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.

Groundwater is an essential part of Darwin’s water supply mix, and is sourced from Howard East Borefield (HEB) and McMinns Borefield in the Koolpinyah Dolostone Aquifer (KDA), east of Darwin. Previous work suggested that electrical conductivity anomalies observed in airborne electromagnetic (AEM) data within 8 km of HEB may be caused by saline groundwater within the KDA that is separated from HEB by geological features that effectively compartmentalise the aquifer. Nevertheless, concerns grew that increased groundwater use may result in migration of saline groundwater towards HEB, which could compromise the groundwater resource. We collected hydrochemistry, including isotopes, time-series groundwater salinity and AEM data to better understand the complexities of the KDA. These data are presented here, along with a hydrodynamic analysis undertaken by the Northern Territory Department of Environment and Natural Resources, which shows that drawdown is occurring more rapidly from the NE of HEB and that dykes ~8 km NE of HEB act as barriers to groundwater flow. We show that groundwater sampled on the NE side of these dykes has a seawater composition. We use new AEM data to map the elevation of the top of unweathered dyke material and to characterise AEM conductors proximal to HEB. Our mapping reveals that the top of the unweathered portion of these dykes is commonly below sea level. We also show that AEM conductors proximal to HEB are more likely mineralised clays than saline groundwater within the aquifer. Drilling is required to confirm these results. Our findings contribute to building a robust conceptual understanding of the KDA and will inform future modelling of the groundwater system. <b>Citation:</b> Haiblen, A.M., Symington, N.J., Woltmann, M.J., Ray, A., Gow, L.J., Leplastrier, A. and McGrath, E.S.B., 2020. A multifaceted approach to investigating hydrogeological complexities in the Koolpinyah Dolostone Aquifer, Howard East, 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.

This Daly Basin dataset contains descriptive attribute information for the areas bounded by the relevant spatial groundwater feature in the associated Hydrogeology Index map. Descriptive topics are grouped into the following themes: Location and administration; Demographics; Physical geography; Surface water; Geology; Hydrogeology; Groundwater; Groundwater management and use; Environment; Land use and industry types; and Scientific stimulus. The Daly Basin is a geological formation consisting of Cambrian to Ordovician carbonate and siliciclastic rocks, formed approximately 541 million to 470 million years ago. The basin stretches about 170 km in length and 30 km in width, shaped as a northwest elongated synform with gentle dips of less than 1 degree, likely due to prolonged sedimentary deposition in the shallow seas of the Centralian Superbasin, possibly along basin-scale faults. The primary groundwater reservoir within the Daly Basin is found in the Cambrian Daly River Group. This group comprises three units: the Tindall Limestone, Jinduckin Formation, and Oolloo Dolostone. The Tindall Limestone, which lies at the base, consists of grey, mottled limestone with some maroon-green siltstone or dark grey mudstone. The transition from the Tindall Limestone to the overlying Jinduckin Formation is marked by a shift from limestone to more siliciclastic rocks, indicating a change from open-shelf marine to peri-tidal environments. The Jinduckin Formation, situated above the Tindall Limestone, is composed of maroon-green dolomitic-siliciclastic siltstone with interbeds of dolomitic sandstone-siltstone, as well as dolostone and dolomitic quartz sandstone lenses. It gradually transitions into the carbonate-rich Oolloo Dolostone, with the highest finely laminated dolomitic sandstone-siltstone interbeds at the top of the Jinduckin Formation. The Oolloo Dolostone, the uppermost unit of the Daly River Group, comprises two members: the well-bedded lower Briggs Member, consisting of fine- to medium-grained crystalline dolostone and dolomitic quartz sandstone, and the massive upper King Member. Overlying the Daly River Group is the Ordovician Florina Formation, consisting of three carbonate intervals separated by two fine-grained, glauconite-bearing quartz sandstone units. The Florina Formation and the Daly River Group are covered unconformably by Cretaceous claystone and sandstone of the Carpentaria Basin, which extends over a significant portion of the Daly Basin.

This service provides access to airborne electromagnetics (AEM) derived conductivity grids in the Upper Darling Floodplain region. The grids represent 30 depth intervals from modelling of AEM data acquired in the Upper Darling Floodplain, New South Wales, Airborne Electromagnetic Survey (https://dx.doi.org/10.26186/147267), an Exploring for the Future (EFTF) project jointly funded by Geoscience Australia and New South Wales Department of Planning and Environment (NSW DPE). The AEM conductivity model delineates important subsurface features for assessing the groundwater system including lithological boundaries, palaeovalleys and hydrostatigraphy.

This service provides access to airborne electromagnetics (AEM) derived conductivity grids in the Upper Darling Floodplain region. The grids represent 30 depth intervals from modelling of AEM data acquired in the Upper Darling Floodplain, New South Wales, Airborne Electromagnetic Survey (https://dx.doi.org/10.26186/147267), an Exploring for the Future (EFTF) project jointly funded by Geoscience Australia and New South Wales Department of Planning and Environment (NSW DPE). The AEM conductivity model delineates important subsurface features for assessing the groundwater system including lithological boundaries, palaeovalleys and hydrostatigraphy.

Catchment-scale hydrological and hydrogeological investigations commonly conclude by finding that particular stream reaches are either gaining or losing; they also often assume that the influence of bedrock aquifers on catchment water balances and water quality is insignificant. However, in many cases, such broad findings are likely to oversimplify the spatial and temporal complexity of the connections between the different hydrological system components, particularly in regions dominated by cycles of droughts and flooding. From a modelling perspective, such oversimplifications can have serious implications on the process of identifying the magnitude and direction of the exchange fluxes between the surface and groundwater systems. In this study, we use 3D geological modelling and historic water chemistry and hydraulic records to identify the origins of groundwater at different locations in the alluvium and along the course of streams in the Lockyer Valley (Queensland, Australia), a catchment impacted by a severe drought (‘Millennium Drought’) from 1998 to 2009, followed by extensive flooding in 2011. We also demonstrate how discharge from the sub-alluvial regional-scale volcanic and sedimentary bedrock influences the water balance and water quality of the alluvium and streams. The investigation of aquifer geometry via development of a three-dimensional geological model combined with an assessment of hydraulic data provided important insights on groundwater flow paths and helped to identify areas where bedrock aquifers interact with shallow alluvial aquifers and streams. Multivariate statistical techniques were then applied as an additional line of evidence to groundwater and surface water hydrochemical data from large historical datasets. This confirmed that most sub-catchments within the Lockyer Valley have distinct water chemistry patterns, which result from mixing of different water sources, including discharge from the sub-alluvial bedrock. Importantly, in addition to the observed spatial variability, time-series hydrochemical groundwater and surface water data further demonstrated that the hydraulic connection between alluvial aquifers, streams and sub-alluvial bedrock aquifers is temporally dynamic with very significant changes occurring at the transition from normal to drought conditions and following flooding, affecting both catchment water quality and water balances. <b>Citation:</b> M. Raiber, S. Lewis, D.I. Cendón, T. Cui, M.E. Cox, M. Gilfedder, D.W. Rassam, Significance of the connection between bedrock, alluvium and streams: A spatial and temporal hydrogeological and hydrogeochemical assessment from Queensland, Australia, <i>Journal of Hydrology</i>, Volume 569, 2019, ISSN 0022-1694, https://doi.org/10.1016/j.jhydrol.2018.12.020.

The presence of Neogene fault systems can have a significant impact on hydraulic connectivity of aquifers, juxtaposing otherwise disconnected aquifers, enhancing recharge and/or discharge or acting as barriers to flow and consequently compartmentalising groundwater resources. Previously, regional airborne electromagnetics (AEM) transects allied with groundwater investigations have pointed to the potential for localised compartmentalisation of the Daly River Basin groundwater systems. However, existing data is sparse, and equivocal. In this context, the main aim of the Daly River Basin Project is to determine if compartmentalisation of the aquifers is a significant factor and thus should be explicitly considered in groundwater modelling and water allocation planning. The objectives of the project main goals of the project are to: (1) map Neogene faults through the use of airborne electromagnetic (AEM) and morphotectonic mapping, and (2) assess the permeability and transmissivity of mapped fault zones and their role in potential groundwater system compartmentalisation. Data acquisition includes 3325 line-kilometres of new AEM and airborne magnetics, ground (ground magnetic resonance (GMR)), and borehole geophysics, drilling, groundwater sampling and hydrochemical analysis, geomorphic and morphotectonics mapping. Hydrogeophysical, geomorphic and hydrogeological data will also be used to better understand groundwater-surface water connectivity and the potential for managed aquifer recharge schemes to replenish extracted groundwater resources. The outcomes of this project will inform decisions on water allocations and underpin effective and efficient groundwater use. This paper specifically reports on the ability of AEM and morphotectonics mapping to identify Neogene fault systems in the Daly River Basin.

This service delivers the base of Cenozoic surface and Cenozoic thickness grids for the west Musgrave province. The gridded data are a product of 3D palaeovalley modelling based on airborne electromagnetic conductivity, borehole and geological outcrop data, carried out as part of Geoscience Australia's Exploring for the Future programme. The West Musgrave 3D palaeovalley model report and data files are available at https://dx.doi.org/10.26186/149152.

This service delivers the base of Cenozoic surface and Cenozoic thickness grids for the west Musgrave province. The gridded data are a product of 3D palaeovalley modelling based on airborne electromagnetic conductivity, borehole and geological outcrop data, carried out as part of Geoscience Australia's Exploring for the Future programme. The West Musgrave 3D palaeovalley model report and data files are available at https://dx.doi.org/10.26186/149152.

The Groundwater Dependent Waterbodies (GDW) dataset is a subset of the Digital Earth Australia (DEA) Waterbodies product that has been combined with the Bureau of Meteorology’s national Groundwater Dependent Ecosystem (GDE) Atlas to produce surface waterbodies that are known/high potential aquatic GDEs. These aquatic GDEs include springs, rivers, lakes and wetlands. Where known/high potential GDEs intersected a DEA waterbody, the entire DEA waterbody polygon was retained and assigned as a GDW. Additional attributes were added to the waterbody polygons to indicate amount of overlap the waterbody had with the GDE(s) as well as the minimum, mean, median and maximum percentage of time that water has been detected in each GDW relative to the total number of clear observations (1986 to present). This web service will display a variety of layers with spatial summary statistics of the GDW dataset. These provide a first-pass representation of known/high potential aquatic GDEs and their surface water persistence, derived consistently from Landsat satellite imagery across Australia.