The Surface Hydrology Points (Regional) dataset provides a set of related features classes to be used as the basis of the production of consistent hydrological information. This dataset contains a geometric representation of major hydrographic point elements - both natural and artificial. This dataset is the best available data supplied by Jurisdictions and aggregated by Geoscience Australia it is intended for defining hydrological features.

Development of coal mines and coal seam gas (CSG) resources can significantly impact groundwater systems, hydrogeological processes and the surface environment. Consequently, a sound understanding of basin-scale hydrogeology Is critical to developing effective water management strategies. The Australian Government Department of Sustainability, Environment, Water, Population and Communities recently funded investigation of the potential impacts of the development of coal mining and CSG production in several Australian coal basins. The Laura Basin was investigated as part of this program due to the significant environmental and cultural heritage values of the region which include several National Parks and the Great Barrier Reef Marine Park. The Laura Basin is a geological basin on Cape York Peninsula, QLD. There has been relatively limited development of the groundwater resources of the basin to date, which predominantly occur in Mesozoic sandstone units, the Dalrymple Sandstone and the Gilbert River Formation, which are contiguous with the Great Artesian Basin rocks of the Carpentaria Basin.

Phase 1 report (Exposure/Impact Analysis) for Assessment of Groundwater Vulnerability to Climate Change in the Pacific Islands Project.

This report describes the findings of the Great Artesian Basin Water Resource Assessment that have led to advancing the understanding of the GAB. It encapsulates findings that are presented in four region reports and a technical report on conceptualising the GAB that were prepared for the Assessment. Advancing the conceptual understanding of the GAB requires careful evaluation of the geological framework (i.e. the layers of rock), description of how the geology translates into hydrostratigraphy (i.e. the relative ability of specific layers to store and transmit water) and investigation of the groundwater conditions (i.e. watertable, groundwater levels, and inferred movement). It is the geological framework, hydrostratigraphy and groundwater conditions that are the basis for conceptualising water resources in the GAB. The conceptual understanding of the GAB provides the foundation for assessing water availability and providing guidance to water policy and water resource planning.

Poster prepared for International Association of Hydrogeologists Congress 2013 The Broken Hill Managed Aquifer Recharge (BHMAR) project has successfully mapped a multi-layered sequence of aquitards and aquifers, as well potential groundwater resource and managed aquifer recharge (MAR) targets, in the top 100m of the Darling Floodplain. Near-surface aquitards overlying the Pliocene target aquifers (fluvial Calivil Formation (CFm) and marine Loxton-Parilla Sands (LPS)), were identified initially as variably conductive layers in airborne electromagnetic (AEM) data, and validated by drilling and complementary borehole geophysical, textural, hydrogeological and hydrochemical studies. The stratigraphic unit underlying the Pliocene aquifers is the Miocene upper Renmark Group (uRG). Drilling and AEM data have confirmed this unit is present throughout the study area, deposited predominantly as thick muds. Facies and biofacies analysis suggests these muds were deposited on a low relief sedimentary plain with a high water table and numerous permanent water bodies, with relatively minor sand bodies deposited in narrow anastomosing fixed channel streams. Groundwater in the upper uRG is saline, and muddy sediments form a strongly conductive layer beneath the Pliocene aquifers. This is a much harder geophysical target than the upper confining aquitards, as the target lies at depths of 80-120m, which is near the depth resolution of the AEM system. Furthermore, there is little conductivity contrast between the Pliocene and uRG sediments except in areas where there is fresh groundwater in the former. Hydrochemical and hydrodynamic data shows that there is limited hydrological connection between the uRG and less saline Pliocene aquifers, except where the Pliocene is underlain by uRG channel sands. These channels are much narrower (10s to ~100m) and thinner (1 to 10m) compared with palaeochannels in the overlying CFm. Where the channels are connected, there can be a distinct salinity gradient from the Pliocene into the uRG sands, indicating localised mixing. Given the potential for up-coning of saline groundwater in these instances, a number of sites (e.g. Menindee Common), have been assessed as unsuitable for MAR. Overall, the uRG muds act as a good lower confining aquitard to the Pliocene aquifers over most of the project area, including a number of potential MAR and groundwater resource targets.

The Great Artesian Basin Research Priorities Workshop, organised by Geoscience Australia (GA), was held in Canberra on 27 and 28 April 2016. Workshop attendees represented a spectrum of stakeholders including government, policy, management, scientific and technical representatives interested in GAB-related water management. This workshop was aimed at identifying and documenting key science issues and strategies to fill hydrogeological knowledge gaps that will assist federal and state/territory governments in addressing groundwater management issues within the GAB, such as influencing the development of the next Strategic Management Plan for the GAB. This report summarises the findings out of the workshop.

Geoscience Australia was recently involved in the reconceptualisation of the hydrogeology of the Great Artesian Basin (GAB), as part of the Great Artesian Basin Water Resource Assessment. The project refined the understanding of key hydrostratigraphic units within the GAB. This brochure describes key aquifers in the GAB and is designed to be distributed with samples from the aquifers. Aquifers covered are the Winton-Mackunda, Cadna-owie-Hooray, Adori Sandstone/Springbok Sandstone, Hutton Sandstone and Precipice Sandstone. Brochure prepared for the International Association of Hydrogeologists Congress 2013, Perth, Australia

This report presents key results of groundwater barometric response function development and interpretation from the Upper Burdekin Groundwater Project in North Queensland, conducted 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 Upper Burdekin Groundwater Project is a collaborative study between Geoscience Australia and the Queensland Government. It focuses on basalt groundwater resources in two geographically separate areas: the Nulla Basalt Province (NBP) in the south and the McBride Basalt Province (MBP) in the north. The NBP and MBP basalt aquifers are heterogeneous, fractured, vesicular systems. This report assesses how water levels in monitoring bores in the NBP and MBP respond to barometric pressure changes to evaluate the degree of formation confinement. The main process used to evaluate water level response to barometric pressure in this study is based on barometric efficiency (BE). The BE of a formation is calculated by dividing the change in monitoring bore water level by the causative barometric pressure change. Both parameters are expressed in the same units, so BE will typically be some fraction between zero and one. BE is not necessarily constant over time; the way BE changes following a theoretical step change in barometric pressure can be described using a barometric response function (BRF). BRFs were calculated in the time domain and plotted as BE against time lag for interpretation. The BRF shape was used to assess the degree of formation confinement. Although there is some uncertainty due to monitoring bore construction issues (including long effective screens) and potentially air or gas trapped in the saturated zone, all BRFs in the current project are interpreted to indicate unconfined conditions. This finding is supported by the identification of recharge at many monitoring bores through hydrograph analysis in other EFTF project components. We conclude that formations are likely to be unconfined at many project monitoring bores assessed in this study.

The Clarence-Moreton and the Surat basins in Queensland and northern New South Wales contain the coal-bearing sedimentary sequences of the Jurassic Walloon Coal Measures, composed of up to approximately 600 m of mudstone, siltstone, sandstone and coal. In recent years, the intensification of exploration for coal seam gas (CSG) resources within both basins has led to concerns that the depressurisation associated with future resource development may cause adverse impacts on water resources in adjacent aquifers. In order to identify the most suitable tracers to study groundwater recharge and flow patterns within the Walloon Coal Measures and their degree of connectivity with over- or underlying formations, samples were collected from the Walloon Coal Measures and adjacent aquifers in the northern Clarence-Moreton Basin and eastern Surat Basin, and analysed for a wide range of hydrochemical and isotopic parameters. Parameters that were analysed include major ion chemistry, -13C-DIC, -18O, 87Sr/86Sr, Rare Earth Elements (REE), 14C, -2H and -13C of CH4 as well as concentrations of dissolved gases (including methane). Dissolved methane concentrations range from below the reporting limit (10 µg/L) to approximately 50 mg/L in groundwaters of the Walloon Coal Measures. However, the high degree of spatial variability of methane concentrations highlights the general complexity of recharge and groundwater flow processes, especially in the Laidley Sub-Basin of the Clarence-Moreton Basin, where numerous volcanic cones penetrate the Walloon Coal Measures and may form pathways for preferential recharge to the Walloon Coal Measures. Interestingly, dissolved methane was also measured in other sedimentary bedrock units and in alluvial aquifers in areas where no previous CSG exploration or development has occurred, highlighting the natural presence of methane in different aquifers. Radiocarbon ages of Walloon Coal Measure groundwaters are also highly variable, ranging from approximately 2000 yrs BP to >40000 yrs BP. While groundwaters sampled in close proximity to the east and west of the Great Dividing Range are mostly young, suggesting that recharge to the Walloon Coal Measures through the basalts of the Great Dividing Range occurs here, there are otherwise no clearly discernable spatial patterns and no strong correlations with depth or distance along inferred flow paths in the Clarence-Moreton Basin. In contrast to this strong spatial variability of methane concentrations and groundwater ages, REE and 87Sr/86Sr isotope ratios of Walloon Coal Measures groundwaters appear to be very uniform and clearly distinct from groundwaters contained in other bedrock units. This difference is attributed to the different source material of the Walloon Coal Measures (mostly basalts in comparison to other bedrock units which are mostly composed of mineralogical more variable Paleozoic basement rocks of the New England Orogen). This study suggests that REE and 87Sr/86Sr ratios may be a suitable tracer to study hydraulic connectivity of the Walloon Coal Measures with over- or underlying aquifers. In addition, this study also highlights the need to conduct detailed water chemistry and isotope baseline studies prior to the development of coal seam gas resources in order to differentiate between natural background values of methane and potential impacts of coal seam gas development.

This project aims to characterise the hydrogeochemistry of groundwater associated with coal seams and surrounding aquifers in the Surat Region and Laura Basin. In addition, the project provides an assessment of the environmental values of groundwater in relation to ecological and human use, and general guidance on groundwater quality monitoring strategies. . Full details of the methodology and findings of the study, including limitations and assumptions are provided in this project technical report.