The contribution of citizen science in managing and monitoring groundwater systems impacted by coal seam gas production: an example from the Surat Basin in Australia's Great Artesian Basin

Monitoring is critical for effective groundwater management, especially in systems with competing groundwater interests, such as the Great Artesian Basin's (GAB) Surat Basin (similar to 180,000 km(2)) in Queensland, Australia. Coal seam gas (CSG) activities in the region have led to public concerns about potential impacts on groundwater and to landholder complaints about impacts on boreholes. To deal with these issues, the Queensland Government established the Groundwater Net and Groundwater Online citizen-science monitoring programs, which started in 2013 and were fully operational by 2018. Groundwater Net is a community-based education and groundwater monitoring program in which over 500 landholders across 16 local groups have attended workshops and provided over 1,000 groundwater-level/pressure readings from their boreholes using the My Groundwater Monitoring website. Annual workshops provide a forum to share and discuss monitoring results and knowledge. Regularly updated status reports compare monitoring data from CSG companies and the government with landholder data. Groundwater Online is a complimentary program using continuous-monitoring loggers and telemetry on 46 private boreholes. Citizen science now provides 13% of GAB monitoring boreholes in the CSG area. By effectively engaging with borehole owners, and empowering them to monitor, many opportunities arise for better groundwater management. Consequently, the spatial reach of groundwater monitoring and its frequency have increased, landholders are educated about groundwater systems, and borehole owners generally feel more confident about monitoring conducted by CSG companies and government

Can collective action address the “tragedy of the commons” in groundwater management? Insights from an Australian case study

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

Influence of model conceptualisation on one-dimensional recharge quantification: Uley South, South Australia

Model conceptualisation is a key source of uncertainty in one-dimensional recharge modelling. The effects of different conceptualisations on transient recharge predictions for the semi-arid Uley South Basin, South Australia, were investigated. One-dimensional unsaturated zone modelling was used to quantify the effect of variations of (1) lithological complexity of the unsaturated zone, and (2) representation of preferential flow pathways. The simulations considered ranges of water-table depths, vegetation characteristics, and top soil thicknesses representative for the study area. Complex lithological profiles were more sensitive to the selected vegetation characteristics and water-table depth. Scenarios considering runoff infiltration into, and preferential flow through sinkholes resulted in higher and faster recharge rates. A comparison of modelled and field-based recharge estimates indicated that: (1) the model simulated plausible recharge rates, (2) only the models with preferential flow correctly reproduced the timing of recharge, and (3) preferential flow is probably redistributed in the unsaturated zone rather than passing to the water table directly. Because different but equally plausible conceptual models produce widely varying recharge rates, field-based recharge estimates are essential to constrain the modelling results

Current practice and future challenges in coastal aquifer management: flux-based and trigger-level approaches with application to an Australian case study

The control of groundwater abstraction from coastal aquifers is typically aimed at minimizing the risk of seawater intrusion, excessive storage depletion and adverse impacts on groundwater-dependent ecosystems. Published approaches to the operational management of groundwater abstraction from regulated coastal aquifers comprise elements of "trigger-level management" and "flux-based management". Trigger-level management relies on measured groundwater levels, groundwater salinities and/or ecosystem health indicators, which are compared to objective values (trigger levels), thereby invoking management responses (e.g. pumping cut-backs). Flux-based management apportions groundwater abstraction rates based on estimates of aquifer recharge and discharge (including environmental water requirements). This paper offers a critical evaluation of coastal aquifer management paradigms using published coastal aquifer case studies combined with a simple evaluation of the Uley South coastal aquifer, South Australia. There is evidence that trigger-level management offers advantages over flux-based approaches through the evaluation of real-time resource conditions and trends, allowing for management responses aimed at protecting against water quality deterioration and excessive storage depletion. However, flux-based approaches are critical for planning purposes, and are required to predict aquifer responses to climatic and pumping stresses. A simplified modelling analysis of the Uley South basin responses to different management strategies demonstrates the advantages of considering a hybrid management approach that includes both trigger-level and flux-based controls. It is recommended that where possible, trigger-level and flux-based approaches be adopted conjunctively to minimize the risk of coastal groundwater degradation and to underpin strategies for future aquifer management and well-field operation

Trigger-level versus flux-based management approaches applied to coastal aquifers

Rome, Ital

Groundwater recharge to a sedimentary aquifer in the topographically closed Uley South Basin, South Australia

The chloride mass balance (CMB) and water-table fluctuation (WTF) analysis methods were used to estimate recharge rates in the Uley South Basin, South Australia. Groundwater hydrochemistry and isotope data were used to infer the nature of recharge pathways and evapotranspiration processes. These data indicate that some combination of two plausible processes is occurring: (1) complete evaporation of rainfall occurs, and the precipitated salts are washed down and redissolved when recharge occurs, and (2) transpiration dominates over evaporation. It is surmised that sinkholes predominantly serve to by-pass the shallow soil zone and redistribute infiltration into the deeper unsaturated zone, rather than transferring rainfall directly to the water table. Chlorofluorocarbon measurements were used in approximating recharge origins to account for coastal proximity effects in the CMB method and pumping seasonality was accounted for in the WTF-based recharge estimates. Best estimates of spatially and temporally averaged recharge rates for the basin are 52-63 and 47-129 mm/year from the CMB and WTF analyses, respectively. Adaptations of both the CMB and WTF analyses to account for nuances of the system were necessary, demonstrating the need for careful application of these methods

An inter-disciplinary approach to evaluate human health risks due to long-term exposure to contaminated groundwater near a chemical complex

Potentially toxic elements (PTEs) are known to threat human health due to exposure to contaminated groundwater. Some of these PTEs can lead to long-term carcinogenic and non-carcinogenic health risks. The Estarreja Chemical Complex (ECC), NW Portugal, has had an intense industrial activity since the early 1950s, which lead to high levels of soil and groundwater contamination. Local populations traditionally rely on groundwater for human and agricultural uses. Although rehabilitation measures have been implemented for the last 20 years, groundwater contamination levels remain high for some PTEs, whose concentrations may be several orders of magnitude higher than human consumption. Two groundwater-sampling campaigns were conducted showing the temporal evolution of groundwater quality and allowing for the calculation of non-cancer and cancer risks due to exposure to PTEs by the ECC-surrounding population, considering groundwater ingestion and dermal contact as exposure pathways. Hair and urine PTE contents were collected during of the second sampling groundwater campaign and were used as biomonitoring to validate the exposure of local population to PTEs. The results show that As is the contaminant with highest non-cancer and cancer health risks for the exposed population, presenting high values particularly in Veiros, Beduído and Pardilhó localities. The most groundwater-contaminated areas coincided with the localities in which inhabitants exhibit higher hair and urinary PTE concentrations. Hair samples show high levels of As, Hg and Ni, while urine samples show high levels for Al, As, Cd, Hg, Pb, Ni and Zn are elevated in localities close to the ECC. Urine and hair proved to be suitable to evaluate short- and long-term exposure to PTEs, and are strongly correlated groundwater PTEs concentrations

Human predisposition to cognitive impairment and its relation with environmental exposure to potentially toxic elements

International audienc