<div>This report brings together data and information relevant to understanding the regional geology, hydrogeology, and groundwater systems of the South Nicholson – Georgina (SNG) region in the Northern Territory and Queensland. This integrated, basin-scale hydrogeological assessment is part of Geoscience Australia’s National Groundwater Systems project in the Exploring for the Future program. While the northern Georgina Basin has been at the centre of recent investigations as part of studies into the underlying Beetaloo Sub-basin, no regional groundwater assessments have focused on central and southern parts of the Georgina Basin since the 1970s. Similarly, there has been no regional-scale hydrogeological investigation of the deeper South Nicholson Basin, although the paucity of groundwater data limited detailed assessment of the hydrogeology of this basin. This comprehensive desktop study has integrated numerous geoscience and hydrogeological datasets to develop a new whole-of-basin conceptualisation of groundwater flow systems and recharge and discharge processes within the regional unconfined aquifers of the Georgina Basin.</div><div><br></div><div>Key outputs arising from this study include: (1) the development of a hydrostratigraphic framework for the region, incorporating improved aquifer attribution for over 5,000 bores; and (2) publicly available basin-scale groundwater GIS data layers and maps, including a regional watertable map for the whole Georgina Basin. This regional assessment provides new insights into the hydrogeological characteristics and groundwater flow dynamics within the Georgina Basin, which can aid in the sustainable management of groundwater for current and future users reliant on this critical water resource.</div><div><br></div><div><br></div>

<div>The Curnamona Province and overlying basins (herein referred to as the Broken Hill region) contain many discrete groundwater systems. These include sedimentary aquifers of the Lake Eyre Basin, Eromanga Basin, Darling Basin and Arrowie Basin, as well as fractured rock aquifers of the Adelaide Superbasin and Curnamona Province. However, there is little known about the hydrogeology or hydrogeochemistry of these aquifers in the Broken Hill region. Given the semi-arid climate in this region, understanding these groundwater systems can better support sustainable use of the groundwater for agriculture, mining and potable water supplies.</div><div>&nbsp;</div><div>Aquifer attribution provides a fundamental starting point for any hydrogeological study. We will present recently released hydrogeochemical data for the Broken Hill region, and our subsequent process for assessing and attributing hydrostratigraphy to the samples. </div><div>The Broken Hill Groundwater Geochemistry dataset (BHGG) was recently released in its entirety (Caritat et al. 2022 http://dx.doi.org/10.11636/Record.2022.020). It contains a compilation of archival CRC LEME hydrochemistry data that was collected as part of several projects from 1999 to 2005. This high-quality dataset contains 275 groundwater samples and includes a comprehensive suite of majors, minors, trace elements and stable isotopes (δ34S, δ18O, δ2H, δ13C, 87Sr/86Sr, 208/207/206Pb/204Pb). </div><div> At the time of collection, some key bore metadata (e.g. bore depths, screen and aquifer information) were missing from the original data compilations and these metadata are crucial for any hydrogeological analysis and interpretation. Therefore, as part of the new BHGG data release we have developed a robust and consistent approach to add bore information and aquifer attribution, value-adding to the original BHGG chemical and isotopic data. This workflow utilises a combination of State databases, reports, field notes, drillhole compilations and geological maps, but still relied on local hydrological expertise to make decisions when encountering incomplete or conflicting information (which is reflected by a confidence rating on the attribution). </div><div> The resulting BHGG product has supported re-assessment of the key hydrogeological and geochemical knowledge gaps in each groundwater system. An overview of knowledge gaps and the new sampling program being undertaken will be included in the presentation. &nbsp;</div><div><br></div>This Abstract was submitted/presented to the 2022 Australasian Groundwater Conference 21-23 November (https://agc2022.com.au/)

This report presents groundwater level information collected during Geoscience Australia’s Musgrave Palaeovalley Project. The Musgrave Palaeovalley Project was conducted as part of Exploring for the Future (EFTF), an Australian Government funded geoscience data and information acquisition program. The eight-year, $225 million program aims to deliver new geoscience data and knowledge to inform decision-making by government, community, and industry on the sustainable development of Australia's mineral, energy, and groundwater resources.</div><div>Groundwater level data was collected during two hydrogeochemical surveys undertaken in March and May 2023 based around the remote communities of Warburton, Kaltukatjara, Wanarn, Blackstone and Jameson in Western Australia and the Northern Territory. Sixteen bores were measured for their groundwater levels. The results are contained herein and within the attached CSV file.

<div>This report summarises information regarding groundwater processes considered to have direct influence on the water balance for the Great Artesian Basin (GAB). These processes are recharge, discharge, and connectivity within the GAB sequence, as well as connectivity with underlying basins and overlying cover. </div><div>The substantial body of literature available on the GAB gives the impression that there is a considerable degree of understanding of the GAB groundwater system. This is, however, misleading. The reality is that many reports and reviews have been cited or reworked from pre-existing studies without carrying over the original uncertainties. Over time, the scale of knowledge gaps has been reduced only incrementally, while there has been a growing appreciation of the complexities in the system. With so much conceptual and quantitative uncertainty, much additional investigation is still required.</div><div><br></div>

<div>Non-technical summaries of groundwater in the remote communities of Warburton, Kaltukatjara (Docker River), Warakurna, Wingellina, Wanarn, Mantamaru (Jameson) and Papulankutja (Blackstone). These summaries are based on research undertaken as part of the Musgrave Palaeovalley Project and full results are available in the Musgrave Palaeovalley Project Synthesis Report (https://dx.doi.org/10.26186/149406).</div>

<div>In response to the acquisition of national-scale airborne electromagnetic surveys and the development of a national depth estimates database, a new workflow has been established to interpret airborne electromagnetic conductivity sections. This workflow allows for high quantities of high quality interpretation-specific metadata to be attributed to each interpretation line or point. The conductivity sections are interpreted in 2D space, and are registered in 3D space using code developed at Geoscience Australia. This code also verifies stratigraphic unit information against the national Australian Stratigraphic Units Database, and extracts interpretation geometry and geological data, such as depth estimates compiled in the Estimates of Geological and Geophysical Surfaces database. Interpretations made using this workflow are spatially consistent and contain large amounts of useful stratigraphic unit information. These interpretations are made freely-accessible as 1) text files and 3D objects through an electronic catalogue, 2) as point data through a point database accessible via a data portal, and 3) available for 3D visualisation and interrogation through a 3D data portal. These precompetitive data support the construction of national 3D geological architecture models, including cover and basement surface models, and resource prospectivity models. These models are in turn used to inform academia, industry and governments on decision-making, land use, environmental management, hazard mapping, and resource exploration.</div>

<div>Australia is the driest inhabited continent on Earth and groundwater is crucial to maintaining the country’s population, economic activities, Indigenous culture and environmental values. Geoscience Australia is renewing a national-scale focus to tackle hydrogeological challenges by building upon our historic legacy in groundwater studies at regional and national scales.</div><div><br></div><div>The most comprehensive hydrogeological coverage of the nation is the 1987 Hydrogeology of Australia map, developed by a predecessor of Geoscience Australia. This map provides an overview of groundwater systems and principal aquifers across Australia, based upon the large sedimentary basins, intervening fractured rock areas and smaller overlying sedimentary/volcanic aquifers. However, the currency and completeness of the information presented and accompanying the national hydrogeology map needs to be improved. Updating the extents, data and scientific understanding of the hydrogeological regions across Australia, and improving the accessibility and useability of this information will address many of its current limitations.</div><div><br></div><div>Geoscience Australia, within its Exploring for the Future program, is compiling hydrogeological and related contextual information clearly and consistently across Australia’s major sedimentary basins and intervening fractured rock provinces. This information has been collected for 41 major hydrogeological regions spanning the continent: 36 sedimentary basins and 5 regions dominated by fractured-rock aquifers. The information, collected through a combination of geospatial analyses of national datasets and high-level summaries of scientific literature, will be presented through Geoscience Australia’s online data discovery portal, thereby enabling improved interrogation and integration with other web mapping services.</div><div><br></div><div>The new compilation of nationally consistent groundwater data and information will help to prioritise future investment for new groundwater research in specific regions or basins, inform the work programs of Geoscience Australia and influence the prioritisation of national hydrogeological research more broadly.&nbsp;</div><div><br></div>This Abstract was submitted/presented to the 2022 Australasian Groundwater Conference 21-23 November (https://agc2022.com.au/)

<div>Groundwater is critical to the survival of a range of ecosystems in Australia through provision of a direct source of water to plants with suitable root systems, and through discharge into surface water systems. Effectively managing groundwater dependent ecosystems (GDEs) alongside other water demands requires the ability to identify, characterise, and monitor vegetation condition.&nbsp;<em>&nbsp;</em><br> As part of the <a href="https://www.eftf.ga.gov.au/upper-darling-river-floodplain-groundwater-study">Exploring for the Future Upper Darling Floodplain</a> (UDF) groundwater project in western New South Wales, we present results from a study testing the suitability of two novel methods (a) recently available tasselled cap percentile products with national coverage through Digital Earth Australia, and (b) dry-conditions interferometric radar (InSAR) coherence images for mapping vegetation that is potentially groundwater dependent. <em>&nbsp;</em></div><div><em>&nbsp;</em></div><div>A combination of greenness and wetness 10th percentile tasselled cap products delineated terrestrial and aquatic GDEs with greater accuracy than existing regional ecosystem mapping, demonstrating the utility of these products for GDE identification. These results suggest the tasselled cap products can be used to support and refine the existing GDE mapping for this region, and further testing of their suitability and application for other regions is warranted.&nbsp;<em>&nbsp;</em></div><div><em>&nbsp;</em></div><div>The InSAR coherence images produced good agreement with the Bureau of Meteorology national GDE Atlas for areas of high probability of groundwater dependence. Although data availability and technical expertise currently lags behind optical imagery products, if research continues to show good performance in mapping potential GDEs and other applications, InSAR could become an important line of evidence within multi-dataset investigations.&nbsp;<em>&nbsp;</em></div><div><em>&nbsp;</em></div><div>Key next steps for improving the utility of these techniques &nbsp;are (a) comparison with vegetation condition data, and (b) further assessment of the likelihood of groundwater dependence through assessing relationships between vegetation condition and groundwater, surface water, and soil moisture availability.<em>&nbsp;</em></div><div>&nbsp;</div><div>This abstract was submitted/presented to the 2023 Australasian Groundwater / New Zealand Hydrological Society (AGC NZHS) Joint Conference (https://www.hydrologynz.org.nz/events-1/australasian-groundwater-nzhs-joint-conference)</div>

This was the first of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop - A clear and consistent inventory of knowledge about Australia’s major hydrogeological provinces.

<div>Groundwater dependent ecosystems (GDEs) rely on access to groundwater on a permanent or intermittent basis to meet some or all of their water requirements (Richardson et al., 2011). The <a href="https://explorer-aws.dea.ga.gov.au/products/ga_ls_tc_pc_cyear_3">Tasseled Cap percentile products</a> created by Digital Earth Australia (2023) were used to identify potential GDEs for the South Nicholson-Georgina basins study area. These percentile products provide statistical summaries (10th, 50th, 90th percentiles) of landscape brightness, greenness and wetness in imagery acquired between 1987 and present day. The 10th percentile greenness and wetness represent the lowest 10% of values for the time period evaluated, e.g. 10th percentile greenness represents the least green period. In arid regions, areas that are depicted as persistently green and/or wet at the 10th percentile have the greatest potential to be GDEs. For this reason, and due to accessibility of the data, the 10th percentile Tasseled Cap greenness (TCG) and Tasseled Cap wetness (TCW) products were used as the basis for the assessment of GDEs for the South Nicholson-Georgina region. The 50th percentile greenness was utilised to create the coefficient of variance (CV) dataset. This data release is an ESRI geodatabase, with layer files, including: - combined classified 10th percentile greenness and wetness dataset (useful to identify potential groundwater dependent vegetation/other GDEs and differentiate between vegetation types) - CV of 50th percentile greenness dataset (useful when used in conjunction with the combined product to help identify groundwater dependent vegetation) For more information and detail on these products, refer to associated <a href="https://dx.doi.org/10.26186/149377">report</a>. </div><div><br></div><div><strong>References</strong></div><div>Digital Earth Australia (2023).&nbsp;<em><a href="https://docs.dea.ga.gov.au/">Digital Earth Australia User Guide.</a></em></div><div>Richardson, S., E. Irvine, R. Froend, P. Boon, S. Barber, and B. Bonneville. 2011a.&nbsp;<em>Australian groundwater-dependent ecosystem toolbox part 1: Assessment framework.</em>&nbsp;Waterlines Report 69. Canberra, Australia: Waterlines.</div><div><br></div>