Evaluation of DC, FDEM and IP resistivity methods for imaging perched saltwater and a shallow channel within coastal tidal flat sediments

Attwa, Mohamed; Günther, Thomas; Grinat, M.; Binot, Franz

doi:10.1016/j.jappgeo.2011.09.002

Cited by 32 publications

(14 citation statements)

References 36 publications

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“…Passive magnetics is a well‐established technique for characterizing the 3‐D structure of magnetized volcanic dykes [e.g., Parasnis , , and references therein] but do not inform on groundwater salinity. Geoelectrical methods, particularly electrical resistivity tomography (ERT), are efficient for mapping complex saltwater distribution in aquifers [e.g., Abdul Nassir et al ., ; Attwa et al ., ; Bourhane et al ., ], more so when combined with groundwater model simulations, which further enables quantification of associated flow and transport and parameter calibration [ Comte and Banton , ; Koukadaki et al ., ; Nguyen et al ., ; Comte et al ., ; Carrera et al ., ; Beaujean et al ., , Van Dam et al ., ].…”

Section: Introductionmentioning

confidence: 98%

Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion: A field‐scale multiphysics approach and parameter evaluation

Comte

Wilson

Ofterdinger

et al. 2017

Water Resources Research

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Volcanic dykes are common discrete heterogeneities in aquifers; however, there is a lack of field examples of, and methodologies for, comprehensive in situ characterization of their properties with respect to groundwater flow and solute transport. We have applied an integrated multiphysics approach to quantify the effect of dolerite dykes on saltwater intrusion in a coastal sandstone aquifer. The approach involved ground geophysical imaging (passive magnetics and electrical resistivity tomography), well hydraulic testing, and tidal propagation analysis, which provided constraints on the geometry of the dyke network, the subsurface saltwater distribution, and the sandstone hydrodynamic properties and connectivity. A three‐dimensional variable‐density groundwater model coupled with a resistivity model was further calibrated using groundwater and geophysical observations. A good agreement of model simulations with tide‐induced head fluctuations, geophysically derived pore water salinities, and measured apparent resistivities was obtained when dykes' hydraulic conductivity, storativity, and effective porosity are respectively about 3, 1, and 1 orders of magnitude lower than the host aquifer. The presence of the dykes results in barrier‐like alterations of groundwater flow and saltwater intrusion. Preferential flow paths occur parallel to observed dyke orientations. Freshwater inflows from upland recharge areas concentrate on the land‐facing side of the dykes and saltwater penetration is higher on their sea‐facing side. This has major implications for managing groundwater resources in dyke‐intruded aquifers, including in coastal and island regions and provides wider insights on preferential pathways of groundwater flow and transport in highly heterogeneous aquifer systems.

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Section: Introductionmentioning

confidence: 98%

Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion: A field‐scale multiphysics approach and parameter evaluation

Comte

Wilson

Ofterdinger

et al. 2017

Water Resources Research

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“…Electrical resistivity tomography (ERT) is one of the most versatile geophysical methods (Loke et al, ). Its sensitivity to water electrical conductivity makes it well suited for the characterization of the distribution of saltwater intrusion (SI) in coastal aquifers (Attwa et al, ; Goebel et al, ; Hermans et al, ; Nguyen et al, ). Submarine groundwater discharge (SGD) is an integral part of the dynamical equilibrium of coastal aquifers.…”

Section: Introductionmentioning

confidence: 99%

Combined Inversion of Land and Marine Electrical Resistivity Tomography for Submarine Groundwater Discharge and Saltwater Intrusion Characterization

Hermans

Paepen

2020

Geophysical Research Letters

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Electrical resistivity tomography (ERT) is particularly suited for the characterization of saltwater intrusion and submarine freshwater discharge, given its sensitivity to the electrical conductivity of pore water. A comprehensive survey might combine land ERT collected during low tide and marine ERT acquired with lower sensitivity due to the presence of a seawater layer, most often, inverted separately. In this contribution, we propose a new methodology to jointly invert land and marine ERT acquired along a same profile, bringing them to a common situation at high tide. We first estimate the electrical resistivity distribution under the land profile. Then, we compute a corrected data set for land ERT, simulating a data set collected with the same level of water as the marine ERT. Finally, both land and marine ERT data sets are inverted jointly. We show that the approach allows to better image the freshwater/saltwater distribution across the shoreline.

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“…The geophysical mapping of subsurface features can provide information about the spatial distribution of physical properties, such as electrical conductivity (or resistivity), dielectric permittivity, magnetic permeability, density and velocity. Among all geophysical techniques, electrical and electromagnetic methods are undoubtedly the leading ones in exploration and management of groundwater in engineering studies (Goldman and Kafri, 2006;Attwa et al, 2011). Two prevalent techniques in groundwater exploration are the methods of ground penetrating radar (GPR) and electrical resistivity tomography (ERT).…”

Section: Introductionmentioning

confidence: 99%

Geophysical investigation of underground water content zones using electrical resistivity tomography and ground penetrating radar: A case study in Hesarak-Karaj, Iran

Afshar

Abedi

Norouzi

et al. 2015

Engineering Geology

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Evaluation of DC, FDEM and IP resistivity methods for imaging perched saltwater and a shallow channel within coastal tidal flat sediments

Cited by 32 publications

References 36 publications

Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion: A field‐scale multiphysics approach and parameter evaluation

Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion: A field‐scale multiphysics approach and parameter evaluation

Combined Inversion of Land and Marine Electrical Resistivity Tomography for Submarine Groundwater Discharge and Saltwater Intrusion Characterization

Geophysical investigation of underground water content zones using electrical resistivity tomography and ground penetrating radar: A case study in Hesarak-Karaj, Iran

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