Tidal Inlet Equilibrium Area Experiments, Inlet Laboratory Investigations

Seabergh, William C.; King, David B.; Stephens, Bettye E.

doi:10.21236/ada397931

Cited by 9 publications

(17 citation statements)

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“…Tidal prism in the novel experiments scaled similarly to cross-sectional area as in natural estuaries (Byrne et al, 1980;Jarrett, 1976;O'Brien, 1969) and previous scale experiments (Mayor-Mora, 1977;Seabergh et al, 2001; Figure 15). However, while some numerical studies (Lanzoni & Seminara, 2002;Zhou et al, 2014) and scale experiments (Stefanon et al, 2010(Stefanon et al, , 2012 show that the PΩ relation (Equation 3) is approached in the initial phase of morphological evolution (not included in Figure 15), this initial imbalance is absent in this study.…”

Section: Mud and Vegetation Effects On Estuary Infillingmentioning

confidence: 58%

Building and Raising Land: Mud and Vegetation Effects in Infilling Estuaries

et al. 2022

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Many Holocene estuaries were infilled to form convergent, single‐channel systems, while others remained partially or wholly unfilled. This difference in the degree of infilling depends partly on the balance between fluvial and coastal sediment input and the hydrodynamics that can export sediment. However, it remains unclear to what degree this balance is tipped by mud supply and eco‐engineering vegetation, and by what planform patterns the infilling proceeds. This study aims to explore experimentally how mud and vegetation change the degree and process of infilling, elevate and merge bars above intertidal levels and affect the planform of estuaries. To this end, three experiments were conducted in the Metronome, a flume that tilts periodically to create tidal currents, wherein forced tidal asymmetry resulted in net importing estuaries. In the second and third experiments, mud was supplied and in the third experiment seedlings were released of three vegetation species with eco‐engineering traits at a laboratory scale. With only sand, the estuary fills sufficiently to form a multi‐channel pattern with intertidal bars. Both mud and vegetation settle on intertidal bars and on the fluvial bay‐head delta, thereby contributing to bar stabilization and further estuary infilling, pointing at effective strategies to keep up with future sea‐level rise. This reduces channel mobility and effectively narrows the summed subtidal channel width toward an ideally converging funnel shape. This seems especially effective where vegetation stabilizes the mud. The experiments suggest that a range of steady states exists between the end‐members of an unfilled and a completely infilled, ideal estuary.

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Section: Mud and Vegetation Effects On Estuary Infillingmentioning

confidence: 58%

Building and Raising Land: Mud and Vegetation Effects in Infilling Estuaries

et al. 2022

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“…Specifically, Hughes [] found that data obtained by analyzing small tidal inlets [ Byrne et al , ] and small‐scale movable‐bed experiments [ Mayor‐Mora , ; Seabergh et al , ] did not agree well with the traditional P ‐Ω relationship as found by Jarrett []. This disagreement suggested that this P ‐Ω relationship relied on additional physical parameters that might not vary significantly for the inlets studied by Jarrett but probably affected the smaller inlets.…”

Section: Discussionmentioning

confidence: 99%

“…The modified tidal prism C I P is plotted versus the inlet cross‐sectional area Ω for inlets of natural systems [ Jarrett , ; Byrne et al , ], laboratory experiments [ Mayor‐Mora , ; Seabergh et al , ; Stefanon et al , ], and the numerically modeled inlets based on ELS and NES simulations. The linear regression line is obtained by fitting the data sets of both field observations and laboratory experiments.…”

Section: Discussionmentioning

confidence: 99%

A comparative study of physical and numerical modeling of tidal network ontogeny

et al. 2014

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We investigate the initiation and long-term evolution of tidal networks by comparing controlled laboratory experiments and their associated scaling laws with outputs from a numerical model. We conducted numerical experiments at both the experimental laboratory scale (ELS) and natural estuary scale (NES) and compared these simulations with experimental data and field observations. Sensitivity tests show that initial bathymetry, frictional parametrization, sediment transport, and bed slope terms play an important role in determining the morphodynamic evolution and the final landscape. Consistent with experimental observations, the morphodynamic feedbacks between flow, sediment transport, and bathymetry gradually lead the system to a less dynamic state, finally reaching a stable network configuration. In both the ELS and NES simulations, the initially planar lagoon with large intertidal areas is subject to erosion, indicating ebb-dominance. Based on quantitative analyses of the ELS and the NES simulations (e.g., geometric characteristics and relationship between modified tidal prism and cross-sectional area), we conclude that numerical simulations are consistent with laboratory experiments and show that both type of models provide a realistic, albeit simplified, representation of natural systems. The combination of laboratory and numerical experiments also allowed us to explore the possibility of reaching a long-term morphodynamic equilibrium. Both the physical and numerical models approach a dynamic equilibrium characterized by negligible gradients in sediment fluxes. The equilibrium configuration appears to be consistent with traditional relationships linking tidal prism and cross-sectional area of the inlet. Finally, this contribution highlights the significance of complementary research between experimental and numerical modeling in investigating long-term morphodynamics of tidal networks.

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“…Les hauteurs d'eau sont relevées à la fois dans l'océan et dans la baie et les vitesses dans le chenal, pour être comparées avec les données expérimentales de Seabergh et al 14 . Ces données sont regroupées dans le tableau ou le déphasage, .s -1 est plus satisfaisant.…”

Section: Calageunclassified

Modélisation morphodynamique d’une embouchure lagunaire

Fiere¹,

Johnson²,

Niemann³

2006

IXèmes Journées, Brest

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RésuméL'objet de cette communication est la modélisation numérique de l'évolution morphologique d'une embouchure lagunaire forcée par les courants de marée. Une lagune schématique est définie à l'aide du modèle DHI d'évolution morphologique MIKE 21 CAMS qui rassemble les modules de calcul hydrodynamique, de propagation des vagues et de transport sédimentaire. Ces moteurs de calculs en différence finies sont combinés afin de simuler l'évolution de la bathymétrie dans le temps. Une fois le modèle numérique calé sur les données expérimentales de Seabergh et al.14 , différents essais mettent en valeurs l'évolution du chenal et notamment l'érosion sur les pentes transversales au courant, érosion responsable de son élargissement. L'importance de cet élargissement est un paramètre clé pour la stabilité d'une lagune. Les sections en travers simulées sont donc comparées avec celles mesurées en laboratoire pour des cas de courant seul. Dans un deuxième temps les différents résultats obtenus avec le modèle CAMS sont confrontés avec le nouveau modèle FM. Ce dernier résout les équations couplées de courants et de vagues par la théorie des volumes finis, sur un maillage non structuré (FM = Flexible Mesh) et offre de nouvelles possibilités pour la modélisation numérique 2D. AbstractThis paper deals with the morphodynamic modelling of cross-section stability at tidal inlets. An idealized inlet is built with the DHI's numerical tool MIKE 21 CAMS which is a control shell that combines MIKE 21 finite different models for waves, flow and sand transport with a bed level update scheme to model the morphological evolution in time. Once the model is calibrated according to the experiments of Seabergh et al.14 , several tests are carried out to show the inlet evolution and particularly the slope erosion which is responsible for its widening. This enlargement is a key parameter for the cross-section stability of an inlet. Simulated cross-sections are thus compared to the results of the lab in pure current cases. In a second time the computations obtained with MIKE 21 CAMS are confronted with those from the DHI's new model FM. This integrates the coupled equations for current and waves using the finite volume theory and allows new possibilities in the 2D numerical modelling.

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Tidal Inlet Equilibrium Area Experiments, Inlet Laboratory Investigations

Cited by 9 publications

References 0 publications

Building and Raising Land: Mud and Vegetation Effects in Infilling Estuaries

Building and Raising Land: Mud and Vegetation Effects in Infilling Estuaries

A comparative study of physical and numerical modeling of tidal network ontogeny

Modélisation morphodynamique d’une embouchure lagunaire

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