Salinity of groundwater directly affects its suitability for different uses, including human consumption, stock water, agricultural use, and mineral or energy extraction. Traditionally, direct measurements of groundwater salinity at monitoring bores that intersect an aquifer have been used to map the spatial distribution of groundwater salinity. However, drilling is a logistically and economically challenging task, and we are usually left with a sparse set of measurements from which to infer groundwater salinity over large spatial extents. Airborne electromagnetic (AEM) sounding provides a solution to this problem. This is because AEM can be flown rapidly and cost-effectively over large swathes of land, and high subsurface bulk conductivities inferred from the AEM are well correlated with groundwater salinity in porous aquifers. We present here a methodology and case study from the Keep River Plains in the Northern Territory that provides information for land and watershed managers about the confidence with which salinity can be mapped over large areas using AEM. Extensive pore fluid sampling of the saturated zone, which lies beneath the watertable, enables this workflow to be used effectively. The results provided by our method can feed into decision making while accounting for uncertainty, enabling remote communities to manage their land and water resources effectively. <b>Citation:</b> Symington, N.,Ray, A., Harris-Pascal, C., Tan, K.P., Ley-Cooper, A.Y., and Brodie, R.C., 2020. Groundwater salinity estimation using borehole and AEM data: a framework for uncertainty analysis. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

This report presents key results from the Upper Burdekin Groundwater Project conducted as part of Exploring for the Future (EFTF)—an eight year Australian Government funded geoscience data and information acquisition program. The first four years of the Program (2016–20) aimed to better understand the potential mineral, energy and groundwater resources in northern Australia. The Upper Burdekin Groundwater Project focused on the McBride Basalt Province (MBP) and Nulla Basalt Province (NBP) in the Upper Burdekin region of North Queensland. It was undertaken as a collaborative study between Geoscience Australia and the Queensland Government. This document reports the key findings of the project, as a synthesis of the hydrogeological investigation project and includes maps and figures to display the results.

The Exploring for the Future Southern Stuart Corridor Groundwater Project undertook extensive multidisciplinary geoscientific investigations across four study areas and six Indigenous communities in central Australia to better understand and characterise groundwater resources. The project was developed to support improvements in water resilience for communities and future agricultural developments in the region. Geoscience Australia collected 9800 line kilometres of airborne electromagnetic data, drilled and installed 15 new monitoring bores, acquired 78 surface nuclear magnetic resonance soundings, recorded downhole geophysical data and groundwater level measurements from >50 bores, and completed hydrochemical analysis of 75 samples. Integration of these datasets provided insights into recharge areas and rates, and potential for managed aquifer recharge. The project also improved our understanding of the geological systems hosting groundwater and interconnections between systems. Potential new groundwater supplies, enhanced understanding of groundwater processes and improved geological models will assist water agencies to better manage groundwater resources across the region. <b>Citation:</b> Hostetler, S., Slatter, E., McPherson, A.A., Tan, K.P., McInnes, D. J., Wischusen, J.D.H. and Ellis, J.H., 2020. A multidisciplinary geoscientific approach to support water resilience in communities in Central Australia. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

The Western Davenport region has been identified as an area of interest for future agricultural development. However, realisation of this potential depends on access to a reliable supply of groundwater, underpinned by rigorous geological and groundwater information. A three-dimensional stratigraphic model has been created for the Western Davenport area of the Southern Stuart Corridor project under the Exploring for the Future program. Our interpretation integrates airborne electromagnetic data with historical drillhole and outcrop data to improve geological and hydrogeological understanding. Results show that stratigraphies of the Wiso and Georgina basins are equivalent and laterally continuous in this area. This enables a more complete hydrostratigraphy to be defined and underpins improved hydrogeological conceptualisation. New hydrochemical data support the conceptual model that the aquifers of the Wiso and Georgina basins are interconnected at a regional scale. The initial assessment of water quality indicates that groundwater may support further agricultural development. Analysis of new water chemistry data has improved understanding of groundwater processes and potential areas of recharge. This work will inform management decisions to enhance the economic and social opportunities in the Western Davenport area, while protecting the environmental and cultural value of water resources. <b>Citation:</b> Northey, J.E., Clark, A.D., Smith, M.L. and Hostetler, S., 2020. Delineation of geology and groundwater resources in a frontier region: Western Davenport, Northern Territory. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

We present a multifaceted hydrogeological investigation of the McBride and Nulla basalt provinces in the Upper Burdekin region, north Queensland. The project aims to better understand their key groundwater system processes to inform future development and water management decisions. This work, carried out as part of the Exploring for the Future Upper Burdekin Groundwater Project, has shown that basalt aquifers in each province are typically unconfined where monitored. Groundwater recharge is widespread but highly variable, largely occurring within the boundaries of the basalt provinces. Groundwater salinity based on electrical conductivity is <1000 μS/cm in the McBride Basalt Province (MBP) and up to 2000 μS/cm in the Nulla Basalt Province (NBP). Groundwater levels have been declining since 2011 (following major flooding in Queensland), showing that the study period covers a small fraction of a longer-functioning dynamic groundwater system. The basalt provinces contain distinct lava flows, and the degree of hydraulic connectivity between them is unclear. Despite similarities in their rock properties, the geometry of lava emplacement leads to different groundwater flow regimes within the two basalt provinces. Radial flow away from the central high elevations towards the edges is characteristic of the MBP, while regional flow from west to east dominates the NBP. Basalt aquifers in both provinces support a range of groundwater-dependent ecosystems, such as springs, some of which sustain flow in tributaries of the Burdekin River. Where streams intersect basalt aquifers, this also results in direct groundwater discharge. Springs and perennial tributaries, particularly emanating from the MBP, provide important inflows to the Burdekin River, especially in the dry season. This work has highlighted that management of MBP and NBP groundwater sources is crucial for maintaining a range of environmental assets in the region and for ensuring access for existing and future users. <b>Citation:</b> Ransley, T.R., Dixon-Jain, P., Cook, S.B., Lai, E.C.S., Kilgour, P., Wallace, L., Dunn, B., Hansen, J.W.L. and Herbert, G., 2020. Hydrogeology of the McBride and Nulla basalt provinces in the Upper Burdekin region, north Queensland. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

Water, energy and mineral resources are vital for Australia’s economic prosperity and sustainable development. However, continued supply of these resources cannot be taken for granted. It is widely accepted that the frontier of exploration now lies beneath the Earth’s surface, making characterisation of the subsurface a unifying challenge. Between 2016 and 2020, the $100.5 million Exploring for the Future program focused on addressing this challenge across northern Australia in order to better define resource potential and boost investment. The program applied a multiscale systems approach to resource assessment based on characterisation of the Australian plate from the surface down to its base, underpinned by methodological advances. The unprecedented scale and diversity of new data collected have resulted in many world-first achievements and breakthrough insights through integrated systems science. Through this multi-agency effort, new continental-scale datasets are emerging to further enhance Australia’s world-leading coverage. The program has identified prospective regions for a wide range of resources and pioneered approaches to exploration undercover that can be applied elsewhere. The outcomes so far include extensive tenement uptake for minerals and energy exploration in covered terranes, and development of informed land-management policy. Here, we summarise the key scientific achievements of the program by reviewing the main themes and interrelationships of 62 contributions, which together constitute the Exploring for the Future: extended abstracts volume. <b>Citation:</b> Czarnota, K., Roach, I.C., Abbott, S.T., Haynes, M.W., Kositcin, N., Ray, A. and Slatter, E., 2020. Exploring for the Future: advancing the search for groundwater, energy and mineral resources. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.