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

Détails

Ressource 1Télécharger: 2020_Palacios_et_al_HESS.pdf (11421.57 [Ko])
Etat: Public
Version: Final published version
Licence: CC BY 4.0
ID Serval
serval:BIB_85A6351E7C6B
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer
Périodique
Hydrology and Earth System Sciences
Auteur⸱e⸱s
Palacios Andrea, Ledo Juan José, Linde Niklas, Luquot Linda, Bellmunt Fabian, Folch Albert, Marcuello Alex, Queralt Pilar, Pezard Philippe A., Martínez Laura, del Val Laura, Bosch David, Carrera Jesús
ISSN
1607-7938
Statut éditorial
Publié
Date de publication
30/04/2020
Volume
24
Numéro
4
Pages
2121-2139
Langue
anglais
Résumé
Surface electrical resistivity tomography (ERT) is a widely used tool to study seawater intrusion (SWI). It is noninvasive and offers a high spatial coverage at a low cost, but its imaging capabilities are strongly affected by decreasing resolution with depth. We conjecture that the use of CHERT (cross-hole ERT) can partly overcome these resolution limitations since the electrodes are placed at depth, which implies that the model resolution does not decrease at the depths of interest. The objective of this study is to test the CHERT for imaging the SWI and monitoring its dynamics at the Argentona site, a well-instrumented field site of a coastal alluvial aquifer located 40 km NE of Barcelona. To do so, we installed permanent electrodes around boreholes attached to the PVC pipes to perform time-lapse monitoring of the SWI on a transect perpendicular to the coastline. After 2 years of monitoring, we observe variability of SWI at different timescales: (1) natural seasonal variations and aquifer salinization that we attribute to long-term drought and (2) short-term fluctuations due to sea storms or flooding in the nearby stream during heavy rain events. The spatial imaging of bulk electrical conductivity allows us to explain non-monotonic salinity profiles in open boreholes (step-wise profiles really reflect the presence of freshwater at depth). By comparing CHERT results with traditional in situ measurements such as electrical conductivity of water samples and bulk electrical conductivity from induction logs, we conclude that CHERT is a reliable and cost-effective imaging tool for monitoring SWI dynamics.
Web of science
Open Access
Oui
Financement(s)
Commission Européenne / H2020 / 722028
Création de la notice
03/08/2021 21:06
Dernière modification de la notice
04/08/2021 6:11
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