Improved characterisation of unmetered stock and domestic groundwater use in the Surat and Southern Bowen basins of the Great Artesian Basin (Australia)

Time-series and current estimates of groundwater use are critical for conceptualisation of groundwater systems and for understanding system responses. A key challenge for managing Australia’s Great Artesian Basin (GAB) is the limited available data on water use. In the absence of an existing method, the Queensland Government’s Office of Groundwater Impact Assessment developed a demand-based method to estimate unmetered stock and domestic (S&D) groundwater use in 2016, with further enhancements since then. The method integrates publicly available datasets including property grazing potential and availability of other water supplies to derive a range of groundwater use estimates. The method also distributes the estimated demand for groundwater use across water supply bores and across screened geological formations based on bore construction and screened-aquifer information. The method has been applied to the GAB’s Surat and southern Bowen basins. Integrating the results and outcomes from related research projects, this article provides an overview of the demand-based method, highlighting new understanding of the temporal and spatial distribution of groundwater use. Results were validated at the bore scale with limited metered bore data, and at the sub-regional level from census data and landholder survey information. Across the Surat Basin, comparisons with previous estimates show, as estimated, a reduction in S&D water extraction from approximately 80,000 to 25,000 ML/year.