Effect of Tidal Stage on Sediment Concentrations and Turbulence by Vessel Wake in a Coastal Plain Saltmarsh

Vessel generated waves can impact shoreline stability and habitat structure in many waterways. Sheltered regions, such as coastal plain saltmarshes, support fragile ecosystems and can be particularly vulnerable to the effects of unregulated vessel operations. Instruments for measuring currents and sediment concentration were deployed in a coastal plain saltmarsh to examine the small-scale physical characteristics of the vessel wake generated by recreational craft typical of this environment. The response to vessel wake varied sharply depending upon the stage of the tide. At low tide, waves breaking on the exposed bank produced high concentrations of suspended material that were transported offshore through turbulent diffusion. When the water elevation exceeded the toe of the marsh scarp, the concentration and turbulent kinetic energy exhibited less of a statistically significant variation in response to vessel passage. For the most energetic flows, the vessel orbital velocities were dwarfed by turbulent fluctuations generated by the sheared tidal boundary layer. While further research is required, preliminary findings indicate that the dissipation of vessel wake energy may stimulate or enhance shear generated turbulence if the characteristic wave period is similar to the characteristic time scale of the energy containing eddies.

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Sediment transport modifications induced by submerged artificial reef systems: a case study for the Gulf of Venice

Oceanological and Hydrobiological Studies ◽

10.2478/s13545-014-0112-4 ◽

2014 ◽

Vol 43 (1) ◽

Cited By ~ 3

Author(s):

Davide Bonaldo ◽

Alvise Benetazzo ◽

Andrea Bergamasco ◽

Francesco Falcieri ◽

Sandro Carniel ◽

...

Keyword(s):

Sediment Transport ◽

Coastal Zone Management ◽

Artificial Reef ◽

Sediment Concentration ◽

Quantitative Information ◽

Small Scale ◽

Zone Management ◽

Basin Scale ◽

Scale Modelling ◽

Maritime Spatial Planning

AbstractThe shallow, gently sloping, sandy-silty seabed of the Venetian coast (Italy) is studded by a number of outcropping rocky systems of different size encouraging the development of peculiar zoobenthic biocenoses with considerably higher biodiversity indexes compared to neighbouring areas. In order to protect and enhance the growth of settling communities, artificial monolithic reefs were deployed close to the most important formations, providing further nesting sites and mechanical hindrance to illegal trawl fishing.In this framework, a multi-step and multi-scale numerical modelling activity was carried out to predict the perturbations induced by the presence of artificial structures on sediment transport over the outcroppings and their implications on turbidity and water quality. After having characterized wave and current circulation climate at the sub-basin scale over a reference year, a set of small scale simulations was carried out to describe the effects of a single monolith under different geometries and hydrodynamic forcings, encompassing the conditions likely occurring at the study sites. A dedicated tool was then developed to compose the information contained in the small-scale database into realistic deployment configurations, and applied in four protected outcroppings identified as test sites. With reference to these cases, under current meteomarine climate the application highlighted a small and localised increase in suspended sediment concentration, suggesting that the implemented deployment strategy is not likely to produce harmful effects on turbidity close to the outcroppings.In a broader context, the activity is oriented at the tuning of a flexible instrument for supporting the decision-making process in benthic environments of outstanding environmental relevance, especially in the Integrated Coastal Zone Management or Maritime Spatial Planning applications. The dissemination of sub-basin scale modelling results via the THREDDS Data Server, together with an user-friendly software for composing single-monolith runs and a graphical interface for exploring the available data, significantly improves the quantitative information collection and sharing among scientists, stakeholders and policy-makers.

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Small Scale Statistics of Turbulent Fluctuations Close to a Stagnation Point

Turbulent Cascades II - ERCOFTAC Series ◽

10.1007/978-3-030-12547-9_14 ◽

2019 ◽

pp. 125-132

Author(s):

Peter D. Huck ◽

Nathanael Machicoane ◽

Romain Volk

Keyword(s):

Stagnation Point ◽

Small Scale ◽

Turbulent Fluctuations

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

Frontiers in Marine Science ◽

10.3389/fmars.2021.719463 ◽

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.

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Large- and small-scale effects of habitat structure on rates of predation: how percent coverage of seagrass affects rates of predation and siphon nipping on an infaunal bivalve

Oecologia ◽

10.1007/bf00341470 ◽

1994 ◽

Vol 98 (2) ◽

pp. 176-183 ◽

Cited By ~ 120

Author(s):

E. A. Irlandi

Keyword(s):

Habitat Structure ◽

Scale Effects ◽

Small Scale ◽

Infaunal Bivalve

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Dead Fuel Loads in North Carolina’s Piedmont and Coastal Plain and a Small Scale Assessment of NFDRS Fuel Models

Remote Sensing and Modeling Applications to Wildland Fires ◽

10.1007/978-3-642-32530-4_14 ◽

2013 ◽

pp. 193-208

Author(s):

Michael J. Gavazzi ◽

Steven G. McNulty ◽

Johnny L. Boggs ◽

Sara E. Strickland ◽

David C. Chojnacky

Keyword(s):

Coastal Plain ◽

Small Scale ◽

Fuel Loads ◽

Scale Assessment ◽

Fuel Models

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Lagrangian and spectral analysis of the forced flow past a circular cylinder using pulsed tangential jets

Journal of Fluid Mechanics ◽

10.1017/jfm.2012.35 ◽

2012 ◽

Vol 696 ◽

pp. 285-300 ◽

Cited By ~ 18

Author(s):

T. Jardin ◽

Y. Bury

Keyword(s):

Circular Cylinder ◽

Time Series Data ◽

Excitation Frequency ◽

Shear Layers ◽

Forced Flow ◽

Series Data ◽

Small Scale ◽

Characteristic Time Scale ◽

Momentum Coefficient ◽

Flow Past

AbstractWe numerically investigate the influence of pulsed tangential jets on the flow past a circular cylinder. To this end a spectral-Lagrangian dual approach is used on the basis of time-series data. The analysis reveals that the flow response to unsteady forcing is driven by strong interactions between shear layers and pulsed jets. The latter preferentially lead to either the lock-on regime or the quasi-steady vortex feeding regime whether the excitation frequency is of the order of, or significantly greater than, the frequency of the natural instability. The intensity of the wake vortices is mainly influenced by the momentum coefficient through the introduction of opposite-sign vorticity in the shear layers. This feature is emphasized using a modal-based time reconstruction, i.e. by reconstructing the flow field upon a specific harmonic spectrum associated with a characteristic time scale. The quasi-steady regime exhibits small-scale counter-rotating vortices that circumscribe the separated region. In the lock-on regime, atypical wake patterns such as 2P or $\mathrm{P} + \mathrm{S} $ can be observed, depending on the forcing frequency and the momentum coefficient, highlighting remarkable analogies with oscillating cylinders.

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Impacts of small-scale faults on continental to coastal plain deposition: Evidence from the Realgrunnen Subgroup in the Goliat field, southwest Barents Sea, Norway

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2018.04.023 ◽

2018 ◽

Vol 95 ◽

pp. 276-302 ◽

Cited By ~ 11

Author(s):

Mark Joseph Mulrooney ◽

Bjarte Rismyhr ◽

Honore Dzekamelive Yenwongfai ◽

Johan Leutscher ◽

Snorre Olaussen ◽

...

Keyword(s):

Coastal Plain ◽

Barents Sea ◽

Small Scale

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Identifying Areas Prone to Dusty Winds for Gas Turbine Inlet Specification

Volume 3: Turbo Expo 2007 ◽

10.1115/gt2007-27820 ◽

2007 ◽

Cited By ~ 2

Author(s):

Charles Brake

Keyword(s):

Risk Factors ◽

Gas Turbine ◽

Gas Turbines ◽

Meteorological Conditions ◽

Small Scale ◽

Local Factors ◽

Intake System ◽

Geographical Spread ◽

The World ◽

High Concentrations

The role and geographical spread of gas turbines is increasing. Because of this, there are more situations where the operator is likely to experience problems with high concentrations of dust overloading the intake system. This work summarizes the causes of dusty winds, areas where they are found, and offers recommendations to assist the inlet specifier. The causes of dusty winds are identified and discussed including desertification, small-scale local factors and meteorological conditions. Areas of the world where dust originates from and areas to which it can be carried are identified. In conclusion, the combinations of these factors are then offered as recommendations for the inlet specifier, to assist in choosing the correct type of filtration for inlets for areas likely to be affected by dust, and identify risk factors with specific types of inlet filter systems in these locations.

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