scholarly journals SEDIMENT TRANSPORT ON THE SOUTH-EAST AUSTRALIAN CONTINENTAL SHELF

1984 ◽  
Vol 1 (19) ◽  
pp. 131 ◽  
Author(s):  
Angus D. Gordon ◽  
John G. Hoffman
Keyword(s):  
Sediment Transport ◽  
Continental Shelf ◽  
Suspended Sediment ◽  
Transport System ◽  
Sediment Concentration ◽  
High Energy ◽  
Sediment Distribution ◽  
Sediment Movement ◽  
Shelf Sediment ◽  
Sea Bed

Engineering projects on the continental shelf off Sydney, Australia, have stimulated investigation into the sediment transport system of the shelf. Investigation activities associated with these projects have included: definition of sea bed morphology, sediment distribution and bedform characteristics; monitoring of steady and wave induced currents; wind data collection; suspended sediment sampling; bottom camera sediment movement investigations and analytical studies of sediment reaction to sea bed forcing functions. Sea bed velocity exceedence relationships for both wave oscillations and steady currents have been determined at depths of 24 m, 60 m and 80 m. Thresholds of sediment movement have been defined. Relative sediment transport computations have been undertaken and studies of suspended sediment concentration profiles are in progress so that absolute transport rates can be determined. The prevailing conditions, which include a mainly south bound current, are seldom sufficient to induce entrainment of shelf sediments. Transport events mainly result from major storms in the Tasman Sea which produce both high energy waves and north bound currents. Although these events are rare and short lived, the combined wave and current shear produced at the sea bed during the events gives rise to entrainment conditions which result in their dominance of the shelf sediment transport system.

scholarly journals Investigating Suspended-Sediment Transport in a Shallow Lake Using a Three-Dimensional Model

2017 ◽  
Author(s):  
Hong-Ming Liu ◽  
Wen-cheng Liu ◽  
Chih-Yu Chiu
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Shallow Lake ◽  
Suspended Sediment Concentration ◽  
Transport Model ◽  
Three Dimensional ◽  
Sediment Concentration ◽  
Suspended Sediment Transport ◽  
Sediment Distribution ◽  
Mean Current

A three-dimensional, unstructured grid, hydrodynamic and suspended-sediment transport model (i.e., SELFE-SED) was developed to simulate temporal and spatial variations of suspended sediment and was applied to the subtropical subalpine Tsuei-Feng Lake (TFL) of Taiwan. The model was validated with measured water level and suspended‑sediment concentration in 2009, 2010, and 2011. The overall model simulation results are in quantitative agreement with the observational data. The validated model was then applied to explore the most important parameter that affects the suspended-sediment concentration and to investigate the effect of wind stress on the mean current and suspended‑sediment distribution in this shallow lake. Modeling results of sensitivity analysis reveal that the settling velocity is a crucial parameter and erosion rate is less important in the suspended-sediment transport model. Remarkable lake circulation was found based on the strength of wind speed and wind direction. Strong wind would result in higher mean current in the top layer and suspended-sediment distribution in the top and bottom layers. This study demonstrated that the wind stress played a significant influence on mean circulation and suspended-sediment transport in a shallow lake.

Research on the Coastal Suspended Sediment Movement of Matakong Island in Guinea, Africa Based on Remote Sensing Data

2013 ◽  
Vol 333-335 ◽  
pp. 275-279
Author(s):  
Yin Cai ◽  
Hong Bo Zhao ◽  
Shu Hua Zuo
Keyword(s):  
Remote Sensing ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Remote Sensing Data ◽  
Sediment Concentration ◽  
Concentration Data ◽  
Sediment Distribution ◽  
Sensing Data ◽  
Sediment Movement ◽  
Wide Range

A wide range of suspended sediment concentration can be obtained by satellite remote sensing. According to the multi-temporal remote sensing data and quasi-simultaneously surface sediment concentration data, research works on the surface suspended sediment distribution and movement trends of Matakong coastal area, Africa were carried out. The results showed that the suspended sediment concentration of the studied area is not large, and the sediment movement is not active. The sediment source comes from the nearshore shallow flats, where they could be entrained by the wind waves and then diffuses by the tidal currents.

scholarly journals FIELD INVESTIGATIONS OF SUSPENDED SEDIMENT TRANSPORT IN THE NEARSHORE ZONE

1984 ◽  
Vol 1 (19) ◽  
pp. 120 ◽  
Author(s):  
R.W. Sternberg ◽  
N.C. Shi ◽  
John P. Downing
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Surf Zone ◽  
Pressure Sensors ◽  
Sediment Concentration ◽  
Daily Basis ◽  
Transport Rate ◽  
Suspended Sediment Transport ◽  
Sediment Distribution ◽  
Longshore Transport

The suspended sediment distribution and longshore sediment transport characteristics at Leadbetter Beach, Santa Barbara, California were investigated using a series of miniature optical backseatter sensors which can measure particle concentrations as high as 180 gm/£ and have 10 Hz frequency response. Vertical arrays of sensors were maintained at up to four positions across the surf zone during 7-25 February 1980 and were operated concurrently with pressure sensors and current meters. Data were collected on a daily basis over 2-4 hour periods. The data were analyzed to reveal concentration profiles of suspended sediment, the average suspended sediment loads, and the longshore particle flux in relation to varying wave conditions. Results show that sediment transport occurs as individual suspension events related to incident wave motions and infragravity motion oscillations within the surf zone; suspended sediment concentration decreases approximately logarithimically away from the seabed; the maximum values of longshore transport rates occur in the mid-surf zone; and the measured suspended sediment longshore transport rate is equal to the total longshore transport rate as predicted by existing transport equations.

scholarly journals Modern sedimentary processes along the Doce river adjacent continental shelf

2015 ◽  
Vol 45 (4) ◽  
pp. 635-644 ◽  
Author(s):  
Valéria da Silva Quaresma ◽  
Geórgia Catabriga ◽  
Silvia Nossa Bourguignon ◽  
Estefânia Godinho ◽  
Alex Cardoso Bastos
Keyword(s):  
Continental Shelf ◽  
River Mouth ◽  
High Energy ◽  
Sediment Supply ◽  
Major Influence ◽  
Carbonate Content ◽  
Sedimentary Processes ◽  
Sediment Distribution ◽  
Shelf Sediment ◽  
Doce River

In areas of the continental shelf where sediment supply is greater than the sediment dispersion capacity, an extensive terrigenous deposits and consequently submerged deltas can be formed. The Eastern Brazilian shelf is characterized by the occurrence of river feed deltas in between starving coasts. Herein, modern sedimentary processes acting along the Doce river adjacent continental shelf are investigated. The main objective was to understand the shelf sediment distribution, recognizing distinct sedimentary patterns and the major influence of river sediment discharge in the formation of shelf deposits. The study used 98 surficial samples that were analyzed for grain size, composition and bulk density. Results revealed 3 distinct sectors: south - dominated by mud fraction with a recent deposition from riverine input until 30 m deep and from this depth bioclastic sands dominate; central north - sand mud dominated, been recognized as a bypass zone of resuspended sediment during high energy events; and north - relict sands with high carbonate content. The modern sedimentation processes along the Doce river continental shelf is dominated by distinct sedimentary regimes, showing a strong fluvial influence associated with wave/wind induced sediment dispersion and a carbonate regime along the outer shelf. These regimes seem to be controlled by the distance from the river mouth and bathymetric gradients.

scholarly journals Numerical Simulation of Deep-Sea Sediment Transport Induced by a Dredge Experiment in the Northeastern Pacific Ocean

2021 ◽  
Vol 8 ◽  
Author(s):  
Kaveh Purkiani ◽  
Benjamin Gillard ◽  
André Paul ◽  
Matthias Haeckel ◽  
Sabine Haalboom ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Pacific Ocean ◽  
Suspended Sediment ◽  
Deep Sea ◽  
Numerical Models ◽  
Sediment Concentration ◽  
Ocean Model ◽  
Small Scale ◽  
Plume Dispersion ◽  
Deep Sea Sediment

Predictability of the dispersion of sediment plumes induced by potential deep-sea mining activities is still very limited due to operational limitations on in-situ observations required for a thorough validation and calibration of numerical models. Here we report on a plume dispersion experiment carried out in the German license area for the exploration of polymetallic nodules in the northeastern tropical Pacific Ocean in 4,200 m water depth. The dispersion of a sediment plume induced by a small-scale dredge experiment in April 2019 was investigated numerically by employing a sediment transport module coupled to a high-resolution hydrodynamic regional ocean model. Various aspects including sediment characteristics and ocean hydrodynamics were examined to obtain the best statistical agreement between sensor-based observations and model results. Results show that the model is capable of reproducing suspended sediment concentration and redeposition patterns observed during the dredge experiment. Due to a strong southward current during the dredging, the model predicts no sediment deposition and plume dispersion north of the dredging tracks. The sediment redeposition thickness reaches up to 9 mm directly next to the dredging tracks and 0.07 mm in about 320 m away from the dredging center. The model results suggest that seabed topography and variable sediment release heights above the seafloor cause significant changes especially for the low sedimentation pattern in the far-field area. Near-bottom mixing is expected to strongly influence vertical transport of suspended sediment.

scholarly journals Transport Mechanism of Suspended Sediments and Migration Trends of Sediments in the Central Hangzhou Bay

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2189
Author(s):  
Zekun Song ◽  
Weiyong Shi ◽  
Junbiao Zhang ◽  
Hao Hu ◽  
Feng Zhang ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Suspended Sediment ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Hangzhou Bay ◽  
The South ◽  
Transport Mode ◽  
Tidal Pumping ◽  
The North

Based on the 2013 field survey data of hydrology, suspended sediments and bottom sediments in the Central Hangzhou Bay, this paper explores the dynamic mechanism of suspended sediments in Hangzhou Bay by employing material flux decomposition. Meanwhile, the migration trends of bed sediments are also investigated by analyzing grain size trends. The results show that during an ebb or flood tide, the hydrograph of suspended sediment concentration of Hangzhou Bay is dominated by an M shape (bimodal), which is attributed primarily to the generation of a soft mud layer and a separate fluid mud layer. Laterally, the distribution of suspended sediment concentration is high in the south and low in the north. From a macroscopic perspective, the net sediment transport in the study area displays a “north-landward and south-seaward” trend, presenting a “C”-shaped transport mode. That is, the sediments are transported from the bay mouth to the bay head on the north side and from the bay head to the bay mouth on the south side. The sediment transports by advection and tidal pumping are predominant, while the sediment transport by vertical circulation makes little contribution to the total sediment transport. Moreover, the sediment transport in the center of the reach area is dominated by advection, whereas that near both sides of the banks is controlled by tidal pumping. The asymmetry of the tides, i.e., flood-dominance in the north and ebb-dominance in the south, is the primary cause of the dynamic mechanism for the overall “C”-shaped transport mode in Hangzhou Bay. Additionally, coupled with the narrow-head wide-mouth geomorphology, Hangzhou Bay remains evolving by south shore silting and north shore scouring.

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