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.

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.

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.

<div>The recent Musgrave Palaeovalley Project set out to map the extent and characterise the palaeovalley architecture of several of these Cenozoic features that overlie the Musgrave Province in central Australia. To effectively model the palaeovalley architecture of these features we collected approximately 20 000 line km of new Airborne Electromagnetics (AEM) and combined it with an array of existing AEM datasets, including AusAEM and high resolution mineral exploration surveys. These older surveys were reprocessed and reinverted to produce a consistent and reliable interpretation throughout. Utilising surface geology and lithology logs to constrain this data set, we mapped the interface between Cenozoic sediments and underlying pre-Cenozoic rocks, producing a continuous three-dimensional model of this boundary throughout the study area.</div><div><br></div><div>Our three-dimensional model enhances the understanding of the West Musgrave palaeovalley system, redefining palaeovalley extents, revealing previously unmapped palaeovalleys and identifying areas with significant accumulations of Cenozoic sediments. This methodology was also extremely useful for investigating palaeovalley geometry, revealing southerly flowpaths consistent with regional expectations but also highlighting areas of palaeovalley deformation where neo tectonic forces have acted to alter historical flow regimes. This deformation is likely to cause groundwater compartmentalisation, mounding or connect different aquifer units. Presented at the 2024 Australian Society of Exploration Geophysicists (ASEG) Discover Symposium

This South Nicholson 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. This South Nicholson 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 South Nicholson Basin is a Mesoproterozoic sedimentary basin spanning Queensland and the Northern Territory and is bordered by neighbouring provinces and basins. The basin unconformably overlies the Lawn Hill Platform of the Mount Isa Province to the east, is bound by the Warramunga and Davenport provinces to the south-west, the Murphy Province to the north and the McArthur Basin to the north-west. It extends southwards under younger cover sequences. Rock units in the basin are correlated with the Roper Group in the McArthur Basin, forming the 'Roper Superbasin.' The underlying Mount Isa Province contains potential shale gas resources. The basin mainly consists of sandstone- and siltstone-bearing units, including the South Nicholson Group, with a prevailing east to east-northeast structural grain. Mild deformation includes shallowly plunging fold axes and numerous faults along a north-west to south-east shortening direction. Major geological events affecting the South Nicholson Basin region include the formation of the Murphy Province's metamorphic and igneous rocks around 1850 million years ago (Ma). The Mount Isa Province experienced deposition in the Leichhardt Superbasin (1800 to 1750 Ma) and Calvert Superbasin (1725 to 1690 Ma). The Isa Superbasin, with extensional growth faulting in the Carrara Sub-basin (~1640 Ma), deposited sediments from approximately 1670 to 1590 Ma. Subsequently, the South Nicholson Group was deposited around 1500 to 1430 Ma, followed by the Georgina Basin's sedimentation. The basin shows potential for sandstone-type uranium, base metals, iron ore, and petroleum resources, while unconventional shale and tight gas resources remain largely unexplored. The Constance Sandstone holds promise as a petroleum reservoir, and the Mullera Formation and Crow Formation serve as potential seals.