Assessing the status of groundwater in the Great Artesian Basin

The project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ (GAB) evaluated existing and new geoscientific data and technologies, including satellite data, to improve our understanding of the groundwater system and water balance in the GAB. An updated classification of GAB aquifers and aquitards has linked the hydrostratigraphic classification used in Queensland (Surat Basin) with that used in South Australia (western Eromanga Basin). Developed using an integrated basin analysis workflow, the revised hydrogeological framework encompasses the entire GAB and is consistent across jurisdictional boundaries. Groundwater recharge rates estimated across the eastern GAB recharge area applied environmental tracers and an improved method that integrates chloride concentration in bores, rainfall, soil clay content, vegetation type and surficial geology. Significant revisions to the mapped geometry and heterogeneity of the groundwater recharge beds, through the use of regional scale airborne electromagnetic (AEM) data, have identified potential connectivity between aquifers, possible structural controls on groundwater flow paths and plausible groundwater sources of spring discharge. A whole-of-GAB water balance compares inflows and outflows to the main regional aquifer groups. While the whole-of-GAB and sub-basin (Surat, Eromanga, Carpentaria basins) water balances provide basin-wide groundwater resource volumes, they also highlight the high uncertainties in the estimates of key water balance components that need to be considered for improved groundwater resource management. Assessment of satellite monitoring data from Gravity Recovery and Climate Experiment (GRACE) and Interferometric Synthetic Aperture Radar (InSAR) shows promise for remote monitoring of groundwater levels at a whole-of-GAB scale in the future to augment existing monitoring networks. This Abstract was submitted/presented to the 2022 Australasian Groundwater Conference 21-23 November (https://agc2022.com.au/)