scholarly journals Characterization of a Shallow Coastal Aquifer in the Framework of a Subsurface Storage and Soil Aquifer Treatment Project Using Electrical Resistivity Tomography (Port de la Selva, Spain)

2021 ◽  
Vol 11 (6) ◽  
pp. 2448
Author(s):  
Alex Sendrós ◽  
Aritz Urruela ◽  
Mahjoub Himi ◽  
Carlos Alonso ◽  
Raúl Lovera ◽  
...  

Water percolation through infiltration ponds is creating significant synergies for the broad adoption of water reuse as an additional non-conventional water supply. Despite the apparent simplicity of the soil aquifer treatment (SAT) approaches, the complexity of site-specific hydrogeological conditions and the processes occurring at various scales require an exhaustive understanding of the system’s response. The non-saturated zone and underlying aquifers cannot be considered as a black box, nor accept its characterization from few boreholes not well distributed over the area to be investigated. Electrical resistivity tomography (ERT) is a non-invasive technology, highly responsive to geological heterogeneities that has demonstrated useful to provide the detailed subsurface information required for groundwater modeling. The relationships between the electrical resistivity of the alluvial sediments and the bedrock and the difference in salinity of groundwater highlight the potential of geophysical methods over other more costly subsurface exploration techniques. The results of our research show that ERT coupled with implicit modeling tools provides information that can significantly help to identify aquifer geometry and characterize the saltwater intrusion of shallow alluvial aquifers. The proposed approaches could improve the reliability of groundwater models and the commitment of stakeholders to the benefits of SAT procedures.

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2400
Author(s):  
Alex Sendrós ◽  
Mahjoub Himi ◽  
Esmeralda Estévez ◽  
Raúl Lovera ◽  
M. Pino Palacios-Diaz ◽  
...  

The geometry and the hydraulic properties of the unsaturated zone is often difficult to evaluate from traditional soil sampling techniques. Soil samples typically provide only data of the upper layers and boreholes are expensive and only provide spotted information. Non-destructive geophysical methods and among them, electrical resistivity tomography can be applied in complex geological environments such as volcanic areas, where lavas and unconsolidated pyroclastic deposits dominate. They have a wide variability of hydraulic properties due to textural characteristics and modification processes suh as compaction, fracturation and weathering. To characterize the subsurface geology below the golf course of Bandama (Gran Canaria) a detailed electrical resistivity tomography survey has been conducted. This technique allowed us to define the geometry of the geological formations because of their high electrical resistivity contrasts. Subsequently, undisturbed soil and pyroclastic deposits samples were taken in representative outcrops for quantifying the hydraulic conductivity in the laboratory where the parametric electrical resistivity was measured in the field. A statistical correlation between the two variables has been obtained and a 3D model transit time of water infiltration through the vadose zone has been built to assess the vulnerability of the aquifers located below the golf course irrigated with reclaimed water.


2017 ◽  
Vol 11 (6) ◽  
pp. 2957-2974 ◽  
Author(s):  
Benjamin Mewes ◽  
Christin Hilbich ◽  
Reynald Delaloye ◽  
Christian Hauck

Abstract. Geophysical methods are often used to characterize and monitor the subsurface composition of permafrost. The resolution capacity of standard methods, i.e. electrical resistivity tomography and refraction seismic tomography, depends not only on static parameters such as measurement geometry, but also on the temporal variability in the contrast of the geophysical target variables (electrical resistivity and P-wave velocity). Our study analyses the resolution capacity of electrical resistivity tomography and refraction seismic tomography for typical processes in the context of permafrost degradation using synthetic and field data sets of mountain permafrost terrain. In addition, we tested the resolution capacity of a petrophysically based quantitative combination of both methods, the so-called 4-phase model, and through this analysed the expected changes in water and ice content upon permafrost thaw. The results from the synthetic data experiments suggest a higher sensitivity regarding an increase in water content compared to a decrease in ice content. A potentially larger uncertainty originates from the individual geophysical methods than from the combined evaluation with the 4-phase model. In the latter, a loss of ground ice can be detected quite reliably, whereas artefacts occur in the case of increased horizontal or vertical water flow. Analysis of field data from a well-investigated rock glacier in the Swiss Alps successfully visualized the seasonal ice loss in summer and the complex spatially variable ice, water and air content changes in an interannual comparison.


2018 ◽  
Vol 19 (1) ◽  
pp. 24-34
Author(s):  
Budy Santoso

Bungaya Kangin Village, Bebandem District, Karangasem Regency, Bali Province consists of paddy fields and settlements, required therefore a water source / aquifer  that can meet all these needs. One of the Geophysical Methods that can identify the aquifer is the Geoelectric Method. Geoelectric method used in this research is Resistivity Method. Data acquisition using Vertical Electrical Sounding (VES) and Electrical Resistivity Tomography (ERT) Methods. VES method is a method of measurement to determine the variation of resistivity vertically at one point. Electrical Resistivity Tomography (ERT) method is a method of measuring resistivity on soil surface / rock by using many electrode (51 electrode), to obtain sub-surface resistivity variation  lateraly and verticaly, to obtain sub-surface image. The equipment used for geoelectric measurements is  Resistivity Meter of Naniura NRD 300 Hf which has been equipped with a switchbox to adjust the displacement of 51 electrodes. Based on the resistivity modeling results, the aquifers in the study area were found in rough sandstones with resistivity values : (49 - 100) Ohm.m.  


2014 ◽  
Vol 31 (2) ◽  
pp. 91-99 ◽  
Author(s):  
Grzegorz Pacanowski ◽  
Paweł Czarniak ◽  
Anna Bąkowska ◽  
Radosław Mieszkowski ◽  
Fabian Welc

Abstract This paper addresses the problem of assessing the leakproofness of the bottom of a deep foundation trench, secured by cavity wall, using geophysical methods of electrical resistivity tomography. The study was conducted on a large construction project in Lublin, in a place where there are complicated soil-water conditions: the groundwater level is above the proposed depth of foundation trench, the subsoil is heterogeneous, and there are karsted and weathered carbonate sediments with confined aquifer below the bottom of the trench. A hydraulic fracture occurred at the bottom of the trench during the engineering works, which caused the water flow into the trench. In order to recognize the soil-water conditions the first stage of geophysical measurements of electrical resistivity tomography (ERT) was made. The applied methodology allowed to determine the extent of the hydraulic fracture zone within the bottom of foundation trench. In order to assess the leakproofness of Diaphragm Wall the geophysical ERT measurements were repeated (stage 2) A clear reduction in the value of the electrical resistivity of soils in the area of hydraulic fracture was caused by clay injection. The results of ERT measurements are discussed and graphically presented.


2016 ◽  
Vol 47 (3) ◽  
pp. 1355
Author(s):  
G. Vargemezis ◽  
N. Diamanti ◽  
I. Fikos ◽  
A. Stampolidis ◽  
Th. Makedon ◽  
...  

Ground penetrating radar (GPR) and electrical resistivity tomography (ERT) surveys have been carried out in the city centre of Thessaloniki (N. Greece), for investigating possible locations of buried building foundations. Geophysical survey has been chosen as a non-destructive investigation method since the area is currently used as a car parking and it is covered by asphalt. The geoelectrical sections derived from ERT data in combination with the GPR profiles provided a broad view of the  subsurface.  Regarding  ERT,  high  resistivity  values  can  be  related  to  buried building remains, while lower resistivity values are more related to the surrounding geological materials. GPR surveying can also indicate man-made structures buried in the ground. Even though the two geophysical methods are affected in different ways by the subsurface conditions, the processed underground images from both techniques revealed great similarity. High resistivity anomalies and distinct GPR signals were observed in certain locations of the area under investigation, which are attributed to buried building foundations as well as the geological structure of the area.


2019 ◽  
Vol 9 (15) ◽  
pp. 2963 ◽  
Author(s):  
Yin-Chun Hung ◽  
Chih-Ping Lin ◽  
Chin-Tan Lee ◽  
Ko-Wei Weng

Electrical resistivity tomography (ERT) is one of the most widely used geophysical methods in geological, hydrogeological, and geo-environmental investigations. Although 3D ERT is now available, 2D ERT remains state-of-the-practice due to its simplicity in fieldwork and lower space requirements. 2D ERT assumes that the ground condition is perpendicular to the survey line and outside the survey line is homogeneous. This assumption can often be violated in conditions such as geologic strikes not perpendicular to the survey line and topographic changes or buried objects near the survey line. Possible errors or artifacts in the 2D resistivity tomogram arising from violating the 2D assumption are often overlooked. This study aimed to numerically investigate the boundary effects on 2D ERT under various simplified conditions. Potential factors including resistivity contrast, depth and size of buried objects, and electrode spacing were considered for the parametric studies. The results revealed that offline geologic features may project onto the 2D tomogram to some extent, depending on the aforementioned factors. The mechanism and implications of boundary effects can be drawn from these parametric studies.


2014 ◽  
Vol 44 (2) ◽  
pp. 133-147 ◽  
Author(s):  
Ivan Dostál ◽  
René Putiška ◽  
David Kušnirák

Abstract Geophysical methods offer a broad spectrum of information by dealing with slope deformations. The electrical resistivity tomography (ERT) method is mainly applied for spatial localization of the landslide body and depicting the shear zone position. This article presents the application of the ERT method for the landslide hazardous areas by means of numerical modelling. Four different synthetic models with very small resistivity contrast (30 Ohm.m/50 Ohm.m), where each model represents a different type of slope deformation, were tested by several factors affecting the final inverse model: measurement point density, L1 and L2 norm and L-norm roughness filter components. The higher measurement points density helps mainly to detect the boundaries at greater depths. Inverse models computed using the L1 norm bring satisfactory results for compact anomalous bodies, i.e. water saturated landslide body. In the case of subtle conductive zones, i.e. shear planes, the L2 norm based inversion is recommended. For enhanced reconstruction of skewed anomalous objects, roughness filter including a diagonal component produces more accurate inverse image. The article also demonstrates the ability of the ERT method to detect and describe the shape of the slope deformation even by a relative subtle resistivity contrast


2016 ◽  
Vol 47 (3) ◽  
pp. 1355
Author(s):  
G. Vargemezis ◽  
N. Diamanti ◽  
I. Fikos ◽  
A. Stampolidis ◽  
Th. Makedon ◽  
...  

Ground penetrating radar (GPR) and electrical resistivity tomography (ERT) surveys have been carried out in the city centre of Thessaloniki (N. Greece), for investigating possible locations of buried building foundations. Geophysical survey has been chosen as a non-destructive investigation method since the area is currently used as a car parking and it is covered by asphalt. The geoelectrical sections derived from ERT data in combination with the GPR profiles provided a broad view of the  subsurface.  Regarding  ERT,  high  resistivity  values  can  be  related  to  buried building remains, while lower resistivity values are more related to the surrounding geological materials. GPR surveying can also indicate man-made structures buried in the ground. Even though the two geophysical methods are affected in different ways by the subsurface conditions, the processed underground images from both techniques revealed great similarity. High resistivity anomalies and distinct GPR signals were observed in certain locations of the area under investigation, which are attributed to buried building foundations as well as the geological structure of the area.


2020 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
Asep Mulyono ◽  
Ilham Arisbaya ◽  
Yayat Sudrajat

Root zone geometry research is usually done in a conventional way which is destructive, time-consuming, and requires a considerable cost. Several non-destructive measurements used geophysical methods have been developed, one of which is the Electrical Resistivity Tomography (ERT) method. Tree root zone determination using ERT has been carried out in Kiara Payung area, Sumedang, West Java, with Maesopsis eminii tree as the object study. A total of 29 ERT lines were measured using dipoledipole configuration with electrodes spacing of 50 cm. The results of two-dimensional (2D) and three-dimensional (3D) inversion modeling show that the ERT method has been successfully imaging the tree root zone. The root zone is characterized as 100-700 Ωm with an elliptical shape geometry of the root plate. The root radius is estimated to be 4-5 m from the stem, the root zone diameter reaches 8-9 m at the shallow soil surface and the root zone depth is approximately 2-2.5 m. ABSTRAK Pencitraan geometri zona perakaran pohon menggunakan electrical resistivity tomography. Penelitian geometri zona perakaran biasa dilakukan dengan cara konvensional yang destruktif, memakan waktu, dan membutuhkan biaya yang tidak sedikit. Beberapa pengukuran non-destruktif menggunakan metode geofisika telah dikembangkan, salah satunya adalah metode Electrical Resistivity Tomography (ERT). Penentuan zona perakaran pohon menggunakan metode ERT telah dilakukan di daerah Kiara Payung, Sumedang, Jawa Barat, dengan pohon Maesopsis eminii sebagai objek studi. Sebanyak 29 lintasan ERT diukur menggunakan konfigurasi dipole-dipole pada dengan jarak antar elektroda 50 cm. Hasil pemodelan inversi dua dimensi (2D) dan tiga dimensi (3D) menunjukkan bahwa metode ERT telah berhasil mencitrakan zona perakaran pohon. Zona perakaran teridentifikasi berada pada nilai resistivitas 100-700 Ωm dengan root plate dan root cross-sections berbentuk elips. Radius akar diperkirakan sejauh 4-5 m dari pangkal batang, sedangkan diameter zona perakaran mencapai sekitar 8-9 m di permukaan tanah dangkal dan kedalaman zona perakaran diperkirakan antara ~2-2.5 m. 


2020 ◽  
Vol 19 (2) ◽  
pp. 77-83
Author(s):  
Yesid Paul Goyes-Peñafiel ◽  
Sait Khurama-Velasquez ◽  
Oleg Nikolaevich-Kovin

Subsurface exploration using geophysical methods has increased the prospective economic possibilities for new non-metallic minerals and other raw materials such as solid hydrocarbons. In this paper, we show results of electrical resistivity tomography (ERT) carried out by using the multi-electrode gradient array, and conducted with the main purpose ofmapping thehighresistivity anomalies relatedto the presence of solid hydrocarbons bodies. ERT profiles were interpreted trough considering the gilsonite evidence on rocky outcrops in the La Luna Formation (Ksl) and their respective lithological contact with the Bocas Formation (Jb). This study concludes that,both on thesurface and in the subsurface, in the stratification plane of La Luna Formation, the gilsonite is a tabular and oblique shape, and the contact Ksl-Jb is faulty with an almost vertical inclination.However,different structural processes have contributed to theirregularformation and massive body of gilsonite. Finally,the study concludes that resistivity tomographies represent a reliable alternative for preliminary exploration stages. Sincethe cost of the methodisrelatively low in Colombia, it also serves as aneconomically viable alternative for small exploratory projects.


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