Numerical simulation on the process of saltwater intrusion and its impact on the suspended sediment concentration in the Changjiang (Yangtze) estuary

2010 ◽  
Vol 28 (3) ◽  
pp. 609-619 ◽  
Author(s):  
Chongguang Pang ◽  
Enbao Zhao ◽  
Yang Yang
Keyword(s):  
Numerical Simulation ◽  
Suspended Sediment ◽  
Saltwater Intrusion ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Yangtze Estuary

Analysis of tidal average saturated suspended sediment concentration of cohesive sediment in the Yangtze Estuary

2021 ◽  
Author(s):  
Junyu Tao ◽  
Peng Hu ◽  
Wei Li ◽  
Zhiguo He
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Cohesive Sediment ◽  
Yangtze Estuary ◽  
Shear Stresses ◽  
The Yangtze Estuary ◽  
Erosion And Deposition ◽  
Deposition Fluxes ◽  
The Impact

<p>It is generally believed that sediment erosion and deposition can’t occur simultaneously, which is also reflected in the classical Partheniades-Krone formulas used to calculate erosion and deposition flux. In this study, the erosion and deposition fluxes of cohesive sediment are integrated in the tidal period respectively, and when they are equal, the corresponding suspended cohesive sediment concentration is called ‘tidal average saturated concentration of cohesive sediment’. Theoretical analysis of the factors affecting the saturated concentration indicates that a large erosion coefficient results in a high saturated concentration level. The corresponding critical erosion and deposition shear stresses (i.e., τ<sub>e </sub>and τ<sub>d</sub>) at saturated concentration have many possibilities. Therefore, it is understandable that good agreement of suspended sediment concentration between simulation and observation have been obtained by adjusting τ<sub>e </sub>and τ<sub>d </sub>in the previous numerical simulation calibration. According to the relative magnitude of τ<sub>e </sub>and τ<sub>d</sub> at saturated concentration, the erosion and deposition fluxes of cohesive sediment can be divided into four situations: weak erosion (i.e., τ<sub>e  ></sub> τ<sub>d</sub>), intense erosion (i.e., τ<sub>e  <</sub> τ<sub>d</sub>), intense deposition (i.e., τ<sub>e  <</sub> τ<sub>d</sub>), and weak deposition (i.e., τ<sub>e > </sub>τ<sub>d</sub> ). A two-dimensional numerical model is applied to calculate the temporal and spatial variation of the saturated concentration of cohesive sediment in the Yangtze Estuary. Simulation results shows the following findings. 1) The impact of the fraction of the kth size class in the surface (top) layer of bed material on erosion flux of non-uniform cohesive sediment is necessary to be considered. Otherwise, the calculated saturated concentration of cohesive sediment is greater than the measured. 2) The differences between saturated concentration and the field calculated/measured suspended sediment concentration can be applied to infer bed erosion/deposition characteristics to some extent, and compared it with the measured erosion/deposition result, which in turn verifies the values of  τ<sub>e </sub>and τ<sub>d</sub> in the model. This finding provides insights for the following research on transport and diffusion of cohesive sediment in estuary and coastal areas.</p>

Retrieval and Analysis on the Sediment Concentration of the South Branch of the Yangtze Estuary Based on TM

2013 ◽  
Vol 353-356 ◽  
pp. 2763-2768 ◽  
Author(s):  
Jia Ling Hao ◽  
Tong Cao ◽  
Zhu Jun Zhang ◽  
Li Ping Yin
Keyword(s):  
Remote Sensing ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Sediment Concentration ◽  
Yangtze Estuary ◽  
The South ◽  
The Yangtze Estuary ◽  
Remote Sensing Technology ◽  
Sensing Technology ◽  
Quantitative Remote Sensing

Suspended sediment concentration is important index of water quality, and assessment coefficient of water environment. Remote sensing technology can overcome the shortcomings of conventional methods, such as low speed, long period, and scarce temporal and spatial data distribution. Thus it is meaningful to introduce remote sensing technology to monitoring suspended sediment. In this paper, two TM/ETM+ images of the Yangtze estuary were utilized, and based on review of available domestic and overseas remote sensing data of suspended sediment, also combined with analysis on the 21 samples of synchronizing collection on April 28, 2009 and 3 samples of synchronizing collection on March 26, 2000 at the same time of satellite passing through respectively, the inversion model of satellite quantitative data was setup correlated to suspended sediment concentration. Then the classification diagram of sediment concentration in the surface water at the South Branch of the Yangtze Estuary was drawn. This study gets the following conclusions:(1) TM4 band reflection coefficient is more related to surface sediment concentration, the correlation coefficient is 0.884. (2)Through the regression analysis, the quantitative remote sensing model is established. By the mode, using satellite picture, sediment concentration distribution map in study area is obtained. (3)The diffusion law of suspended sediment, the range of high turbid water region and the estuarine sediment transportation were further discussed from monitoring data, and its characteristic phenomenon were observed and the cause was also explained.

A Study of Suspended Sediment Transport Characteristics in the Offshore of Yangtze Estuary

2013 ◽  
Vol 477-478 ◽  
pp. 829-835
Author(s):  
Li Bing Huang ◽  
Yi Tian Li
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Spring Tide ◽  
Sediment Concentration ◽  
Yangtze Estuary ◽  
Practical Significance ◽  
Longitudinal Distribution ◽  
Suspended Sediment Transport ◽  
Offshore Area ◽  
Good Consistency

Estuarine offshore area is the gathering area of sediment which is from watershed into sea. There has important theoretical and practical significance about researching the transport characteristics and the variation trend of the suspended sediment concentration (SSC) in this area. On the basis of analyzing the long data about recent 50 years to the Yangtze estuarine offshore area, there are some results: in time aspects, the SSC in dry season is higher than it in flood season, and the SSC in spring tide is higher than it in neap tide; in longitudinal distribution aspects, there is a decreasing trend about SSC from west to east, and the decreasing level of the SSC is ever-reduced from west to east until the SSC remains basically low and unchanged in the east of 123°E; in transverse distribution aspects, the SSC has high locations. Furthermore, there has a preliminary discussion for the variation of the SSC in the offshore area with the reduce of the sediment from watershed, comparing with the last century (1950s, 1970s, 1980s, 1990s), the SSC in the offshore area has a reductive trend, it shows good consistency between the variation of the SSC in the estuarine offshore area and the decrease of sediment from the Yangtse River into sea.

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