Phase relationships between fine sediment suspensions and tidal currents in coastal seas

Bass, Sarah; Aldridge, John; McCave, I Nick; Vincent, Christopher E.

doi:10.1029/2001jc001269

Cited by 55 publications

(55 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, in natural environments, flocculation is also impacted by a range of additional factors, such as hysteresis due to different time scales of aggregation and break-up ), spatial variability (van Leussen, 1999Fugate and Friedrichs, 2003), physico-chemical and biological effects van Leussen (1999), and sediment provenance (Jago and Jones, 1998;Bass et al, 2002;Fettweis et al, 2012).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Effective energy controls on flocculation under various wave-current regimes

et al. 2016

View full text Add to dashboard Cite

Transport of sediments is a critical process in the coastal zone because of its relation with coastal erosion, productivity and pollution. Of particular interest are the dynamics of suspended cohesive sediments, known as flocs, which can aggregate and break-up during the flocculation process. This changes their size, density, settling velocity and overall transport. Even though turbulence is widely accepted to be an important control on floc aggregation and break-up, specific and detailed floc behaviour is still not fully understood. The present study seeks to help in the understanding of the intra-tidal turbulence-induced flocculation under different current-wave regimes. Observations of floc size and currents at high sample rates are used to investigate the changes throughout a fortnightly cycle. The occurrence of waves at different stages during the sampling period enabled determination of three regimes of currents dominant, combined waves and currents,

show abstract

Section: Accepted M Manuscriptmentioning

confidence: 99%

Effective energy controls on flocculation under various wave-current regimes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…This strongly suggests that local resuspension, rather than advection, causes the high variations in the near-bed concentrations. The observed phase lag between the surface concentrations and the tidal current and the amplitude attenuation of the surface concentrations adds to the suggestion of local resuspension and settling by the tidal current being the most important process (Bass and et al, 2002;Yu et al, 2011).…”

Section: Tidal Cycle Dynamicsmentioning

confidence: 99%

Observations of a narrow zone of high suspended particulate matter (SPM) concentrations along the Dutch coast

Hout

Gerkema

Nauw

et al. 2015

Continental Shelf Research

View full text Add to dashboard Cite

The objective of the study described in this paper is to localize the transport path of suspended particulate matter (SPM) in the Dutch coastal zone in the southern North Sea. It is known that a large mass of SPM is transported northward from the Strait of Dover, which is however mostly hidden from satellite and other surface measurements. The study area is located at 80 km north of the Rhine-Meuse estuary mouth in the far-field plume of the region of freshwater influence (ROFI). We investigate the occurrence and persistence of a turbidity maximum zone (TMZ) in an area closer to the coast than studied in previous observational programs. Shipboard measurements of vertical profiles of SPM concentrations, density and current velocities with a high cross-shore spatial resolution are presented. A turbidity maximum zone is found at a distance between 0.5 and 3 km from the coast along 30 km of the coastline. Observed concentrations are shown to vary strongly within a tidal cycle, and also between contrasting meteorological conditions in terms of the springneap tidal cycle, the significant wave height and the wind force. Temporary stratification is observed during spring tides, and occurs on the ebb phase of the tidal cycle. Cross-shore transports at a transect perpendicular to the coast show an accumulation of SPM in the TMZ within one tidal cycle.Possible mechanisms for this accumulation close to the coast are discussed.2

show abstract

“…In particular, observed suspended sediment concentrations have been interpreted as the result from the combined effect of tidal resuspension and tidal advection of a horizontal concentration gradient in tidally dominated coastal and shelf seas (e.g., Weeks et al, 1993;Jones et al, 1996;Jago and Jones, 1998;Bass et al, 2002). In regions where the largest tidal constituent is M2, tidal resuspension produces peaks with M4 variability while advection of horizontal gradients produces peaks with M2 variability, which can combine and result in the so-called twinpeak feature (Weeks et al, 1993).…”

Section: *Manuscriptmentioning

confidence: 99%

“…A strong semi-diurnal variability in SSC is typically explained by advective processes in tidally-dominated environments (e.g., Weeks et al, 1993;Jones et al, 1996;Jago and Jones, 1998;Bass et al, 2002), twin-peaks resulting from the superposition of tidal resuspension on these advective processes. In the Dee Estuary, the situation is unfortunately complicated by the presence of a number of processes related to baroclinic behaviour, periodic stratification, mixed sediments and it is not evident whether the same conceptual explanation remains valid.…”

Section: Observed Sediment Dynamicsmentioning

confidence: 99%

Modelling-based assessment of suspended sediment dynamics in a hypertidal estuarine channel

et al. 2014

View full text Add to dashboard Cite

We investigate the dynamics of suspended sediment transport in a hypertidal estuarine channel which displays a vertically sheared exchange flow. We apply a three-dimensional process-based model coupling hydrodynamics, turbulence, and sediment transport to the Dee Estuary, in the north-west region of the UK. The numerical model is used to reproduce observations of suspended sediment and to assess physical processes responsible for the observed suspended sediment concentration patterns.The study period focuses on a calm period during which wave-current interactions can reasonably be neglected. Good agreement between model and observations has been obtained. A series of numerical experiments aims to isolate specific processes and confirm that the suspended sediment dynamics result primarily from advection of a longitudinal gradient in concentration during our study period, combined with resuspension and vertical exchange processes. Horizontal advection of sediment presents a strong semidiurnal variability, while vertical exchange processes (including time-varying settling as a proxy for flocculation) exhibit a quarter-diurnal variability. Sediment input from the river is found to have very little importance and spatial gradients in suspended concentration are generated by spatial heterogeneity in bed sediment characteristics and spatial variations in turbulence and bed shear stress.

show abstract

Phase relationships between fine sediment suspensions and tidal currents in coastal seas

Cited by 55 publications

References 17 publications

Effective energy controls on flocculation under various wave-current regimes

Effective energy controls on flocculation under various wave-current regimes

Observations of a narrow zone of high suspended particulate matter (SPM) concentrations along the Dutch coast

Modelling-based assessment of suspended sediment dynamics in a hypertidal estuarine channel

Contact Info

Product

Resources

About