Numerical study of wave effects on groundwater flow and solute transport in a laboratory beach

Geng, Xiaolong; Boufadel, Michel C.; Xia, Yuqiang; Li, Hailong; Zhao, Lin; Jackson, Nancy L.; Miller, Richard S.

doi:10.1016/j.jconhyd.2014.07.001

Cited by 66 publications

(61 citation statements)

References 46 publications

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“…Waves drive large volumes of water exchange across the CUA-ocean interface [Li et al, 1999]. It is challenging to quantify wave-driven recirculation from field data alone, but estimates have been provided through numerical studies [e.g., Xin et al, 2010;Bakhtyar et al, 2011;Geng et al, 2014;Robinson et al, 2014;Xin et al, 2014].…”

Section: Wavesmentioning

confidence: 99%

“…Apart from this study and a few others including laboratory experiments [Boufadel et al, 2007;Heiss et al, 2015;Malott et al, 2016;Sous et al, 2016;Turner et al, 2016;Malott et al, 2017], investigations of wave-induced water exchange and groundwater dynamics have mostly been based on numerical simulations due to the challenge of measuring wave-induced groundwater flows in the field, including how to decouple wave and tide effects. Simulation of wave hydrodynamics coupled with densitydependent groundwater flow is computationally challenging but has been attempted by Bakhtyar et al [2012] and Geng et al [2014], who solved the Reynolds-Averaged Navier-Stokes (RANs) equations to simulate wave motion across a permeable beach surface. Both studies illustrate the 20 complexity of wave-induced groundwater flows induced by individual waves with Bakhtyar et al [2012] also demonstrating the additional impact of waves on beach morphology changes (e.g., wave-driven erosion/accretion).…”

Section: Wavesmentioning

confidence: 99%

“…Further, this ratio controls tide-induced recirculation rate and thus the rate of oxygen and organic matter delivery from the ocean to the STE. Even neglecting reactions, both tide and wave-induced circulations and associated saltwater-freshwater mixing can considerably reduce organic contaminant concentrations at the seabed via dilution [Robinson et al, 2007b;Robinson et al, 2009;Geng et al, 2014]. [Zhang et al, 2002;Brovelli et al, 2007;Bakhtyar et al, 2013;Liu et al, 2016].…”

Section: Organic Contaminantsmentioning

confidence: 99%

See 2 more Smart Citations

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

228

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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Section: Wavesmentioning

confidence: 99%

Section: Wavesmentioning

confidence: 99%

Section: Organic Contaminantsmentioning

confidence: 99%

See 1 more Smart Citation

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

228

148

View full text Add to dashboard Cite

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“…As discussed above, many studies focused on the sea-groundwater interactions in subsurface beach zones, which are substantially influenced by waves and tides, and are subject to density-dependent flow patterns [22,[25][26][27]. Additionally, the effects of fluctuating water levels due to waves are much more significant than the effects of variations in water densities as reported by Rimmer et al [28].…”

Section: Introductionmentioning

confidence: 99%

“…Xin et al [19] reported that wave-induced circulations increased both water flows in the nearshore zone and the exchange between the subterranean estuary and ocean, contributing 61% of the total submarine groundwater discharge for simulated conditions. Furthermore, tide (or wave)-driven groundwater table fluctuations in coastal regions were also shown to impact solute exchange across the sediment-surface water interface [19][20][21][22]. Chen and Pinder [1] reported that tidal fluctuations decrease the average concentrations of groundwater contaminants discharging into coastal waters.…”

Section: Introductionmentioning

confidence: 99%

Simulating the Effects of Lake Wind Waves on Water and Solute Exchange across the Lakeshore Using Hydrus-2D

Šimůnek

Wang

et al. 2017

Water

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Abstract:Wind waves, which frequently occur on large surface water bodies such as lakes, may temporarily alter flow patterns in a subsurface zone and the corresponding water and nutrient interactions between surface waters and shallow groundwaters. To better understand these processes, soil flume experiments were carried out to investigate wind wave-driven water and chloride interactions across the lake-groundwater interface, and the Hydrus-2D model was used to analyze and evaluate the observed experimental results. Two interaction cases between the lake and groundwater systems were considered: groundwater discharging into a lake (the GDL case), and lake water recharging groundwater (the LRG case). For comparison, no-wave conditions for both the GDL and LRG cases were also analyzed. The results revealed that, similarly to no-wave conditions, water and chloride exchange fluxes between the lake and groundwater systems under wave conditions occurred mainly within narrow bands near the intersection of the water level in the lake and the interface in both the GDL and LRG cases, and then exponentially decreased along the interface. Most water and chloride that infiltrated into the subsurface zone through the upper part of the interface during a wave crest returned to the lake through the lower part during a wave trough in both the GDL and LRG cases, creating local recirculation zones in the subsurface near the interface. Such recirculation produced a more frequent exchange of water and solute across the interface compared with those under no-wave conditions. During a one-day period after wind waves started, the total exchange fluxes of water and chloride to the lake decreased by 36.2% and 71.9%, respectively, compared to the no-wave conditions in the GDL case. In the LRG case, the total exchange water fluxes to the subsurface increased by 89.7%, while the total exchange chloride fluxes increased only slightly (4.5%) compared to the no-wave conditions due to the difference in chloride concentrations between the upper and lower parts of the interface. The sensitivity analysis revealed that the hydraulic conductivity of the lakeshore zone and the characteristics of the waves were important factors influencing water and chloride exchange between the lake and groundwater systems. The simulated results helped us to better understand water and solute interactions in the lake-groundwater system during windy periods.

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Numerical study of solute transport in shallow beach aquifers subjected to waves and tides

Geng

Boufadel

2015

JGR Oceans

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A numerical study was conducted to investigate the fate of solute in a laboratory beach in response to waves and tides. A new temporal upscaling approach labeled ''net inflow'' was introduced to address impacts of waves on solute transport within beaches. Numerical simulations using a computational fluid dynamic model were used as boundary conditions for the two-dimensional variably saturated flow and solute transport model MARUN. The modeling approach was validated against experimental data of solute transport due to waves and tides. Exchange fluxes across the beach face and subsurface solute transport (e.g., trajectory, movement speed, and residence time) were quantified. Simulation results revealed that waves increased the exchange fluxes, and engendered a wider exchange flux zone along the beach surface. Compared to tide-only forcing, waves superimposed on tide caused the plume to be deeper into the beach, and to migrate more seaward. The infiltration into the beach was found to be directly proportional to the general hydraulic gradient in the beach and inversely proportional to the matrix retention (or capillary) capacity. The simulations showed that a higher inland water table would attenuate wave-caused seawater infiltration, which might impact beach geochemical processes (e.g., nutrient recycle and redox condition), especially at low tide zone. The concept of biochemical residence time maps (BRTM) was introduced to account for the net effect of limiting concentration of chemicals on biochemical reactions. It was found that waves shifted the BRTMs downward and seaward in the beach, and subsequently they engendered different biochemical conditions within the beach.

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Numerical study of wave effects on groundwater flow and solute transport in a laboratory beach

Cited by 66 publications

References 46 publications

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

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

Simulating the Effects of Lake Wind Waves on Water and Solute Exchange across the Lakeshore Using Hydrus-2D

Numerical study of solute transport in shallow beach aquifers subjected to waves and tides

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