to this information, the Yangtze River estuarine turbidity maximum is analyzed as the typical estuarine turbidity maximum. The results show that North Channel turbidity maximum is different with the others for different hydrodynamics. The Delft3D model is applied to simulation the phenomena and the results are agreed with the analysis.

Recent Evolution and Future Prediction of the Delta at the Yangtze River Mouth

2013 ◽  
Vol 353-356 ◽  
pp. 2699-2704 ◽  
Author(s):  
Ming Li ◽  
Yun Ping Yang ◽  
Yi Tian Li
Keyword(s):  
Mathematical Model ◽  
Yangtze River ◽  
River Mouth ◽  
Sediment Discharge ◽  
The Yangtze River ◽  
Discharge Data ◽  
One Dimensional ◽  
Water And Sediment ◽  
The Future ◽  
The One

In this study, an empirical curve describing the relation between erosion and deposition rate and water/sediment discharge was developed based on the recent evolution trend of the submerged delta at the Yangtze River Mouth, and the one-dimensional mathematical model for unsteady water-and sediment-transport was calibrated using the water and sediment discharge data after water impounding to predict the water and sediment discharge for the future 10 years and the future evolution of the submerged delta at the Yangtze River Mouth. The results showed that the 10 m and 20 m isobaths areas of the submerged delta changed with the water and sediment discharge from siltation to siltation slowing down to erosion. Siltation increased with large amount of rain received by the watershed during 1997-2000, while continuous retreat of erosion happened during 2000-2009. Using the one-dimensional mathematical model for river water and sediment calibrated and tested with data collected after impounding, the water and sediment discharges were calculated for Series 60 and 90, and its evolution in 2013-2022 was predicted for the delta. For Series 60, its 10 cm and 20 cm isobaths areas showed alternative scour and siltation, while the delta showed trends of erosion. For Series 90, its 10 m and 20 m isobaths showed substantial siltation in flood years. The water and sediment discharges since the Three Gorges Reservoirs was filled were lower than the calculated results for both Series 60 and 90. If the water and sediment discharges continue to decease, the delta will take an erosion trend.

Three-dimensional evolution of the Yangtze River mouth, China during the Holocene: impacts of sea level, climate and human activity

2018 ◽  
Vol 185 ◽  
pp. 938-955 ◽  
Author(s):  
Zhanghua Wang ◽  
Yoshiki Saito ◽  
Qing Zhan ◽  
Xiaomei Nian ◽  
Dadong Pan ◽  
...  
Keyword(s):  
Sea Level ◽  
Human Activity ◽  
Yangtze River ◽  
Three Dimensional ◽  
River Mouth ◽  
The Yangtze River ◽  
The Holocene

Intensity distribution and effect of the Nov. 9, 1996 earthquake of M S=6.1 in offshore outside the Yangtze River Mouth on the South Korea

2003 ◽  
Vol 16 (4) ◽  
pp. 473-475
Author(s):  
Li Yu-che ◽  
Lee Dukkee ◽  
Oh Seokhoon ◽  
Yoon Yonghoon
Keyword(s):  
South Korea ◽  
Intensity Distribution ◽  
Yangtze River ◽  
River Mouth ◽  
The Yangtze River ◽  
The South

scholarly journals Contribution of River Mouth Reach to Sediment Load of the Yangtze River

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
C. Wang ◽  
S. B. Dai ◽  
L. S. Ran ◽  
L. Jiang ◽  
W. T. Li
Keyword(s):  
Yangtze River ◽  
Sediment Load ◽  
Quantitative Estimation ◽  
River Mouth ◽  
The Yangtze River ◽  
Sand Mining ◽  
The Three Gorges ◽  
Sediment Loss ◽  
Before And After ◽  
River Channel Morphology

This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD) in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr) occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr) and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach.

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