Groundwater flow and salt transport in a subterranean estuary driven by intensified wave conditions

Robinson, Clare, Xin, Pei, Li, Ling and Barry, D. A. (2014) Groundwater flow and salt transport in a subterranean estuary driven by intensified wave conditions. Water Resources Research, 50 1: 165-181. doi:10.1002/2013WR013813


Author Robinson, Clare
Xin, Pei
Li, Ling
Barry, D. A.
Title Groundwater flow and salt transport in a subterranean estuary driven by intensified wave conditions
Journal name Water Resources Research   Check publisher's open access policy
ISSN 0043-1397
1944-7973
Publication date 2014
Year available 2014
Sub-type Article (original research)
DOI 10.1002/2013WR013813
Open Access Status DOI
Volume 50
Issue 1
Start page 165
End page 181
Total pages 17
Place of publication Hoboken, NJ United States
Publisher Wiley-Blackwell Publishing, Inc.
Collection year 2015
Language eng
Subject 2312 Water Science and Technology
Abstract A numerical study, based on a density-dependent variably saturated groundwater flow model, was conducted to investigate flow and salt transport in a nearshore aquifer under intensified wave conditions caused by offshore storms. Temporally varying onshore hydraulic gradients due to wave setup were determined as the seaward boundary condition for the simulated aquifer. The results showed a rapid increase in influxes across the aquifer-ocean interface in response to the wave event followed by a more gradual increase in effluxes. The upper saline plume first widened horizontally as the wave setup point moved landward. It then expanded vertically with recirculating seawater pushed downward by the wave-induced hydraulic gradient. The time for the salt distribution to return to the prestorm condition was up to a hundred days and correlated strongly with the time for seawater to recirculate through the aquifer. The pathways of recirculating seawater and fresh groundwater were largely modified by the wave event. These pathways crossed through the same spatial locations at similar times, indicating significant salt-freshwater mixing. The flow and salt transport dynamics were more responsive to wave events of longer duration and higher intensity, especially in more permeable aquifers with lower fresh groundwater discharge. Despite their larger response, aquifers with higher permeability and beach slope recovered more rapidly postevent. The rapid recovery of the flows compared with the salinity distribution should be considered in field data interpretation. Due to their long-lasting impact, wave events may significantly influence the geochemical conditions and the fate of chemicals in a subterranean estuary. Key Points Intensified waves perturb flow and transport in a subterranean estuary Lengthy period (months) for salinity distribution to recover from a wave event Exchange fluxes and flows respond and recover rapidly following a wave event
Keyword Aquifer ocean exchange
Coastal aquifer
Numerical modeling
Submarine Groundwater Discharge
Wave effects
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Civil Engineering Publications
Official 2015 Collection
 
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