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Understanding the rate of extraction from bores (or wells) can be essential in estimating groundwater discharge at a regional scale and understanding pressures on sustainable use. The challenges in doing so include the impracticality of directly measuring extractions from all, or even a large proportion of, operating bores using flow meters, especially in rural and remote areas. This challenge may be addressed by metering a representative sample of bores and generalising results to develop estimation methods; however, even achieving this presents considerable obstacles. While the benefits of metering a subset of bores to progress groundwater science and management are recognised, the obstacles to implementing metering and guidance on overcoming them are not well documented. In the Surat Basin, Australia, most groundwater bores are used for stock watering and domestic purposes, with less than 0.1% metered. As part of a research program to understand regional groundwater extraction in this area, a voluntary bore metering program has been undertaken. In this paper the challenges that arose when recruiting participants, installing and maintaining flow metering equipment, and interpreting and using data collected are described. Lessons learnt during implementation of the program that can guide other voluntary metering of rural groundwater extractions are discussed. [ABSTRACT FROM AUTHOR]

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 management in the Great Artesian Basin (Australia) is challenging due to the large areas and heterogeneity of sequences involved. This challenge has often been addressed with up-scaled conceptual models; however, where there is significant heterogeneity or local competing groundwater uses, more detail is required. When good understanding of heterogeneity within sequences is not available, the upscaled approach can lead to a disparity between model predictions based on homogenisation inherent in upscaling and the observed behaviour of heterogeneous systems, leading to bias in results. This requires improved conceptual resolution of these heterogeneous systems. Geological data are often insufficient to achieve the required resolution. This paper reports on the use of hydrochemical data from existing bores in the Walloon subgroup of the Surat Basin, using compositional data analysis techniques to refine the unit description. The approach moves beyond simple hydrochemical characterisations of water type via conventional hydrochemical interpretations to use a combination of centred- and isometric-log ratios to describe discrete end members. The results show that, despite similar water types, the upper Juandah and lower Taroom coal seams of Walloon subgroup are distinguished by an inverse relationship between ions Cl−, Ca2+, Mg2+, Sr2+, Li− and H+ and ions HCO3−, F− and B3+, and by an isometric log ratio that describes the balance between the activities of Cl, H+ and HCO3. These relationships suggest that higher-resolution conceptual models based on flow paths mapped from hydrochemical data can form the basis for refined groundwater models that address both heterogeneity and regional model domains. [ABSTRACT FROM AUTHOR]

Co-management through local collective action appeals as a way of effectively responding to critical groundwater management issues, including groundwater quality degradation and pumping that lowers water tables. Co-management may also build sufficient trust for stakeholders to agree to investigate, and potentially implement, new opportunities for the use and management of groundwater resources. This paper examines the potential of collective action to underpin co-management and lead to improved groundwater management. The case study is the Angas Bremer (AB) irrigation district in South Australia, which provides a rare example of community-lead groundwater management since the late 1970s. The key questions were: (1) Was the AB an example of collective action, and did that spark successful co-management? and, (2) What were the key outcomes of collective action throughout the years? Data were gathered through semi-structured interviews with key stakeholders. By working together, and with government departments, AB irrigators successfully recovered an aquifer that was at risk of depletion and salinization. Drawing on this evidence, it is suggested that co-management through local collective action may be a useful option for those setting out to improve the social acceptability of new groundwater initiatives in farming landscapes, including managed aquifer recharge (MAR) and conjunctive use of surface water and groundwater. [ABSTRACT FROM AUTHOR]

Overcoming barriers to large-scale urban redevelopment on brownfield land is an essential step in the global drive toward achieving the UN's sustainable development goals. Arguably the most significant barrier is site contamination. Decision support tools (DSTs) are potentially effective ways to assess contaminated sites and evaluate different remediation/management strategies as appropriate to local conditions. Whilst there has been extensive development of DSTs for single contaminated sites, only a limited number are available for assessing contamination at the 'precinct' (district) scale. This paper presents a framework and simple DST for the assessment of contaminated groundwater, using Australia's largest urban redevelopment project, Fishermans Bend in Melbourne, as a case study. The value of the inclusion of precinct-wide data into individual site-scale investigations is demonstrated via the DST. Common contaminant sources identified across Fishermans Bend include fill contaminated with heavy metals, legacy landfill leachate containing heavy metals and per- and poly-fluoroalkyl substances (PFAS), and naturally occurring ammonia and methane in organic-rich sediments. By comparison, point sources of heavy metals and PFAS appear related to industrial sources. By using the DST, environmental practitioners and auditors can more effectively separate background conditions from point sources, characterise the ambient conditions of the aquifer and their relationships to natural and anthropogenic processes, and use contaminant data to inform remedial options assessment. Where these increasingly complex and varied environmental datasets can be collected, stored and managed within one central database, cross- or inter-disciplinary collaborations may drive improvements in solving environmental problems which typically arise during the redevelopment process. [ABSTRACT FROM AUTHOR]

Managed aquifer recharge (MAR) is a tool available to water-resources managers that assists agencies to secure water supplies and protect aquifers and groundwater-dependent ecosystems in the face of climate change and growing water demand. Yet few natural-resources managers have access to a coordinated set of policies that enable the potential benefits of MAR to be fully realised in urban and rural areas. This paper reviews contemporary Australian water-resource policies and systematically applies a refined set of 'robust separation of rights' principles based on secure entitlements, annual allocations and end-use obligations to guide the coordination of policies specific to each of the four operational processes central to MAR schemes: source water harvesting, aquifer recharge, recovery of stored water and end use. Particular attention is given to the formulation of policies relating to the recovery of water, including the feasibility for market exchange of permanent and temporary rights to recover recharged water, as these have the potential to greatly expand the role of MAR. Aquifer characteristics, existing groundwater extractions and potential third party effects need to be taken into account in determining both recovery entitlements and annual allocations. A transitional pathway to implement novel MAR policies is suggested. [ABSTRACT FROM AUTHOR]

Groundwater extraction can have varied and diffuse effects. Negative external effects may include costs imposed on other groundwater users and on surrounding ecosystems. Environmental damages are commonly not reflected in market transactions. Groundwater transfers have the potential to cause spatial redistribution, concentration, and qualitative transformation of the impacts from pumping. An economically and environmentally sound groundwater transfer scheme would ensure that marginal costs from trades do not exceed marginal benefits, accounting for all third-party impacts, including those of a non-monetary nature as well as delayed effects. This paper proposes a menu of possible management strategies that would help preclude unacceptable impacts by restricting transfers with certain attributes, ideally ensuring that permitted transfers are at least welfare-neutral. Management tools would require that transfers limit or reduce environmental impacts, and provide for the compensation of financial impacts. Three management tools are described. While these tools can limit impacts from a given level of extraction, they cannot substitute for sustainable overall withdrawal limits. Careful implementation of transfer limits and exchange rates, and the strategic use of management area boundaries, may enable a transfer system to restrict negative externalities mainly to monetary costs. Provision for compensation of these costs could be built into the system. [ABSTRACT FROM AUTHOR]