The Ovens/Oaklands Graben is located in the Central West of NSW near the town of Jerilderie. It generally trends north-south while the present day river system trends east-west.

Groundwater comes from a combination of recent alluvial aquifers and deeper Tertiary aquifers associated with the Shepparton Formation and Renmark Group.

There are relatively few bores/wells that penetrate completely through the Tertiary formations and into the underlying Permian Formation. One that did, was the well Jeriderie 1.

Jerilderie 1 also performed several drill stem tests (DST) which showed that there was some remarkably fresh water (< 100 mg/L TDS) at depth (in addition to the DST, the geophysical log for Jerilderie 1 also shows a zone of fresh water). What makes this remarkable is that the average salinity of the overlying aquifers is 5 to 15 times higher than that found in the Permian. In fact the Permian under the Ovens Graben has a lower salinity than the overlying river system.

A quick, interpretation of a seismic line through the Ovens Graben. Note the structural complexity creating compartments limiting groundwater flow.

There is strong structural control within the Ovens Graben driven by faults within the basement. This has acted to create compartments that separate individual aquifers across the faults (east-west). This suggests that groundwater recharge does not come from the present day river system or overlying aquifers.

Instead, FrOG Tech speculates that the major north-south trending faults act as conduits along strike, transporting fresh water from high rainfall areas to the south (Snowy Mountains). If true, the Permian Aquifer could act as an emergency water supply during periods of drought or be used as part of a water banking scheme. Reducing reliance on the over used Tertiary aquifers.