Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring

Arnaud Watlet, Olivier Kaufmann, Antoine Triantafyllou, Amaël Poulain, Jonathan E. Chambers, Philip I. Meldrum, Paul B. Wilkinson, Vincent Hallet, Yves Quinif, Michel Van Ruymbeke, Michel Van Camp

Research output: Contribution to journalArticle

14 Downloads (Pure)

Abstract

Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip discharge spots traditionally monitored in caves and aims to support modelling approaches of karst hydrological processes.

Original languageEnglish
Pages (from-to)1563-1592
Number of pages30
JournalHydrology and Earth System Sciences
Volume22
Issue number2
DOIs
Publication statusPublished - 1 Mar 2018

Fingerprint

vadose zone
tomography
karst
electrical resistivity
infiltration
groundwater
monitoring
cave
recharge
porosity
karstification
structural analysis
buffering
geological structure
clay soil
carbonate rock
evapotranspiration
conductivity
seasonal variation
soil moisture

Cite this

Watlet, A., Kaufmann, O., Triantafyllou, A., Poulain, A., Chambers, J. E., Meldrum, P. I., ... Van Camp, M. (2018). Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring. Hydrology and Earth System Sciences, 22(2), 1563-1592. https://doi.org/10.5194/hess-22-1563-2018
Watlet, Arnaud ; Kaufmann, Olivier ; Triantafyllou, Antoine ; Poulain, Amaël ; Chambers, Jonathan E. ; Meldrum, Philip I. ; Wilkinson, Paul B. ; Hallet, Vincent ; Quinif, Yves ; Van Ruymbeke, Michel ; Van Camp, Michel. / Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring. In: Hydrology and Earth System Sciences. 2018 ; Vol. 22, No. 2. pp. 1563-1592.
@article{7a32a4795b9c41dfbb88734a9aa6b197,
title = "Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring",
abstract = "Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip discharge spots traditionally monitored in caves and aims to support modelling approaches of karst hydrological processes.",
author = "Arnaud Watlet and Olivier Kaufmann and Antoine Triantafyllou and Ama{\"e}l Poulain and Chambers, {Jonathan E.} and Meldrum, {Philip I.} and Wilkinson, {Paul B.} and Vincent Hallet and Yves Quinif and {Van Ruymbeke}, Michel and {Van Camp}, Michel",
year = "2018",
month = "3",
day = "1",
doi = "10.5194/hess-22-1563-2018",
language = "English",
volume = "22",
pages = "1563--1592",
journal = "Hydrology and Earth System Sciences",
issn = "1027-5606",
publisher = "European Geosciences Union",
number = "2",

}

Watlet, A, Kaufmann, O, Triantafyllou, A, Poulain, A, Chambers, JE, Meldrum, PI, Wilkinson, PB, Hallet, V, Quinif, Y, Van Ruymbeke, M & Van Camp, M 2018, 'Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring', Hydrology and Earth System Sciences, vol. 22, no. 2, pp. 1563-1592. https://doi.org/10.5194/hess-22-1563-2018

Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring. / Watlet, Arnaud; Kaufmann, Olivier; Triantafyllou, Antoine; Poulain, Amaël; Chambers, Jonathan E.; Meldrum, Philip I.; Wilkinson, Paul B.; Hallet, Vincent; Quinif, Yves; Van Ruymbeke, Michel; Van Camp, Michel.

In: Hydrology and Earth System Sciences, Vol. 22, No. 2, 01.03.2018, p. 1563-1592.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Imaging groundwater infiltration dynamics in the karst vadose zone with long-term ERT monitoring

AU - Watlet, Arnaud

AU - Kaufmann, Olivier

AU - Triantafyllou, Antoine

AU - Poulain, Amaël

AU - Chambers, Jonathan E.

AU - Meldrum, Philip I.

AU - Wilkinson, Paul B.

AU - Hallet, Vincent

AU - Quinif, Yves

AU - Van Ruymbeke, Michel

AU - Van Camp, Michel

PY - 2018/3/1

Y1 - 2018/3/1

N2 - Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip discharge spots traditionally monitored in caves and aims to support modelling approaches of karst hydrological processes.

AB - Water infiltration and recharge processes in karst systems are complex and difficult to measure with conventional hydrological methods. In particular, temporarily saturated groundwater reservoirs hosted in the vadose zone can play a buffering role in water infiltration. This results from the pronounced porosity and permeability contrasts created by local karstification processes of carbonate rocks. Analyses of time-lapse 2-D geoelectrical imaging over a period of 3 years at the Rochefort Cave Laboratory (RCL) site in south Belgium highlight variable hydrodynamics in a karst vadose zone. This represents the first long-term and permanently installed electrical resistivity tomography (ERT) monitoring in a karst landscape. The collected data were compared to conventional hydrological measurements (drip discharge monitoring, soil moisture and water conductivity data sets) and a detailed structural analysis of the local geological structures providing a thorough understanding of the groundwater infiltration. Seasonal changes affect all the imaged areas leading to increases in resistivity in spring and summer attributed to enhanced evapotranspiration, whereas winter is characterised by a general decrease in resistivity associated with a groundwater recharge of the vadose zone. Three types of hydrological dynamics, corresponding to areas with distinct lithological and structural features, could be identified via changes in resistivity: (D1) upper conductive layers, associated with clay-rich soil and epikarst, showing the highest variability related to weather conditions; (D2) deeper and more resistive limestone areas, characterised by variable degrees of porosity and clay contents, hence showing more diffuse seasonal variations; and (D3) a conductive fractured zone associated with damped seasonal dynamics, while showing a great variability similar to that of the upper layers in response to rainfall events. This study provides detailed images of the sources of drip discharge spots traditionally monitored in caves and aims to support modelling approaches of karst hydrological processes.

UR - http://www.scopus.com/inward/record.url?scp=85042710871&partnerID=8YFLogxK

U2 - 10.5194/hess-22-1563-2018

DO - 10.5194/hess-22-1563-2018

M3 - Article

AN - SCOPUS:85042710871

VL - 22

SP - 1563

EP - 1592

JO - Hydrology and Earth System Sciences

JF - Hydrology and Earth System Sciences

SN - 1027-5606

IS - 2

ER -