Groundwater-level variation during semidiurnal spring tidal cycles on a sandy beach

Lanyon, JA; Eliot, Ian; Clarke, D.J.

doi:10.1071/mf9820377

Cited by 77 publications

(35 citation statements)

References 12 publications

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“…At the same time however, these high-frequency components have a relatively high decay rate and therefore as time progresses they disappear first leaving the slower moving, lower-frequency components which contribute to the observed time lag between peaks. [36] The pore pressure wave at all locations bears some resemblance to that observed for tidal water table waves [e.g., Lanyon et al, 1982;Nielsen, 1990;Raubenheimer et al, 1999] in that they are temporally skewed with a steep rise in pressure followed by a more gradual decline [see also Hegge and Masselink, 1991]. For the tidal case this has been explained by the beach matrix being able to ''fill more easily than it can drain'' [e.g., Lanyon et al, 1982].…”

Section: Pore Pressure Wave Propagation Landward Of the Runup Limitmentioning

confidence: 99%

“…[36] The pore pressure wave at all locations bears some resemblance to that observed for tidal water table waves [e.g., Lanyon et al, 1982;Nielsen, 1990;Raubenheimer et al, 1999] in that they are temporally skewed with a steep rise in pressure followed by a more gradual decline [see also Hegge and Masselink, 1991]. For the tidal case this has been explained by the beach matrix being able to ''fill more easily than it can drain'' [e.g., Lanyon et al, 1982]. More accurately the steep rise is a result of the rising shoreline bringing the forcing closer to the observation point along the sloping boundary, which increases the curvature in the water table and in turn induces a strong inflow into the porous matrix (Figure 7).…”

Section: Pore Pressure Wave Propagation Landward Of the Runup Limitmentioning

confidence: 99%

“…[4] Most previous investigations into the coupling of the ocean with coastal aquifers have been based on tidally induced water table fluctuations [e.g., Lanyon et al, 1982;Nielsen, 1990;Baird and Horn, 1996;Li et al, 1997a;Baird et al, 1998;Raubenheimer et al, 1999] although field observations from exposed coasts have shown that wave forcing is at least as important [e.g., Kang et al, 1994;Nielsen, 1999;Cartwright et al, 2004a]. Until recently, the coupling of the swash zone with the porous beach matrix had received relatively little attention.…”

Section: Introductionmentioning

confidence: 99%

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Swash‐aquifer interaction in the vicinity of the water table exit point on a sandy beach

et al. 2006

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[1] The coupling of sandy beach aquifers with the swash zone in the vicinity of the water table exit point is investigated through simultaneous measurements of the instantaneous shoreline (swash front) location, pore pressures and the water table exit point. The field observations reveal new insights into swash-aquifer coupling not previously gleaned from measurements of pore pressure only. In particular, for the case where the exit point is seaward of the observation point, the pore pressure response is correlated with the distance between the exit point and the shoreline in that when the distance is large the rate of pressure drop is fast and when the distance is small the rate decreases. The observations expose limitations in a simple model describing exit point dynamics which is based only on the force balance on a particle of water at the sand surface and neglects subsurface pressures. A new modified form of the model is shown to significantly improve the model-data comparison through a parameterization of the effects of capillarity into the aquifer storage coefficient. The model enables sufficiently accurate predictions of the exit point to determine when the swash uprush propagates over a saturated or a partially saturated sand surface, potentially an important factor in the morphological evolution of the beach face. Observations of the shoreward propagation of the swash-induced pore pressure waves ahead of the runup limit shows that the magnitude of the pressure fluctuation decays exponentially and that there is a linear increase in time lags, behavior similar to that of tidally induced water table waves. The location of the exit point and the intermittency of wave runup events is also shown to be significant in terms of the shore-normal energy distribution. Seaward of the mean exit point location, peak energies are small because of the saturated sand surface within the seepage face acting as a ''rigid lid'' and limiting pressure fluctuations. Landward of the mean exit point the peak energies grow before decreasing landward of the maximum shoreline position.

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Section: Pore Pressure Wave Propagation Landward Of the Runup Limitmentioning

confidence: 99%

Section: Pore Pressure Wave Propagation Landward Of the Runup Limitmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Swash‐aquifer interaction in the vicinity of the water table exit point on a sandy beach

et al. 2006

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“…Early work examining the influence of tides on groundwater dynamics in CUAs focused mainly on tide-induced watertable fluctuations [e.g., Lanyon et al, 1982;Parlange et al, 1984;Nielsen, 1990;. 13 However, over the last decade major research efforts were devoted to understanding the influence of tides on water exchange across the CUA-ocean interface, and the flow and saltwater-freshwater mixing in a STE.…”

Section: Tidesmentioning

confidence: 99%

Groundwater dynamics in subterranean estuaries of coastal unconfined aquifers: Controls on submarine groundwater discharge and chemical inputs to the ocean

Robinson¹,

Xin²,

Santos³

et al. 2018

Advances in Water Resources

232

148

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Sustainable coastal resource management requires sound understanding of interactions between coastal unconfined aquifers and the ocean as these interactions influence the flux of chemicals to the coastal ocean and the availability of fresh groundwater resources. The importance of submarine groundwater discharge in delivering chemical fluxes to the coastal ocean and the critical role of the subterranean estuary (STE) in regulating these fluxes is well recognized. STEs are complex and dynamic systems exposed to various physical, hydrological, geological, and chemical conditions that act on disparate spatial and temporal scales. This paper provides a review of the effect of factors that influence flow and salt transport in STEs, evaluates current understanding on the interactions between these influences, and synthesizes understanding of drivers of nutrient, carbon, greenhouse gas, metal and organic contaminant fluxes to the ocean.Based on this review, key research needs are identified. While the effects of density and tides are well understood, episodic and longer-period forces as well as the interactions between multiple influences remain poorly understood. Many studies continue to focus on idealized nearshore aquifer systems and future work needs to consider real world complexities such as geological heterogeneities, and non-uniform and evolving alongshore and cross-shore morphology. There is also a significant need for multidisciplinary research to unravel the interactions between physical and biogeochemical processes in the STE, as most existing studies treat these processes in isolation. Better understanding of this complex and dynamic system can improve sustainable management of coastal water resources under the influence of anthropogenic pressures and climate change.

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“…These include field observations (e.g. Lanyon et al, 1982;Nielsen, 1990;Turner et al, 1997;Raubenheimer et al, 1999), laboratory experiments (e.g. Parlange et al, 1984;Nielsen et al, 1997;Boufadel et al, 1998;Ataie-Ashtiani et al, 1999;Cartwright et al, 2003), analytical modelling (e.g.…”

Section: Introductionmentioning

confidence: 99%

Influence of hysteresis on groundwater wave dynamics in an unconfined aquifer with a sloping boundary

Jazayeri

Cartwright

Perrochet

et al. 2015

Journal of Hydrology

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Please cite this article as: Jazayeri Shoushtari, S.M.H., Cartwright, N., Perrochet, P., Nielsen, P., Influence of hysteresis on groundwater wave dynamics in an unconfined aquifer with a sloping boundary, Journal of Hydrology (2015), doi: http://dx.doi.org/10. 1016/j.jhydrol.2015.11.020 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractIn this paper, the influence of hysteresis on water table dynamics in an unconfined aquifer was examined using a numerical model to solve Richards unsaturated flow equation.The model was subject to simple harmonic forcing across a sloping boundary with a seepage face boundary condition.Time series from both hysteretic and non-hysteretic models were subject to harmonic analysis to extract the amplitude and

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Groundwater-level variation during semidiurnal spring tidal cycles on a sandy beach

Cited by 77 publications

References 12 publications

Swash‐aquifer interaction in the vicinity of the water table exit point on a sandy beach

Swash‐aquifer interaction in the vicinity of the water table exit point on a sandy beach

Groundwater dynamics in subterranean estuaries of coastal unconfined aquifers: Controls on submarine groundwater discharge and chemical inputs to the ocean

Influence of hysteresis on groundwater wave dynamics in an unconfined aquifer with a sloping boundary

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