Browsing by Author "Hartland, A"

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    14C activity of DIC and DOC within a clayey-silt aquitard
    (University of New South Wales and Australian Nuclear Science and Technology Organisation, 2015-07-10) Timms, W; Hartland, A; Jacobsen, GE; Cendón, DI; Crane, R; McGeeney, D
    Not provided to ANSTO Library.
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    Assessment of interaction between alluvial, volcanic and GAB aquifers using 3D visualisation and environmental tracers, Lockyer Valley, southeast Queensland, Australia
    (Australian Geosciences Council, 2012-08-05) Raiber, M; Cox, ME; Cendón, DI; Hartland, A
    A detailed 3D lithological model framework was developed using GOCAD software to understand interactions between alluvial, volcanic and GAB aquifers and the spatial and temporal distribution of groundwater recharge to the alluvium of the Lockyer Valley. Groundwater chemistry, isotope data (H20-δ2H and δ18O , 87Sr/86Sr, 3H and 14C) and groundwater level time-series data from approximately 550 observation wells were integrated into the catchment-wide 3D model to assess the recharge processes involved. This approach enabled the identification of zones where recharge to the alluvium primarily occurs from stream water during episodic flood events. Importantly, the study also demonstrates that in some sections of the alluvium recharge is also from storm rainfall and seepage discharge from the underlying GAB aquifers. These other sources of recharge are indicated by (a) the absence of a response of groundwater levels to flooding in some areas, (b) old radiocarbon ages, and (c) distinct bedrock water chemistry and δ2H and δ18O signatures in alluvial groundwater at these locations. Integration of isotopes, water chemistry and time-series displays of groundwater levels before and after the 2010/2011 flood into the 3D model suggest that the spatial variations in the alluvial groundwater response are mostly controlled by valley morphology and lithological (i.e. permeability) variations within the alluvium. Examination of the groundwater level variations in the 3D model also enabled quantification of the volumetric change of groundwater stored in the unconfined alluvial aquifer prior to and post-flood events.
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    Isoscapes: a 3D visualisation approach to study aquifer connectivity during drought and flood, Lockyer Valley, southeast Queensland, Australia,
    (International Association of Hydrogeologists, 2013-09-16) Raiber, M; Cox, ME; Cendón, DI; Hartland, A; James, A
    A 3D geological model of the Lockyer Valley, southeast Queensland, was developed using GOCAD software as a framework to study interactions between alluvial, basaltic and sedimentary bedrock aquifers of the Clarence-Moreton Basin and the spatial and temporal variability of recharge to the alluvium. The isotopic data (δ2h and δ18O, 87Sr/86Sr, 3H and 14C), water chemistry and time-series of groundwater levels before and after the 2010/2011 flood, were integrated within the 3D hydrogeological framework using Groundwater Visualisation System (GVS). Groundwater “isoscapes" (i.e. isotopic landscapes) were developed by spatial interpolation of isotopic results from more than 180 bores to enable the identification of different sources of water that contribute to recharge. The isotopic parameters are displayed as colour-contoured surfaces of the different aquifers and as coloured cylinders of variable thickness marking the position and thickness of the screened interval. Interpretation of isotopic values and their spatial relationships show that recharge to the alluvium primarily occurs from streams following episodic flood events. However, importantly, the study also demonstrates that in some sections of the alluvial plain, recharge to the alluvium is derived from both diffuse rainfall recharge and seepage discharge from the underlying Great Artesian Basin (GAB) aquifers. Bedrock seepage recharge dominates in some parts of the alluvial aquifer during droughts, enhanced by continuous pumping of the alluvial aquifer during the drought, as indicated by overall longer groundwater residence times, and high groundwater salinities. In addition, the hydrochemical signature of recharge from the bedrock is characterised by an isotopic depletion of δ2H and δ18O, and more radiogenic 87Sr/86Sr ratios in alluvial groundwater. The spatial variability of the responses is mostly controlled by catchment morphology and lithological (i.e. permeability) variations within the alluvium. Assessment of the unconfined groundwater levels in the 3D geological model enabled quantification of the volumetric change of groundwater stored in the alluvial aquifer system before and after flood events.