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Ian Cartwright - One of the best experts on this subject based on the ideXlab platform.
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environmental isotopes as indicators of inter Aquifer mixing wimmera region murray basin southeast australia
Chemical Geology, 2010Co-Authors: Tamie Renee Weaver, Ian Cartwright, Dioni I Cendon, Ian SwaneAbstract:Abstract Complex groundwater flow systems in confined Aquifers that result from geological structures, stratigraphic changes, or the absence of efficient aquitards are difficult to constrain using physical parameters alone. Despite a relatively simple Aquifer configuration, the distribution of groundwater total dissolved solids (TDS) concentrations, δ13C values, 87Sr/86Sr ratios, and 14C activities (a14C) in groundwater in the Wimmera region of the southern Murray Basin implies that considerable inter-Aquifer flow has occurred. Given the presence of both silicate and carbonate Aquifers, δ13C values and 87Sr/86Sr ratios are the key parameters that demonstrate inter-Aquifer flow. Locally, between 40 and 95% of water from one Aquifer has infiltrated the underlying Aquifer homogenising many aspects of the groundwater geochemistry. Groundwater residence times estimated from a14C range from modern to > 30 ka and the distribution of 14C residence times confirm that inter-Aquifer flow is regional scale and long term. Recharge of the deepest Aquifers occurs across a broad region and not solely at the basin margins. Vertical leakage rates are ~ 6–10 × 10−3 m/year and long-term recharge rates 0.1–0.2 mm/year (
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distinguishing groundwater flow paths in different fractured rock Aquifers using groundwater chemistry dandenong ranges southeast australia
Hydrogeology Journal, 2005Co-Authors: Sarah Tweed, Tamie Renee Weaver, Ian CartwrightAbstract:Major ion geochemistry is used to qualitatively interpret groundwater residence times within an Aquifer, and the extent of mixing between Aquifers with distinctive mineralogy. In conjunction with hydraulic heads and stable isotope geochemistry, flow paths and inter-Aquifer exchange are defined in a fractured-rock Aquifer system in the Dandenong Ranges, southeast Australia. Stable isotopes indicate modern seasonal recharge throughout the system. At high elevations in the sub-catchment, which includes both marine Silurian-Devonian sedimentary and Tertiary basalt Aquifers, Cl is derived primarily from cyclic salts, and differences in mineralogy result in groundwater from the basalt Aquifer having higher TDS contents (123–262 mg/L) and (Ca+Mg)/Na ratios (0.9–1.3) than groundwater from the sedimentary Aquifer (TDS: 55–79 mg/L; (Ca+Mg)/Na: 0.1–0.2). At low elevations, in areas of local groundwater discharge, the more regional flow system in the Silurian-Devonian sediments contains additional Cl from water–rock interaction and has distinctly higher TDS contents (517–537 mg/L). Differences in groundwater chemistry between the Aquifers and between shallower and deeper flow systems highlights areas of inter-Aquifer mixing. This is particularly important for Aquifer vulnerability where groundwater quality in the deeper Aquifer may be impacted by surface activities.
Hongbin Zhan - One of the best experts on this subject based on the ideXlab platform.
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groundwater flow to a well in a strip shaped unconfined fractured Aquifer system with a transition zone
Journal of Hydrology, 2021Co-Authors: Mohammad M. Sedghi, Hongbin ZhanAbstract:Abstract Semi-infinite unconfined-fractured strip shaped Aquifer systems are common in alluvial plain margins, but have received little attention in the hydrogeological community. Thus, the aim of this study is to present semi-analytical solutions of flow to a well in these Aquifer systems. Two conceptual models are considered: 1-An unconfined Aquifer with a lateral fractured Aquifer and a pumping well installed in the unconfined Aquifer (model I); 2-An unconfined Aquifer with a lateral fractured Aquifer and a pumping well installed in the fractured Aquifer (model II). A transition zone is considered between two Aquifers. Three-dimensional groundwater flows are considered in unconfined, fractured and transition zone Aquifers. Homogeneous, anisotropic hydraulic conductivity and instantaneous drainage water table condition are assumed first but can be relaxed to accommodate delayed drainage water table condition if needed. The point sink/source solutions are obtained via finite and infinite Fourier transforms for space and Laplace transform for time. The line sink/source solutions are obtained via integration along the desired direction. The uniform flux and uniform head boundary conditions are considered for the pumping well. The vertical distribution of the flux toward the well screen is explored. The effects of inner well condition on the variation of the dimensionless drawdown and boundary depletion volume are investigated. We investigate the influences of the hydraulic parameters of the transition zone on the spatial and temporal variations of the sensitivity of the drawdown to hydraulic parameters of the Aquifer system. Furthermore, the influences of the transition zone on the spatial distribution of the drawdown are explored. The results of this study can be utilized to evaluate head distribution in the Aquifer system; to calculate the water budget of the alluvial Aquifers near a fractured one; to analyze the influences of a transition zone on the head and flow distribution in the Aquifer system.
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Flow to a well in an unconfined-fractured and leaky wedge-shaped Aquifer system
Journal of Hydrology, 2018Co-Authors: Mohammad M. Sedghi, Hongbin ZhanAbstract:Abstract Wedge-shaped Aquifers are usually formed where two linear boundaries intersect. These types of Aquifers are commonly seen in river basins and alluvial fans, but have received much less attention in the hydrological sciences community. Fundamental understanding of the effects of lateral boundaries on the hydrodynamic process in such Aquifers is quite poor, particularly for unconfined-fractured and leaky wedge-shaped Aquifer systems, which will be the concern of this study. Solutions of flow to a well in an unconfined-fractured wedge-shaped two Aquifer system are obtained using Laplace, Hankel and Fourier transforms. An infinitesimal radius pumping well partially penetrates the overlying unconfined Aquifer. Both Aquifer layers are homogeneous and anisotropic bounded by two intersecting linear lateral boundaries of constant-head or barrier types and the Aquifer system is semi-infinite in radial direction. The time domain drawdowns are obtained via the Stehfest algorithm and Gaussian Quadrature. The inter-porosity flow in the underlying fracture Aquifer, the instantaneous water table drainage, the horizontal and vertical hydraulic conductivity anisotropy and the wedge angle are taken into account. Eliminating the inter-porosity flow in the underlying fractured Aquifer, the presented solution reduces to a leaky wedge-shaped Aquifer case. The influences of the underlying fractured Aquifer hydraulic parameters on the overlying unconfined Aquifer for different wedge angles and linear lateral boundaries types are explored using dimensionless drawdown and scaled sensitivity curves. The results of this study can be utilized to obtain hydraulic parameters of an alluvial and river basin unconfined-fractured wedge-shaped Aquifer systems. The presented solution can also be used for water budget assessment of river basin Aquifers.
Mohammad M. Sedghi - One of the best experts on this subject based on the ideXlab platform.
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groundwater flow to a well in a strip shaped unconfined fractured Aquifer system with a transition zone
Journal of Hydrology, 2021Co-Authors: Mohammad M. Sedghi, Hongbin ZhanAbstract:Abstract Semi-infinite unconfined-fractured strip shaped Aquifer systems are common in alluvial plain margins, but have received little attention in the hydrogeological community. Thus, the aim of this study is to present semi-analytical solutions of flow to a well in these Aquifer systems. Two conceptual models are considered: 1-An unconfined Aquifer with a lateral fractured Aquifer and a pumping well installed in the unconfined Aquifer (model I); 2-An unconfined Aquifer with a lateral fractured Aquifer and a pumping well installed in the fractured Aquifer (model II). A transition zone is considered between two Aquifers. Three-dimensional groundwater flows are considered in unconfined, fractured and transition zone Aquifers. Homogeneous, anisotropic hydraulic conductivity and instantaneous drainage water table condition are assumed first but can be relaxed to accommodate delayed drainage water table condition if needed. The point sink/source solutions are obtained via finite and infinite Fourier transforms for space and Laplace transform for time. The line sink/source solutions are obtained via integration along the desired direction. The uniform flux and uniform head boundary conditions are considered for the pumping well. The vertical distribution of the flux toward the well screen is explored. The effects of inner well condition on the variation of the dimensionless drawdown and boundary depletion volume are investigated. We investigate the influences of the hydraulic parameters of the transition zone on the spatial and temporal variations of the sensitivity of the drawdown to hydraulic parameters of the Aquifer system. Furthermore, the influences of the transition zone on the spatial distribution of the drawdown are explored. The results of this study can be utilized to evaluate head distribution in the Aquifer system; to calculate the water budget of the alluvial Aquifers near a fractured one; to analyze the influences of a transition zone on the head and flow distribution in the Aquifer system.
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Flow to a well in an unconfined-fractured and leaky wedge-shaped Aquifer system
Journal of Hydrology, 2018Co-Authors: Mohammad M. Sedghi, Hongbin ZhanAbstract:Abstract Wedge-shaped Aquifers are usually formed where two linear boundaries intersect. These types of Aquifers are commonly seen in river basins and alluvial fans, but have received much less attention in the hydrological sciences community. Fundamental understanding of the effects of lateral boundaries on the hydrodynamic process in such Aquifers is quite poor, particularly for unconfined-fractured and leaky wedge-shaped Aquifer systems, which will be the concern of this study. Solutions of flow to a well in an unconfined-fractured wedge-shaped two Aquifer system are obtained using Laplace, Hankel and Fourier transforms. An infinitesimal radius pumping well partially penetrates the overlying unconfined Aquifer. Both Aquifer layers are homogeneous and anisotropic bounded by two intersecting linear lateral boundaries of constant-head or barrier types and the Aquifer system is semi-infinite in radial direction. The time domain drawdowns are obtained via the Stehfest algorithm and Gaussian Quadrature. The inter-porosity flow in the underlying fracture Aquifer, the instantaneous water table drainage, the horizontal and vertical hydraulic conductivity anisotropy and the wedge angle are taken into account. Eliminating the inter-porosity flow in the underlying fractured Aquifer, the presented solution reduces to a leaky wedge-shaped Aquifer case. The influences of the underlying fractured Aquifer hydraulic parameters on the overlying unconfined Aquifer for different wedge angles and linear lateral boundaries types are explored using dimensionless drawdown and scaled sensitivity curves. The results of this study can be utilized to obtain hydraulic parameters of an alluvial and river basin unconfined-fractured wedge-shaped Aquifer systems. The presented solution can also be used for water budget assessment of river basin Aquifers.
Neal Farmer - One of the best experts on this subject based on the ideXlab platform.
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movement of coliform bacteria and nutrients in ground water flowing through basalt and sand Aquifers
Journal of Environmental Quality, 2001Co-Authors: James A Entry, Neal FarmerAbstract:Large-scale deposition of animal manure can result in contamination of surface and ground water and in potential transfer of disease-causing enteric bacteria to animals or humans. We measured total coliform bacteria (TC), fecal coliform bacteria (PC), NO 3 , NI-I4, total P, and POt in ground water flowing from basalt and sand Aquifers, in wells into basalt and sand Aquifers, in irrigation water, and in river water. Samples were collected monthly for 1 yr. Total coliform and FC numbers were always higher in irrigation water than in ground water, indicating that soil and sediment filtered most of these bacteria before they entered the Aquifers. Total coliform and FC numbers in ground water were generally higher in the faster flowing basalt Aquifer than in the sand Aquifer, indicating that the slower flow and finer grain size may filter more TC and FC bacteria from water. At least one coliform bacterium/101) mL of water was found in ground water from both basalt and sand Aquifers, indicating that ground water pumped from these Aquifers is not necessarily safe for human consumption according to the American Public Health Association and the USEPA. The NO3 concentrations were usually higher in water flowing from the sand Aquifer than in water flowing from the basalt Aquifer or in perched water tables in the basalt Aquifer. The PO4 concentrations were usually higher in water flowing from the basalt Aquifer than in water flowing from the sand Aquifer. The main concern is fecal contamination of these Aquifers and health consequences that may arise from human consumption.
Mark Bakker - One of the best experts on this subject based on the ideXlab platform.
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Steady groundwater flow through many cylindrical inhomogeneities in a multi-Aquifer system
Journal of Hydrology, 2003Co-Authors: Mark BakkerAbstract:A new approach is presented for the simulation of steady-state groundwater flow in multi-Aquifer systems that contain many cylindrical inhomogeneities. The hydraulic conductivity of all Aquifers and the resistance of all leaky layers may be different inside each cylinder. The approach is based on separation of variables and combines principles of the theory for multi-Aquifer flow with principles of the analytic element method. The solution fulfills the governing differential equations exactly everywhere; the head, flow, and leakage between Aquifers may be computed analytically at any point in the Aquifer system. The boundary conditions along the circumference of the cylinder are satisfied approximately, but may be met at any precision. Two examples are discussed to illustrate the accuracy of the approach and the significance of inhomogeneities in multi-Aquifer systems. The first application simulates the vertical and horizontal, advective spreading of a conservative tracer in a homogeneous Aquifer that is overlain by an Aquifer with cylindrical inclusions of higher permeability. The second application concerns the three-dimensional shape of the capture zone of a well that is screened in the bottom Aquifer of a three-Aquifer system. The capture zone extends to the top Aquifer due to cylindrical holes of lower resistance in the separating clay layers.