Modelling Cohesive Sediment Dynamics in the Marine Environment

Kombiadou, Katerina; Krestenitis, Yannis Ν.

doi:10.5772/51061

Cited by 2 publications

(2 citation statements)

References 48 publications

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“…The observations lead to the conclusion that the sedimentation foci are also reflected in the density profiles. Samples from BB exhibit sediments mostly in the preconsolidated and consolidated stage, following a classification stated by Kombiadou and Krestenitis (2013), while sediments taken from NH are classified as (mobile and stationary) mud.…”

Section: Densitymentioning

confidence: 99%

Spatial and Temporal Variability of Bed Exchange Characteristics of Fine Sediments From the Weser Estuary

Patzke

Nehlsen²,

Fröhle³

et al. 2022

Front. Earth Sci.

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Sedimentation of fine-grained sediments in estuaries is a natural physical phenomenon influenced by biogeochemical processes. In the estuarine turbidity maximum (ETM), enhanced net deposition of sediments is observed even in areas with higher hydrodynamic exposure, such as the navigational channel. Maintenance dredging is a common method to maintain the navigational channel, which requires large financial effort and has potential negative impacts on the environment. Research at the Institute for River and Coastal Engineering addresses the challenge of understanding the processes leading to net sedimentation and accumulation in estuarine navigational channels in reach of the ETM. In this contribution, investigations of bed exchange properties of estuarine cohesive sediments conducted in field and laboratory studies are presented. The results provide rarely available and estuary-specific parameters characterizing sediment transport, mainly related to erosion processes. By performing field campaigns within the ETM of the Weser estuary, cores of freshly deposited sediments have been sampled from two sites (Blexer Bogen and Nordenham) along the center of the navigational channel. Sediment characteristics (grain size distribution, water content, loss on ignition, density profiles) have been derived, and the erodibility of the deposits is investigated both quasi in situ and in the laboratory using an erosion microcosm system. Erodibility experiments are run in a closed system so sediment concentration above the lutocline increases during the experiment. This is a unique feature of this study, and it is expected to produce more natural characteristics of net erosion. By proving the reproducibility of the natural structure of the deposited sediments (stratification and density profiles) in the laboratory, systematic studies for analyzing the sensitivity of determined parameters (shear stresses and erosion rates) to varying environmental conditions (settling conditions and density) could be performed. Temporal development of suspended sediment concentration and erosion rates is the main result of the erodibility experiments, from which we derive bandwidths for erosion parameters, like floc erosion rate, critical shear for floc erosion, and critical shear for mass erosion.

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Section: Densitymentioning

confidence: 99%

Spatial and Temporal Variability of Bed Exchange Characteristics of Fine Sediments From the Weser Estuary

Patzke

Nehlsen²,

Fröhle³

et al. 2022

Front. Earth Sci.

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“…Therefore, there is still no reliable relationship based on sediment or environmental properties which can hold in general and for different situations. Thus, they must either be measured or calibrated (e.g., [59][60][61][62][63]).…”

Section: Numerical Modelmentioning

confidence: 99%

Improvement in the Sediment Management of a Lagoon Harbor: The Case of Marano Lagunare, Italy

Bosa

Petti

Pascolo

2021

Water

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Port silting is a common and natural process which often causes serious inconveniences for safe navigation and requires expensive dredging operations to keep the port operative. Sediment deposition is closely related to the exchange water between the basin and the surrounding environment; one way to limit deposits is by reducing the flow entering the port. However, this may be in contrast with the need for adequate sediment quality, which in turn is closely related to an appropriate water current. This seems to be particularly important in lagoon environments, where sediments are often polluted, making its disposal more complicated and costly. The present paper investigates the situation of the port of Marano Lagunare (Italy) by means of a bidimensional morphological-hydrodynamic and spectral coupled model. To reduce the sediment input into the port, the closure of a secondary port entrance is usually suggested. However, this work demonstrates that a complete dredging of the secondary port inlet allows for an increase in water circulation or efficiency renewal, which ensures a better oxygenation at the bottom of the canals.

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Modelling Cohesive Sediment Dynamics in the Marine Environment

Cited by 2 publications

References 48 publications

Spatial and Temporal Variability of Bed Exchange Characteristics of Fine Sediments From the Weser Estuary

Spatial and Temporal Variability of Bed Exchange Characteristics of Fine Sediments From the Weser Estuary

Improvement in the Sediment Management of a Lagoon Harbor: The Case of Marano Lagunare, Italy

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