A Process-Based Approach to Sediment Transport

Abstract

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.

Propagation of tidal waves up in Yangtze Estuary during the dry season

“…The tidal current limit will vary in the reach between Zhenjiang and Jiangyin, which are, respectively, 360 and 240 km from the mouth when the climate changes from the dry season to the flood season. Due to the gradually widening river section downstream from Jiangyin, the river flow slows down in the seaward direction and is weaker than the tidal current in the estuary area which has the mean magnitude of about 1 m/s [Chu et al, 2011]. While the symmetric semidiurnal tides are observed outside of the mouth, tidal asymmetry occurs inside the mouth with average flood and ebb durations of 5 and 7.4 h, respectively, at ZJZ [Zhang et al, 2011].…”

Analysis on residual coarse sediment transport in estuaries

“…The model has been calibrated and validated against measurements of water levels and currents during spring and neap tides in dry and wet seasons (Chu et al, 2010). The computed amplitudes and phases of the tidal water level constituents (M 2 , S 2 , N 2 , K 2 , K 1 , O 1 , P 1 and M 4 ) were found to agree well with observations.…”

“…The upstream boundary is located at Datong, the tidal limit of the river, with the measured discharge as a boundary condition. At the open sea boundary the water level according to the astronomic tidal constituents (M 2 , S 2 , N 2 , K 2 , K 1 , O 1 , P 1 and M 4 ) is imposed (for further detail referring Chu et al, 2009Chu et al, , 2010. The results of the hydrodynamic model for the Yangtze Estuary are used in this study.…”

“…The tidal current constituents in the Yangtze Estuary have been computed with a 2DH process-based model for the Yangtze Estuary (Chu et al, 2009(Chu et al, , 2010. The model covers the entire tidal region of the Yangtze Estuary, the Hangzhou Bay and a large part of the adjacent East China Sea (see Fig.…”

Effects of Sediment‐Induced Density Gradients on the Estuarine Turbidity Maximum in the Yangtze Estuary

“…An ETM stretching about 60 km in the mouth zone of the Yangtze Estuary occupies the region of the North and South Passages where bottom SSC can be >10 kg/m 3 (Lin et al., 2019). The dynamics controlling the formation of ETM in the Yangtze have been extensively studied based on field observations (Li & Zhang, 1998; Song et al., 2013; Wu et al., 2012) and numerical models (Chu et al., 2010; Song & Wang, 2013; Wan & Wang, 2017). Figure 1 provides an example of high near‐bottom SSC of ∼30 kg/m 3 (∼1 m thick) lasting for 3–4 h in the middle of the North Passage (NP) (see Figure 2).…”