Monitoring Saline Intrusion of a Coastal Aquifer with Automated Electrical Resistivity Tomography

Ogilvy, R.D.; Kuras, O.; Meldrum, Philip; Wilkinson, Paul; Chambers, J. E.; Sen, M.; Tsourlos, Panagiotis

doi:10.3997/2214-4609.20147014

Cited by 3 publications

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“…Time-lapse resistivity surveying attempts to detect variations in the electrical properties of the subsurface with time (Giordano et al 2017;Loke et al 2017;Du et al 2018;Shin et al 2019). The time-lapse electrical resistivity surveying carried out in the work has been shown in previous work to be a powerful tool for monitoring saline intrusion at different periods in time (Slater et al 2002;Singha and Gorelick 2005;Cassiani et al 2006;Leroux and Dahlin 2006;de Franco et al 2009;Ogilvy et al 2009).…”

Section: Time Lapse Imagesmentioning

confidence: 99%

“…Time-lapse geo-electrical surveying attempts to detect variations in the electrical properties of the subsurface with time, introducing an additional dimension into the data collection (Giordano et al 2017;Loke et al 2017;Du et al 2018;Shin et al 2019). This technique can be carried out over short time periods (e.g., several days with readings taken every few hours) and has been used for the evaluation of the migration of contamination plumes (Chambers et al 2004;Radulescu et al 2007), early detection of dam failure (Shin et al 2019) the detection and monitoring of concentration of conductive contaminants within aquifers (Chambers et al 2004;Cassiani et al 2006;Oldenborger et al 2007), the quantification of superficial water infiltration rates into the subsurface (Barker and Moore 1998), and tracer test monitoring (Monego et al 2010;Ward et al 2010). Long-term time-lapse resistivity surveys have been applied in the monitoring of seasonal variations on seepage rates (Johansson and Dahlin 1996;Sjödahl et al 2008) and the monitoring of salinity within aquifers in coastal areas (Leroux and Dahlin 2006;de Franco et al 2009;Ogilvy et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Time-lapse electrical resistivity investigation of seawater intrusion in coastal aquifer of Ibeno, Southeastern Nigeria

et al. 2020

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Saltwater intrusion, erosion, and periodic flooding during severe storms are some of the critical problems bedeviling the precarious coastal environment of Nigeria. A time-lapse study aimed at monitoring the dynamics of saltwater intrusion within the coastland surrounding Ibeno, southeastern Nigeria is presented. Three (3) vertical electrical soundings (VES) and four time-lapse electrical resistivity tomography (ERT) profiles with minimum and maximum electrode spacing of 5 m and 40 m and profile lengths of 120 m and 150 m respectively were acquired in 2016 and 2017 using the Wenner and Schlumberger arrays. Data acquired from the field surveys were modeled with WINRESIST and RES2DINV software to generate 1D and 2D resistivity images of the subsurface. The VES results with a maximum survey length of AB = 300 m revealed a four-layer KH curve. The 2D geo-electrical sections delineated contrast between the high resistivity values obtained for the saturated freshwater zones and the low resistivity values obtained for the saturated saltwater zone. Expectedly, the intrusion was dominant nearer the coastline than inland. The salinity changes are believed to have been caused by both incremental tides passing through highly porous materials in the active-salinity change area and over-pumping of groundwater. The time-lapse resistivity measurements showed significant, active lateral salinity changes rapidly intruding the freshwater aquifers. The study demonstrates the application of time-lapse 2D ERT and vertical electrical sounding in identifying the spatial and temporal changes of saltwater intrusion in the coastal aquifer.

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Section: Time Lapse Imagesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time-lapse electrical resistivity investigation of seawater intrusion in coastal aquifer of Ibeno, Southeastern Nigeria

et al. 2020

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“…This technique can be carried out through short time periods (several days with readings taken every few hours) to evaluate the migration of contamination plumes (Radulescu et al, 2007), detection and monitoring of concentration of a conductive contaminant within aquifers (Cassiani et al, 2006;Chambers et al, 2004;Oldenborger et al, 2007), quantification of superficial water infiltration rates into the subsurface (Barker and Moore, 1998) and tracer test monitoring (Monego et al, 2010;Ward et al, 2010). Long term time-lapse resistivity surveys have been applied to monitor seasonal variations on seepage rates (Johansson and Dahlin, 1996;Sjödahl et al, 2008), monitoring salinity within aquifers in coastal areas (de Franco et al, 2009;Leroux and Dahlin, 2006;Ogilvy et al, 2009), safety assessment for storage of nuclear waste (Yaramanci, 2000), estimation of subsurface temperature variation (Morard et al, 2008), observing changes in liquid water saturation and temperature in frozen ground (Hauck, 2002) and monitoring permafrost active layer thickness variation (Kneisel, 2006). In the Irish context, the use of time-lapse resistivity is limited; Gibson (2003Gibson ( , 2005 used this technique for monitoring seasonal effects on limestone bedrock and the movement of contamination plumes in a landfill.…”

Section: Introductionmentioning

confidence: 99%

Time-lapse resistivity analysis of Quaternary sediments in the Midlands of Ireland

Pellicer

Zarroca

Gibson

2012

Journal of Applied Geophysics

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a b s t r a c t a r t i c l e i n f oElectrical Resistivity Tomography (ERT) data are influenced by a number of factors associated with the subsurface such as porosity, moisture content and lithology; as well as external factors such as rainfall and temperature. Two time-lapse ERT profiles with 5 m and two with 2 m electrode spacings were acquired over a range of Quaternary sediment types encompassing till, esker gravel, glaciofluvial sand and silt and glaciolacustrine silt/clay. Data were collected on a monthly basis during 2006 at a site located in the Midlands of Ireland in order to evaluate the influence of such conditioning factors on the resistivity of the subsurface. Effective recharge, the depth of investigation, the texture and the internal architecture of the different sediment types and temperature variation are the main factors influencing the resistivity seasonal variation. The shallow subsurface (b 3 m depth) showed a direct relationship between resistivity variation and effective recharge, whereas, an increasing time-lag between effective recharge and resistivity was recorded at increasing depths. As a result of the time-lag, it was possible to determine the rate of movement of the wetting/drying front for the unconsolidated relatively sorted coarse sediments recorded on the site at 7.8 cm/day. Conversely, poorly sorted and fine sediments show little resistivity variation and the velocity of the wetting front could not be estimated. Other factors influencing the electrical response of the subsurface are the electrode spacing used for data collection and the seasonal temperature variation of the subsurface. Two methods for temperature correction of electrical resistivity data were tested in this study -both gave similar results. Resistivity values recorded in the shallow subsurface (b 5 m) show variations of over 15% subsequent to temperature correction. The results illustrate that seasonal temperature changes and their influence on subsurface temperature have to be accounted for in data interpretation and emphasise the potential of this technique for the estimation of the rate of movement of the wetting/drying front in soft sediments.

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Joint inversion of 2D resistivity and seismic travel time data to image saltwater intrusion over karstic areas

Hamdan

Vafidis

2012

Environ Earth Sci

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Monitoring Saline Intrusion of a Coastal Aquifer with Automated Electrical Resistivity Tomography

Cited by 3 publications

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Time-lapse electrical resistivity investigation of seawater intrusion in coastal aquifer of Ibeno, Southeastern Nigeria

Time-lapse electrical resistivity investigation of seawater intrusion in coastal aquifer of Ibeno, Southeastern Nigeria

Time-lapse resistivity analysis of Quaternary sediments in the Midlands of Ireland

Joint inversion of 2D resistivity and seismic travel time data to image saltwater intrusion over karstic areas

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