A study of non-linear tidal propagation in shallow inlet/estuarine systems Part I: Observations

Aubrey, David G.; Speer, Paul E.

doi:10.1016/0272-7714(85)90096-4

Cited by 307 publications

(203 citation statements)

References 14 publications

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“…5c, the relative phase of the horizontal velocity (φ u M 4 − 2φ u M 2 ) is shown. The relative phase between the semi-diurnal tidal velocity and its first overtide, i.e., the M 4 velocity, determines whether there is flood or ebb dominance (Aubrey and Speer 1985). If the relative phase is between −90…”

Section: Model Setupmentioning

confidence: 99%

The effect of tidal asymmetry and temporal settling lag on sediment trapping in tidal estuaries

2010

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Over decades and centuries, the mean depth of estuaries changes due to sea-level rise, land subsidence, infilling, and dredging projects. These processes produce changes in relative roughness (friction) and mixing, resulting in fundamental changes in the characteristics of the horizontal (velocity) and vertical tides (sea surface elevation) and the dynamics of sediment trapping. To investigate such changes, a 2DV model is developed. The model equations consist of the widthaveraged shallow water equations and a sediment balance equation. Together with the condition of morphodynamic equilibrium, these equations are solved analytically by making a regular expansion of the various physical variables in a small parameter. Using these analytic solutions, we are able to gain insight into the fundamental physical processes resulting in sediment trapping in an estuary by studying various forcings separately. As a case study, we consider the Ems estuary. Between 1980 and 2005, successive deepening of the Ems estuary has significantly altered the tidal and sediment dynamics. The tidal range and the surface sediment concentration has increased and the position of the turbidity zone has shifted into the freshwater zone. The model is used to determine the causes of these historical changes. It is found that the increase of the tidal amplitude toward the end of the embayment is the combined effect of the deepening of the estuary and a 37% and 50% reduction in the vertical eddy viscosity and stress parameter, respectively. The physical mechanism resulting in the trapping of sediment, the number of trapping regions, and their sensitivity to grain size are explained by careful analysis of the various contributions of the residual sediment transport. It is found that sediment is trapped in the estuary by a delicate balance between the M 2 transport and the residual transport for fine sediment (w s = 0.2 mm s −1 ) and the residual, M 2 and M 4 transports for coarser sediment (w s = 2 mm s −1 ). The upstream movement of the estuarine turbidity maximum into the freshwater zone in 2005 is mainly the result of changes in tidal asymmetry. Moreover, the difference between the sediment distribution for different grain sizes in the same year can be attributed to changes in the temporal settling lag.

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Section: Model Setupmentioning

confidence: 99%

The effect of tidal asymmetry and temporal settling lag on sediment trapping in tidal estuaries

2010

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“…Semidiurnal tides range from 1 to 1.5 m, and salinities range from 25 to 30 parts per thousand (ppt) [Aubrey and Speer, 1985;Roman et al, 1990]. Spartina altemifiora marsh comprises large islands in the center of the system (see Figure 1) and forms a nearly continuous but narrow fringe along the shore typically 3-10 m wide.…”

Section: Study Areamentioning

confidence: 99%

The discharge of nitrate‐contaminated groundwater from developed shoreline to marsh‐fringed estuary

Portnoy¹,

Nowicki²,

Roman³

et al. 1998

Water Resources Research

104

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Abstract. As residential development, on-site wastewater disposal, and groundwater contamination increase in the coastal zone, assessment of nutrient removal by soil and sedimentary processes becomes increasingly important. Nitrogen removal efficiency depends largely on the specific flow paths taken by groundwater as it discharges into nitrogen-limited estuarine waters. Shoreline salinity surveys, hydraulic studies, and thermal infrared imagery indicated that groundwater discharge into the Nauset Marsh estuary (Eastham, Massachusetts) occurred in high-velocity seeps immediately seaward of the upland-fringing salt marsh. Discharge was highly variable spatially and occurred through permeable, sandy sediments during low tide. Seepage chamber monitoring showed that dissolved inorganic nitrogen (principally nitrate) traversed nearly conservatively from the aquifer through shallow estuarine sediments to coastal waters at flux rates of 1-3 mmol m -2 h -1. A significant relationship between pore water NO3-N concentrations and NO3-N flux rates may provide a rapid method of estimating nitrogen loading from groundwater to the water column.

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“…Aubrey and Speer (1985), Friedrichs and Aubrey (1988) and Friedrichs and Madsen (1992) offshore tidal constituents, showing how the offshore tide becomes strongly distorted as it propagates into shallow estuarine systems. More recently, Stanev et al (2003) used a simple analytical theory to perform a volumetric analysis based on the basin hypsometry of the Wadden Sea, highlighting the fact that idealized models are helpful to understand the basic processes underlying advanced modeling.…”

Section: Introductionmentioning

confidence: 99%

Tsunami Response in Semienclosed Tidal Basins Using an Aggregated Model

et al. 2012

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An aggregated model to evaluate tsunami response in semienclosed water bodies is presented in this work. The model is based on one-dimensional shallow water equations and can include long-wave external forcing such as a tsunami. It has been successfully validated against experimental data from a physical model, and its predictions for a case study have been compared with results from the Cornell multigrid coupled tsunami (COMCOT) model. The model can be used as a predictive tool because a calibration using a theoretical value for expansion and contraction losses has been performed and differences with the typical calibration are less than 10%, which is considered acceptable. This allows using the model in the absence of measured data, which is very difficult to obtain in case of a tsunami event. A case study for the Gulf of Cádiz (Spain) has been simulated with the COMCOT model. The aggregated model predicted the response for a harbor more accurately than for estuarine systems with tidal flats. Nevertheless, the aggregated model has been demonstrated as a useful general tool to predict the response of semienclosed tidal basins to a tsunami event, and hybrid models coupling advanced models to simulate ocean tsunami propagation with the model presented here would be useful in developing coastal warning alert systems.

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A study of non-linear tidal propagation in shallow inlet/estuarine systems Part I: Observations

Cited by 307 publications

References 14 publications

The effect of tidal asymmetry and temporal settling lag on sediment trapping in tidal estuaries

The effect of tidal asymmetry and temporal settling lag on sediment trapping in tidal estuaries

The discharge of nitrate‐contaminated groundwater from developed shoreline to marsh‐fringed estuary

Tsunami Response in Semienclosed Tidal Basins Using an Aggregated Model

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