Sediment fluxes within salt marsh tidal creek systems in the Yangtze Estuary

Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the...

Distinctive sedimentary processes on two contrasting tidal flats of the Yellow River Delta

Coastal tidal flats provide valuable ecosystems, but are highly sensitive to tidal dynamics, sea-level rise, and human activities. Tidal inundation depth and frequency are known to affect tidal flat morphodynamics. However, the causes, processes and extent remain uncertain, particularly given the associated changes in sediment availability. In...

Modulation of sediment load recovery downstream of Three Gorges Dam in the Yangtze River

The sediment load in the Yangtze River downstream of the Three Gorges Dam (TGD) has substantially declined in recent decades. The decrease is more profound below the TGD, e.g., a 97% decrease at Yichang, compared with that at the delta apex, 1200 km downstream, e.g., a 75% decrease, implying along-river sediment recovery. Two large river...

Impact of Reduced Fluvial Sediment Supply on Saltwater Intrusion in the Yangtze Estuary

A decline of the fluvial sediment supply leads to coastal erosion and land loss. However, the fluvial sediment load may influence not only coastal morphodynamics but also estuarine hydrodynamics and associated saltwater intrusion. Previous studies revealed that suspended sediments influence estuarine hydrodynamics through various flow...

Feedback Effects of Sediment Suspensions on Transport Mechanisms in an Estuarine Turbidity Maximum

The mechanisms controlling the formation of an estuarine turbidity maximum (ETM) in estuaries have been extensively investigated, but one aspect that has received much less scientific attention is the role of high suspended sediment concentrations in combination with tidal asymmetry in ETM formation. Particularly in highly turbid estuaries,...

Review of the action of organic matter on mineral sediment flocculation

Sediment is found throughout the world’s alluvial plain rivers, estuarine coasts and adjacent seas and is thereby a key factor in major ecosystems. Suspended mineral sediment can affect the biological activity of microorganisms and plants, by reducing light penetration in the water column or by binding to organic matter. Biological processes...

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

An estuarine turbidity maximum (ETM) is a region of elevated suspended sediment concentration (SSC) resulting from residual transport mechanisms driven by river flow, tides, and salinity-induced density gradients (SalDG). However, in energetic and highly turbid environments such as the Yangtze Estuary, SedDG may also substantially contribute...

Changjiang Delta in the Anthropocene: Multi-scale hydro-morphodynamics and management challenges

The Changjiang Delta (CD) is one of well-studied large deltas of critical socio-economical and ecological importance regionally and global representativeness. Cumulated field data and numerical modeling has facilitated scientific understanding of its hydro-morphodynamics at multiple spatial and time scales, but the changing boundary forcing...

Regime shifts in the Changjiang (Yangtze River) Estuary: The role of concentrated benthic suspensions

Channel deepening often triggers positive feedback between tidal deformation, sediment import and drag reduction, which leads to the regime shift in estuaries from low-turbid to hyper-turbid state. In this study, a transition in profiles of suspended sediment concentration (SSC) is hypothesised by including a positive feedback loop of...

An integrated optic and acoustic (IOA) approach for measuring suspended sediment concentration in highly turbid environments

Accurate measurement of suspended sediment concentration (SSC) in highly turbid environments has been a problem due to optical or acoustic signal saturation and attenuation. The saturation returns a limited measurement range, and the attenuation raises an ambiguity problem that a low optical or acoustic output could mean a low or a high SSC....

Quantification of Tidal Asymmetry and Its Nonstationary Variations

Tidal wave deformation and tidal asymmetry widely occur in tidal estuaries and lagoons. Tidal asymmetry has been intensively studied because of its controlling role on residual sediment transport and large‐scale morphological evolution. There are several methods available to characterize tidal asymmetry prompting the need for an overview of...

From the headwater to the delta: A synthesis of the basin-scale sediment load regime in the Changjiang River

Many large rivers in the world delivers decreasing sediment loads to coastal oceans owing to reductions in sediment yield and disrupted sediment deliver. Understanding the sediment load regime is a prerequisite of sediment management and fluvial and deltaic ecosystem restoration. This work examines sediment load changes across the Changjiang...

How have the river discharges and sediment loads changed in the Changjiang River basin downstream of the Three Gorges Dam?

Streamflow and sediment loads undergo remarkable changes in worldwide rivers in response to climatic changes and human interferences. Understanding their variability and the causes is of vital importance regarding river management. With respect to the Changjiang River (CJR), one of the largest river systems on earth, we provide a...

An analysis on half century morphological changes in the Changjiang Estuary: Spatial variability under natural processes and human intervention

Examination of large scale, alluvial estuarine morphology and associated time evolution is of particular importance regarding management of channel navigability, ecosystem, etc. In this work, we analyze morphological evolution and changes of the channel-shoal system in the Changjiang Estuary, a river- and tide-controlled coastal plain estuary,...

A study of in-situ sediment flocculation in the turbidity maxima of the Yangtze Estuary

In order to improve our understandings of temporal and vertical variations of sediment flocculation dynamics within the turbidity maxima (TM) of the highly turbid Yangtze Estuary (YE), we deployed LISST-100C, a laser instrument for in-situ monitor of the sizes and concentrations of flocculated particles in a wet season. Field data in terms of...

The role of river flow and tidal asymmetry on 1-D estuarine morphodynamics

Numerous research efforts have been devoted to understanding estuarine morphodynamics under tidal forcing. However, the impact of river discharge on estuarine morphodynamics is insufficiently examined. Inspired by the Yangtze Estuary, this work explores the morphodynamic impact of river discharge in a 560 km long tidal basin based on a 1-D model...