The thalweg is the line of lowest elevation within a valley. The thalweg data represent the palaeo-thalweg of the Neogene Palaeovalleys of the Anangu Pitjantjatjara Yankunytjatjara Lands (APY) Lands based on airborne electromagnetic (AEM) geophysical data collected in 2016 under the South Australian Government's PACE initiative.Due to the variable incision rate and the undulating palaeotopography of the variably weathered basement, several AEM depth slices had to be utilised for thalweg mapping. The thalweg was mapped by a combination of observation-based interpretation of the AEM depth slices as well as automated mapping utilising ArcGIS.

This new thalweg data can be used to identify the deepest part of the palaeovalley that has the highest potential for good quality groundwater with high flow rates (Costar et al. 2019; Krapf et al. 2019).