scholarly journals A PROCESS-BASED APPROACH TO SEDIMENT TRANSPORT

2011 ◽  
Vol 1 (32) ◽  
pp. 83 ◽  
Author(s):  
Ao Chu ◽  
Zhengbing Wang ◽  
Huib De Vriend ◽  
Marcel Stive
Keyword(s):  
Sediment Transport ◽  
Yangtze Estuary ◽  
Hangzhou Bay ◽  
Good Representation ◽  
The Yangtze Estuary ◽  
Proposed Model ◽  
Extensive Flow ◽  
Sediment Data ◽  
Mouth Bars ◽  
Insight Into

A process-based model for the Yangtze Estuary is constructed to study the sediment transport in the estuary. The proposed model covers the entire tidal region of the estuary, the Hangzhou Bay and a large part of the adjacent sea. The dominant processes, fluvial and tidal, are included in the model. The calibration of the model against extensive flow, water level, salinity and suspended sediment data shows a good representation of observed phenomena. With the present calibrated and validated model, the residual flow field and the residual sediment transport field are obtained. The residual sediment transport pattern gives insight into the morphological behaviour of the mouth bars.

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

Water ◽  
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.

scholarly journals Phosphorus sorption and buffering mechanisms in suspended sediments from the Yangtze Estuary and Hangzhou Bay, China

2013 ◽  
Vol 10 (5) ◽  
pp. 3341-3348 ◽  
Author(s):  
M. Li ◽  
M. J. Whelan ◽  
G. Q. Wang ◽  
S. M. White
Keyword(s):  
Fine Particle ◽  
Suspended Sediments ◽  
Yangtze Estuary ◽  
Buffering Capacity ◽  
Phosphate Adsorption ◽  
Hangzhou Bay ◽  
Phosphorus Sorption ◽  
The Yangtze Estuary ◽  
Different Temperatures ◽  
Increasing Temperature

Abstract. The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus (P) behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO42− when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC0) vary from 0.014 mg L−1 to 0.061 mg L−1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K) in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures.

scholarly journals Phosphorus sorption and buffering mechanisms in suspended sediments from the Yangtze Estuary and Hangzhou Bay, China

2012 ◽  
Vol 9 (12) ◽  
pp. 17519-17538 ◽  
Author(s):  
M. Li ◽  
M. J. Whelan ◽  
G. Wang ◽  
S. M. White
Keyword(s):  
Fine Particle ◽  
Suspended Sediments ◽  
Yangtze Estuary ◽  
Buffering Capacity ◽  
Phosphate Adsorption ◽  
Hangzhou Bay ◽  
Phosphorus Sorption ◽  
The Yangtze Estuary ◽  
Different Temperatures ◽  
Increasing Temperature

Abstract. The adsorption isotherm and the mechanism of the buffering effect are important controls on phosphorus behaviors in estuaries and are important for estimating phosphate concentrations in aquatic environments. In this paper, we derive phosphate adsorption isotherms in order to investigate sediment adsorption and buffering capacity for phosphorus discharged from sewage outfalls in the Yangtze Estuary and Hangzhou Bay near Shanghai, China. Experiments were also carried out at different temperatures in order to explore the buffering effects for phosphate. The results show that P sorption in sediments with low fine particle fractions was best described using exponential equations. Some P interactions between water and sediment may be caused by the precipitation of CaHPO4 from Ca2+ and HPO42− when the phosphate concentration in the liquid phase is high. Results from the buffering experiments suggest that the Zero Equilibrium Phosphate Concentrations (EPC0) vary from 0.014 mg l−1 to 0.061 mg l−1, which are consistent with measured phosphate concentrations in water samples collected at the same time as sediment sampling. Values of EPC0 and linear sorption coefficients (K) in sediments with high fine particle and organic matter contents are relatively high, which implies that they have high buffering capacity. Both EPC0 and K increase with increasing temperature, indicating a higher P buffering capacity at high temperatures.

A 2D/3D hydrodynamic and sediment transport model for the Yangtze Estuary, China

2009 ◽  
Vol 77 (1-2) ◽  
pp. 114-136 ◽  
Author(s):  
Kelin Hu ◽  
Pingxing Ding ◽  
Zhengbing Wang ◽  
Shilun Yang
Keyword(s):  
Sediment Transport ◽  
Transport Model ◽  
Yangtze Estuary ◽  
The Yangtze Estuary ◽  
Sediment Transport Model

Influence of Upstream Runoff Variation on Suspended Sediment in Yangtze Estuary

2012 ◽  
Vol 256-259 ◽  
pp. 2573-2576 ◽  
Author(s):  
Chao Feng Tong ◽  
Tao Yin ◽  
Jian Shi ◽  
Yu Yang Shao
Keyword(s):  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Concentration Field ◽  
Sediment Concentration ◽  
Yangtze Estuary ◽  
Hangzhou Bay ◽  
The Yangtze Estuary ◽  
The North ◽  
Runoff Variation ◽  
Water Conservancy Project

For the construction of water conservancy project in the upstream of the Yangtze River and the human activities, the runoff and sediment discharge from the upstream to East China Sea have changed greatly. To explore the distribution characteristics of suspended sediment in Yangtze Estuary under the new upstream boundary condition, a 2-D flow-sediment numerical model including the Yangtze Estuary and the Hangzhou Bay was established. Four different runoffs, which are 4,620m³/s, 11,000m³/s, 75,900m³/s and 90,000m³/s respectively, and the correspond sediment discharges were considered. The result indicates that, with the increase of upstream runoff, the sediment intrusion from the top of the North Branch into the North Branch decreases and the suspended sediment concentration field in the South Branch changes is greater than that in the North Branch. In the same region, the sediment concentration decreases during rising tide while it increases at low tide. The change of the core position for suspended sediment field is insignificant.

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