Time-lapse cross-hole electrical resistivity tomography (CHERT) for
monitoring seawater intrusion dynamics in a Mediterranean aquifer

Pierluissi, Andrea Palacios; Ledo, Juanjo; Linde, Niklas; Carrera, Jesús

doi:10.5194/hess-2019-408

Cited by 7 publications

(6 citation statements)

References 30 publications

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“…At our study site, the significant increase (1 order of magnitude; Fig. 4) in both the terrestrial and marine SGD after EPE, may be mediated by different processes: (1) increase of terrestrial groundwater discharge due to aquifer infiltration of rainfall, subsequent increase of hydraulic gradient, and displacement of stored water towards the sea (Anwar et al, 2014;Palacios et al, 2019;Santos et al, 2012;Yu et al, 2017), (2) increase in the exchange of seawater and density-driven discharge due to movements of the fresh-saltwater mixing zone, and (3) increase of shoreface circulation of seawater and porewater exchange due to the effect of sea level rise and waves associated with the EPE (Fig. 2).…”

Section: Episodic Eventsmentioning

confidence: 90%

“…2). As inferred by electric resistivity tomography profiles shown in Palacios et al (2019), conductivity variations in the piezometric wells of the study site were not derived from dilution with low-conductivity rainwater, but associated with the movement of the mixing zone due to EPE. Significant wave height fluctuations occurred, associated mainly with changes in wind and atmospheric pressure during the EPEs, increasing rapidly from 2 to 5 m above the baseline value of approximately 0.5 m. Similarly, the MSL presented oscillations linked to the EPE, which are usually associated with atmospheric fronts and strong winds, and also to seasonal meteorology, with higher MSL values from October to December than from January to April.…”

Section: Meteorological and Hydrological Contextmentioning

confidence: 94%

“…Groundwater samples for Ra isotopes (10 -25 L) and nutrients were collected periodically from 2015 to 2020 in several piezometers at the experimental site of the Medistraes project, located in the coastal alluvial aquifer of the Argentona ephemeral stream (corresponding to Transect 1). The experimental site consists of 16 piezometers located at 30 to 100 m from the coastline with screened depths of 15 to 25 m, with 2 m screened intervals for each (see Folch et al, 2020;Palacios et al, 2019, for more details about the experimental site; Fig. 1).…”

Section: Field Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Extreme precipitation events induce high fluxes of groundwater and associated nutrients to the coastal ocean

Diego-Feliu

Rodellas

Alorda-Kleinglass

et al. 2022

Preprint

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Abstract. Current Submarine Groundwater Discharge (SGD) studies are commonly conducted under aquifer baseflow conditions, neglecting the influence of episodic events that can significantly increase the supply of nutrients and water. This limits our understanding of the social, biogeochemical, and ecological impacts of SGD. In this study, we evaluated the influence of an extreme precipitation event (EPE) on the magnitude of both the terrestrial and marine components of SGD. To do so, three seawater sampling campaigns were performed at a Mediterranean ephemeral stream-dominated basin after an extreme precipitation event (~90 mm in few hours) and in baseflow conditions. Results indicate that the groundwater flows of terrestrial and marine SGD after the extreme precipitation event were 1 order of magnitude higher than those in baseflow conditions. SGD induced by extreme precipitation events, which only take place a few days per year, represented up to one third of the annual discharge of groundwater and associated nutrients at the study site. This work accentuates the need to account for episodic increases in the supply of water and nutrients when aiming at providing reliable annual SGD estimates, particularly in the current context of climate change, since the occurrence of such events is expected to increase worldwide.

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Section: Episodic Eventsmentioning

confidence: 90%

Section: Meteorological and Hydrological Contextmentioning

confidence: 94%

Section: Field Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Extreme precipitation events induce high fluxes of groundwater and associated nutrients to the coastal ocean

Diego-Feliu

Rodellas

Alorda-Kleinglass

et al. 2022

Preprint

Self Cite

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“…This, together with the reducing conditions fonded at the deepest part of the site (Martínez-Pérez et al 2018, Internal communication), should ensure reliable operation for the foreseeable duration of the project. More details in the CHERT configuration can be found in Palacios et al 2020. The installation stage consisted of fixing electrodes and fiber optic lines to the casing by means of nylon flanges, which effectively acted as centralizers to protect the two lines ( Figure 3). Had the wells been deeper, more sturdy protection and centering system would have been needed.…”

Section: Installation Of Annulus Fiber Optic Cable and Electrodes Durmentioning

confidence: 99%

Combining fiber optic DTS, cross-hole ERT and time-lapse induction logging to characterize and monitor a coastal aquifer

Folch

Val

Luquot

et al. 2020

Journal of Hydrology

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…de Franco et al, 2009 ;Ogilvy et al, 2009). Coastal long-term time lapse cross-hole ERT was used to improve knowledge of SI at the Argentona site (Palacios et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Combining resistivity and frequency domain electromagnetic methods to investigate submarine groundwater discharge (SGD) in the littoral zone

Paepen¹,

Hanssens²,

Smedt³

et al. 2020

Preprint

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Abstract. Submarine groundwater discharge (SGD) is an important gateway for nutrients and pollutants from land to sea. The study of SGD is thus important for nearshore ecosystems and the management of coastal freshwater reserves. The discharge occurs at the limit between land and sea, a dynamic environment, making the assessment difficult. And more important, SGD is characterized by a significant spatial and temporal variability. Therefore, a variety of techniques and measurements in multiple periods is needed to capture the magnitude of SGD in one particular site. To detect zones of discharge, we combine several geophysical methods in the intertidal zone, as well as on the upper beach, in the dunes, and shallow coastal area. Electrical resistivity tomography (ERT) – on land, roll-along ERT and on sea, marine continuous resistivity profiling (CRP) – is used from the shallow continental shelf up to the dunes, combined to frequency domain electromagnetics (FDEM) mapping in the intertidal zone. The highly saline environment we work in causes FDEM instruments operated under low induction number (LIN) to underestimate the apparent electrical conductivity (ECa). Here, we apply a quadrature-phase algorithm to obtain a robust ECa (rECa), valid at low and high induction numbers. De Westhoek (Belgium) was chosen as a test site, which is bordered by the North Sea. It is a strong dynamic environment, with semi-diurnal tides between 3 and 5 m. Providing approximately 6 hours between low and high tide, this leaves little time to work close to the low water line. CRP is usually applied in calmer conditions, but we prove that a survey is possible on the North Sea, providing additional information to the ERT survey which is mainly restricted to the land. The 2D inversion models created from ERT and CRP data clearly indicate the presence of SGD on the lower beach (in the East) or below the low water line (in the West of the study area). The discharge originates from a potable freshwater lens underneath the dunes, which delimit the sandy beach. The fresh groundwater flows underneath a thick saltwater lens, present from the dunes to the lower beach, which is fully observed with ERT. FDEM mapping reveals discharge at the same locations and clearly displays the lateral variation of the zone of discharge. ERT, CRP, and FDEM are complementary tools in the investigation of SGD. They provide a high-resolution 3D image of the salt and freshwater distribution in phreatic coastal aquifer over a relatively large area, both off- and onshore.

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Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer

Cited by 7 publications

References 30 publications

Extreme precipitation events induce high fluxes of groundwater and associated nutrients to the coastal ocean

Extreme precipitation events induce high fluxes of groundwater and associated nutrients to the coastal ocean

Combining fiber optic DTS, cross-hole ERT and time-lapse induction logging to characterize and monitor a coastal aquifer

Combining resistivity and frequency domain electromagnetic methods to investigate submarine groundwater discharge (SGD) in the littoral zone

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