Numerical Experiment of Cohesive Sediment Transport in the Yangtze Estuary Considering the Influence of the Three Gorges Dam

Abstract In order to study the changes of stagnation points in the Yangtze Estuary influenced by the Three Gorges Dam operation, 3-D hydrodynamic and sediment transport model ECOMSED was used to simulate the dynamic process of flow varying with the river discharge and tide of the Yangtze Estuary. The results show that the location of stagnation points varied markedly in different areas after the impoundment of the Three Gorges Dam, with the large extent of downward movement during flood periods due to the hydrodynamic enhancement of the Yangtze River in the North Branch, while the movement range was smaller in the South Branch. Along with the runoff changes, the variation extent from big to small is North Channel, South Passage and North Passage, while the rank order changed as South Passage, North Channel and North Passage as valued by the tidal changes. After the impoundment of the Three Gorges Dam, the movement range of stagnation points reduced because of the reduction in river discharge. Thus, it can be considered that the turbidity maximum zone has a decreasing trend which might lead to changes in geomorphic features of the Yangtze Estuary.

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Influence of the Three Gorges Dam on total suspended matters in the Yangtze Estuary and its adjacent coastal waters: Observations from MODIS

Remote Sensing of Environment ◽

10.1016/j.rse.2013.10.002 ◽

2014 ◽

Vol 140 ◽

pp. 779-788 ◽

Cited By ~ 97

Author(s):

Lian Feng ◽

Chuanmin Hu ◽

Xiaoling Chen ◽

Qingjun Song

Keyword(s):

Coastal Waters ◽

Yangtze Estuary ◽

Three Gorges Dam ◽

Three Gorges ◽

The Yangtze Estuary ◽

The Three Gorges ◽

Suspended Matters ◽

The Three Gorges Dam

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

Earth Surface Processes and Landforms ◽

10.1002/esp.4850 ◽

2020 ◽

Vol 45 (8) ◽

pp. 1846-1859 ◽

Cited By ~ 1

Author(s):

Yiwei Lyu ◽

Sergio Fagherazzi ◽

Shan Zheng ◽

Guangming Tan ◽

Caiwen Shu

Keyword(s):

Sediment Transport ◽

Suspended Sediment ◽

Yangtze River ◽

Three Gorges Dam ◽

Suspended Sediment Transport ◽

Three Gorges ◽

The Three Gorges ◽

The Three Gorges Dam

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A Computationally Efficient Shallow Water Model for Mixed Cohesive and Non-Cohesive Sediment Transport in the Yangtze Estuary

Water ◽

10.3390/w13101435 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1435

Author(s):

Peng Hu ◽

Junyu Tao ◽

Aofei Ji ◽

Wei Li ◽

Zhiguo He

Keyword(s):

Sediment Transport ◽

Yangtze Estuary ◽

Water Model ◽

Cohesive Sediments ◽

Shallow Water Model ◽

Computationally Efficient ◽

Time Step ◽

The Yangtze Estuary ◽

Erosion Coefficient ◽

Cohesive Sediment Transport

In this paper, a computationally efficient shallow water model is developed for sediment transport in the Yangtze estuary by considering mixed cohesive and non-cohesive sediment transport. It is firstly shown that the model is capable of reproducing tidal-hydrodynamics in the estuarine region. Secondly, it is demonstrated that the observed temporal variation of suspended sediment concentration (SSC) for mixed cohesive and non-cohesive sediments can be well-captured by the model with calibrated parameters (i.e., critical shear stresses for erosion/deposition, erosion coefficient). Numerical comparative studies indicate that: (1) consideration of multiple sediment fraction (both cohesive and non-cohesive sediments) is important for accurate modeling of SSC in the Yangtze Estuary; (2) the critical shear stress and the erosion coefficient is shown to be site-dependent, for which intensive calibration may be required; and (3) the Deepwater Navigation Channel (DNC) project may lead to enhanced current velocity and thus reduced sediment deposition in the North Passage of the Yangtze Estuary. Finally, the implementation of the hybrid local time step/global maximum time step (LTS/GMaTS) (using LTS to update the hydro-sediment module but using GMaTS to update the morphodynamic module) can lead to a reduction of as high as 90% in the computational cost for the Yangtze Estuary. This advantage, along with its well-demonstrated quantitative accuracy, indicates that the present model should find wide applications in estuarine regions.

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