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Continuous electrical imaging for mapping aquifer recharge along reaches of the Namoi River in Australia

Kelly, B.F.J.; Allen, D.; Ye, K. and Dahlin, Torleif LU (2009) In Near Surface Geophysics 7(4). p.259-270
Abstract
In this study the capacity of towed floating electrical imaging for mapping a known aquifer recharge zone in more detail is investigated. A 50 km reach of the Namoi River, Australia, was surveyed. The river is perched up to 16 m above an unconfined aquifer that extends to 30 m below the ground surface. The unconfined aquifer overlies a semi-confined aquifer system. The electrical array consists of two current electrodes near the boat, followed by nine potential electrodes. The sequence of 1D electrical sounding curves generated was automatically inverted to obtain a layered earth electrical model along the river to a depth of approximately 40 m. There was weak correlation between the water conductivity measured in boreholes and the layered... (More)
In this study the capacity of towed floating electrical imaging for mapping a known aquifer recharge zone in more detail is investigated. A 50 km reach of the Namoi River, Australia, was surveyed. The river is perched up to 16 m above an unconfined aquifer that extends to 30 m below the ground surface. The unconfined aquifer overlies a semi-confined aquifer system. The electrical array consists of two current electrodes near the boat, followed by nine potential electrodes. The sequence of 1D electrical sounding curves generated was automatically inverted to obtain a layered earth electrical model along the river to a depth of approximately 40 m. There was weak correlation between the water conductivity measured in boreholes and the layered earth electrical model. Lithological logs from boreholes near the river indicate that the major layers seen in the electrical conductivity cross-section correspond to the major sedimentary units. Groundwater mounding in the vicinity of the river has been monitored after flooding. The groundwater flood mounds coincide with the location of the predominantly low electrically conductive sediments mapped beneath the river. This suggests that aquifer recharging waters migrate via the sands and gravels, then pool at the water table before dissipating. This survey demonstrates that mapping intervals of low electrically conductive sediments beneath the river maps potential aquifer recharge pathways. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Near Surface Geophysics
volume
7
issue
4
pages
259 - 270
publisher
EAGE
external identifiers
  • Scopus:77951086561
ISSN
1873-0604
DOI
10.3997/1873-0604.2009024
language
English
LU publication?
yes
id
f7b4ee00-9c22-4a68-9b5b-b63f48b4dbc6 (old id 2367717)
date added to LUP
2012-03-01 13:06:31
date last changed
2016-10-13 05:02:07
@misc{f7b4ee00-9c22-4a68-9b5b-b63f48b4dbc6,
  abstract     = {In this study the capacity of towed floating electrical imaging for mapping a known aquifer recharge zone in more detail is investigated. A 50 km reach of the Namoi River, Australia, was surveyed. The river is perched up to 16 m above an unconfined aquifer that extends to 30 m below the ground surface. The unconfined aquifer overlies a semi-confined aquifer system. The electrical array consists of two current electrodes near the boat, followed by nine potential electrodes. The sequence of 1D electrical sounding curves generated was automatically inverted to obtain a layered earth electrical model along the river to a depth of approximately 40 m. There was weak correlation between the water conductivity measured in boreholes and the layered earth electrical model. Lithological logs from boreholes near the river indicate that the major layers seen in the electrical conductivity cross-section correspond to the major sedimentary units. Groundwater mounding in the vicinity of the river has been monitored after flooding. The groundwater flood mounds coincide with the location of the predominantly low electrically conductive sediments mapped beneath the river. This suggests that aquifer recharging waters migrate via the sands and gravels, then pool at the water table before dissipating. This survey demonstrates that mapping intervals of low electrically conductive sediments beneath the river maps potential aquifer recharge pathways.},
  author       = {Kelly, B.F.J. and Allen, D. and Ye, K. and Dahlin, Torleif},
  issn         = {1873-0604},
  language     = {eng},
  number       = {4},
  pages        = {259--270},
  publisher    = {ARRAY(0x7a0b028)},
  series       = {Near Surface Geophysics},
  title        = {Continuous electrical imaging for mapping aquifer recharge along reaches of the Namoi River in Australia},
  url          = {http://dx.doi.org/10.3997/1873-0604.2009024},
  volume       = {7},
  year         = {2009},
}