Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning

Previous studies on saltwater up-coning are mostly based on the assumption of a homogeneous aquifer and neglect the effect of heterogeneity. A numerical study was carried out to explore the impact of a low-permeability (k) layer on the pumping efficiency under threats of saltwater up-coning. It is f...

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Main Authors: Zhenyu Wu, Maozhu Tang, Edoardo Daly, Chunhui Lu
Format: Article
Language:English
Published: Frontiers Media S.A. 2022-07-01
Series:Frontiers in Environmental Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fenvs.2022.946112/full
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author Zhenyu Wu
Maozhu Tang
Edoardo Daly
Chunhui Lu
author_facet Zhenyu Wu
Maozhu Tang
Edoardo Daly
Chunhui Lu
author_sort Zhenyu Wu
collection DOAJ
description Previous studies on saltwater up-coning are mostly based on the assumption of a homogeneous aquifer and neglect the effect of heterogeneity. A numerical study was carried out to explore the impact of a low-permeability (k) layer on the pumping efficiency under threats of saltwater up-coning. It is found that the presence of the low-k layer could impede up-coning of saltwater, thereby improving significantly pumping efficiency, as expected. For the cases adopted, when the permeability of the 2 m thick low-k layer is three orders of magnitude less than that of the corresponding homogeneous aquifer, the pumping duration (i.e., the time before the salinity of pumped water reaches 2%) can be up to about 10 times longer than that of the homogeneous aquifer case. Additionally, a sound linear relationship could be developed between the normalized pumping duration of the layered case (E) (defined as the difference of the pumping duration between layered and homogeneous cases relative to the pumping duration in the homogeneous case) and the permeability of the homogeneous aquifer relative to that of the low-k layer (β). However, a short low-k layer may lead to the failure of this linear relationship. Moreover, a thicker low-k layer leads to a larger E when all other conditions are unchanged. When varying the location of the low-k layer, the large E occurs for the low-k layer located below and near the well bottom. The results obtained in the current study offer significant implications for preventing saltwater up-coning and improving the pumping efficiency through natural and artificial barriers.
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spelling doaj.art-23f0a86f8075496894fa11dc813722072022-12-22T00:34:32ZengFrontiers Media S.A.Frontiers in Environmental Science2296-665X2022-07-011010.3389/fenvs.2022.946112946112Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-ConingZhenyu Wu0Maozhu Tang1Edoardo Daly2Chunhui Lu3State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, ChinaDepartment of Civil Engineering, Monash University, Clayton, VIC, AustraliaDepartment of Civil Engineering, Monash University, Clayton, VIC, AustraliaState Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing, ChinaPrevious studies on saltwater up-coning are mostly based on the assumption of a homogeneous aquifer and neglect the effect of heterogeneity. A numerical study was carried out to explore the impact of a low-permeability (k) layer on the pumping efficiency under threats of saltwater up-coning. It is found that the presence of the low-k layer could impede up-coning of saltwater, thereby improving significantly pumping efficiency, as expected. For the cases adopted, when the permeability of the 2 m thick low-k layer is three orders of magnitude less than that of the corresponding homogeneous aquifer, the pumping duration (i.e., the time before the salinity of pumped water reaches 2%) can be up to about 10 times longer than that of the homogeneous aquifer case. Additionally, a sound linear relationship could be developed between the normalized pumping duration of the layered case (E) (defined as the difference of the pumping duration between layered and homogeneous cases relative to the pumping duration in the homogeneous case) and the permeability of the homogeneous aquifer relative to that of the low-k layer (β). However, a short low-k layer may lead to the failure of this linear relationship. Moreover, a thicker low-k layer leads to a larger E when all other conditions are unchanged. When varying the location of the low-k layer, the large E occurs for the low-k layer located below and near the well bottom. The results obtained in the current study offer significant implications for preventing saltwater up-coning and improving the pumping efficiency through natural and artificial barriers.https://www.frontiersin.org/articles/10.3389/fenvs.2022.946112/fulllow-permeability layerup-coningnumerical modellingpumping efficiencygroundwater
spellingShingle Zhenyu Wu
Maozhu Tang
Edoardo Daly
Chunhui Lu
Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
Frontiers in Environmental Science
low-permeability layer
up-coning
numerical modelling
pumping efficiency
groundwater
title Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
title_full Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
title_fullStr Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
title_full_unstemmed Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
title_short Impact of a Low-Permeability Layer on the Pumping Efficiency Under Threats of Saltwater Up-Coning
title_sort impact of a low permeability layer on the pumping efficiency under threats of saltwater up coning
topic low-permeability layer
up-coning
numerical modelling
pumping efficiency
groundwater
url https://www.frontiersin.org/articles/10.3389/fenvs.2022.946112/full
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