Sediment Transport in Estuarine Areas

Prentice, J. E.; Reg, I. R.; Colleypriest, C.; Kirby, R.; Sutcliffe, P.; Dobson, M. R.; D'Olier, B.; Elvines, M. F.; Comp, None KILENYI, TOM, GECO Geophysical; Maddrell, Roger; Phinn, T. R.

doi:10.1038/2181207a0

Cited by 12 publications

(5 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Certainly, the number of channels present is suggestive of mutually evasive tidal streams, a commonly observed characteristic of macro-tidal estuaries (Robinson, 1956;Wright et al, Robinson (1960) inferred that most of the channels running through the outer Thames were flood channels, and that ebb channels were present only in the far southwest close to the Thames river entrance (Oaze Deep and The Warp). This is supported to some extent by Prentice et al (1968) who showed that seabed biofacies within the Southend region extended seaward within channels of The Warp and Oaze Deep. Evidence from sand waves, found around the northern extents ('heads') of the central sand banks, and at each end of the Suffolk banks and offshore ridges, show abrupt reversals in asymmetry, and associated sediment transport directions, indicating that both flood and ebb tidal currents are actively moving sediment but that dominance is less clear-cut (Prentice et al, 1968;Langhorne, 1973;Caston, 1981;Harris, 1988).…”

Section: Introductionmentioning

confidence: 67%

“…This is supported to some extent by Prentice et al (1968) who showed that seabed biofacies within the Southend region extended seaward within channels of The Warp and Oaze Deep. Evidence from sand waves, found around the northern extents ('heads') of the central sand banks, and at each end of the Suffolk banks and offshore ridges, show abrupt reversals in asymmetry, and associated sediment transport directions, indicating that both flood and ebb tidal currents are actively moving sediment but that dominance is less clear-cut (Prentice et al, 1968;Langhorne, 1973;Caston, 1981;Harris, 1988).…”

Section: Introductionmentioning

confidence: 67%

“…A commonly mooted assumption is that the gross configuration is associated with underlying topography within the clay basement (Prentice et al, 1968;Harris, 1988). However, Harris (1988) observed that the broad bathymetric highs of the outer Thames banks, and the strong tidal signature of the intervening channels set the system apart from other large estuary mouths such as the Severn (southwest UK) or Moreton Bay (east Australia).…”

Section: Introductionmentioning

confidence: 96%

See 2 more Smart Citations

Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary

Burningham

French

2011

Hydrobiologia

View full text Add to dashboard Cite

This article analyses the morphological history of the outer Thames seabed, covering over 3,000 km 2 from Aldeburgh (Suffolk), to Southendon-Sea (Essex) and Margate (Kent). The region has been depicted on bathymetric charts since the sixteenth century, and has been formally charted since the eighteenth century. Charts published since the early 1800s incorporate sufficient grid reference or ground control detail for georectification onto a common coordinate system (British National Grid). The morphological history of the outer seabed was thus reconstructed through the digitisation and interpolation of soundings onto a regular grid (3D surface). The evolution of seabed morphology was examined using transects, bathymetric change maps and spatial statistics. The results show considerable spatial variability in seabed behaviour. Within the central Thames, banks have experienced significant depth changes can be associated with lateral shifts in individual banks. Some of the outer banks in this region exhibit progressive elongation. Shifts in bank position across the Suffolk shoreface appear to be more subtle, and there is evidence here of both onshore and offshore migration. There is no clear evidence of any regionally coherent response to large-scale historical forcing such as sea-level rise.

show abstract

Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 67%

Section: Introductionmentioning

confidence: 96%

See 1 more Smart Citation

Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary

Burningham

French

2011

Hydrobiologia

View full text Add to dashboard Cite

show abstract

“…Since deposition of the suspended load, and arrest of movement of the traction carpet, are both very temporary and mobile phases, it is hardly to be expected that they will leave much permanent record within the sediment body. Borings in the Black Deep area (M addrell & Prentice 1967) and in the Maplin Sands show that the buried channels of the estuary are in the m ain filled at their base w ith shelly gravel, which rapidly fines upwards into the well-sorted fine sand which forms the bulk of the sediment body of the Thames estuary (Prentice 1968). I f subsidence of the region and the consequent flooding of the Tham es river system with sea w ater was perfectly even, it is to be expected that the mobile m uddy phases would simply move u p stream.…”

Section: R Elation To Subsidencementioning

confidence: 99%

Sedimentation in the inner estuary of the Thames, and its relation to the regional subsidence

Prentice¹

1972

Phil. Trans. R. Soc. Lond. A

View full text Add to dashboard Cite

The Inner Thames Estuary is defined as that part of the estuary which lies above the point of widening at Southend and the tidal limit at Teddington Weir (figure 1). In respect of sedimentation it may be divided into three zones. From Teddington to below Tower Bridge the river carries mainly land-derived sediment suspension load is low, and deposition on the bed and banks is slight. From Woolwich Reach to Gravesend Reach is a zone of high suspended load and much sedimentation - these are the ‘Mud Reaches’. Below that, down to Sea Reach, sedimentation is dominated by bed-load transport from the sea. The sedimentation pattern of the Mud Reaches is related to the position of the salt-water-freshwater mixing zone, and so is most sensitive to relative changes of sea level. In point of fact the constitution of this mud is widely variable, varying from 80 down to 10 % of clay, while still retaining its fluid and mobile character. This fluidity appears to be due largely to the loose packing of the flocculated clay particles which it contains, although the relatively high organic content of the mud undoubtedly plays a part. It would, however, be wrong to attribute the peculiar problem associated with the accumulation of fluid mud in the Thames to the organic pollution of the river, for similar deposits are shown in many less-polluted estuaries, e.g. the Taw-Torridge, the Gironde, etc.

show abstract

“…The Delta is an estuary, which is marked by complex sediment processes driven by interaction between rivers and the sea (Prentice et al, 1968; Seymore, 1989). Given the important role the Delta plays as described in the preceding section, proper sediment management is key for the well‐being of the communities and ecosystem within and surrounding it (Schoellhamer et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Suspended sediment concentration estimation in the Sacramento‐San Joaquin Delta of California using long short‐term memory networks

Kim¹,

He²,

Sandhu³

2022

Hydrological Processes

View full text Add to dashboard Cite

Sedimentation is an important aspect of water resources management with many implications. Often, process-based methods are employed to predict and assess the amount of sediment in water, but there are still challenges because the mechanisms that govern sediment transport are not yet fully understood. Furthermore, complex domains make model calibration difficult. Thus, as a complementary tool, a machinelearning model was developed in the present study to emulate an existing processbased model in simulating suspended sediment concentration (SSC). It employs the long short-term memory (LSTM) networks, which are a type of artificial neural networks (ANNs) designed for supervised learning of a sequence of data (e.g., time series). The model was applied to the Sacramento-San Joaquin Delta (the Delta) of California, USA, which is characterized by an interconnected system of sloughs, waterways, and a tidal outlet. The model training was performed with historical records of flow, stage and SSC at various locations within the Delta. The study period was 2010 through 2016, but the training period (i.e., range of observed data used to train the model) was varied to assess the model's sensitivity to the inputs and to determine the optimum model setup. Comparison between the model-estimated SSC and the observation at 12 key locations within the Delta showed that the estimation accuracy of the LSTM model during the study period is comparable or superior to that of the Delta Simulation Model II-General Transport Model (DSM2-GTM), a process-based operational hydrodynamics and water quality model for the Delta. In terms of the ratio of the root-mean-square error to the standard deviation (RSR), LSTM models generally showed higher predictability than DSM2-GTM in all test cases investigated, with the lowest (most desirable) and highest (least desirable) LSTM-based RSR being 0.21 and 1.14, respectively. In comparison, the lowest and highest RSR values with DSM2-GTM were 0.26 and 3.70, respectively. The median LSTM-based RSR of all study locations is around 0.7 while its DSM2-GTM counterpart is about 1.0. LSTM models also yielded remarkably higher (more desirable) Nash-Sutcliffe Efficiency values. Moreover, visual inspection found that LSTM models better captured the timing and magnitude of peaks as well as the temporal variations in the SSC time series. The LSTM model's performance was further analysed with hydro-meteorological data (precipitation and wind speed) incorporated in

show abstract

Sediment Transport in Estuarine Areas

Cited by 12 publications

References 1 publication

Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary

Seabed dynamics in a lage coastal embayment: 180 years of morphological change in the outer Thames estuary

Sedimentation in the inner estuary of the Thames, and its relation to the regional subsidence

Suspended sediment concentration estimation in the Sacramento‐San Joaquin Delta of California using long short‐term memory networks

Contact Info

Product

Resources

About