scholarly journals Saltwater Intrusion Appraisal of Shallow Aquifer in Burutu Area of the Western Niger Delta with 2D Electrical Resistivity Tomography

2017 ◽  
Vol 21 (2) ◽  
pp. 372 ◽  
Author(s):  
Oghenero Ohwoghere-Asuma ◽  
L. Felix Chinyem ◽  
Oghenevovwero Emmanuel Essi
Keyword(s):  
Electrical Resistivity ◽  
Niger Delta ◽  
Saltwater Intrusion ◽  
Electrical Resistivity Tomography ◽  
Shallow Aquifer ◽  
Resistivity Tomography

scholarly journals Interpretasi Electrical Resistivity Tomography (ERT) untuk Pendugaan Air Tanah Dangkal pada Formasi Gunungapi Muda

2020 ◽  
Vol 3 (1) ◽  
pp. 49 ◽  
Author(s):  
Erik Febriarta ◽  
Suswanti Suswanti ◽  
Sembodo Noviandaru
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Soil Surface ◽  
Igneous Rocks ◽  
Shallow Aquifer ◽  
Rock Outcrops ◽  
Resistivity Tomography ◽  
Surface Appearance ◽  
Hydrogeological Characteristics ◽  
Groundwater Basin

Aquifers or groundwater saturated areas in the slope morphology of Merapi volcano are relatively thin due to massive rock outcrops above the surface. Because these massive igneous rocks dominate the local geological appearance, the groundwater potential on the upper foot slope is relatively lower than the lower one that has thicker aquifer materials (sand). This study was designed to investigate the thickness of potential groundwater and identify the aquifer materials by geoelectrical methods using the Electrical Resistivity Tomography (ERT) configuration. ERT has several advantages, including its ability to present multi-log lithology vertically and produce a more detailed surface appearance. In this study, rock resistivity values were measured with a survey line stretching across 250 m. The geoelectrical imaging produced actual values (potential values) of the rock resistivities through the matching curve and inversion techniques. Afterward, the actual resistivities were matched with the standard electrical resistivity of rocks and their respective hydrogeological characteristics, i.e., the capacity to store and transmit water. Interpretation on rock resistivities detected groundwater at a depth of 0.5-12 m in Manisrenggo. This shallow aquifer has an impermeable layer composed of igneous rocks, which are massive breccia, that lie in one layer of sand. According to the Groundwater Basin Map, these rock formations are part of the Karanganyar-Boyolali Groundwater Basin. The shallow aquifers and hydraulic gradient lead to the emergence of seeps or flushes on the soil surface.

scholarly journals A new approach for time-lapse data weighting in electrical resistivity tomography

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. E325-E333 ◽  
Author(s):  
Nolwenn Lesparre ◽  
Frederic Nguyen ◽  
Andreas Kemna ◽  
Tanguy Robert ◽  
Thomas Hermans ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Time Lapse ◽  
Shallow Aquifer ◽  
Data Sets ◽  
Resistivity Tomography ◽  
New Approach ◽  
Data Weighting ◽  
Data Error ◽  
Over Time

Applications of time-lapse inversion of electrical resistivity tomography allow monitoring variations in the subsurface that play a key role in a variety of contexts. The inversion of time-lapse data provides successive images of the subsurface properties showing the medium evolution. Image quality is highly dependent on the data weighting determined from the data error estimates. However, the quantification of errors in the inversion of time-lapse data has not yet been addressed. We have developed a methodology for the quantification of time-lapse data error based on the analysis of the discrepancy between normal and reciprocal readings acquired at different times. We applied the method to field monitoring data sets collected during the injection of heated water in a shallow aquifer. We tested different error models to indicate that the use of an appropriate time-lapse data error estimate yielded significant improvements in terms of imaging. An adapted inversion weighting for time-lapse data implies that the procedure does not allow an over-fitting of the data, so the presence of artifacts in the resulting images is greatly reduced. Our results determined that a proper estimate of time-lapse data error is mandatory for weighting optimally the inversion to obtain images that best reflect the evolution of medium properties over time.

scholarly journals Imaging the extent of saltwater intrusion in the Luy river coastal aquifer (Binh Thuan) using electrical resistivity tomography (ERT)

2021 ◽  
Author(s):  
Cong-Thi Diep
Keyword(s):  
Electrical Resistivity ◽  
Coastal Aquifer ◽  
Saltwater Intrusion ◽  
Electrical Resistivity Tomography ◽  
Salt Water ◽  
Groundwater Resources ◽  
Left Bank ◽  
Resistivity Tomography ◽  
South Central ◽  
Recharge Sources

<p><strong>Imaging the extent of salt water intrusion in the Luy river coastal aquifer (Binh Thuan) using electrical resistivity tomography (ERT)</strong></p><p>Diep Cong-Thi<sup>1,3</sup>, Linh Pham Dieu<sup>1,3</sup>, Robin Thibaut<sup>1</sup>, Marieke Paepen<sup>1</sup>, Hieu Huu Ho<sup>3</sup>,</p><p>Frédéric Nguyen<sup>2</sup>, Thomas Hermans<sup>1</sup></p><p><sup> </sup></p><p><sup>1</sup>Department of Geology,<sup></sup>Ghent University, 9000-Gent, Belgium</p><p><sup>2 </sup>Department of Urban and Environmental Engineering,<sup></sup>Liege University and Department of Civil Engineering, KU Leuven, B- 4000 Liège and 3000 Leuven, Belgium</p><p><sup>3 </sup>Department of Marine Geology, Vietnam Institute of Geosciences and Mineral Resources (VIGMR), 100000 Hanoi, Vietnam</p><p>  ABSTRACT</p><p>Seawater intrusion has been one of the most concerning issues of the Vietnam South Central provinces in recent years, especially in the Binh Thuan province which is characterized by a hyper-arid climate. During the dry season extending from November to April, seawater intrudes through estuaries and threatens groundwater resources. The latter are under increasing pressure due to water extraction for agri- and aquaculture. To evaluate the current state of salinity in the shallow coastal aquifer, 21 electrical resistivity tomography (ERT) measurements were collected along the downstream part of the Luy river based on the previous saltwater intrusion boundary which was estimated from water samples collected from shallow boreholes. The data were inverted to get the resistivity distribution of the subsurface and interpreted in terms of salinity. Comparison with well data shows that resistivity values below 6.5 Ohm.m correspond to the presence of saltwater in the aquifers. On the right bank of the river, a higher elevation dune area contains a freshwater aquifer which limits the intrusion of saltwater. On the left bank dominated by lowland areas, saline water fills almost the entire thickness of the aquifer, except locally for small thin freshwater lenses. At larger distances from the sea, the aquifer displays a complex distribution of fresh and saline lenses. Those variations seem to be correlated with the presence of clay lenses, recharge sources and irrigation practices. ERT data also reveals the depth of the rock basement. The geophysical observations show that the extension of saltwater intrusion is much larger and more complex than expected from existing borehole data and is not limited to interaction with the river.</p><p>KEYWORDS: saltwater intrusion, groundwater, electrical resistivity tomography, Luy river. <sup> </sup></p><p>*Corresponding Authors. Email: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]; [email protected]</p>

scholarly journals Geoelectrical Surveys for Characterization of the Coastal Saltwater Intrusion in Metapontum Forest Reserve (Southern Italy)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Antonio Satriani ◽  
Antonio Loperte ◽  
Vito Imbrenda ◽  
Vincenzo Lapenna
Keyword(s):  
Electrical Resistivity ◽  
High Resolution ◽  
Saltwater Intrusion ◽  
Electrical Resistivity Tomography ◽  
Southern Italy ◽  
Soil Salinization ◽  
Forest Reserve ◽  
Resistivity Tomography ◽  
Integrated Study

A geoelectrical survey was carried out in the Metapontum Forest Reserve located along the Ionian coast of the Basilicata region (Southern Italy). In this work we used the method of two-dimensional electrical resistivity tomography for obtaining high-resolution electrical images in the investigated site. In particular, three electrical resistivity tomography, all orthogonal to the coastline, in the investigated area were carried out. To complete and integrate the geophysical data, soil and groundwater samplings, seventeen and five, respectively, were analyzed using chemical physical techniques. Geoelectrical survey, supported by laboratory analysis of soil and water samples have revealed the presence of a process of saltwater in coastal Forest Reserve of Metapontum, which have caused the decline of the existing pine forest with the consequent erosion and desertification problems. The results have disclosed the way to identify and discriminate large areas affected by intensive soil salinization and high resolution electrical images of the subsurface electrical resistivity plays a key role in delineating the saltwater intrusion front in coastal areas. Furthermore, our integrated study represents a contribution to the future programs for the protection, planning, and management of the terrestrial and marine resources in this coastal area.

scholarly journals High-Resolution Electrical Resistivity Tomography (ERT) to Characterize the Spatial Extension of Freshwater Lenses in a Salinized Coastal Aquifer

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 1067 ◽  
Author(s):  
Nicolas Greggio ◽  
Beatrice Giambastiani ◽  
Enrico Balugani ◽  
Chiara Amaini ◽  
Marco Antonellini
Keyword(s):  
Electrical Resistivity ◽  
High Resolution ◽  
Electrical Resistivity Tomography ◽  
Decision Makers ◽  
Shallow Aquifer ◽  
Electrode Spacing ◽  
Coastal Zones ◽  
Aquifer Recharge ◽  
Resistivity Tomography ◽  
Freshwater Lenses

High-resolution electrical resistivity tomography (ERT) with electrode spacing of 1 m proved to be an effective methodology to characterize ephemeral, sparse, and discontinuous freshwater lenses within the almost completely salinized shallow aquifer of the low coastal zone near Ravenna. ERT profiles with a vertical resolution of 0.25–0.5 m, once calibrated with groundwater data (water table depth and electrical conductivity) collected in multi-level sampler systems at the same spatial resolution, are reliable and provide repeatable measurements in time. The ERT methodology allows for fast data acquisition over large areas and it also permits the study of the evolution in time of freshwater availability in coastal zones, which is important for local ecosystems and soil resources. This makes high-resolution ERT a valid tool to aid local stakeholders and decision makers to effectively manage freshwater lenses, and guarantee their preservation or augmentation by means of managed aquifer recharge.

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