Non-linear tidal distortion in shallow well-mixed estuaries: a synthesis

Friedrichs, Carl T.; Aubrey, David G.

doi:10.1016/0272-7714(88)90082-0

Cited by 598 publications

(617 citation statements)

References 9 publications

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“…Higher tidal harmonics of the fundamental tidal periodicities are created by non-linear tidal propagation (Pingree and Griffiths, 1979). Assessing the level of tidal asymmetry has previously been investigated by means of estuary form analysis (Dronkers, 1998) and by means of tidal analysis comparing the M 2 and M 4 tidal constituents (Friedrichs and Aubrey, 1988). 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 .…”

Section: Tidal Asymmetrymentioning

confidence: 99%

“…Together with other higher order harmonics the M 4 is responsible for distortion of the tidal wave. Indeed it has been found to be the main contributor to tidal distortion (asymmetry) in coastal areas (Friedrichs and Aubrey, 1988). An investigation into the spatial variability of the M 4 tide in the Irish Sea is presented in Davies and Lawrence (1994).…”

Section: Realistic Model Bathymetrymentioning

confidence: 99%

“…Conversely, 'top-down' models use basin scale morphological behaviour such as analysing geometrical relationships to predict changes. Examples of this include regime relationships like the tidal prism relationships of O'Brien (1939) and Eyesink (1991), form analysis (Prandle and Rahman, 1980) and tidal asymmetry analysis (Dronkers, 1986;Friedrichs and Aubrey, 1988). A mixture of these two approaches is seen in semi-empirical or 'hybrid' models which combine the complex 'bottom-up' method for simulating hydrodynamics, but use empirical formulae to simulate morphological changes (for example, van Dongeren and de Vriend, 1994).…”

Section: Introduction and Objectivesmentioning

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

128

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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: Realistic Model Bathymetrymentioning

confidence: 99%

Section: Introduction and Objectivesmentioning

confidence: 99%

See 1 more Smart Citation

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

Moore¹,

Wolf²,

Souza³

et al. 2009

Geomorphology

128

View full text Add to dashboard Cite

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“…They are defined by the presence of tidal creeks, marsh plains, and emergent vegetation that absorb energy, exchange nutrients and sediment, and generally produce system carbon (Mitsch and Gosselink 2007;Kneib et al 2008). Process feedbacks between tide, sediment, and vegetation dynamics make each component at once system driver, and system function (Reed 1988;Friedrichs and Aubrey 1988;Silvestri and Marani 2004;Kirwan and Murray 2007). These interactions generate sharp residence time and scalar gradients and ecotonal diversity (McLusky and M. Elliott 2004).…”

Section: Introductionmentioning

confidence: 99%

“…However, estuarine tides are distorted by processes that compete to produce either faster flood or ebb currents (Friedrichs and Aubrey 1988). When the duration of ebb tide is shorter than flood tide, stronger peak ebb currents compensate and the system is considered ebb dominant.…”

Section: Introductionmentioning

confidence: 99%

Broad Timescale Forcing and Geomorphic Mediation of Tidal Marsh Flow and Temperature Dynamics

Enright

Culberson

Burau

2013

Estuaries and Coasts

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Tidal marsh functions are driven by interactions between tides, landscape morphology, and emergent vegetation. Less often considered are the diurnal pattern of tide extremes and seasonal variation of solar insolation in the mix of tidal marsh driver interactions. This work demonstrates how high-frequency hydroperiod and water temperature variability emerges from disparate timescale interactions between tidal marsh morphology, tidal harmonics, and meteorology in the San Francisco Estuary. We compare the tidal and residual flow and temperature response of neighboring tidal sloughs, one possessing natural tidal marsh morphology, and one that is modified for water control. We show that the natural tidal marsh is tuned to lunar phase and produces tidal and fortnight water temperature variability through interacting tide, meteorology, and geomorphic linkages. In contrast, temperature variability is dampened in the modified slough where overbank marsh plain connection is severed by levees. Despite geomorphic differences, a key finding is that both sloughs are heat sinks in summer by latent heat flux-driven residual upstream water advection and sensible and long-wave heat transfer. The precession of a 335-year tidal harmonic assures that these dynamics will shift in the future. Water temperature regulation appears to be a key function of natural tidal sloughs that depends critically on geomorphic mediation. We investigate approaches to untangling the relative influence of sun versus tide on residual water and temperature transport as a function of system morphology. The findings of this study likely have ecological consequences and suggest physical process metrics for tidal marsh restoration performance.

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Linking channel hydrology with riparian wetland accretion in tidal rivers

2014

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[1] The hydrologic processes by which tide affects river channel and riparian morphology within the tidal freshwater zone are poorly understood yet are fundamental to predicting the fate of coastal rivers and wetlands as sea level rises. We investigated patterns of sediment accretion in riparian wetlands along the nontidal through oligohaline portion of two coastal plain rivers in Maryland, U.S., and how flow velocity, water level, and suspended sediment concentration (SSC) in the channel may have contributed to those patterns. Sediment accretion was measured over a 1 year period using artificial marker horizons, channel hydrology was measured over a 1 month period using acoustic Doppler current profilers, and SSC was predicted from acoustic backscatter. Riparian sediment accretion was lowest at the nontidal sites (mean and standard deviation = 8 ± 8 mm yr À1 ), highest at the upstream tidal freshwater forested wetlands (TFFW) (33 ± 28 mm yr À1 ), low at the midstream TFFW (12 ± 9 mm yr À1 ), and high at the oligohaline (fresh-to-brackish) marshes (19 ± 8 mm yr À1 ). Channel maximum flood and ebb velocity was twofold faster at the oligohaline than tidal freshwater zone on both tidal rivers, corresponding with the differences in in-channel SSC: The oligohaline zone's SSC was more than double the tidal freshwater zone's and was greater than historical SSC at the nontidal gages. The tidal wave characteristics differed between rivers, leading to significantly greater in-channel SSC during floodplain inundation in the weakly convergent than the strongly convergent tidal river. High sediment accretion at the upstream TFFW was likely due to high river discharge following a hurricane.

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Non-linear tidal distortion in shallow well-mixed estuaries: a synthesis

Cited by 598 publications

References 9 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

Broad Timescale Forcing and Geomorphic Mediation of Tidal Marsh Flow and Temperature Dynamics

Linking channel hydrology with riparian wetland accretion in tidal rivers

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