A new physical barrier system for seawater intrusion control

Antoifi Abdoulhalik, Ashraf Ahmed, G. A. Hamill

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The construction of subsurface physical barriers is one of various methods used to control seawater intrusion (SWI) in coastal aquifers. This study proposes the mixed physical barrier (MPB) as a new barrier system for seawater intrusion control, which combines an impermeable cutoff wall and a semi-permeable subsurface dam. The effect of the traditionally-used physical barriers on transient saltwater wedge dynamics was first explored for various hydraulic gradients, and the workability of the MPB was thereafter thoroughly analysed. A newly developed automated image analysis based on light-concentration conversion was used in the experiments, which were completed in a porous media tank. The numerical code SEAWAT was used to assess the consistency of the experimental data and examine the sensitivity of the performance of the barriers to various key parameters. The results show that the MPB induced a visible lifting of the dense saline flux upward towards the outlet by the light freshwater. This saltwater lifting mechanism, observed for the first time, induced significant reduction to the saline water intrusion length. The use of the MPB yielded up to 62% and 42% more reduction of the saltwater intrusion length than the semi-permeable dam and the cutoff wall, respectively. The performance achieved by the MPB with a wall depth of 40% of the aquifer thickness was greater than that of a single cutoff wall with a penetration depth of 90% of the aquifer thickness (about 13% extra reduction). This means that the MPB could produce better seawater intrusion reduction than the traditionally used barriers at even lower cost.
LanguageEnglish
Pages416-427
Number of pages12
JournalJournal of Hydrology
Volume549
Early online date05 Apr 2017
DOIs
Publication statusPublished - Jun 2017

Fingerprint

cutoff wall
seawater
dam
aquifer
saline intrusion
coastal aquifer
image analysis
porous medium
penetration
hydraulics
cost
experiment
water

Cite this

Abdoulhalik, Antoifi ; Ahmed, Ashraf ; Hamill, G. A. / A new physical barrier system for seawater intrusion control. In: Journal of Hydrology. 2017 ; Vol. 549. pp. 416-427.
@article{9c1bef1fcc0a4d33860fab465249af6b,
title = "A new physical barrier system for seawater intrusion control",
abstract = "The construction of subsurface physical barriers is one of various methods used to control seawater intrusion (SWI) in coastal aquifers. This study proposes the mixed physical barrier (MPB) as a new barrier system for seawater intrusion control, which combines an impermeable cutoff wall and a semi-permeable subsurface dam. The effect of the traditionally-used physical barriers on transient saltwater wedge dynamics was first explored for various hydraulic gradients, and the workability of the MPB was thereafter thoroughly analysed. A newly developed automated image analysis based on light-concentration conversion was used in the experiments, which were completed in a porous media tank. The numerical code SEAWAT was used to assess the consistency of the experimental data and examine the sensitivity of the performance of the barriers to various key parameters. The results show that the MPB induced a visible lifting of the dense saline flux upward towards the outlet by the light freshwater. This saltwater lifting mechanism, observed for the first time, induced significant reduction to the saline water intrusion length. The use of the MPB yielded up to 62{\%} and 42{\%} more reduction of the saltwater intrusion length than the semi-permeable dam and the cutoff wall, respectively. The performance achieved by the MPB with a wall depth of 40{\%} of the aquifer thickness was greater than that of a single cutoff wall with a penetration depth of 90{\%} of the aquifer thickness (about 13{\%} extra reduction). This means that the MPB could produce better seawater intrusion reduction than the traditionally used barriers at even lower cost.",
author = "Antoifi Abdoulhalik and Ashraf Ahmed and Hamill, {G. A.}",
year = "2017",
month = "6",
doi = "10.1016/j.jhydrol.2017.04.005",
language = "English",
volume = "549",
pages = "416--427",
journal = "Journal of Hydrology",
issn = "0022-1694",
publisher = "Elsevier",

}

A new physical barrier system for seawater intrusion control. / Abdoulhalik, Antoifi; Ahmed, Ashraf; Hamill, G. A.

In: Journal of Hydrology, Vol. 549, 06.2017, p. 416-427.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A new physical barrier system for seawater intrusion control

AU - Abdoulhalik, Antoifi

AU - Ahmed, Ashraf

AU - Hamill, G. A.

PY - 2017/6

Y1 - 2017/6

N2 - The construction of subsurface physical barriers is one of various methods used to control seawater intrusion (SWI) in coastal aquifers. This study proposes the mixed physical barrier (MPB) as a new barrier system for seawater intrusion control, which combines an impermeable cutoff wall and a semi-permeable subsurface dam. The effect of the traditionally-used physical barriers on transient saltwater wedge dynamics was first explored for various hydraulic gradients, and the workability of the MPB was thereafter thoroughly analysed. A newly developed automated image analysis based on light-concentration conversion was used in the experiments, which were completed in a porous media tank. The numerical code SEAWAT was used to assess the consistency of the experimental data and examine the sensitivity of the performance of the barriers to various key parameters. The results show that the MPB induced a visible lifting of the dense saline flux upward towards the outlet by the light freshwater. This saltwater lifting mechanism, observed for the first time, induced significant reduction to the saline water intrusion length. The use of the MPB yielded up to 62% and 42% more reduction of the saltwater intrusion length than the semi-permeable dam and the cutoff wall, respectively. The performance achieved by the MPB with a wall depth of 40% of the aquifer thickness was greater than that of a single cutoff wall with a penetration depth of 90% of the aquifer thickness (about 13% extra reduction). This means that the MPB could produce better seawater intrusion reduction than the traditionally used barriers at even lower cost.

AB - The construction of subsurface physical barriers is one of various methods used to control seawater intrusion (SWI) in coastal aquifers. This study proposes the mixed physical barrier (MPB) as a new barrier system for seawater intrusion control, which combines an impermeable cutoff wall and a semi-permeable subsurface dam. The effect of the traditionally-used physical barriers on transient saltwater wedge dynamics was first explored for various hydraulic gradients, and the workability of the MPB was thereafter thoroughly analysed. A newly developed automated image analysis based on light-concentration conversion was used in the experiments, which were completed in a porous media tank. The numerical code SEAWAT was used to assess the consistency of the experimental data and examine the sensitivity of the performance of the barriers to various key parameters. The results show that the MPB induced a visible lifting of the dense saline flux upward towards the outlet by the light freshwater. This saltwater lifting mechanism, observed for the first time, induced significant reduction to the saline water intrusion length. The use of the MPB yielded up to 62% and 42% more reduction of the saltwater intrusion length than the semi-permeable dam and the cutoff wall, respectively. The performance achieved by the MPB with a wall depth of 40% of the aquifer thickness was greater than that of a single cutoff wall with a penetration depth of 90% of the aquifer thickness (about 13% extra reduction). This means that the MPB could produce better seawater intrusion reduction than the traditionally used barriers at even lower cost.

U2 - 10.1016/j.jhydrol.2017.04.005

DO - 10.1016/j.jhydrol.2017.04.005

M3 - Article

VL - 549

SP - 416

EP - 427

JO - Journal of Hydrology

T2 - Journal of Hydrology

JF - Journal of Hydrology

SN - 0022-1694

ER -