Authors / CoAuthors
McPherson, A. | Rollet, N. | Vizy, J. | Kilgour, P.
Abstract
As part of the Great Artesian Basin (GAB) Project a pilot study was conducted in the northern Surat Basin, Queensland, to test the ability of existing and new geoscientific data and technologies to further improve our understanding of hydrogeological systems within the GAB, in order to support responsible management of basin water resources. This report presents selected examples from the preliminary interpretation of modelled airborne electromagnetic (AEM) data acquired as part of this pilot study. The examples are selected to highlight key observations from the AEM with potential relevance to groundwater recharge and connectivity. Previous investigations in the northern Surat Basin have suggested that diffuse groundwater recharge rates are generally low (in the order of only a few millimetres per year) across large areas of the GAB intake beds—outcropping geological units which represent a pathway for rainfall to enter the aquifers—and that, within key aquifer units, recharge rates and volumes can be heterogeneous. Spatial variability in AEM conductivity responses is identified across different parts of the northern Surat Basin, including within the key Hutton Sandstone aquifer. Consistent with findings from other studies, this variability is interpreted as potential lithological heterogeneity, which may contribute to reduced volumes of groundwater entering the deeper aquifer. The influence of geological structure on aquifer geometry is also examined. Larger structural zones are seen to influence both pre- and post-depositional architecture, including the presence, thickness and dip of hydrogeological units (or parts thereof). Folds and faults within the Surat Basin sequences are, in places, seen as potential groundwater divides which may contribute to compartmentalisation of aquifers. Discrete faults have the potential to influence inter-aquifer connectivity. The examples presented here demonstrate the utility of AEM models, in conjunction with other appropriate geophysical and geological data, for characterising potential recharge areas and pathways within the main GAB aquifer units, by helping to better define aquifer geometry, lithological heterogeneity and possible structural controls. Such assessments have the potential to further improve our understanding of groundwater recharge and flow path variability at local to regional scales. Acquisition of broader AEM data coverage across groundwater recharge areas, along with complementary geophysical, geological and hydrogeological data, would further assist in quantifying recharge variability, facilitating revised water balance estimates for the basin and thereby supporting GAB water resource management and policy decision-making.
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document
eCat Id
146502
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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- theme.ANZRC Fields of Research.rdf
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- ENVIRONMENTAL SCIENCESPHYSICAL SCIENCESEARTH SCIENCES
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- Great Artesian Basin
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- Northern Surat Basin
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- airborne electromagnetic
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- Published_External
Publication Date
2022-12-21T01:38:05
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completed
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Project report
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geoscientificInformation environment inlandWaters
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Record RECORD: 2022/017
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The Australian Government, through the National Water Infrastructure Development Fund – Expansion, commissioned Geoscience Australia to undertake the project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (referred to herein as the ‘Project’) (http://www.ga.gov.au/scientific-topics/water/groundwater/gab#heading-1). Commencing in July 2019 and finishing in June 2022, the Project has acquired new geoscience and remotely sensed data, and developing and evaluating techniques and tools for assessing the status of GAB groundwater systems to support water resource management.
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[-26.981, -23.5489, 145.7004, 150.4655]
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