The methodology to create this grid dataset is documented in AGS Report 98. The grid dataset is an index of regional hydraulic pathways developed from spatial geological attributes related to Neogene-Quaternary hydrostratigraphic units (AGS Report 93) and bedrock sandstone properties (AGS Open File Report 2019-03). Low rating values indicate the potential of the geological materials to more readily transmit groundwater vertically than high rating values.
Brief overview of methodology
- Paleogene–Quaternary stratigraphic units (AGS Report 93) ranked in terms of approximate hydraulic conductivity and thickness.
- Bedrock sandstone abundance (AGS Open File Report 2019-03) ranked in terms of net-to-gross sandstone ratio (NGR) for uppermost 50 m.
- Rankings summed and reclassified from 1 to 5 to create a regional hydraulic pathway map, where 1 represents areas with a high likelihood and 5 represents areas with a low likelihood of being a permeable vertical hydraulic pathway.