The Great Artesian Basin (GAB) Groundwater Recharge Zones and Extent Boundary 2022 dataset provides Geoscience Australia’s latest interpretation of the extent of:
· the GAB and its four component geological sub-basins – the Eromanga, Carpentaria, Surat and Clarence-Moreton basins; and
· the GAB aquifer outcrop/subcrop areas that comprise the groundwater recharge zones of the GAB.
These datasets are an updated regional interpretation for mapping at approximately 1:1 000 000 to produce a broad scale overview, and examination of small areas by collecting extra data is most likely to produce results that differ from this regional interpretation.
The GAB Groundwater Recharge Zones and Extent Boundary 2022 data compilation comprises the following:
1. GAB extent boundaries 2022
· GAB_Basin_2022 – polygon covering the extent of the of the Great Artesian Basin as defined by Geoscience Australia
· GAB_SubBasins_2022 – polygon dataset defining the extents of the component geological sub-basins of the GAB: Eromanga Basin, Surat Basin, Carpentaria Basin and Clarence-Moreton
· GAB_Basin_BoundarySource_2022 – line dataset containing information on the different data sources used to define the boundary of the GAB and sub-basin subdivisions.
2. GAB Groundwater Recharge Zones 2022
· GAB_RechargeZones_2022 – polygon dataset depicting areas of recharge within the GAB
· GAB_RechargeZones_2022.lyr – group layer file containing:
· GAB_RechargeZones_2022_geology (symbolised by geology type)
· GAB_RechargeZones_2022_aquifer (symbolised by GAB aquifer)
· GAB_RechargeZones_2022_cover (symbolised by qualitative cover classes)
· GAB_RechargeZones_2022_source (symbolised by datasets utilised to determine recharge zones),
1. Great Artesian Boundaries Basin boundaries
The GAB boundary follows the geological margins of its four component sub-basins – the Eromanga, Carpentaria, Surat and Clarence-Moreton sub-basins (GAB_SubBasins_2022). In certain areas the boundary diverges from these geological basin margins and dissects outcropping geological units, delineating externally-draining groundwater regions not flowing into the GAB. In these areas the boundary is based on interpreted groundwater divides, indicated by topographic divides, derived from the 1 second SRTM (Gallant et al. 2011).
- Groundwater recharge zone boundaries
This dataset contains the mapped outcrop and subcrop extents of the regional aquifers of the GAB that constitute the groundwater recharge zones of the GAB.
Groundwater recharge zones delineate areas where water infiltrates the aquifers of the GAB. The spatial extents of the recharge zones are defined by a combination of the outcrop extents of aquifer units, and interpolation between outcrops, in cases where the units are covered by a veneer of unconsolidated deposits.
The numerous geological units that comprise the aquifers of the GAB are grouped into the following regional aquifers (in age order):
· Winton-Mackunda Aquifer and Equivalents
· Cadna-owie – Hooray Aquifer and Equivalents
· Adori-Springbok Aquifer
· Birkhead Formation partial aquifer
· Hutton Aquifer and Equivalents
· Boxvale Sandstone Member Aquifer
· Precipice Aquifer and Equivalents
The Groundwater recharge zones have been modified from Ransley et al., 2015 to incorporate revised geology mapping for QLD and NSW (refer to metadata available with download).
References:
Gallant, J., Wilson, N., Dowling, T., Read, A., Inskeep, C. 2011. SRTM-derived 1 Second Digital Elevation Models Version 1.0. Record 1. Geoscience Australia, Canberra. https://pid.geoscience.gov.au/dataset/ga/72759
Ransley, T., Radke, B., Kellett, J., Bell, J., Stewart, G 2015. Great Artesian Basin - Groundwater/aquifer recharge zones. Geoscience Australia, Canberra. http://pid.geoscience.gov.au/dataset/ga/81687
