An up-scaling Approach to Groundwater and Aquifer Characterisation in the Australian Outback

Australia's sustained economic growth and development over the past decade has been accompanied by an increased demand for water, particularly groundwater. Drivers for that demand include new industries, new mines, the need to secure urban and regional water supply. With reference to an example from the Murchison region of Western Australia we examine an approach that could use AEM to aid the scaling-up from a local to catchment-scale hydrogeological framework for groundwater assessment. It draws on local scale AEM surveys and hydrogeological studies, along with a regional scale model of the landscape geomorphology to determine an optimal approach to AEM data acquisition at the catchment scale, as an aid to groundwater resource assessment. Local scale studies using TDHEM data, linked to both water resource investigations and mineral exploration have demonstrated application in defining the extent and quality of groundwater resource in the sedimentary palaeovalley aquifers of the study area. This knowledge was used in combination with terrain indices to define an optimal AEM survey resolution given a limited, fixed budget.