This report was compiled and written to summarise the four-year Palaeovalley Groundwater Project which was led by Geoscience Australia from 2008 to 2012. This project was funded by the National Water Commission's Raising National Water Standards Program, and was supported through collaboration with jurisdictional governments in Western Australia, South Australia and the Northern Territory. The summary report was published under the National Water Commission's 'Waterlines' series. This document is supported by related publications such as the palaeovalley groundwater literature review, the WASANT Palaeovalley Map and associated datasets, and four stand-alone GA Records that outline the detailed work undertaken at several palaeovalley demonstration sites in WA, SA and the NT. Palaeovalley aquifers are relied upon in outback Australia by many groundwater users and help underpin the economic, social and environmental fabric of this vast region. ‘Water for Australia’s arid zone – Identifying and assessing Australia’s palaeovalley groundwater resources’ (the Palaeovalley Groundwater Project) investigated palaeovalleys across arid and semi-arid parts of Western Australia (WA), South Australia (SA) and the Northern Territory (NT). The project aimed to (a) generate new information about palaeovalley aquifers, (b) improve our understanding of palaeovalley groundwater resources, and (c) evaluate methods available to identify and assess these systems.

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 airborne electromagnetics (AEM) derived conductivity grids for depth intervals representing the top 22 layers from AEM modelling in the West Musgrave region (https://dx.doi.org/10.26186/147969). The grids were generated from the AEM conductivity models released as part of the Western Resource Corridor AusAEM survey (https://dx.doi.org/10.26186/147688), the Earaheedy and Desert Strip AusAEM survey (https://pid.geoscience.gov.au/dataset/ga/145265) and several industry surveys (https://dx.doi.org/10.26186/146278) from the West Musgraves region. The AEM conductivity models resolve important subsurface features for assessing the groundwater system including lithological boundaries, palaeovalleys and hydrostatigraphy.

This service delivers airborne electromagnetics (AEM) derived conductivity grids for depth intervals representing the top 22 layers from AEM modelling in the West Musgrave region (https://dx.doi.org/10.26186/147969). The grids were generated from the AEM conductivity models released as part of the Western Resource Corridor AusAEM survey (https://dx.doi.org/10.26186/147688), the Earaheedy and Desert Strip AusAEM survey (https://pid.geoscience.gov.au/dataset/ga/145265) and several industry surveys (https://dx.doi.org/10.26186/146278) from the West Musgraves region. The AEM conductivity models resolve important subsurface features for assessing the groundwater system including lithological boundaries, palaeovalleys and hydrostatigraphy.

<div>Reliable water availability is critical to supporting communities and industries such as mining, agriculture and tourism. In remote and arid areas such as in the Officer – Musgrave region of central Australia, groundwater is the only viable source of water for human and environmental use. Groundwater systems in remote regions such as the Musgrave Province are poorly understood due to sparse geoscientific data and few detailed scientific investigations. The Musgrave palaeovalley module will improve palaeovalley groundwater system understanding in the Musgrave Province and adjacent basins to identify potential water sources for communities in the region. This report summarises the state of knowledge for the region on the landscape, population, water use, geology and groundwater systems. An analysis of the current and potential future water needs under different development scenarios captures information on how water is used in an area covering three jurisdictions and several potentially competing land uses.</div><div>The Musgrave Palaeovalley study area is generally flat, low-lying desert country. The Musgrave, Petermann, Mann and Warburton ranges in the centre of the area are a significant change in elevation and surface materials, comprising rocky hills, slopes and mountains with up to 800&nbsp;m of relief above the sand plains. Vegetation is generally bare or sparse, with isolated pockets of grassy or woody shrub lands. Soils are typically Tenosols, Rudosols and Kandosols.</div><div><br></div><div>There are four main hydrogeological systems in the study area. These are the fractured and basement rocks, local Quaternary sediments regional sedimentary basins and palaeovalley aquifers. These systems are likely to be hydraulically connected. Within palaeovalleys, three main hydrostratigraphic units occur. The upper Garford Formation is a sandy unconfined aquifer with a clay rich base (lower Garford Formation) which acts as a partial aquitard where present. The Pidinga Formation represents a coarser sandy or gravelly channel base, which is partly confined by the lower Garford Formation aquitard. The aquifers are likely to be hydraulically connected on a regional scale. Further to the west, equivalent units are identified and named in palaeovalley systems on the Yilgarn Craton. </div><div><br></div><div>Groundwater is recharged by episodic, high-intensity rainfall events and mostly discharges via evapotranspiration. Recharge is higher around the ranges, and lower over the flatter sand plains. Palaeovalley aquifers likely receive some groundwater inflow from underlying basin systems and fractured rock systems. Regional groundwater movement is topographically controlled, moving from the ranges towards surrounding areas of lower elevation. In some palaeovalleys groundwater discharges at playa lakes. Water table gradients are very low. More groundwater isotope and tracer data is required to understand potential connectivity between basin, fractured rock and palaeovalley systems.</div><div>Groundwater quality is brackish to saline, although pockets of fresher groundwater occur close to recharge areas and within the deeper and coarse-grained Garford Formation. Groundwater resources generally require treatment prior to use Most groundwater in the region is suitable for stock use. </div><div><br></div><div>Existing palaeovalley mapping is restricted to inferring extents based on landscape position and mapped surface materials. Utilising higher resolution digital elevation models and more recently acquired remotely sensed data will refine mapped palaeovalley extents. Improving the modelling of the distribution and depth of palaeovalleys in greater detail across the region is best aided through interpretation of airborne electromagnetic (AEM) data.</div><div>Based on the successes of integrating AEM with other geoscientific data in South Australia, we have acquired 25,109 line km of new AEM across the WA and NT parts of our study area. We will integrate this data with reprocessed and inverted publicly available AEM data, existing borehole information, existing and newly acquired hydrochemical data, and new surface magnetic resonance data to model the three dimensional distribution of palaeovalleys in the study area. We will use these models and data as the basis for conceptualising the hydrogeology of the palaeovalley systems, and provide information back to local communities and decision-makers to inform water management decisions. The data will also provide valuable precompetitive information for future economic development in the region.</div><div><br></div>

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.

<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 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 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 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.