<div>Geoscience Australia's Exploring for the Future Program (EFTF) is supporting regional and national-scale initiatives to address Australia’s hydrogeological challenges using an integrated geoscience systems approach. An important early step in the EFTF groundwater program focused on developing a national hydrogeological inventory of Australia’s major groundwater basins and fractured rock provinces. The inventory has its roots in the seminal 1987 Hydrogeology of Australia map, the first continental-scale map of groundwater systems and principal aquifers (Jacobson and Lau, 1987). Seeking to enhance and modernise the supporting information base for the national map, the inventory combines a curated selection of geospatial data attributes supported by focused narrative on the geology and hydrogeology of each basin and fractured rock province.</div><div>&nbsp;</div><div>The national hydrogeological inventory has a broad range of benefits for Australian groundwater users, managers and policy makers. These include the provision of an updated knowledge base covering the hydrogeology and groundwater systems of the major hydrogeological provinces of the nation, as well as important contextual information. The extensive catalogue of knowledge contained in the inventory also enables an objective approach to identify and prioritise areas for further regional assessment.</div><div>&nbsp;</div><div>Based on analysis of data compiled for the national inventory, the Lake Eyre Basin in arid central Australia was the first region prioritised for more detailed hydrogeological assessment during EFTF. The integration of a variety of basin- to national-scale geoscience datasets enabled significant advances in geological and hydrogeological understanding and the development of a new geological model for the three main basin depo-centres, namely the Tirari and Callabonna Sub-basins, and the Cooper Creek Palaeovalley. The geological modelling has further supported a range of hydrogeological applications, including substantial improvements in the number of bores with aquifer attribution, as well as the first regional watertable map across the basin. Abstract submitted and presented at the 2023 AGC NZHS Joint Conference Auckland, NZ (https://www.agcnzhs2023conference.co.nz/)

<div>The Lake Eyre surface water catchment covers around 1,200,000 km2 of central Australia, about one-sixth of the entire continent. It is one of the largest endorheic river basins in the world and contains iconic arid streams such as the Diamantina, Finke and Georgina rivers, and Cooper Creek. The Lake Eyre region supports diverse native fauna and flora, including nationally significant groundwater-dependent ecosystems such as springs and wetlands which are important cultural sites for Aboriginal Australians.</div><div><br></div><div>Much of the Lake Eyre catchment is underlain by the geological Lake Eyre Basin (LEB). The LEB includes major sedimentary depocentres such as the Tirari and Callabonna sub-basins which have been active sites of deposition throughout the Cenozoic. The stratigraphy of the LEB is dominated by the Eyre, Namba and Etadunna formations, as well as overlying Pliocene to Quaternary sediments.</div><div><br></div><div>The National Groundwater Systems Project, part of Geoscience Australia's Exploring for the Future Program (https://www.eftf.ga.gov.au/), is transforming our understanding of the nation's major aquifer systems. With an initial focus on the Lake Eyre Basin, we have applied an integrated geoscience systems approach to model the basin's regional stratigraphy and geological architecture. This analysis has significantly improved understanding of the extent and thickness of the main stratigraphic units, leading to new insights into the conceptualisation of aquifer systems in the LEB.</div><div><br></div><div>Developing the new understanding of the LEB involved compilation and standardisation of data acquired from thousands of petroleum, minerals and groundwater bores. This enabled consistent stratigraphic analysis of the major geological surfaces across all state and territory boundaries. In places, the new borehole dataset was integrated with biostratigraphic and petrophysical data, as well as airborne electromagnetic (AEM) data acquired through AusAEM (https://www.eftf.ga.gov.au/ausaem). The analysis and integration of diverse geoscience datasets helped to better constrain the key stratigraphic horizons and improved our overall confidence in the geological interpretations.</div><div><br></div><div>The new geological modelling of the LEB has highlighted the diverse sedimentary history of the basin and provided insights into the influence of geological structures on modern groundwater flow systems. Our work has refined the margins of the key depocentres of the Callabonna and Tirari sub-basins, and shown that their sediment sequences are up to 400 m thick. We have also revised maximum thickness estimates for the main units of the Eyre Formation (185 m), Namba Formation (265 m) and Etadunna Formation (180 m).</div><div><br></div><div>The geometry, distribution and thickness of sediments in the LEB is influenced by geological structures. Many structural features at or near surface are related to deeper structures that can be traced into the underlying Eromanga and Cooper basins. The occurrence of neotectonic features, coupled with insights from geomorphological studies, implies that structural deformation continues to influence the evolution of the basin. Structures also affect the hydrogeology of the LEB, particularly by compartmentalising groundwater flow systems in some areas. For example, the shallow groundwater system of the Cooper Creek floodplain is likely segregated from groundwater in the nearby Callabonna Sub-basin due to structural highs in the underlying Eromanga Basin.</div><div> Abstract submitted and presented at the 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Adavale Basin region. This data guide gives examples of how these data can be used. The data package included with this data guide captures existing knowledge of Lake Eyre Basin aquifers in the Adavale Basin region and their properties, including salinity, water levels, resource size, potential aquifer yield and surface water interactions. The methods to derive these data for the Lake Eyre Basin aquifer in the Adavale Basin region are outlined in the associated metadata files. These are described in groundwater conceptual models (Gouramanis et al., 2023). The Lake Eyre Basin overlying the Adavale Basin includes one broadly defined aquifer: Cenozoic hydrostratigraphic unit (Cenozoic aquifer). Compiled data are assigned to these intervals and used to characterise groundwater systems at the basin scale. The data are compiled for a point-in-time to inform decisions on potential resource developments in the Basin. The available historical groundwater data can be used to assess the potential effects on groundwater. The data can also be used for other purposes, such as exploring unallocated groundwater resource potential. Data to January 2022 are used for this compilation.

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Galilee Basin region. This web service summarises salinity, water levels, resource size, potential aquifer yield and surface water–groundwater interactions for the Lake Eyre Basin located within the Galilee Basin region.

<div>Cooper Creek is a dryland river system that extends from the western Great Dividing Range in Central Queensland to Lake Eyre in South Australia. The middle course of the Cooper Creek is characterised by anabranching river channels across a wide floodplain that flow intermittently due to monsoonal flooding event higher in the catchment. As floodwaters recede, freshwater stagnates within numerous deeper segments of river channels forming ‘waterholes’ which support ecosystems with significant ecological and cultural value. However, there is little evidence that shallow groundwater discharges into these surface water bodies and the link between surface water and groundwater is not well understood. This study aims to demonstrate how airborne electromagnetics (AEM) and other geoscientific data can be integrated to identify recharge within shallow saline groundwater systems, which are so common in arid inland Australia.</div><div> The regional water table underneath the floodplain is shallow (<10m) and highly saline (>38,000 TDS), with a chemical signature suggesting salts were concentrated by evapotranspiration. Surface swelling clays likely limits the amount of recharge that occurs through the floodplain itself. However, a detailed study by Cendón et al (2010) found that during high flow events, floodwater scoured the base of the waterholes allowing freshwater to recharges into the shallow groundwater system forming chemically distinct freshwater lenses.</div><div> AEM is a geophysical technique capable of estimating bulk conductivity for the top few hundred metres of the subsurface. Part of the AusAEM Eastern Resource Corridor survey (Ley-Cooper 2021) crossed the Cooper Creek floodplain with a 20km line spacing. The bulk conductivity models delivered as part of this survey resolved the top of the saline water table regionally. In several locations, we identified resistive lenses sitting on the shallow water table which coincide with river channels that are frequently inundated.</div><div><br></div><div>Cendón, D.I., Larsen, J.R., Jones, B.G., Nanson, G.C., Rickleman, D., Hankin, S.I., Pueyo, J.J. and Maroulis, J., 2010. Freshwater recharge into a shallow saline groundwater system, Cooper Creek floodplain, Queensland, Australia.&nbsp;<em>Journal of Hydrology</em>,&nbsp;<em>392</em>(3-4), pp.150-163.</div><div>LeyCooper, Y. 2021. Exploring for the Future AusAEM Eastern Resources Corridor: 2021 Airborne Electromagnetic Survey TEMPEST® airborne electromagnetic data and GALEI inversion conductivity estimates. Geoscience Australia, Canberra.</div> This Abstract was submitted/presented to the 2022 Australasian Groundwater Conference 21-23 November (https://www.aig.org.au/events/australasian-groundwater-conference-2022/)

<div>This data package contains interpretations of airborne electromagnetic (AEM) conductivity sections in the Exploring for the Future (EFTF) program’s Eastern Resources Corridor (ERC) study area, in south eastern Australia. Conductivity sections from 3 AEM surveys were interpreted to provide a continuous interpretation across the study area – the EFTF AusAEM ERC (Ley-Cooper, 2021), the Frome Embayment TEMPEST (Costelloe et al., 2012) and the MinEx CRC Mundi (Brodie, 2021) AEM surveys. Selected lines from the Frome Embayment TEMPEST and MinEx CRC Mundi surveys were chosen for interpretation to align with the 20&nbsp;km line-spaced EFTF AusAEM ERC survey (Figure 1).</div><div>The aim of this study was to interpret the AEM conductivity sections to develop a regional understanding of the near-surface stratigraphy and structural architecture. To ensure that the interpretations took into account the local geological features, the AEM conductivity sections were integrated and interpreted with other geological and geophysical datasets, such as boreholes, potential fields, surface and basement geology maps, and seismic interpretations. This approach provides a near-surface fundamental regional geological framework to support more detailed investigations. </div><div>This study interpreted between the ground surface and 500&nbsp;m depth along almost 30,000 line kilometres of nominally 20&nbsp;km line-spaced AEM conductivity sections, across an area of approximately 550,000&nbsp;km2. These interpretations delineate the geo-electrical features that correspond to major chronostratigraphic boundaries, and capture detailed stratigraphic information associated with these boundaries. These interpretations produced approximately 170,000 depth estimate points or approximately 9,100 3D line segments, each attributed with high-quality geometric, stratigraphic, and ancillary data. The depth estimate points are formatted for compliance with Geoscience Australia’s (GA) Estimates of Geological and Geophysical Surfaces (EGGS) database, the national repository for standardised depth estimate points. </div><div>Results from these interpretations provided support to stratigraphic drillhole targeting, as part of the Delamerian Margins NSW National Drilling Initiative campaign, a collaboration between GA’s EFTF program, the MinEx CRC National Drilling Initiative and the Geological Survey of New South Wales. The interpretations have applications in a wide range of disciplines, such as mineral, energy and groundwater resource exploration, environmental management, subsurface mapping, tectonic evolution studies, and cover thickness, prospectivity, and economic modelling. It is anticipated that these interpretations will benefit government, industry and academia with interest in the geology of the ERC region.</div>

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Galilee Basin region. This data guide gives examples of how these data can be used. The data package included with this data guide captures existing knowledge of Lake Eyre Basin aquifers in the Galilee Basin region and their properties, including salinity, water levels, resource size, potential aquifer yield and indicators of surface water interactions. The methods used to derive these data for the Lake Eyre Basin aquifer in the Galilee Basin region are outlined in the associated metadata files. These are described in groundwater conceptualisation models (Hostetler et al., 2023). The Lake Eyre Basin overlying the Galilee Basin includes one broadly defined aquifer that includes multiple aquifer systems that are defined as Cenozoic aquifers. Compiled data was assigned to this interval and were used to characterise groundwater systems at the basin scale. The data are compiled for a point-in-time to inform decisions on resource development activities Basin. The available historical groundwater data can be used to assess the potential effects on groundwater for different development scenarios. The data can also be used for other purposes, such as exploring unallocated groundwater resource potential. Data to January 2022 are used for this compilation.

This data package, completed as part of Geoscience Australia’s National Groundwater Systems (NGS) Project, presents results of the second iteration of the 3D Great Artesian Basin (GAB) and Lake Eyre Basin (LEB) (Figure 1) geological and hydrogeological models (Vizy & Rollet, 2023) populated with volume of shale (Vshale) values calculated on 2,310 wells in the Surat, Eromanga, Carpentaria and Lake Eyre basins (Norton & Rollet, 2023). This provides a refined architecture of aquifer and aquitard geometry that can be used as a proxy for internal, lateral, and vertical, variability of rock properties within each of the 18 GAB-LEB hydrogeological units (Figure 2). These data compilations and information are brought to a common national standard to help improve hydrogeological conceptualisation of groundwater systems across multiple jurisdictions. This information will assist water managers to support responsible groundwater management and secure groundwater into the future. This 3D Vshale model of the GAB provides a common framework for further data integration with other disciplines, industry, academics and the public and helps assess the impact of water use and climate change. It aids in mapping current groundwater knowledge at a GAB-wide scale and identifying critical groundwater areas for long-term monitoring. The NGS project is part of the Exploring for the Future (EFTF) program—an eight-year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program. The program seeks to inform decision-making by government, community, and industry on the sustainable development of Australia's mineral, energy, and groundwater resources, including those to support the effective long-term management of GAB water resources. This work builds on the first iteration completed as part of the Great Artesian Basin Groundwater project (Vizy & Rollet, 2022; Rollet et al., 2022), and infills previous data and knowledge gaps in the GAB and LEB with additional borehole, airborne electromagnetic and seismic interpretation. The Vshale values calculated on additional wells in the southern Surat and southern Eromanga basins and in the whole of Carpentaria and Lake Eyre basins provide higher resolution facies variability estimates from the distribution of generalised sand-shale ratio across the 18 GAB-LEB hydrogeological units. The data reveals a complex mixture of sedimentary environments in the GAB, and highlights sand body development and hydraulic characteristics within aquifers and aquitards. Understanding the regional extents of these sand-rich areas provides insights into potential preferential flow paths, within and between the GAB and LEB, and aquifer compartmentalisation. However, there are limitations that require further study, including data gaps and the need to integrate petrophysics and hydrogeological data. Incorporating major faults and other structures would also enhance our understanding of fluid flow pathways. The revised Vshale model, incorporating additional boreholes to a total of 2,310 boreholes, contributes to our understanding of groundwater flow and connectivity in the region, from the recharge beds to discharge at springs, and Groundwater Dependant Ecosystems (GDEs). It also facilitates interbasinal connectivity analysis. This 3D Vshale model offers a consistent framework for integrating data from various sources, allowing for the assessment of water use impacts and climate change at different scales. It can be used to map groundwater knowledge across the GAB and identify areas that require long-term monitoring. Additionally, the distribution of boreholes with gamma ray logs used for the Vshale work in each GAB and LEB units (Norton & Rollet, 2022; 2023) is used to highlight areas where additional data acquisition or interpretation is needed in data-poor areas within the GAB and LEB units. The second iteration of surfaces with additional Vshale calculation data points provides more confidence in the distribution of sand bodies at the whole GAB scale. The current model highlights that the main Precipice, Hutton, Adori-Springbok and Cadna-owie‒Hooray aquifers are relatively well connected within their respective extents, particularly the Precipice and Hutton Sandstone aquifers and equivalents. The Bungil Formation, the Mooga Sandstone and the Gubberamunda Sandstone are partial and regional aquifers, which are restricted to the Surat Basin. These are time equivalents to the Cadna-owie–Hooray major aquifer system that extends across the Eromanga Basin, as well as the Gilbert River Formation and Eulo Queen Group which are important aquifers onshore in the Carpentaria Basin. The current iteration of the Vshale model confirms that the Cadna-owie–Hooray and time equivalent units form a major aquifer system that spreads across the whole GAB. It consists of sand bodies within multiple channel belts that have varying degrees of connectivity' i.e. being a channelised system some of the sands will be encased within overbank deposits and isolated, while others will be stacked, cross-cutting systems that provide vertical connectivity. The channelised systemtransitions vertically and laterally into a shallow marine environment (Rollet et al., 2022). Sand-rich areas are also mapped within the main Poolowanna, Brikhead-Walloon and Westbourne interbasinal aquitards, as well as the regional Rolling Downs aquitard that may provide some potential pathways for upward leakage of groundwater to the shallow Winton-Mackunda aquifer and overlying Lake Eyre Basin. Further integration with hydrochemical data may help groundtruth some of these observations. This metadata document is associated with a data package including: • Seventeen surfaces with Vshale property (Table 1), • Seventeen surfaces with less than 40% Vshale property (Table 2), • Twenty isochore with average Vshale property (Table 3), • Twenty isochore with less than 40% Vshale property (Table 4), • Sixteen Average Vshale intersections of less than 40% Vshale property delineating potential connectivity between isochore (Table 5), • Sixteen Average Vshale intersections of less than 40% Vshale property delineating potential connectivity with isochore above and below (Table 6), • Seventeen upscaled Vshale log intersection locations (Table 7), • Six regional sections showing geology and Vshale property (Table 8), • Three datasets with location of boreholes, sections, and area of interest (Table 9).

Geoscience Australia’s regional assessments and basin inventories are investigating Australia’s groundwater systems to improve knowledge of the nation’s groundwater potential under the Exploring for the Future (EFTF) Program and Geoscience Australia’s Strategy 2028. Where applicable, integrated basin analysis workflows are being used to build geological architecture advancing our understanding of hydrostratigraphic units and tie them to a nationally consistent chronostratigraphic framework. Here we focus on the Great Artesian Basin (GAB) and overlying Lake Eyre Basin (LEB), where groundwater is vital for pastoral, agricultural and extractive industries, community water supplies, as well as supporting indigenous cultural values and sustaining a range of groundwater dependent ecosystems such as springs and vegetation communities. Geoscience Australia continued to revise the chronostratigraphic framework and hydrostratigraphy for the GAB infilling key data and knowledge gaps from previous compilations. In collaboration with Commonwealth and State government agencies, we compiled and standardised thousands of boreholes, stratigraphic picks, 2D seismic and airborne electromagnetic data across the GAB. We undertook a detailed stratigraphic review on hundreds of key boreholes with geophysical logs to construct consistent regional transects across the GAB and LEB, using geological time constraints from hundreds of boreholes with existing and newly interpreted biostratigraphic data. We infilled the stratigraphic correlations along key transects across Queensland, New South Wales, South Australia and Northern Territory borders to refine nomenclature and stratigraphic relationships between the Surat, Eromanga and Carpentaria basins, improving chronostratigraphic understanding within the Jurassic to Cretaceous units. We extended the GAB geological framework to the overlying LEB to better resolve the Cenozoic stratigraphy and potential hydrogeological connectivity. New data and information fill gaps and refine the previous 3D hydrogeological model of the entire GAB and LEB. The new 3D geological and hydrostratigraphic model provides a framework to integrate additional hydrogeological and rock property data. It assists in refining hydraulic relationships between aquifers within the GAB and provides a basis for developing more detailed hydrogeological system conceptualisations. This is a step towards the future goal of quantifying hydraulic linkages with underlying basins, and overlying Cenozoic aquifers to underpin more robust understanding of the hydrogeological systems within the GAB. This approach can be extended to other regional hydrogeological systems. This Abstract was submitted/presented at the 2023 Australasian Exploration Geoscience Conference (AEGC) 13-18 March (https://2023.aegc.com.au/)

Publicly available groundwater data have been compiled to provide a common information base to inform environmental, resource development and regulatory decisions in the Cooper Basin region. This web service summarises salinity, water levels, resource size, potential aquifer yield and surface water–groundwater interactions for the Lake Eyre Basin located within the Cooper Basin region.