Morphology and asymmetry of the vertical tide in the Westerschelde estuary

Wang, Zheng Bing; Jeuken, M.; Gerritsen, H.; Vriend, H.J. de; Kornman, B.A.

doi:10.1016/s0278-4343(02)00134-6

Cited by 138 publications

(123 citation statements)

References 13 publications

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“…The M 2 constituent is the dominant lunar semi-diurnal tidal constituent (M for moon, subscript 2 for twice daily in frequency) and the M 4 constituent is a quarterdiurnal non-linear harmonic overtide of M 2 . The overall effect of tidal asymmetry on morphology has been considered in some detail in Wang et al, 2002. If the ebb duration is longer than the flood, continuity arguments state that there should be a shorter, more intense (higher velocity) flood flow . Higher flood velocities result in increased shear at the sea bed during the flood compared to the ebb.…”

Section: Tidal Asymmetrymentioning

confidence: 99%

“…Both the navigability of the estuarine channels and geological evolution of estuaries are affected by tidal asymmetry . Tidal asymmetry is, therefore, a controlling factor for morphological development in tidal basins (Wang et al, 2002). Consequently, it is of paramount importance when studying the sediment dynamics of an estuary to understand the nature of the tidal propagation therein.…”

Section: Tidal Asymmetrymentioning

confidence: 99%

“…Estuarine hypsometry refers to the distribution of basin surface area to elevation and has been suggested as a controlling factor of the vertical tidal propagation (Boon and Byrne, 1981). Several studies have investigated the application of empirical formulae to hypsometrical relationships, following the pioneering work of Strahler (1952) (such as Boon, 1975;Boon and Byrne, 1981;Wang et al, 2002). Several approaches are discussed in detail in Townend (2008).…”

Section: Idealised Modellingmentioning

confidence: 99%

“…An immature estuary will have γ=3.5-5.0 and be little infilled (having reasonably vertical sides) and be associated with flood dominance. Here the system may be shallow but is likely to have large inter-tidal basin storage (Wang et al, 2002). Furthermore, flood dominance is likely where bottom friction influences are important, as this contributes to overtides (higher harmonics), which will be further discussed in sections 4.2.1 and section 5.…”

Section: Modern Dee Estuary Bathymetry -Lidar Surveysmentioning

confidence: 99%

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Morphological evolution of the Dee Estuary, Eastern Irish Sea, UK: A tidal asymmetry approach

Moore¹,

Wolf²,

Souza³

et al. 2009

Geomorphology

127

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Asymmetry in the tide (unequal ebb and flood duration) is a dominant factor in causing residual sediment transport and morphological changes in estuaries. The evolution of estuarine morphology is a process of dynamic equilibrium in the shortterm, while these features are ephemeral in the long-term. In this study we investigate the spatial distribution of tidal distortion and asymmetry of the Dee estuary, UK, by 3-dimensional numerical modelling methods. High resolution LIDAR surveys are used to underpin and explain our numerical modelling results in terms of basin hypsometry and areas of recent erosion and deposition. Harmonic analysis of the numerical modelling results showed that the shallower intertidal areas (sand and mud banks) were the most tidally asymmetric, showing flood dominance. The main navigation channels showed some ebb dominance but the tides here were relatively undistorted. This overall flood dominance is likely to induce net sediment import to the Dee, which explains known historical morphological changes (large scale accretion over the last 2 centuries) and also recent morphological changes as seen from the LIDAR surveys (which show predominantly net accretion between 2003 and 2006). Hypsometrical analysis suggests the Dee may be approaching equilibrium, and that the flood dominance and sedimentation rate may therefore decrease in the future. In an infilling estuary, an increase in the area and elevation of tidal flats can eventually shift an estuary towards ebb dominance, as shown by previous research and by 'idealised estuary' modelling results presented in this study. The large tidal amplitude to hydraulic depth ratio of the Dee, however, suggests that the tidal flats would have to be very extensive indeed for this to occur. 1

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Section: Tidal Asymmetrymentioning

confidence: 99%

Section: Tidal Asymmetrymentioning

confidence: 99%

Section: Idealised Modellingmentioning

confidence: 99%

Section: Modern Dee Estuary Bathymetry -Lidar Surveysmentioning

confidence: 99%

See 2 more Smart Citations

Morphological evolution of the Dee Estuary, Eastern Irish Sea, UK: A tidal asymmetry approach

Moore¹,

Wolf²,

Souza³

et al. 2009

Geomorphology

127

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“…Tidal velocity asymmetries, defined as occurring when the duration of the outflowing tide exceeds that of the in-flowing tide, have been observed elsewhere; these are mainly due to the combined effects of the mean basin depth, the depths of intratidal shoals and the relative prism volume. In some systems the wind also can modify the difference in the duration of the ebb and flood tides (WANG et al, 2002); those authors also highlighted the importance of asymmetry in the sediment transport dominated by suspended load.…”

Section: Discussionmentioning

confidence: 99%

Export of materials along a tidal river channel that links a coastal lagoon to the adjacent sea

et al. 2012

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A B S T R A C TIntratidal variability and flux of salt, chlorophyll-a and suspended materials were evaluated in a shallow tropical tidal channel linking a coastal lagoon to the western Gulf of Mexico. Velocity, temperature and conductivity were used to calculate the fluxes. Data were recorded during three tidal velocity cycles (tvc) under extreme river discharge conditions. Chlorophyll-a and suspended materials were determined below the surface. In both seasons (dry and rainy), the flow was ebbdominated and with longer duration than when in flood. Maximum current velocities were 0.30 m s -1 in May (dry season) and 0.60 m s -1 in September (rainy season). In the dry season the mean chlorophyll-a export was of 7.56 Kg over tvc while the import was of 3.32 Kg. In the rainy season mean export (47.3 Kg) was 6 times greater than the import (7.93 Kg over tvc). Phytoplankton was dominated by organisms of marine origin. The mean of exported, suspended materials in the rainy season (111.3 Kg) was 4.6 times greater (859 Kg) than that in the dry season (184.7 Kg over tvc). Tidal velocity asymmetry is an effective mechanism of exportation, introducing relatively warm and saltier water into the river through the tidal channel. R E S U M OA variabilidade intramaré, o fluxo de salinidade, a clorofila-a e material em suspensão foram avaliados em um canal superficial de maré tropical em uma lagoa costeira ao oeste do Golfo do México. Os dados de velocidade, temperatura e condutividade foram usados para cálculo dos fluxos durante três ciclos de velocidades das marés (tvc) sob condições extremas de descarga. A Clorofila-a e material em suspensão foram determinados abaixo em subsuperfície. Em ambas as estações (seca e chuvosa), o fluxo dominante foi durante o refluxo e com duração maior durante o fluxo de entrada. A máxima velocidade encontrada foi 0.30 m s -1 em maio (estação seca) e 0.60 m s -1 em setembro (estação chuvosa). Durante a época seca foram exportadas 7.56 Kg de clorofila-a, enquanto a importação foi de 3.32 Kg. Durante a temporada de chuva a média exportada (47.3 Kg) foi seis vezes maior que a importada (7.93 Kg). A concentração media de material em suspensão exportado durante a época de chuvas (111.3 Kg) foi 4.6 vezes maior (859 Kg) que durante estação de seca (184.7 Kg). A assimetria das marés é um mecanismo efetivo de transporte, introduzindo no rio águas relativamente quentes e mais salinas através do canal de maré.

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Propagation of tidal waves up in Yangtze Estuary during the dry season

Tong

Lee

et al. 2015

JGR Oceans

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Tide is one of the most important hydrodynamic driving forces and has unique features in the Yangtze Estuary (YE) due to the complex geometry of third-order bifurcations and four outlets. This paper characterizes the tidal oscillations, tidal dampening, tidal asymmetry, and tidal wave propagation, which provides insights into the response of the estuary to tides during the dry season. The structural components of tidal oscillations are initially attained by tidal analysis. The increasingly richer spectrum inside the estuary shows an energy transfer corresponding to the generation and development of nonlinear overtides and compound tides. A 2-D numerical model is further set up to reproduce tidal dynamics in the estuary. The results show that the estuary is a strongly dissipative estuary with a strong nonlinear phenomenon. Three amplifications are presented in the evolution process of tidal ranges due to the channel convergence. Tidal asymmetry is spatiotemporally characterized by the M 4 /M 2 amplitude ratio, the 2M 2-M 4 phase difference, and the flood-ebb duration-asymmetry parameter, and the estuary tends to be flood-dominant. There exists mimic standing waves with the phase difference of the horizontal and vertical tide close to 908 when tidal wave propagates into the estuary, especially during the neap tide. In addition, the differences in tidal distortion, tidal ranges, and tidal waves along the two routes in the South Branch (S-B) suggest the branched system behaves differently from a single system.

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Morphology and asymmetry of the vertical tide in the Westerschelde estuary

Cited by 138 publications

References 13 publications

Morphological evolution of the Dee Estuary, Eastern Irish Sea, UK: A tidal asymmetry approach

Morphological evolution of the Dee Estuary, Eastern Irish Sea, UK: A tidal asymmetry approach

Export of materials along a tidal river channel that links a coastal lagoon to the adjacent sea

Propagation of tidal waves up in Yangtze Estuary during the dry season

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