Geophysical Surveys for Saltwater Intrusion Assessment Using Electrical Resistivity Tomography and Electromagnetic Induction Methods

Document Type : Research Article


1 Corresponding Author, Department of Geology and Environment, Faculty of Science, Ghent University, Ghent, Belgium. E-mail:

2 Department of Geology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, Iran. E-mail:

3 Department of Petroleum Exploration, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran. E-mail:

4 Department of Petroleum Exploration, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran. E-mail:

5 Department of Petroleum Exploration, Faculty of Mining Engineering, Sahand University of Technology, Tabriz, Iran. E-mail:


Saltwater intrusion is as an environmental hazard in coastal lines if not appropriately managed. The over-exploitation, over-population and climate change have invited and pushed the saltwater landwards and polluted the freshwater aquifers. This research studies the results of the implemented project at the coast of Saint Andre' located in Koksijde, Belgium, to study this phenomenon through near-surface geophysics. Two geophysical methods, including Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EMI) were used to identify the saltwater intrusion. The present study aimed to investigate the possibility of saltwater intrusion, its extension and assess the government reclamation attempts to push back the saltwater. In the inversions, the Depth of Investigation Index (DOI) and the topography effect were evaluated. The subsurface conductivity of both methods was compared. The reliability of both methods to identify the saltwater intrusion has been established; however, the ERT survey provided a more comprehensive visualization than the EMI. The saltwater intrusion was found in the first 80 m of the coastal line with resistivity values of 2 to 5 Ohm.m; however, the infiltration of freshwater and the reclamation operation have stopped the further progress salinity into the dunes. Local possibilities of brackish water or clay lenses were identified with 7 to 25 Ohm.m resistivity values. The freshwater body was observed at distances between 120 and 220 m of the ERT line with values between 46 and 136 Ohm.m. The results were correlated with other studies, proving the reliability of the models.


Main Subjects

Abarca, E., Vázquez-Suñé, E., Carrera, J., Capino, B., Gámez, D., & Batlle, F. (2006). Optimal design of measures to correct seawater intrusion. Water Resour. Res., 42,
Allen, D.M., & Matsuo, G.P. (2002). Results on the Groundwater Geochemistry Study on Hornby Island, British Columbia. Burnaby, B.C., Simon Fraser University. p. 9-12.
An, Q., Wu, Y., Taylor, S., & Zhao, B. (2009). Influence of the Three Gorges Project on saltwater intrusion in the Yangtze River Estuary. Environmental Geology, 56(8), 1679-1686.
Barlow, P.M., & Reichard, E.G. (2009). Saltwater intrusion in coastal regions of North America. Hydrogeol. J., 18, 247–260.,
Bell, T.H., Barrow, B.J., & Miller, J.T. (2001). Subsurface discrimination using electromagnetic induction sensors. IEEE transactions on geoscience and remote sensing, 39(6), 1286-1293.
Chang, S.W., Clement, T.P., Simpson, M.J., & Lee, K.K. (2011). Does sea-level rise have an impact on saltwater intrusion?. Advances in water resources, 34(10), 1283-1291.
Dahlin, T., & Zhou, B. (2004). A numerical comparison of 2D resistivity imaging with ten electrode arrays. Geophysics. Prospect. 52(5), 379–398,
Dahlin, T. (1996). 2D resistivity surveying for environmental and engineering applications. First Break, 14. 275-284.
De Franco, R., Biella, G., Tosi, L., Teatini, P., Lozej, A., Chiozzotto, B., Giada, M., Rizzetto, F., Claude, C., Mayer, A., Bassan, V., & Gasparetto-Stori, G. (2009). Monitoring the saltwater intrusion by time-lapse electrical resistivity tomography: The Chioggia test site (Venice Lagoon, Italy). Journal of Applied Geophysics, 69(3-4), 117-130.
DeGroot-Hedlin, C., & Constable, S. (1990). Occam's inversion to generate smooth, two-dimensional models form magneto telluric data. Geophysics, 55, 1613-1624.
De Latte., S. (2021). Characterisation of the saltwater/freshwater interface between Koksijde and Oostduinkerke using electrical resistivity tomography. Master's thesis. University of Ghent.
De Moor, G., & De Breuck, W. (1969). De freatische waters in het Oostelijk Kustgebied en in de Vlaamse vallei. Natuurwet. Tijdschr., 51(1-2), 3-68, + 8 annexes.
Doolittle, J.A., & Brevik, E.C. (2014). The use of electromagnetic induction techniques in soils studies. Geoderma, 223, 33-45.
Essink, G.H.O. (2001). Saltwater intrusion in a three-dimensional groundwater system in the Netherlands: a numerical study. Transport in porous media, 43(1), 137-158.
Everett, M.E. (2013). Near-surface applied geophysics. Cambridge University Press.
Everett, M.E. (2012). Theoretical developments in electromagnetic induction geophysics with selected applications in the near-surface. Surveys in geophysics, 33(1), 29-63.
Fennema, R.J., & Newton, V.P. (1982). Ground Water Resources of the Eastern Shore of Virginia. Commonwealth of Virginia, State Water Control Board, Richmond, VA, Planning Bulletin, 332, 74 pp.
Fitts, C.R. (2002). Groundwater science. Elsevier.
Flanzenbaum, J. (1986). Evaluation of saltwater intrusion into the Coastal Aquifer of Southern Virginia. M.Sc. Thesis, University of Virginia, 141 p.
Friedman, S.P. (2005). Soil properties influencing apparent electrical conductivity: a review. Computers and Electronics in Agriculture, 46(1-3), 45-70.
Frohlich, R.K., Urish, D.W., Fuller, J., & Reilly, M.O. (1994). Use of geoelectrical method in groundwater pollution surveys in a coastal environment. Journal of Applied Geophysics, 32, 139–154.
García-Tomillo, A., de Figueiredo, T., Dafonte, J.D., Almeida, A., & Paz-González, A. (2018). Effects of machinery trafficking in an agricultural soil assessed by Electrical Resistivity Tomography (ERT). Open Agriculture, 3(1), 378-385.
Geets, S. (1988). Ieper Groep. In: Mar_echal, R. & Laga, P., Voorstel Lithostratigra_sche Indeling van het Paleogeen. Nationale Commissies voor Stratigra_e, pp. 81-115.
Genotics limited catalogue (2017). Geophysical Instrumentation for Exploration & the Environment.
George, A. (2006). Development of geoelectrical techniques for investigation and monitoring of landfills. Cardiff University (United Kingdom).
Geotomo Software (2002), Rapid two-dimensional resistivity and induced polarization inversion using the least-squares method. RES2DINV manual.
Geotomo Software (2020), Rapid two-dimensional resistivity and induced polarization inversion using the least-squares method. RES2DINV manual.
Goebel, M., Pidlisecky, A., & Knight, R. (2017). Resistivity imaging reveals a complex pattern of saltwater intrusion along the Monterey coast. Journal of Hydrology, 551, 746-755.
Goldman, M., & Kafri, U. (2006). Hydrogeophysical applications in coastal aquifers. In: Appl. Hydrogeophys. Springer, Netherlands, pp. 233–254.
Goodell, H.G. (1986). A study of saltwater intrusion into the surface aquifer and the underlying of Yorktown Aquifer of Coastal Virginia. Final Report to Virginia Environmental Endowment Richmond, VA, 14 pp.
Janssen, M.P.J.M. (1993). Duinen voor de wind: Past (diep) in_ltratie in het streefbeeld van natuurontwikkeling?. H2O, (26), 388-393.
Jeřábek, J., Zumr, D., & Dostál, T. (2017). Identifying the plow pan position on cultivated soils by measurements of electrical resistivity and penetration resistance. Soil and Tillage Research, 174, 231-240.
Jongmans, D., & Garambois, S. (2007). Geophysical investigation of landslides: a review. Bulletin de la Société géologique de France, 178(2), 101-112.
Kebede, S.A., & Nicholls, J.R. (2010). Population and assets exposed to coastal flooding in Dar es Salaam (Tanzania): vulnerability to climate extremes. University of Southampton, United Kingdom. es Salaam_City-Analysis_Final-Report_1_.pdf
Kirsch, R. (2009). Petrophysical Properties ofPermeable and Low Permeable Rocks. In: Groundwater Geophysics: Tool for Hydrogeology, Kirsch, R. (Ed.). 2nd Edn., Springer, Berlin, Heidelberg.
Kight, R., & Endres, A.L. (2005). An introduction to rock physics principles for near-surface geophysics. In: Near-Surface Geophysics. Society of Exploration Geophysics, Tulsa, pp. 31–70.
Lashkaripour, Ghafoori, M., & Dehghani, A. (2005). Electrical resistivity survey for predicting Samsor aquifer properties, southeast Iran. Geophysical Research Abstracts (7) (Europian Geosciences Union).
Lebbe, L., Vandenbohede, A., & Courtens, C. (2011). Grondwaterstudie in kader van uitbreiding van het Zwin.
Loke, M.H., & Barker, R.D. (1994). Rapid least-squares inversion of apparent resistivity pseudo sections. In 56th EAEG Meeting (pp. cp-47). European Association of Geoscientists and Engineers.
Mansourian, D., Cornelis, W., & Hermans, T. (2020). Exploring geophysical methods for mapping soil strength in relation to soil compaction. Master's thesis. Ghent University.
Martínez, J., Benavente, J., García-Aróstegui, J.L., Hidalgo, M.C., & Rey, J. (2009). Contribution of electrical resistivity tomography to the study of detrital aquifers affected by seawater intrusion–extrusion effects: The river Vélez delta (Vélez-Málaga, southern Spain). Eng. Geol., 108, 161–168,
Martorana, R., Capizzi, P., D’Alessandro, A., & Luzio, D. (2017). Comparison of different sets of array configurations for multichannel 2D ERT acquisition. Journal of Applied Geophysics, 137, 34-48.
McNeill, J.D. (1980). Electrical conductivity of soils and rock. Technical Note TN-5. Geonic Limited, Mississauga, Ontario, Canada.
Maślakowski, M., Kowalczyk, S., Mieszkowski, R., & Józefiak, K. (2014). Using Electrical Resistivity Tomography (ERT) as a tool in geotechnical investigation of the substrate of a highway. Studia Quaternaria, 31(2), 83-89.
Matthijs, J., Lanckacker, T., De Koninck, R., Deckers, J., Lagrou, D., & Broothaers, M. (2013). Geologisch 3D lagenmodel van Vlaanderen en het Brussels Hoofdstedelijk Gewest { versie 2, G3Dv2 [online]. Studie uitgevoerd door VITO in opdracht van de Vlaamse overheid, Departement Leefmilieu, Natuur en Energie, Afdeling Land en Bodembescherming, Ondergrond, Natuurlijke Rijkdommen, 21p., VITO-rapport 2013/R/ETE/43. [Accessed November 5th, 2019]. Available at: (in Dutch).
Mtoni, Y., Mjemah, I.C., Van Camp, M., & Walraevens, K. (2011). Enhancing Protection of Dar es Salaam Quaternary Aquifer: Groundwater Recharge Assessment. Springer, Environmental Earth Sciences, Advances in Research of Aquatic Environment, (1), 299-306 (DOI 10.1007/978-3-642-19902-8).
Mtoni, Y.E. (2013). Saltwater intrusion in the coastal strip of Dar es Salaam Quaternary aquifer, Tanzania (Doctoral dissertation, Ghent University).
Nguyen, F., Kemna, A., Antonsson, A., Engesgaard, P., Kuras, O., Ogilvy, R., Gisbert, J., Jorreto, S., & Pulido-Bosch, A. (2009). Characterization of seawater intrusion using 2D electrical imaging. Near Surf. Geophys., 7, 377–390.
Nicholls, R.J. (2011). Planning for the impacts of sea-level rise. Oceanography, 24(2), 144-157.
Norconsult (2007). Development of a Future Water Source for Dar es Salaam, Tanzania. Pre-design and Environmental report, Phase 2. Part 2: Review of Social and Environmental Factors.
Nowroozi, A.A., Horrocks, S.B., & Henderson, P. (1999). Saltwater intrusion into the freshwater aquifer in the eastern shore of Virginia: a reconnaissance electrical resistivity survey. Journal of Applied Geophysics, 42(1), 1-22.
Obikoya, I.B., & Bennell, J.M. (2012). Geophysical investigation of fresh-saline water interface in the coastal area of Abergwyngregyn. Journal of Environmental protection, 3, 1039-1046.
Ogilvy, R.D., Meldrum, P.I., Kuras, O., Wilkinson, P.B., Chambers, J.E., Sen, M., Pulido-Bosch, A., Gisbert, J., Jarrett, S., Frances, I., & Tsourlos, P. (2009). Automated monitoring of coastal aquifers with electrical resistivity tomography. Near Surf. Geophys., 7, 367–375.
Oldenburg, D.W., & Li, Y. (1999). Estimating depth of investigation in dc resistivity and IP surveys. Geophysics, 64(2), 403-416.
Papadopoulou, M.P., Karatzas, G.P., Koukadaki, M.A., & Trichakis, Y. (2005). Modeling the saltwater intrusion phenomenon in coastal aquifers – a case study in the industrial zone of Herakleto in Crete. Global NEST Journal. 7(2), 197-203.
Polemio, M., Casarano, D., & Limoni, P.P. (2010). Apulian coastal aquifers and management criteria In: SWIM 21 - 21st Salt Water Intrusion Meeting. Edited by: MT Condesso de Melo, L Lebbe, JV Cruz, R Coutinho, C Langevin, A Buxo, 203-206.
Romero‐Ruiz, A., Linde, N., Keller, T., & Or, D. (2018). A review of geophysical methods for soil structure characterization. Reviews of Geophysics, 56(4), 672-697.
Ronczka, M., Voß, T., & Günther, T. (2015). Cost-efficient imaging and monitoring of saltwater in a shallow aquifer by using long electrode ERT. Journal of Applied Geophysics, 122, 202-209.
Salami, O. (2020) Evaluation of soil compaction of an agricultural field using 2D electrical resistivity tomography (ERT). Master's thesis. University of Gent.
Telford, W.M., Geldart, L.P., Sherif, R.E., & Keys, D.A. (1990). Applied geophysics. Cambridge Univ. Press, Cambridge, 770p.
Toy, C. (2015). Monitoring Shallow Vadose Zone Moisture Dynamics using Electrical Resistivity Tomography and Electromagnetic Induction (M.Sc. thesis, University of Waterloo).
Werner, A.D., Bakker, M., Post, V.E.A., Vandenbohede, A., Lu, C., Ataie-Ashtiani, B., Simmons, C.T., & Barry, D.A. (2013). Seawater intrusion processes, investigation, and management: recent advances and future challenges. Adv. Water Resour., 51, 3–26.
Walraevens, K., Lebbe, L., Van Camp, M., Angius,, Serra, M.A., Vacca,, A., Massidda, R., & De Breuck, W. (1993). Salt/freshwater flow and distribution in a cross-section at Oostduinkerke (western coastal plain of Belgium). Study and modeling of Saltwater Intrusion into Aquifers. Proceedings of 12th Saltwater Intrusion.
Walraevens, K., Martens, K., & De Breuck, W. (1994). Salt/freshwater distribution in the polder area near Axel (Zealand-Flanders). Proceedings of the 13th Salt-Water Intrusion Meeting, Cagliari (1994), 321-334.
Wiederhold, H., Sulzbacher, H., Grinat, M., Günther, T., Igel, J., Burschil, T., & Siemon, B. (2013). Hydrogeophysical characterization of fresh-water/saltwater systems — case study: Borkum Island, Germany. First Break, 31, 109–117.
Zarroca, M., Bach, J., Linares, R., & Pellicer, X.M. (2011). Electrical methods (VES and ERT) for identifying, mapping, and monitoring different saline domains in a coastal plain region (Alt Empordà, Northern Spain). J. Hydrol., 409, 407–422,
Zohdy, A.A.R., Eaton, G.P., & Mabey, D.R. (1974). Application of surface geophysics to groundwater investigation, U.S.G.S. Techniques of Water-Resource Investigation, Book 2.