Two-dimensional DNAPL migration affected by groundwater flow in unconfined aquifer

Kamon, Masashi; Endo, Kazuto; Kawabata, Junichi; Inui, Tomoyuki; Tanaka, Katsumi

doi:10.1016/j.jhazmat.2004.02.033

Cited by 37 publications

(27 citation statements)

References 20 publications

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“…The increasing flow velocity also promotes PCE redistribution and restrains the occurrence of preferential flow along artificial interfaces. This is because greater hydrodynamic pressure reduces pore PCE pressure and capillary pressure between the aqueous and NAPL phases, which accelerates the vertical PCE migration (Kamon et al 2004). Figure 3 shows the effect of flow velocity on PCE migration for layered-lenses cases.…”

Section: Resultsmentioning

confidence: 99%

“…The migration behavior and distribution of DNAPL spills in the subsurface may be influenced by many factors including the physicochemical properties of the DNAPLs Phelan et al 2004;Mastrocicco et al 2011), spill rate (Christ et al 2005;Wang 2013;Okuda et al 2014), groundwater flow velocity (Kamon et al 2004;Erning et al 2012), and soil heterogeneity (Powers et al 1998;Bradford et al 2003;Fagerlund et al 2006;Yang et al 2013). Among them, groundwater flow velocity and heterogeneity are most commonly encountered factors that are generally considered to vary in the subsurface-for instance, flow velocity may be enhanced in sandy aquifers at the foothills of mountains or surrounding groundwater production facilities.…”

Section: Introductionmentioning

confidence: 99%

“…Several experiments (Kamon et al 2004;Luciano et al 2010Luciano et al , 2012 and numerical simulations (Erning et al 2009(Erning et al , 2010 have addressed the effect of groundwater flow velocity (v w ) on DNAPL migration. Kamon et al (2004) and Luciano et al (2010) conducted two-dimensional (2-D) tank experiments to assess the influence of hydraulic gradient, and found that the lateral flow not only increased the infiltration rate, but also promoted downward migration and the redistribution process, which reduced pore DNAPL pressure and the amount remaining at residual saturation.…”

Section: Introductionmentioning

confidence: 99%

“…Kamon et al (2004) and Luciano et al (2010) conducted two-dimensional (2-D) tank experiments to assess the influence of hydraulic gradient, and found that the lateral flow not only increased the infiltration rate, but also promoted downward migration and the redistribution process, which reduced pore DNAPL pressure and the amount remaining at residual saturation. Erning et al (2009) performed 2-D simulation of DNAPL infiltration, and concluded that high groundwater flow velocity influenced the position, size and architecture of DNAPL, which decreased the maximum DNAPL saturation.…”

Section: Introductionmentioning

confidence: 99%

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Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

et al. 2015

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Understanding the migration of dense non-aqueous phase liquids (DNAPLs) in complex subsurface systems is important for evaluating contamination source zones and designing remediation schemes after spill events. Six sandbox experiments were performed to explore the individual effect of flow velocity, and the combined effect of flow velocity and layered lenses on a DNAPL (PCE) migration in porous media. DNAPL saturation was measured using a light transmission system, and saturation distribution was quantified by spatial moments. The experimental results show that large flow velocity significantly promotes lateral and vertical migration of the low-viscosity DNAPL, while when layered lenses exist, the infiltration rate decreases and horizontal spread increases. Migration processes were numerically simulated, and the modelling results tested against experimental results. Furthermore, migration of DNAPLs with different viscosities was simulated to explore the combined effects of flow velocity and geological heterogeneity. Simulation results show that enhanced heterogeneity makes low-viscosity DNAPLs migrate along preferential pathways, resulting in irregular DNAPL morphology. Layered lenses combined with heterogeneity complicate the effect of flow velocity on the migration of low-viscosity DNAPLs by changing percolation paths. Results also demonstrate that flow velocity exhibits relatively little influence on the migration of medium/high-viscosity DNAPLs, which is predominantly controlled by viscosity and heterogeneity. Enhanced heterogeneity has a larger effect on migration behavior. Findings indicate that the migration paths and position of the source zone could change significantly, due to the combined effect of groundwater flow velocity and geological heterogeneity; thus, comprehensive hydrogeological investigation is needed to characterize the source zone.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

et al. 2015

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“…Toyoura sand is widely used as a standard sand in geotechnical studies in Japan (Kamon et al 2004). Standard sands and river sands were used in an unsaturated condition having 0.1, 0.2, and 0.3 m 3 /m 3 for the volumetric soil water content, with the soil porosity range around 0.40-0.45 for the soil column test using the FDR dielectric device.…”

Section: Methodsmentioning

confidence: 99%

Spatial pore characteristics of unsaturated soils caused by dielectric geometric factors under permittivity method with 1 GHz frequency range

Kim

Chung

et al. 2010

Environ Earth Sci

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A dielectric measurement device called a frequency domain reflectometry (FDR) has been designed and constructed for the dielectric measurement of unsaturated soil consisting of a volumetric soil water content of about 0.1, 0.2, and 0.3 m 3 /m 3 with different soil porosity around 0.40-0.45, respectively. The dielectric constant is measured in the frequency range 1 GHz. Soil calibration tests and tracer injection tests on standard sand and river sand are carried out in the laboratory. FDR measurement probes at different soil depths allow volumetric soil water content and dielectric constant measurements. The tracer concentration in the pore water is monitored by determining the dielectric constant, from the soil impedance. From the relationship between volumetric soil water content and dielectric constant, the specific calibration equations for the unsaturated soils were derived, and one can easily estimate the volumetric soil water content from the response of the measured dielectric constant for the soils. In the study of dielectric mixture models using a-value of 0.5 which is dielectric geometric factor, the effective porosity for the soils was computed to a range of 87-92% compared with the soil porosity.

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Electrical permittivity and resistivity time lapses of multiphase DNAPLs in a lab test

Orlando

Renzi

2015

Water Resour. Res.

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Dense Non-Aqueous Phase Liquids (DNAPLs) induce variation in electromagnetic characteristics of the ground, e.g., electric permittivity and resistivity. The most used indirect methods in the mapping of these physical characteristics are electrical resistivity and ground penetrating radar. To better understand the effect of DNAPL release on electrical permittivity and resistivity in a water saturated medium, we carried out a controlled laboratory experiment where the host material was simulated by glass beads and the DNAPL by HFE-7100 (hydrofluoroether). The experiment measured the electric resistivity and permittivity of each fluid, the multiphase fluid system, and the host material, along with time-lapse electrical resistivity and GPR measurements in a controlled cell. We found that the different phases of DNAPL within a saturated medium (free, dissolved, and gaseous phase) affect the physical characteristics differently. The reflection pull-up behind contaminated sediments, which is normally detected by GPR, was mainly inferred from the HFE free phase. The dissolved phase causes small variations in electric permittivity not usually readily detected by GPR measurements. Both the dissolved and free HFE phases induce variation in resistivity. The study showed that GPR and electrical resistivity differ in sensitivity to the different HFE phases, and can be complementary in the characterization of DNAPL contaminated sites.

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Two-dimensional DNAPL migration affected by groundwater flow in unconfined aquifer

Cited by 37 publications

References 20 publications

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

Influence of flow velocity and spatial heterogeneity on DNAPL migration in porous media: insights from laboratory experiments and numerical modelling

Spatial pore characteristics of unsaturated soils caused by dielectric geometric factors under permittivity method with 1 GHz frequency range

Electrical permittivity and resistivity time lapses of multiphase DNAPLs in a lab test

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