Abstract

A hydrochemistry-based study has highlighted potential management implications for selected aquifers and springs located within the Lake Blanche and Lake Callabonna region in the far north of South Australia. The interpretation of hydrochemical and environmental tracers from 14 springs and 17 water wells, as well as historically available data, were used to establish five hydrochemical-based aquifer types for the region: 1. Fractured rock crystalline basement aquifer. 2. Patchawarra Formation (Cooper Basin) aquifer. 3. J-K aquifer (Algebuckina Sandstone, Cadna-owie Formation and lateral equivalents) of the Great Artesian Basin. 4. A sandstone unit or units interpreted to occur within the Neocretaceous Rolling Downs Group, which is informally termed the ‘Rolling Downs Group sandstone (RDGS) aquifer’. 5. Cenozoic aquifer. Two key findings from this study have potential implications for ongoing resource management. First, artesian groundwater conditions were identified for the first time within sandstones found within the Neocretaceous confining layer (the RDGS aquifer). Although the exact stratigraphic nomenclature of this sandstone unit is not yet confirmed, groundwater sourced from this unit is currently being used for stock. Second, the RDGS aquifer may contribute to spring flow at Lake Blanche and Lake Callabonna. Similarly, the fractured rock aquifer may be a source of water for the Petermorra Springs complex. Beyond certain results from these three spring complexes, the majority of hydrochemical and environmental tracer analyses infer that the J-K aquifer is the primary source aquifer supporting spring flow.