ELEMENTAL COMPOSITION OF SUSPENDED SEDIMENTS FROM THE CHANGJIANG RIVER AND ITS ENVIRONMENTAL IMPLICATION

2012 ◽  
Vol 32 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Chen ZENG ◽  
Shouye YANG ◽  
Lei WANG ◽  
Hao WANG ◽  
Xiaoli LIU
Keyword(s):  
Elemental Composition ◽  
Suspended Sediments ◽  
Changjiang River ◽  
Environmental Implication ◽  
The Changjiang River

scholarly journals Source and flux of POC in a karstic area in the Changjiang River watershed: impacts of reservoirs and extreme drought

2016 ◽  
Vol 13 (12) ◽  
pp. 3687-3699 ◽  
Author(s):  
Hongbing Ji ◽  
Cai Li ◽  
Huaijian Ding ◽  
Yang Gao
Keyword(s):  
Organic Carbon ◽  
Surface Sediments ◽  
Nitrogen Isotopes ◽  
Suspended Sediments ◽  
Extreme Drought ◽  
Changjiang River ◽  
Carbonate Minerals ◽  
The Changjiang River ◽  
Wujiang River ◽  
Tightly Coupled

Abstract. Isotopes of carbon (C) and nitrogen (N) along with C / N ratios of particulate organic carbon (POC) were used to identify source and transformation of organic carbon in the suspended and surface sediments in a typical karstic watershed (the Wujiang River, an important tributary of the Changjiang River). Isotope data for suspended sediments indicate that POC was mainly derived from phytoplankton and C3-dominated soil with an increased contribution of phytoplankton in sites directly affected by the reservoir. In contrast, the POC in surface sediments was mainly derived from C3- and C4-dominated soil with little reservoir influence. The positive correlations of carbon and nitrogen isotopes between suspended and surface sediments indicated that these two carbon pools are tightly coupled. Our conservative estimation suggests that 1.17  ×  1010 g of POC is transported to the Three Gorges Reservoir during the study period in 2013. POC yield in the Wujiang River (0.13 t km−2 yr−1) is much lower than those of large rivers with a high abundance of carbonate minerals. Based on the distribution pattern of POC yield, it is inferred that carbonate minerals (lithology) do not contribute significantly to the riverine POC. The cascade of reservoirs and extreme drought had a significant influence on the POC flux in the Wujiang River.

MODERN SEDIMENTATION RATE OF THE SUBMARINE DELTA OF THE CHANGJIANG RIVER

2010 ◽  
Vol 30 (3) ◽  
pp. 1-6 ◽  
Author(s):  
Andong WANG ◽  
Shaoming PAN ◽  
Yongzhan ZHANG ◽  
Zhiyong LIU
Keyword(s):  
Sedimentation Rate ◽  
Changjiang River ◽  
The Changjiang River

Simulation to Investigate the Reasons for the Sediment Deposition in the Upper Reach of the Deepwater Navigation Channel in the Changjiang River Estuary

2012 ◽  
Vol 610-613 ◽  
pp. 1237-1241
Author(s):  
Jie Gu ◽  
Wei Chen ◽  
Xin Qin ◽  
Dan Qing Ma ◽  
Xiao Li Wang ◽  
...  
Keyword(s):  
River Estuary ◽  
Sediment Deposition ◽  
Changjiang River ◽  
Changjiang River Estuary ◽  
The Changjiang River ◽  
The North ◽  
Velocity Magnitude ◽  
Navigation Channel ◽  
The Changjiang River Estuary ◽  
Set Up

At present, the upper reach of the Deepwater Navigation Channel is silted heavily, which brings negative influences on navigation. A two-dimensional numerical model is set up to simulate the hydrodynamics of the Changjiang River Estuary with Delft3D-FLOW in this paper. This model has been validated with the observed tidal level, flow velocity magnitude and direction, and the computed results agree well with the observed data, which also shows the model can well simulate the hydrodynamics of the Changjiang River Estuary caused by the Deepwater Navigation Channel Project. Based on the analysis of computed results, especially the velocity along the South Passage and North Passage, the flood and ebb flow in the Hengsha Passage, and the flow spilt ratio of South Passage and North Passage, it presents that one fundamental reason for the sediment deposition in the upper reach of the Deepwater Navigation Channel is that the velocity along the North Passage is far less than that along South Passage, above all, the velocity in North Passage upstream of the Hengsha Passage is even smaller; another reason is that the flood and ebb flow of Hengsha Passage are large, which weakens the water exchange between the North Passage and South Channel.

scholarly journals Assessment of Extreme Storm Surges over the Changjiang River Estuary from a Wave–Current Coupled Model

2021 ◽  
Vol 9 (11) ◽  
pp. 1222
Author(s):  
Yutao Chi ◽  
Zengrui Rong
Keyword(s):  
Return Period ◽  
River Estuary ◽  
Coupled Model ◽  
Storm Surges ◽  
Distribution Model ◽  
Changjiang River ◽  
Changjiang River Estuary ◽  
The Changjiang River ◽  
The Changjiang River Estuary ◽  
The Impact

Disastrous storm surges and waves caused by typhoons are major marine dynamic disasters affecting the east China coast and the Changjiang River Estuary, especially when they occur coincidentally. In this study, a high-resolution wave–current coupled model consisting of ADCIRC (Advanced Circulation) and SWAN (Simulating Waves Nearshore) was established and validated. The model shows reasonable skills in reproducing the surge levels and waves. The storm surges and associated waves are then simulated for 98 typhoons affecting the Changjiang River Estuary over the past 32 years (1987–2018). Two different wind fields, the ERA reanalysis and the ERA-based synthetic wind with a theoretical typhoon model, were adopted to discern the potential uncertainties associated with winds. Model results forced by the ERA reanalysis show comparative skills with the synthetic winds, but differences may be relatively large in specific stations. The extreme surge levels with a 50-year return period are then presented based on the coupled model results and the Gumbel distribution model. Higher risk is presented in Hangzhou Bay and the nearshore region along the coast of Zhejiang. Comparative runs with and without wave effects were conducted to discern the impact of waves on the extreme surge levels. The wave setup contributes to 2–12.5% of the 50-year extreme surge level. Furthermore, the joint exceedance probabilities of high surge levels and high wave height were evaluated with the Gumbel–logistic statistic model. Given the same joint return period, the nearshore region along the coast of Zhejiang is more vulnerable with high surges and large waves than the Changjiang River Estuary with large waves and moderate surges.

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