<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>

<div>Geoscience Australia, in partnership with Commonwealth, State and Territory governments is delivering national and regional groundwater investigations through the Exploring for the Future (EFTF) Program to support water management decisions. Geoscience Australia’s groundwater studies apply innovative geoscience tools and robust geoscientific workflows to increase knowledge and understanding of groundwater systems and assessment of groundwater resource potential for economies, communities and the environment.&nbsp;</div> This presentation was given at the 2022 Australasian Groundwater Conference 21-23 November (https://agc2022.com.au/)

This was the fourth of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop - Detailed Groundwater Science Inventory Geology, hydrogeology and groundwater systems in the Kati Thanda-Lake Eyre Basin.

<div>This was the last of five presentations held on 31 July 2023 as part of the National Groundwater Systems Workshop. Towards developing a 3D hydrogeological framework for Australia: A common chronostratigraphic framework for aquifers&nbsp;</div><div><br></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>Aboriginal and Torres Strait Islander peoples hold a wealth of traditional knowledge about their land and waters gathered and passed down from observations over thousands of years. Geoscience Australia (GA) is the national geoscience public sector organisation that advises on the geology, hydrogeology, and geography of Australia by applying science and technology to describe and understand the Earth. Respectful and successful two-way engagement with Indigenous peoples provides an opportunity to identify and share traditional understanding, complementing geoscientific studies and preserving traditional knowledge Through its Innovate Reconciliation Action Plan, GA is committed to building mutually beneficial relationships with Aboriginal and Torres Strait Islander peoples. Aligned with this vision, and as part of the Exploring for the Future Program, GA engaged a subject matter expert to undertake a scoping study. The aim of this study was to provide advice to strengthen the internal processes it uses to engage and undertake projects with Indigenous peoples. Drawing on two case studies (northeast NSW; eastern WA), a framework was developed to guide GA staff in the collection and recording of information and knowledge in a culturally appropriate manner. The project also delivered a road map to achieve better engagement and inclusion of Indigenous peoples in geoscience studies, to be tested and refined in future work programs. The road map is built on six key elements: (1) increasing Indigenous employment; (2) building partnerships; (3) respecting timeframes; (4) embedding Indigenous values and culture; (5) adhering to ethical practices and principles; and (6) embracing two-way knowledge sharing. Trust is crucial to building a partnership with Indigenous communities, binding the six elements of the road map. In the future GA hopes to share the outcomes with other organisations, from applying the framework and road map aimed at improving engagement with Indigenous peoples in groundwater activities and the geosciences more broadly. Presented at the 2022 Australasian Groundwater Conference (AGC)

<div>The interpretation of AusAEM airborne electromagnetic (AEM) survey conductivity sections in the Canning Basin region delineates the geo-electrical features that correspond to major chronostratigraphic boundaries, and captures detailed stratigraphic information associated with these boundaries. This interpretation forms part of an assessment of the underground hydrogen storage potential of salt features in the Canning Basin region based on integration and interpretation of AEM and other geological and geophysical datasets. A main aim of this work was to interpret the AEM to develop a regional understanding of the near-surface stratigraphy and structural geology. This regional geological framework was complimented by the identification and assessment of possible near-surface salt-related structures, as underground salt bodies have been identified as potential underground hydrogen storage sites. This study interpreted over 20,000 line kilometres of 20&nbsp;km nominally line-spaced AusAEM conductivity sections, covering an area approximately 450,000 km2 to a depth of approximately 500&nbsp;m in northwest Western Australia. These 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 interpretation produced approximately 110,000 depth estimate points or 4,000 3D line segments, each attributed with high-quality geometric, stratigraphic, and ancillary data. The depth estimate points are formatted for Geoscience Australia’s Estimates of Geological and Geophysical Surfaces database, the national repository for formatted depth estimate points. Despite these interpretations being collected to support exploration of salt features for hydrogen storage, they are also intended for use in a wide range of other disciplines, such as mineral, energy and groundwater resource exploration, environmental management, subsurface mapping, tectonic evolution studies, and cover thickness, prospectivity, and economic modelling. Therefore, these interpretations will benefit government, industry and academia interested in the geology of the Canning Basin region.</div>

<div>As part of the $225 million Exploring for the Future programme, Geoscience Australia have undertaken an investigation into the resource potential of the Officer-Musgrave-Birrindudu region. Part of this project focusses on characterising palaeovalley groundwater resources within the West Musgrave region of Australia. This GA Record is a technical report detailing the science undertaken as part of the Musgrave Palaeovalley groundwater project. The project aimed to improve understanding of the region's palaeovalley architecture, groundwater quality, and overall hydrogeology to support responsible water resource management. The most significant work undertaken included three-dimensional modelling of palaeovalley architecture, groundwater characterisation using hydrochemistry, groundwater model conceptualisation and a detailed review of local groundwater around remote communities in the region. This work will underpin responsible groundwater management into the future.</div>

<div>Understanding groundwater flow dynamics within the Great Artesian Basin (GAB) is critical for responsible management of groundwater from an environmental, economic and cultural perspective. Numerical groundwater flow modelling involves generating a simplified representation of a groundwater system and using Darcy’s Law to simulate groundwater flow rates and the distribution of hydraulic heads throughout the system. This is a pilot study aimed at developing a workflow for groundwater flow modelling of the Great Artesian Basin using Bayesian methods. In this report, we present our initial results from building and running a steady-state groundwater flow model of the entire GAB. We demonstrate a Bayesian inference framework to generate an ensemble of groundwater flow models allowing an assessment of the uncertainty of model parameters and flow velocities.&nbsp;</div><div>Several models have been built to simulate groundwater flow across various areas and layers of the GAB. Most of these models aimed to predict the likely impacts on the groundwater system of some future scenario, generally climate change or groundwater extraction relating to mining activities. While these models are well-suited to their purpose, their focus on particular regions or aquifers makes them unsuitable for investigating large-scale groundwater flow throughout the GAB. In contrast, the model built as part of this study captures the entire GAB and aims to simulate large-scale flow. Although not in scope for this pilot study, the questions a model at this scale is capable of addressing include characterising 3D flow within hydrogeological layers, computing groundwater flux between aquifers and between sub-basins, inferring hydraulic properties and identifying poor quality data. As this model is steady-state and uses hydraulic head data from before the year 2000, it provides a baseline estimate of groundwater flow without considering recent anthropogenic forcing or transient system stresses.&nbsp;</div><div>The GAB is represented as a 14 hydrogeological layer model including basement, Permo-Carboniferous basins, Mesozoic sedimentary aquifers and aquitards and Cenozoic layers. This includes updated hydrogeological surfaces from the GAB project. The input data consisted of 8,065 hydraulic head measurements and 6,151 estimates of recharge rate while the model parameters were a single hydraulic conductivity value for each of the 14 layers. The modelling domain was discretised using 10 x 10 km cells in the horizontal plane and the mesh was deformed vertically to fit between the topography and the basement surface, with the resulting mesh having a vertical discretisation of no coarser than 50 metres. The top boundary condition was a constant head boundary that was a smoothed version of topography. The sides and bottom of the model have no flux boundary conditions and a buffer zone around the GAB was included to minimise boundary effects.&nbsp;&nbsp;</div><div>In total 2500 groundwater flow simulations were run using a Bayesian inversion framework. The inversion sampled various combinations of input parameters to find models with a relatively low misfit, which was calculated by squaring the difference between the observed and simulated values of hydraulic head and recharge. Rather than searching for a global minima, the Metropolis Hastings Markov Chain Monte Carlo sampling algorithm was used to explore a range of possible models and estimate the posterior distribution of each layer’s hydraulic conductivity.&nbsp;</div><div>The model performed adequately and the model parameters were generally consistent with the prior probability distributions based on previous modelling studies. However, the posterior distribution of model parameters were very broad indicating the model was not particularly informative in its current form.&nbsp;&nbsp;</div><div>Groundwater flow velocity vectors from the maximum likelihood model were used to investigate groundwater trends within the Cadna-owie-Hooray aquifer. Uncertainty of model predictions were investigated by calculating the groundwater flow velocity variance across the ensemble. This study demonstrates that it is technically feasible to use Bayesian inference to probabilistically mode groundwater flow across the entire GAB. However, for this approach to yield useful results, more work is required to understand the impacts of simplifying assumptions about layer properties, the quality of the input data and model structure on the resulting flow model.&nbsp;</div><div><br></div>

<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>