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Understanding groundwater use, both current and historical, is important for understanding the hydrogeology of groundwater systems, and for water planning. The Queensland portion of Australia's Great Artesian Basin (GAB) is managed under the Water Plan (Great Artesian Basin and Other Regional Aquifers) 2017. Methods were developed to estimate current and historical abstractions from the different hydrostratigraphic units of the basin. In the first stage, source aquifers were assigned to ~96,000 bores within the Queensland GAB footprint. Of these, 31,503 bores were assigned directly to the GAB, with other bores sourcing groundwater from units above or below the GAB. In the second stage, current groundwater use for all bores and historic groundwater-use trends were estimated, covering the 115-year period between 1900 and 2015. These estimates took account of periods of inactivity at the bore, the aquifer condition (sub-artesian, artesian), and the nature of discharge (controlled or uncontrolled). The process used publicly available datasets. This paper presents an overview of the methodology and how the estimates were used to support water planning. The current groundwater use from the GAB in Queensland was estimated to be 322 GL/year, which is lower than previous estimates, partly because of improved estimation techniques, the bore capping and piping programs that have been in progress since 1989, and the naturally reducing discharge rates from uncontrolled artesian bores. [ABSTRACT FROM AUTHOR]

Groundwater resources in Queensland (Australia) have been depleting in many aquifers for the last 100 years and natural recharge processes are not replenishing these resources at the rate of extraction. At the same time, the need to address carbon emissions to reach global climate-change targets is becoming increasingly recognised. Plentiful deep fresh groundwater is available but is difficult, and typically uneconomical, to access due to the high costs of borehole drilling and completion. The emerging concept of 'enhanced water recovery' (EWR) hypothesises that carbon dioxide (CO2) injection into the deep aquifers will increase pressure, making groundwater more easily available at shallower depths across a broad region while simultaneously contributing to a reduction in CO2 emissions. One example where this has been proposed is in the Great Artesian Basin's Surat Basin in Queensland. The findings from a series of focus groups held with different stakeholders, including agricultural producers, rural residents, and urban residents, demonstrate how different groups perceived the risks and benefits of injecting CO2 as part of the carbon capture and storage (CCS) process to raise borehole water levels. The paper discusses the trade-offs that the different stakeholder groups found more acceptable. The significance of this research is that it will be the first to publish public responses to an emerging technology that has the potential to provide multiple benefits in terms of climate-change mitigation and groundwater use. [ABSTRACT FROM AUTHOR]