scholarly journals MORPHOLOGICAL RESPONSE TO THE DEEP WATERWAY PROJECT AROUND THE CHANGJIANG ESTUARY, CHINA

2011 ◽  
Vol 1 (32) ◽  
pp. 11
Author(s):  
Lingzhi Pan ◽  
Pingxing Ding ◽  
Jianzhong Ge
Keyword(s):  
Sediment Transport ◽  
High Resolution ◽  
Phase I ◽  
Morphological Change ◽  
Changjiang Estuary ◽  
Morphological Response ◽  
The Changjiang Estuary ◽  
The North ◽  
High Resolution Bathymetry ◽  
Evolution Trend

Changjiang Estuary is characterized by complex branches and outlets (North Branch, North Channel, North Passage and South Passage). The relatively shallow bathymetry around the mouth limits the navigational potentials (Fig.1). The Deep Waterway Project (DWP) was carried out in the North Passage of South Channel for the purpose of deepening the navigational channel from 7.0m in July 1998 to 8.5m in July 2001 (Phase I), 10.0m in May 2005 (Phase II) and 12.5m in May 2010 (Liu et al. 2004). In addition to dredging, two dykes were constructed to reduce the sediment transport from Jiuduansha and Hengsha Shoals into North Passage. A set of groins was built with connection to dykes for the purpose of strengthening the currents in the middle of channel, which helps the maintenance of the navigational capability. The construction has significantly changed the local bathymetry in the Changjiang Estuary and within the channel. The high-resolution bathymetry measurements were made over seasons. An evolution trend of the morphological change is revealed, which is discussed in this paper.

scholarly journals FORMATION, TRANSPORT AND BREAKDOWN OF NEAR-BED HIGH-CONCENTRATED MUD SUSPENSION WITHIN THE NORTH PASSAGE OF THE CHANGJIANG ESTUARY

2018 ◽  
pp. 51
Author(s):  
Jianzhong Ge ◽  
Zaiyang Zhou ◽  
Pingxing Ding
Keyword(s):  
Sediment Transport ◽  
Survey Methodology ◽  
Changjiang Estuary ◽  
Sediment Deposition ◽  
Turbidity Maximum ◽  
The Changjiang Estuary ◽  
Physical Mechanisms ◽  
The North

The turbidity maximum region of the Changjiang Estuary would potentially produce near-bed high-concentrated mud suspension (HCMS), which significantly contributes to the sediment transport and morphology within estuary channel. However, the near-bed high-concentrated mud suspension is technologically difficult to be observed and measured in traditional survey methodology. HCMS can frequently occur around an estuary as a result of sediment deposition, mass or bulk erosion, and convergence under physical mechanisms (Bruens et al., 2002; Winterwerp, 2002, 2011).

Numerical Analysis of Ebb Water Split Ratio of the South and North Branch in the Changjiang Estuary

2013 ◽  
Vol 807-809 ◽  
pp. 1624-1627
Author(s):  
Ji Zhong Yang ◽  
Jie Gu ◽  
Dan Qing Ma ◽  
Xiao Li Wang ◽  
Tian Hu ◽  
...  
Keyword(s):  
Spring Tide ◽  
Changjiang Estuary ◽  
The South ◽  
The Changjiang Estuary ◽  
Hydrodynamic Analysis ◽  
The North ◽  
Split Ratio ◽  
Calculation Results ◽  
Set Up ◽  
The One

The change of water split ratio has important impacts on the fluvial process, saltwater intrusion and navigation in estuary area. A 2D hydrodynamics numerical model of the Changjiang Estuary was set up using Delft3D-FLOW. The calculation results are consistent well with the real measured data, which indicates that the model can be used in hydrodynamic analysis. Simulation results show that the ebb water split ratio of the North Branch in the flood season is larger than that in the dry season, while the situation of the South Branch is opposite. Under the condition of different tidal types, the ebb water split ratio for the North Branch is maximum during the spring tide, and minimum during the neap tide, while the one during the middle tide takes the second place.

scholarly journals Impacts of the Qingcaosha Reservoir on saltwater intrusion in the Changjiang Estuary

2021 ◽  
Vol 4 (1) ◽  
pp. 17-35
Author(s):  
Zhangliang Ding ◽  
Jianrong Zhu ◽  
Hanghang Lyu
Keyword(s):  
Saltwater Intrusion ◽  
Neap Tide ◽  
Spring Tide ◽  
Changjiang Estuary ◽  
Water Diversion ◽  
The Changjiang Estuary ◽  
The North ◽  
Salinity Increase ◽  
Hydrodynamic Processes ◽  
Changxing Island

The massive Qingcaosha Reservoir (QCSR) is located in the Changjiang Estuary along the northwest coast of Changxing Island. The reservoir significantly narrowed the upper reaches of the North Channel and deepened the channel near the reservoir. These topographical changes inevitably influenced hydrodynamic processes and saltwater intrusion in the estuary. A well-validated model was employed to investigate the influence of the QCSR on saltwater intrusion in the Changjiang Estuary. The model results showed that the narrowed upper reaches of the North Channel decreased the water diversion ratio and thus increased salinity in the North Channel. During the moderate tide after neap tide, the salinity decreased at the water intake of the QCSR because saltwater intrusion was obstructed at flood slack at the surface, while the salinity increase during the moderate tide after spring tide was mainly due to the intensified saltwater intrusion during spring tide. The deepening of the channel near the QCSR resulted in an increased water diversion ratio, and the salinity in the Eastern Chongming Shoal decreased by more than 0.5 psu during spring tide; however, the saltwater intrusion was enhanced due to the strengthened baroclinic force, which is proportional to the water depth. During neap tide, the salinity in the entire North Channel decreased because of a 1.4% increase in the water diversion ratio of the North Channel and the relatively weak tide.

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