Regional-scale analysis of the effect of managed aquifer recharge on saltwater intrusion in irrigated coastal aquifers: long-term groundwater observations and model simulations in NE Tunisia

Sarra Bachtouli (Corresponding Author), Jean-Christophe Comte

Research output: Contribution to journalArticle

Abstract

In overexploited coastal aquifers threatened or affected by saline intrusion, managed aquifer recharge (MAR) is increasingly applied in the aim of maintaining or recovering freshwater quantity and quality. The long-term regionalscale effectiveness of MAR, however, lacks field examples. The Korba coastal aquifer (Tunisia) has been increasingly overexploited since the 1960s and intensively studied over the last few decades. Groundwater abstraction has resulted in a decline of groundwater levels and a dramatic increase in salinity through both lateral seawater intrusion and shallow salinization from irrigation. MAR strategies, including freshwater injection wells and sewage-water infiltration basins, have been progressively implemented since 1990. Using 50 years of groundwater head and salinity records, a regional three-dimensional numerical groundwater model is calibrated to study the spatiotemporal dynamics of groundwater salinization including the past and future impact of the MAR operations. Results suggest that lateral seawater intrusion
from the coast and shallow infiltration of evapoconcentrated saline irrigation water are the two interlinked dominant regional processes of groundwater salinization, equivalent in magnitude. In accordance with the groundwater
observations, simulated historical MAR operations are shown to have contributed to slowdown and stabilized the regional salinization, which contrasts with the steady rise that is obtained in the hypothetical absence of MAR. The
future MAR simulation scenarios suggest that spatial management of irrigation supplies and injection points from dam freshwater has a potential for further reducing the salinization of shallow groundwater and potentially reversing the
inland progression of the seawater front. Further works should look at reconciling modelling recommendations with management practice options.
Original languageEnglish
Pages (from-to)91-110
Number of pages19
JournalJournal of Coastal Research
Volume35
Issue number1
DOIs
Publication statusPublished - 1 Jan 2019

Fingerprint

saline intrusion
coastal aquifer
recharge
salinization
aquifer
groundwater
simulation
irrigation
seawater
infiltration
groundwater abstraction
salinity
analysis
effect
management practice
sewage
dam
well
water
coast

Keywords

  • irrigated agriculture
  • groundwater management
  • Irrigated agriculture
  • AREA
  • BAJA-CALIFORNIA
  • SEAWATER INTRUSION
  • ARTIFICIAL RECHARGE
  • EXAMPLE
  • SALINIZATION
  • FRESH
  • CAP-BON

ASJC Scopus subject areas

  • Water Science and Technology
  • Earth-Surface Processes
  • Ecology

Cite this

@article{01a0adfb10744cc884a05deb885c3a52,
title = "Regional-scale analysis of the effect of managed aquifer recharge on saltwater intrusion in irrigated coastal aquifers: long-term groundwater observations and model simulations in NE Tunisia",
abstract = "In overexploited coastal aquifers threatened or affected by saline intrusion, managed aquifer recharge (MAR) is increasingly applied in the aim of maintaining or recovering freshwater quantity and quality. The long-term regionalscale effectiveness of MAR, however, lacks field examples. The Korba coastal aquifer (Tunisia) has been increasingly overexploited since the 1960s and intensively studied over the last few decades. Groundwater abstraction has resulted in a decline of groundwater levels and a dramatic increase in salinity through both lateral seawater intrusion and shallow salinization from irrigation. MAR strategies, including freshwater injection wells and sewage-water infiltration basins, have been progressively implemented since 1990. Using 50 years of groundwater head and salinity records, a regional three-dimensional numerical groundwater model is calibrated to study the spatiotemporal dynamics of groundwater salinization including the past and future impact of the MAR operations. Results suggest that lateral seawater intrusionfrom the coast and shallow infiltration of evapoconcentrated saline irrigation water are the two interlinked dominant regional processes of groundwater salinization, equivalent in magnitude. In accordance with the groundwaterobservations, simulated historical MAR operations are shown to have contributed to slowdown and stabilized the regional salinization, which contrasts with the steady rise that is obtained in the hypothetical absence of MAR. Thefuture MAR simulation scenarios suggest that spatial management of irrigation supplies and injection points from dam freshwater has a potential for further reducing the salinization of shallow groundwater and potentially reversing theinland progression of the seawater front. Further works should look at reconciling modelling recommendations with management practice options.",
keywords = "irrigated agriculture, groundwater management, Irrigated agriculture, AREA, BAJA-CALIFORNIA, SEAWATER INTRUSION, ARTIFICIAL RECHARGE, EXAMPLE, SALINIZATION, FRESH, CAP-BON",
author = "Sarra Bachtouli and Jean-Christophe Comte",
note = "We acknowledge the DGRE of Tunisia and the Regional Commissariat of Agricultural Development of Nabeul (CRDANabeul) for providing access to the technical hydrogeological data of the Eastern Coastal Aquifer of Cap Bon (piezometric and groundwater salinity monitoring, irrigation, groundwater abstraction, and recharge). We also acknowledge the funding from the Tunisian Ministry of Higher Education and Scientific Research for supporting summer placements in Queen's University Belfast and the University of Aberdeen (2014 and 2015). We expand our acknowledgments to three anonymous reviewers for their relevant comments that contributed to improve the final manuscript.",
year = "2019",
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doi = "10.2112/JCOASTRES-D-17-00174.1",
language = "English",
volume = "35",
pages = "91--110",
journal = "Journal of Coastal Research",
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TY - JOUR

T1 - Regional-scale analysis of the effect of managed aquifer recharge on saltwater intrusion in irrigated coastal aquifers

T2 - long-term groundwater observations and model simulations in NE Tunisia

AU - Bachtouli, Sarra

AU - Comte, Jean-Christophe

N1 - We acknowledge the DGRE of Tunisia and the Regional Commissariat of Agricultural Development of Nabeul (CRDANabeul) for providing access to the technical hydrogeological data of the Eastern Coastal Aquifer of Cap Bon (piezometric and groundwater salinity monitoring, irrigation, groundwater abstraction, and recharge). We also acknowledge the funding from the Tunisian Ministry of Higher Education and Scientific Research for supporting summer placements in Queen's University Belfast and the University of Aberdeen (2014 and 2015). We expand our acknowledgments to three anonymous reviewers for their relevant comments that contributed to improve the final manuscript.

PY - 2019/1/1

Y1 - 2019/1/1

N2 - In overexploited coastal aquifers threatened or affected by saline intrusion, managed aquifer recharge (MAR) is increasingly applied in the aim of maintaining or recovering freshwater quantity and quality. The long-term regionalscale effectiveness of MAR, however, lacks field examples. The Korba coastal aquifer (Tunisia) has been increasingly overexploited since the 1960s and intensively studied over the last few decades. Groundwater abstraction has resulted in a decline of groundwater levels and a dramatic increase in salinity through both lateral seawater intrusion and shallow salinization from irrigation. MAR strategies, including freshwater injection wells and sewage-water infiltration basins, have been progressively implemented since 1990. Using 50 years of groundwater head and salinity records, a regional three-dimensional numerical groundwater model is calibrated to study the spatiotemporal dynamics of groundwater salinization including the past and future impact of the MAR operations. Results suggest that lateral seawater intrusionfrom the coast and shallow infiltration of evapoconcentrated saline irrigation water are the two interlinked dominant regional processes of groundwater salinization, equivalent in magnitude. In accordance with the groundwaterobservations, simulated historical MAR operations are shown to have contributed to slowdown and stabilized the regional salinization, which contrasts with the steady rise that is obtained in the hypothetical absence of MAR. Thefuture MAR simulation scenarios suggest that spatial management of irrigation supplies and injection points from dam freshwater has a potential for further reducing the salinization of shallow groundwater and potentially reversing theinland progression of the seawater front. Further works should look at reconciling modelling recommendations with management practice options.

AB - In overexploited coastal aquifers threatened or affected by saline intrusion, managed aquifer recharge (MAR) is increasingly applied in the aim of maintaining or recovering freshwater quantity and quality. The long-term regionalscale effectiveness of MAR, however, lacks field examples. The Korba coastal aquifer (Tunisia) has been increasingly overexploited since the 1960s and intensively studied over the last few decades. Groundwater abstraction has resulted in a decline of groundwater levels and a dramatic increase in salinity through both lateral seawater intrusion and shallow salinization from irrigation. MAR strategies, including freshwater injection wells and sewage-water infiltration basins, have been progressively implemented since 1990. Using 50 years of groundwater head and salinity records, a regional three-dimensional numerical groundwater model is calibrated to study the spatiotemporal dynamics of groundwater salinization including the past and future impact of the MAR operations. Results suggest that lateral seawater intrusionfrom the coast and shallow infiltration of evapoconcentrated saline irrigation water are the two interlinked dominant regional processes of groundwater salinization, equivalent in magnitude. In accordance with the groundwaterobservations, simulated historical MAR operations are shown to have contributed to slowdown and stabilized the regional salinization, which contrasts with the steady rise that is obtained in the hypothetical absence of MAR. Thefuture MAR simulation scenarios suggest that spatial management of irrigation supplies and injection points from dam freshwater has a potential for further reducing the salinization of shallow groundwater and potentially reversing theinland progression of the seawater front. Further works should look at reconciling modelling recommendations with management practice options.

KW - irrigated agriculture

KW - groundwater management

KW - Irrigated agriculture

KW - AREA

KW - BAJA-CALIFORNIA

KW - SEAWATER INTRUSION

KW - ARTIFICIAL RECHARGE

KW - EXAMPLE

KW - SALINIZATION

KW - FRESH

KW - CAP-BON

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U2 - 10.2112/JCOASTRES-D-17-00174.1

DO - 10.2112/JCOASTRES-D-17-00174.1

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JO - Journal of Coastal Research

JF - Journal of Coastal Research

SN - 0749-0208

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