Tidal influence on behaviour of a coastal aquifer adjacent to a low-relief estuary

Mao, X., Enot, P., Barry, D. A., Li, L., Binley, A. and Jeng, D. -S. (2006) Tidal influence on behaviour of a coastal aquifer adjacent to a low-relief estuary. Journal of Hydrology, 327 1-2: 110-127. doi:10.1016/j.jhydrol.2005.11.030


Author Mao, X.
Enot, P.
Barry, D. A.
Li, L.
Binley, A.
Jeng, D. -S.
Title Tidal influence on behaviour of a coastal aquifer adjacent to a low-relief estuary
Journal name Journal of Hydrology   Check publisher's open access policy
ISSN 0022-1694
Publication date 2006-07-30
Year available 2006
Sub-type Article (original research)
DOI 10.1016/j.jhydrol.2005.11.030
Open Access Status Not yet assessed
Volume 327
Issue 1-2
Start page 110
End page 127
Total pages 18
Place of publication Amsterdam
Publisher Elsevier Science Bv
Language eng
Abstract The tidal influence on groundwater hydrodynamics, salt-water intrusion and submarine groundwater discharge from coastal/estuarine aquifers is poorly quantified for systems with a mildly sloping beach, in contrast to the case where a vertical beach face is assumed. We investigated the effect of beach slope for a coastal aquifer adjacent to a low-relief estuary, where industrial waste was emplaced over the aquifer. The waste was suspected to discharge leachate towards the estuary. Field observations at various locations showed that tidally induced groundwater head fluctuations were skewed temporally. Frequency analysis suggested that the fluctuation amplitudes decreased exponentially and the phase-tags increased Linearly for the primary tidal signals as they propagated inland. Salinisation zones were observed in the bottom part of the estuary and near the beach surface. Flow and transport processes in a cross-section perpendicular to the estuary were simulated using SEAWAT-2000, which is capable of depicting density-dependent flow and multi-species transport. The simulations showed that the modelled water table fluctuations were in good agreement with the monitored data. Further simulations were conducted to gain insight into the effects of beach slope. In particular the limiting case of a vertical beach face was considered. The simulations showed that density difference and tidal forcing drive a more complex hydrodynamic pattern for the mildly sloping beach than the vertical beach, as well as a profound asymmetry in tidally induced water table fluctuations and enhanced salt-water intrusion. The simulation results also indicated that contaminant transport from the aquifer to the estuary was affected by the tide, where for the mildly sloping beach, the tide tended to intensify the vertical mass exchange in the vicinity of the shorelines, (c) 2005 Elsevier B.V. All rights reserved.
Keyword Engineering, Civil
Geosciences, Multidisciplinary
Water Resources
Seawat-2000
Salt-water Intrusion
Water Table Fluctuation
Numerical Model
Submarine Groundwater Discharge
Water-table Fluctuations
Unconfined Aquifers
Field Observations
Surface-water
Beach
Sea
Transport
Intrusion
Dynamics
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Civil Engineering Publications
 
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Created: Tue, 14 Aug 2007, 02:25:17 EST