The focus of this project is to use data from space gravity missions to track changes in total water storage in northern Australia and to investigate the viability of this approach for monitoring Australia’s water resources. The specific objective of the project is to “develop time series of changes in total water storage across northern Australia to provide insights into changes in water resources.” Data from the Gravity Recovery and Climate Experiment (GRACE) mission was analysed for the period January 2003 to August 2016 and monthly estimates of changes (relative to a mean gravity field value in 2008) were developed. The analysis was done using the ANU GRACE software, which has been developed specifically to enable estimates to be tailored to the pattern and shape of Australian drainage basins. Estimates in irregularly shaped regions of approximately 90,000 km2 have been provided, along with visualisation tools to enable time series of total water storage changes to be made. This package contains: 1) Final report provided to Geoscience Australia by ANU 2) GRACE total water storage change dataset The dataset includes the original data provided by ANU as well as images/video derived from the data to help with visualisation. a) ANU_iter2_australia.nc: the total water storage changes estimate from GRACE satellite gravity mission measurements b) BOM-final.nc, GLDAS-CLSM-final.nc, GLDAS-NOAH-final-nc: the canopy, snow and soil water storage changes estimate from hydrological models c) mascons_stage5_V004_australia: the mascon file describing the geometry of the mascon grid over australia d) plot_ewh_time_series.py, plot_soil_moisture_time_series.py and plot_gw_time_series.py: python scripts allowing to plot time series of total water storage, canopy, snow or soil water storage and groundwater storage for any latitude, longitude in Australia e) map_mascons_australia.py and map_ewh_australia.py: python scripts to create maps of the mascon geometry and ewh anomaly f) monthly images of the total water storage and videos depicting changes for each month over the years (2003-2016) and video with all months stitched together. Geoscience Australia commissioned the work as part of the 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.

<div>The project ‘Assessing the Status of Groundwater in the Great Artesian Basin’ assessed 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 was produced, linking the hydrostratigraphic classification used in Queensland (Surat Basin) with that used in South Australia (western Eromanga Basin). This revised hydrogeological framework was produced at the whole-of-GAB scale, through the development and application of an integrated basin analysis workflow, producing an updated whole-of-GAB stratigraphic interpretation that is consistent across jurisdictional boundaries. Groundwater recharge rates were estimated across eastern GAB recharge area using environmental tracers and an improved method that integrates chloride concentration in bores, rainfall, soil clay content, vegetation type and surficial geology. Significant revisions were made to the geometry and heterogeneity of the groundwater recharge beds, by acquiring, inverting and interpreting regional scale airborne electromagnetic (AEM) geophysical data, identifying potential connectivity between aquifers, possible structural controls on groundwater flow paths and plausible groundwater sources of spring discharge. A whole-of-GAB water balance was developed to compare inflows and outflows to the main regional aquifer groups. While the whole-of-GAB and sub-basin water balances provide basin-wide perspectives of the groundwater resources, they also highlight the high uncertainties in the estimates of key water balance components that need to be considered for 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 presentation was given at the 2022 Australasian Groundwater Conference 21-23 November (https://www.aig.org.au/events/australasian-groundwater-conference-2022/)