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.

This Bowen 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 Bowen Basin is part of the Sydney–Gunnedah–Bowen basin system and contains up to 10,000 m of continental and shallow marine sedimentary rocks, including substantial deposits of black coal. The basin's evolution has been influenced by tectonic processes initiated by the New England Orogen, commencing with a phase of mechanical extension, and later evolving to a back-arc setting associated with a convergent plate margin. Three main phases of basin development have been identified; 1) Early Permian: Characterized by mechanical extension, half-graben development, thick volcanic units and fluvio-lacustrine sediments and coal deposits. 2) Mid Permian: A thermal relaxation event led to the deposition of marine and fluvio-deltaic sediments, ending with a regional unconformity. 3) Late Permian and Triassic: Foreland loading created a foreland basin setting with various depositional environments and sediment types, including included fluvial, marginal marine, deltaic and marine sediments along with some coal deposits in the late Permian, and fluvial and lacustrine sediments in the Triassic. Late Permian peat swamps led to the formation of extensive coal seams dominating the Blackwater Group. In the Triassic, fluvial and lacustrine deposition associated with foreland loading formed the Rewan Formation, Clematis Sandstone Group, and Moolayember Formation. The basin is a significant coal-bearing region with over 100 hydrocarbon accumulations, of which about one third are producing fields. The Surat Basin overlies the southern Bowen Basin and contains varied sedimentary assemblages hosting regional-scale aquifer systems. Cenozoic cover to the Bowen Basin includes a variety of sedimentary and volcanic rock units. Palaeogene and Neogene sediments mainly form discontinuous units across the basin. Three of these units are associated with small eponymous Cenozoic basins (the Duaringa, Emerald and Biloela basins). Unnamed sedimentary cover includes Quaternary alluvium, colluvium, lacustrine and estuarine deposits; Palaeogene-Neogene alluvium, sand plains, and duricrusts. There are also various Cenozoic intraplate volcanics across the Bowen Basin, including central volcanic- and lava-field provinces.

This report presents key results from the Ti Tree Basin project completed as part of Exploring for the Future (EFTF)—an eight year, $225 million Australian Government funded geoscience data and information acquisition program focused on better understanding the potential mineral, energy and groundwater resources across Australia. The Ti Tree Basin is one of four Northern Territory water management areas in the Southern Stuart Corridor (SSC) area, part of Geoscience Australia’s Exploring for the Future project. The Ti Tree Basin is approximately 150–200 kilometres north of Alice Springs. The intracratonic basin is infilled Cenozoic alluvial and lacustrine sediments. Since the 1960s the basin has been the focus of many government investigations and policies into its groundwater potential. Most have concentrated on the relatively shallow Cenozoic aquifers less than 100 metres below surface. Wischusen et al. (2012) identified the potential of the deeper aquifers (at depths of greater than 100 m) to expand the potential water resources of the Ti Tree Basin. This report uses three sets of AEM data, two acquired by Geoscience Australia and one from historic mineral exploration, to map the depth to basement in the Ti Tree Basin. We confirm the prediction of Wischusen et al. (2012) that there is significant potential for a much thicker Cenozoic succession in the Basin and show that up to 500 m of sediments are present in fault bounded structures. We demonstrate that these sediments occur in two successions, one of probably Eocene age within narrow, fault-bounded troughs and the other of probable Miocene to Pliocene age occurring across a wider area. The two successions are separated by a low angle unconformity. We interpret the lower succession as forming during strike-slip opening of the basin, and the upper succession as being deposited by passive basin infill. The faults forming the deep basin show are mostly congruent with basement structures previously interpreted from aeromagnetic data. Most of the lower succession has not been fully penetrated by earlier drilling. The interpreted AEM data shows that the deep Ti Tree Basin may contain extensive sandy aquifer units whose potential are completely unexplored. We recommend further investigations, including further stratigraphic drilling, mapping of the uniformity surface, and installation of monitoring bores, to more fully explore the potential of the deep Ti Tree Basin.

This web service provides access to groundwater raster products for the Upper Burdekin region, including: inferred relative groundwater recharge potential derived from weightings assigned to qualitative estimates of relative permeability based on mapped soil type and surface geology; Normalised Difference Vegetation Index (NDVI) used to map vegetation with potential access to groundwater in the basalt provinces, and; base surfaces of basalt inferred from sparse available data.

The Great Artesian Basin (GAB), a hydrogeological entity that contains predominantly the Jurassic-Cretaceous Eromanga, Surat and Carpentaria geological basins, is the largest groundwater basin in Australia. It underlies one fifth of the continent, including parts of Queensland, New South Wales, South Australia and the Northern Territory. Groundwater from the GAB is a vital resource for agricultural and extractive industries, as well as for community water supply. It supports cultural values and sustains a range of groundwater-dependent ecosystems. Water managers from each jurisdiction regulate GAB resources using hydrogeological conceptualisations based on a diverse historical geoscientific nomenclature that is often unique to a jurisdiction. However, the basin and its resources are continuous across borders, and recent studies have shown high spatial variability in the hydrostratigraphic units across the basin. There is, therefore, a clear need to map the geological complexity consistently at a basin-wide scale in order to provide a hydrogeological framework to underpin effective long-term management of GAB water resources. The present study is part of the Australian Government funded project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ to refine the basin conceptualisation and water balance estimates (Figure 1.1). This study focuses on an updated GAB hydrogeological architecture by compiling and standardising existing and newly interpreted biostratigraphic and well formation picks from geological logs, 2D seismic and airborne electromagnetic data in a consistent chronostratigraphic framework. This framework is used to correlate geological units across the GAB. The basin-wide correlation identifies age-equivalent sediments in different depositional settings encompassing transgressive and regressive phases. Biostratigraphic control using a common unified zonation scheme is used to identify lithological correlations. Rock properties are attributed based on sediment facies deposited during similar geological events. The approach provides a consistent way of mapping the distribution and properties of aquifers and aquitards across the GAB. In particular, the refined correlation of Jurassic and Cretaceous units between the Surat and Eromanga basins improves the resolution of hydrogeological unit geometry and lithological variation that may influence groundwater flow within and between aquifers. The 3D hydrogeological architecture developed provides a model for refining hydrogeological conceptualisations and assists in revising GAB water balance estimates. Key findings are: • The new 3D model of the GAB extends the connectivity of aquifers across the entire GAB, with potential implications for jurisdictional groundwater management. For example, the Adori Sandstone, which was previously mapped largely in the central and eastern Eromanga Basin, potentially has connectivity with the time-equivalent Springbok Sandstone in the Surat Basin across the boundary between the two basins (the Nebine Ridge). Coincident with the Nebine Ridge is a groundwater divide that tends to segregate groundwater flow between the two basins. However, cumulative impacts from excessive pumping could cause the groundwater divide to migrate due to the continuation of sandstone unit (and connectivity) across the Nebine Ridge. In addition, the Adori Sandstone is connected with the time-equivalent Algebuckina Sandstone found towards the western margin of the Eromanga Basin, which suggests there is potential for connectivity from basin margin to basin centre. This key finding improves estimates of volume and distribution of sandstone of this aquifer across all GAB jurisdictions. • The extent of other hydrogeological units have also been refined. For instance the Cadna-owie-Hooray aquifer of Ransley et al. (2015) is now separated into two units 1. Murta Formation/Hooray–Namur–Mooga sandstones aquifer and the 2. Cadna-owie–Bungil formation and equivalents aquifer. The updated mapping highlights that the upper Cadna-owie‒Bungil‒Wyandra aquifer extends across the whole GAB, and is potentially confined by the underlying Murta and lower Cadna-owie‒Bungil aquitards and overlying Rolling Downs aquitard. Higher resolution mapping of sub-units within the Cadna-owie–Bungil–Hooray and equivalents aquifer provides an improved understanding of lithological variability and the potential compartmentalisation of groundwater that may be isolated from from regional flow paths (i.e. ‘dead ends’). The lithological variability mapping within hydrogeological units highlights zones of potential connectivity where leakage may occur between the deeper and shallower aquifers, affecting upward loss of groundwater from GAB aquifers in areas distal to the outcropping recharge beds. • The new lithology mapping also highlights that the Birkhead and Westbourne formations, classified as interbedded aquitard and tight aquitard, respectively, in the Eromanga Basin, correlate laterally with time-equivalent intervals within the Algebuckina Sandstone aquifer, suggesting connection between the Hutton, Adori and Namur‒Hooray aquifers across the central and western Eromanga Basin. • The new 3D model updates hydrogeological conceptualisations in the GAB and improves groundwater balance estimates for the GAB (Ransley et al., 2022.). It is also used to constrain a regional-scale groundwater flow dynamics model for the region, including uncertainty analysis within a Bayesian framework (Knight et al., 2022). This aspect of the study is assessing a powerful approach for solving non-unique inverse problems in terms of quantifying model uncertainty. This is crucial in providing a context for, and awareness of, uncertainties in system conceptualisation that need to be accounted for, or at least acknowledged up front. • This study compiles, collates and integrates existing and newly acquired geoscientific data characterising Jurassic Cretaceous geological units that represent the hydrostratigraphy of the GAB. The updated stratigraphy improved correlations between the Eromanga, Surat and Carpentaria basins leading to better hydrogeological interpretations at the whole of GAB scale. The work draws upon the results of other recent studies to gain new insights into the geological architecture and depositional history, which have implications for groundwater occurrence and flow within and between key GAB aquifers. This updated understanding has basin-wide implications for water management, and plays a key role in revising water balance estimates for the whole GAB. The chronostratigraphic approach used here can be applied at a national scale to correlate consistently hydrostratigraphic units, providing a broader context for groundwater systems assessments.

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.

This Lake Eyre 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 Lake Eyre Basin (LEB) is a vast endorheic basin covering approximately 15% of the Australian continent, spanning about 1.14 million square kilometres. Its development began during the Late Palaeocene due to tectonic subsidence in north-eastern South Australia, resulting in a wide and shallow intra-cratonic basin divided into Tirari and Callabonna Sub-basins by the Birdsville Track Ridge. The depocenter of the LEB has shifted southwards over time. During the Cenozoic era, sediment accumulation was highest near the Queensland-Northern Territory border. The depo-center was in the southern Simpson Desert by the late Neogene, and is currently in Kati Thanda-Lake Eyre, leading to the deposition of various sedimentary formations, which provide a record of climatic and environmental changes from a wetter environment in the Palaeogene to the arid conditions of the present. The LEB is characterized by Cenozoic sediments, including sand dunes and plains in the Simpson, Strezelecki, Tirari, and Strezelecki deserts, mud-rich floodplains of rivers like Cooper, Diamantina, and Georgina, and extensive alluvial deposits in the Bulloo River catchment. The basin's geology comprises rocks from different geological provinces, ranging from Archean Gawler Craton to the Cenozoic Lake Eyre Basin. The Callabonna Sub-basin, confined by the Flinders Ranges to the west, contains formations such as the Eyre and Namba formations, representing fluvial and lacustrine environments. The Cooper Creek Palaeovalley hosts formations like the Glendower, Whitula, Doonbara, and Caldega, and features significant Quaternary sedimentary fill. The Tirari Sub-basin, located on the border regions of three states, contains formations like the Eyre, Etadunna, Mirackina, Mount Sarah Sandstone, Yardinna Claystone, Alberga Limestone, and Simpson Sand. The northwest of Queensland includes smaller Cenozoic basins, likely infilled ancient valleys or remnants of larger basins. The Marion-Noranside Basin has the Marion Formation (fluvial) and Noranside Limestone (lacustrine), while the Austral Downs Basin comprises the Austral Downs Limestone (spring and lacustrine). The Springvale and Old Cork Basins tentatively have Eocene and Miocene ages. Cenozoic palaeovalleys in the Northern Territory are filled with fluvial sands, gravels, lignites, and carbonaceous deposits and are confined by surrounding basins. Overall, the sedimentary sequences in the Lake Eyre Basin provide valuable insights into its geological history, climate shifts, and topographic changes, contributing to our understanding of the region's development over time.

This Gippsland 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 Gippsland Basin is an asymmetrical east-trending rift structure that originated during rifting in the Late Jurassic to Early Cretaceous, as Australia and Antarctica began to separate. Over time, it developed into a continental passive margin basin, with sedimentation continuing to the present day. The basin is characterized by four main phases of tectonic evolution, interspersed with eustatic sea-level variations: initial rifting and extension, mid-Cretaceous contraction, renewed extension, and cessation of rifting in the middle Eocene. The basin's geological structures consist of mainly east to north-east trending features, with the west dominated by north-east structures due to the influence of basement trends. Major fault systems are prominent, compartmentalizing the basin into platforms and depressions separated by bedrock highs. The basin's complex stratigraphic succession reveals fluvial, deltaic, marginal marine, and open marine depositional environments. The sedimentary sequence includes terrigenous siliciclastic sediments from the Upper Cretaceous to Eocene, followed by post-rift sands, clays, coals, and limestones/marls of Oligocene to Holocene age. The Gippsland Basin's sediments are subdivided into four main stratigraphic groups: the Strzelecki, Latrobe, Seaspray, and Sale groups. The Strzelecki Group, dating from the Late Jurassic to Early Cretaceous, consists of non-marine sedimentary rocks deposited in fluvial and lacustrine environments. The Latrobe Group, from Late Cretaceous to early Oligocene, contains siliciclastic sediments deposited in various non-marine to marginal marine settings, showing significant lateral lithofacies variations. The Seaspray Group, dating from Oligocene to Pliocene, formed during a post-rift phase, characterized by marine limestone and marl units and continental clastic sediments. Lastly, the Sale Group consists of Miocene-to-Recent continental clastic sediments forming a thin veneer over the onshore portion of the basin. The Gippsland Basin also contains several basaltic lava fields, with two notable volcanic units—the Thorpdale Volcanics and Carrajung Volcanics—part of the Older Volcanics in Victoria. Overall, the Gippsland Basin's geological history and diverse sedimentary deposits make it a significant area for various geological and geophysical studies, including its hydrocarbon resources concentrated in offshore Latrobe Group reservoirs.

This Canning 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 Canning Basin, characterized by mostly Paleozoic sedimentary rocks with a maximum thickness of over 15,000 m, went through four major depositional phases from Early Ordovician to Early Cretaceous. The basin contains two main depocenters, the Fitzroy Trough-Gregory Sub-basin in the north and the Willara Sub-basin-Kidson Sub-basin in the south. The depositional history includes marine, evaporite, fluvial, deltaic, glacial, and non-marine environments. The basin's evolution began with extension and rapid subsidence in the Early Ordovician, followed by a sag stage with evaporite and playa conditions in the Late Ordovician and Silurian. The Devonian to Early Carboniferous phase involved marine, reef, fluvio-deltaic, and terrestrial sedimentation in the north and marginal marine to terrestrial systems in the south. The Late Carboniferous to mid-Triassic period saw non-marine and marine settings, including glacial environments. The basin then experienced mid-Jurassic to Early Cretaceous deposition, mainly in deltaic and non-marine environments. Throughout its history, the Canning Basin encountered multiple tectonic phases, including extension, compression, inversion, and wrench movements, leading to various depositional settings and sediment types. Around 250 petroleum wells have been drilled in the basin, with production mainly from Permo-Carboniferous sandstones and Devonian carbonates. Several proven and untested plays, such as draped bioherms, anticlinal closures, and fault blocks, provide potential for hydrocarbon exploration. Late Carboniferous and Jurassic mafic sills intersected in wells indicate additional geological complexity. Additionally, some areas of the Canning Basin are considered suitable for CO2 storage.

This Karumba 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 Karumba Basin is a shallow geological basin in Queensland, Australia, composed of sedimentary rocks and unconsolidated sediments that cover the Mesozoic Carpentaria Basin. Deposition started during the Late Cretaceous to Early Paleocene and has continued into the Holocene. The basin extends from western Cape York Peninsula into the Gulf of Carpentaria, where it connects with Cenozoic sediment deposits in Papua New Guinea. Although the sediments in both areas share lithostratigraphic and biostratigraphic similarities, their tectonic histories differ. The basin's structural geology is relatively uniform, with a significant downwarp known as the Gilbert-Mitchell Trough in Cape York Peninsula and another depocenter offshore in the Gulf of Carpentaria. The depositional history and stratigraphy of the Karumba Basin can be divided into three cycles of deposition, erosion, weathering, and the formation of stratigraphic units. The earliest cycle (the Bulimba Cycle) began in the Late Cretaceous to Early Paleocene, with episodes of significant uplift along the eastern margins of the basin. This resulted in the deposition of the Bulimba Formation and the Weipa Beds, primarily consisting of claystone, sandstone, conglomerate, and siltstone with minor coal layers. This cycle was followed by a period of planation and deep weathering, creating the Aurukun Surface. The second cycle (the Wyaaba Cycle) was initiated by large-scale earth movements along the Great Dividing Ranges, forming much of the eastern boundary of the Karumba Basin, and leading to the formation of the Wyaaba beds and other equivalent units. These beds consist mainly of fluvial to paralic clay-rich sandstone, conglomerate, siltstone, and claystone. In the south-west, Oligocene to Pliocene limestone deposits also formed in lacustrine settings, and were sourced from and deposited upon the underlying Georgina Basin. The cycle ended with ensuing periods of erosion and weathering and the development of the Pliocene Kendall Surface, as well as widespread basaltic volcanism. The final cycle (the Claraville Cycle) started in the Pliocene and continues to the present. It has experienced several episodes of uplift and deposition controlled by sea level change, climate variability and volcanism in the south. The Claraville beds are unconsolidated sediments, chiefly comprised of clayey quartzose sand and mud with minor gravels, reaching approximately 148 m thickness offshore, and approximately 70 m onshore. As this cycle is still ongoing, no terminal surface has been formed, and most units consist of unconsolidated surficial sediments.