Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers

This investigation concerns the establishing of theoretical framework of a numerical model which governs the selective withdrawal from a densitystratified groundwater reservoir to meet a certain desired water quality constraint. The general class of groundwater systems consists of a saturated porou...

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Main Author:	Jong, Tze Yong
Format:	Thesis
Language:	English English
Published:	2000
Subjects:	Ground Water - Pollution - Quality
Online Access:	http://psasir.upm.edu.my/id/eprint/10507/1/FK_2000_35_.pdf
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id	my-upm-ir.10507
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spelling	my-upm-ir.105072024-04-03T03:24:39Z Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers 2000-03 Jong, Tze Yong This investigation concerns the establishing of theoretical framework of a numerical model which governs the selective withdrawal from a densitystratified groundwater reservoir to meet a certain desired water quality constraint. The general class of groundwater systems consists of a saturated porous medium where the denser saltwater tends to remain separated from the overlying freshwater. Pumping from such a stratified reservoir may result in deliveries of water of undesirable quality resulting from the unsteady mixing which occurs between the salt and freshwater layers. The equations which govern the flow of fluids and mass transport of the pollutant through the stratified groundwater reservoir were developed together with the initial and boundary conditions. The flow and solute equations were then solved by using SUTRA model that employs Galerkin finite element method. In order to verify the numerical model, an experimental laboratory sand model was constructed to study the selective withdrawal phenomenon. Four experimental tests with different set of values of well penetration depth and pumping rate were carried out to determine the pressure head and concentration distribution in the aquifer domain. To further verify the numerical model, comparisons were carried out between the numerical solutions of pressure head and concentration distribution and the experimental results, and they showed the maximum difference of 10% and 11% respectively. Good agreement was obtained as a result of these comparisons. Sensitivity analysis was carried out in order to study the effect of variations of dispersivity coefficients on the concentration distributions. It was found that increasing the dispersivity coefficients would enlarge the mixing zone above the saltwater-freshwater interface, thus caused the saltwater moving further upward to the pumping well. At the same time, a case study was also conducted at Sg. Langat basin to test the applicability of the model to the real field conditions. From the simulation of the test well with the data provided by the Geological Survey Department of Malaysia, it was found that the critical time period where the salinity-polluted water will be pumped towards the well is approximately 92 hour after the start of non-stop pumping with constant discharge rate of 114m3/hr. Ground Water - Pollution - Quality 2000-03 Thesis http://psasir.upm.edu.my/id/eprint/10507/ http://psasir.upm.edu.my/id/eprint/10507/1/FK_2000_35_.pdf text en public masters Universiti Putra Malaysia Ground Water - Pollution - Quality Faculty of Engineering Ghazali, Abdul Halim English
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English English
advisor	Ghazali, Abdul Halim
topic	Ground Water - Pollution - Quality
spellingShingle	Ground Water - Pollution - Quality Jong, Tze Yong Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
description	This investigation concerns the establishing of theoretical framework of a numerical model which governs the selective withdrawal from a densitystratified groundwater reservoir to meet a certain desired water quality constraint. The general class of groundwater systems consists of a saturated porous medium where the denser saltwater tends to remain separated from the overlying freshwater. Pumping from such a stratified reservoir may result in deliveries of water of undesirable quality resulting from the unsteady mixing which occurs between the salt and freshwater layers. The equations which govern the flow of fluids and mass transport of the pollutant through the stratified groundwater reservoir were developed together with the initial and boundary conditions. The flow and solute equations were then solved by using SUTRA model that employs Galerkin finite element method. In order to verify the numerical model, an experimental laboratory sand model was constructed to study the selective withdrawal phenomenon. Four experimental tests with different set of values of well penetration depth and pumping rate were carried out to determine the pressure head and concentration distribution in the aquifer domain. To further verify the numerical model, comparisons were carried out between the numerical solutions of pressure head and concentration distribution and the experimental results, and they showed the maximum difference of 10% and 11% respectively. Good agreement was obtained as a result of these comparisons. Sensitivity analysis was carried out in order to study the effect of variations of dispersivity coefficients on the concentration distributions. It was found that increasing the dispersivity coefficients would enlarge the mixing zone above the saltwater-freshwater interface, thus caused the saltwater moving further upward to the pumping well. At the same time, a case study was also conducted at Sg. Langat basin to test the applicability of the model to the real field conditions. From the simulation of the test well with the data provided by the Geological Survey Department of Malaysia, it was found that the critical time period where the salinity-polluted water will be pumped towards the well is approximately 92 hour after the start of non-stop pumping with constant discharge rate of 114m3/hr.
format	Thesis
qualification_level	Master's degree
author	Jong, Tze Yong
author_facet	Jong, Tze Yong
author_sort	Jong, Tze Yong
title	Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
title_short	Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
title_full	Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
title_fullStr	Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
title_full_unstemmed	Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers
title_sort	groundwater utilization from density-stratified non-homogeneous unconfined aquifers
granting_institution	Universiti Putra Malaysia
granting_department	Faculty of Engineering
publishDate	2000
url	http://psasir.upm.edu.my/id/eprint/10507/1/FK_2000_35_.pdf
_version_	1804888555704549376

Groundwater Utilization from Density-Stratified Non-Homogeneous Unconfined Aquifers

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