The $35.4 million Geological and Bioregional Assessment (GBA) Program assesses potential environmental impacts of unconventional gas resource development. The geological and environmental knowledge, data and tools produced by the Program is informing decision-making, regulatory frameworks and appropriate management approaches to underpin coordinated management of potential impacts across governments, industry, land users and the community.
About the region
The 130,000 km 2 Cooper GBA region contains diverse habitats that support important environmental, cultural, social and economic values that interact and respond to the episodic, irregular and extreme boom-and-bust periods that are characteristic of the Channel Country in Queensland and South Australia. The braided channels, vast floodplains and terminal lakes of Cooper Creek include internationally and nationally listed wetlands, as well as regionally protected areas. Most of the region is used to graze sheep and cattle on natural pastures. Flooding provides a significant boost to agricultural productivity in the region.
The assessment considers potential impacts on these landscapes, protected areas and threatened species. Results are reported as ‘areas of concern’ – based on evaluation of the likelihood and consequence of potential impacts, and where compliance with existing mitigation strategies is required.
About the assessment
Unconventional gas resources are found in a range of geological settings in the Cooper GBA region and include shale gas, tight gas and deep coal gas. Accessing these resources involves a range of activities including drilling, hydraulic fracturing, construction of roads, well pads, pipelines and processing facilities, extraction of water, and establishment of facilities to manage waste and wastewater. The assessment considered potential impacts from these activities on water and the environment in the Cooper GBA region. It does not replace site specific assessments or consider other unconventional gas resource types, such as coal seam gas. The outcomes of this assessment provide regional knowledge, data and tools for regulators and proponents to use to inform more detailed environmental impact assessment, management and monitoring for potential future developments.
The assessment is based on a maximum development scenario matching current conventional gas production in the Cooper GBA region of 92 petajoules per year over a 50-year period.Under this scenario, a projected 1,180 petroleum wells are estimated to disturb a total of 27 km 2 of the Cooper GBA region. The total development area, including undisturbed areas between well pads, roads and seismic lines, is estimated to be up to 7350 km 2. Under this scenario, development would extract or reuse up to 20 gigalitres of water over 50 years, equivalent to 400 megalitres per year.
The assessment determined with high confidence that all potential impacts on water and the environment in the Cooper GBA region from unconventional gas resource development can be mitigated through compliance with existing regulatory and management controls. Confidence in this assessment will be improved as knowledge about potential ecological impacts increases. Future monitoring objectives can be prioritised using the impact assessment and structure of the causal network to establish baseline conditions, detect changes, trends and impacts, monitor for compliance and address knowledge gaps.
Potential impacts on water
Surface water can be extracted under licence from river channels, the floodplain and permanent waterholes. Further, construction activities for roads and development facilities can obstruct the flow of water across the floodplain. For the first time, a state-of-the-art flood inundation model has been developed for the Cooper Creek floodplain, one of the most complex floodplains in the world. The model can evaluate how future development could impact on flooding to show regulators and proponents how proposed activities could impact on surface water flows on the floodplain.
The assessment determined with high confidence that existing licensed surface water extraction – approximately 2% of annual flows – will not impact flows or alter scouring or flooding in Cooper Creek. Activities that block or obstruct surface water flow are of ‘potential concern’ for about 6% (1,613 km 2) of the Cooper Creek floodplain. Further investigation of changes to agricultural productivity, protected wetlands, as well as protected fauna and flora on the floodplain is warranted. Despite this, there is high confidence that state regulations, as well as industry mitigation strategies, can mitigate potential impacts in sensitive areas including permanent waterholes.
Leaks and spills could release chemicals or compounds used in unconventional gas resource development, or produced as a result of development, into the environment. If a spill occurs near surface waters, chemicals could either directly enter the water, or result in soil contamination that then pollutes water. Contamination of groundwater is of ‘potential concern’ where groundwater is close to the surface (less than 9 m).
Controlled release of wastewater is the intentional and approved release of treated water into the environment, including evaporation from storage ponds, reuse for operations water, dust suppression, irrigation or stock drinking water, and disposal of treated wastewater into existing drainage features in the landscape.
If a spill occurs near surface waters, contaminants could spread rapidly and accumulate in sediments. Surface water contamination is of ‘potential concern’ in 12% of the Cooper GBA region. Compliance reporting shows existing regulations, approval conditions and industry practices are effective in preventing, or ensuring quick remediation of, spills and leaks.
Controlled release of wastewater to the environment is strongly regulated by both state and Commonwealth governments and is of ‘low concern’. Stringent approval conditions, monitoring, treatment and compliance requirements ensure that the treated wastewater is consistent with the sensitivity of the receiving environment.
Groundwater extraction is a likely source of water for unconventional gas operations in the Cooper GBA region. As costs increase with depth, it is assumed groundwater would be sourced from the shallower aquifers in the region, where possible, in preference to deeper confined aquifers. Groundwater extraction must adhere to Queensland and South Australian government regulations and must not affect other water users including groundwater-dependent ecosystems.
Compromised aquitard integrity describes changes in the integrity of low permeability rock layers between gas reservoirs and aquifers. This is important where there is concern for groundwater contamination resulting from unconventional gas resource development activities including hydraulic fracturing. Compromised well integrity refers to breaches of a well system that allow the unintended movement of fluids, including contaminants, outside of the well. Standards require two independent well barriers that form a protective leak-tight seal between the well and surrounding rock.
The assessment determined that potential impacts on groundwater-dependent ecosystems due to groundwater extraction are generally of ‘low concern’. Exceptions are ecosystems dependent on the Cenozoic aquifer in the west of the Cooper GBA region and near existing groundwater bores accessing the Cadna-owie – Hooray aquifer, where it is less than 150 m thick, in the south-west of the region. Sourcing groundwater from other aquifers, or reuse of wastewater, could avoid potential impacts on groundwater-dependent ecosystems in these areas.
Hydraulic fracture growth into an aquifer, well or fault has a low likelihood of occurring and natural barriers, such as the Nappamerri aquitard, protect overlying aquifers from contamination. Compromised aquitard integrity is of ‘potential concern’ in an area of less than 0.01% of the Cadna-owie – Hooray aquifer where the Nappamerri aquitard is less than 155 m thick. Existing controls outlined in environmental management plans mitigate potential impacts on Cadna-owie – Hooray aquifer condition. Aquifer contamination due to compromised well integrity is of ‘very low concern’ based on findings from domestic and international inquiries.
Potential impacts on the environment
Riparian ecosystems are an important component of the aquatic habitat and include plants and animals that are dependent on the presence of rivers and streams. Riparian communities provide a range of ecosystem services including supply of organic materials to the river system, regulation of the riverine microclimate and provision of habitat for many species. Riparian vegetation in the Cooper GBA region is relatively undisturbed and covers over 5,000 km 2 (about 4%), with around one-third overlying areas prospective for the development of unconventional gas resources.
Wetlands include swamps, marshes, billabongs and lakes, natural or artificial, and permanent or temporary. In the Cooper GBA region, more than 90 types of wetland ecosystems provide habitat for thousands of species. Some wetlands support populations of wetland bird species in excess of 20,000 birds. Wetland vegetation is relatively undisturbed and covers over 12,000 km 2 (about 9%), with almost half overlying areas prospective for unconventional gas resources. Supply of water to wetlands is naturally highly variable and water quality is dependent on local rainfall or connectivity with Cooper Creek. Wetlands and riparian areas have cultural and economic value to local Indigenous peoples.
In the arid environment of the Cooper GBA region, permanent waterholes are important refuges for native plants and animals during dry times and have customary, spiritual and economic values to Traditional Owners. The Cooper GBA region contains over 3,000 waterholes; 48 are permanent and overlie areas prospective for development of unconventional gas resources. Investigations at 17 of these waterholes confirmed that groundwater below waterholes is recharged from surface water.
Protected riparian and wetland ecosystems in the Cooper GBA region include the Ramsar-listed Coongie Lakes, wetlands listed in the Directory of important wetlands in Australia and the Channel Country Strategic Environmental Area (SEA) protected under Queensland Government legislation, as well as habitat for the grey grasswren and the Australian painted snipe.
The assessment determined with high confidence that compliance with existing protections, including legislated no-go areas, and industry controls can minimise future impacts on riparian vegetation. Indirect impacts from unconventional gas resource development are more difficult to mitigate and are of ‘potential concern’ in over 30% of riparian areas. Stressors include accidental release of chemicals and invasive plants and predators.
Potential impacts associated with site disturbance are of ‘potential concern’ for nearly half of the area of wetland vegetation; and invasive plants and predators are of ‘potential concern’ for all wetland ecosystems including protected wetlands in the Cooper GBA region. Compliance with existing approval conditions and protocols in regulatory frameworks is needed to ensure potential impacts are effectively mitigated.
Indirect impacts on waterholes along the Cooper Creek could degrade up to 36% of waterhole habitats. Impacts include soil and surface water contamination from spills and leaks, as well as habitat degradation, fragmentation and loss due to invasive herbivores and livestock grazing, invasive plants and altered fire regimes. There is high confidence in avoidance and mitigation strategies prescribed in state-based regulations and relevant environmental management plans.
Floodplains result from complex interactions between flow, sediment regimes and the character of the river valley. Floodplains in the Cooper GBA region are typical of mid or lower river valleys, meaning the energy associated with flows is lower, valleys tend to be wider, and significant amounts of sediment are deposited in large slow-moving floods, leading to very large floodplains, over 60 km wide in places. Over 25,000 km 2 (about 19%) of the Cooper GBA region is floodplain, mostly undisturbed, and close to one-third overlies areas prospective for unconventional gas resources.
The frequency and duration of flooding is important to floodplain environments as it controls vegetation growth and the potential growing period for plants. Floodplain ecosystems are less diverse than riparian, wetland or dryland ecosystems in the region, containing 6 regional ecosystem types in Queensland and 5 in South Australia. Vegetation is characterised by sparse or open shrublands and low woodlands and provides habitat for protected fauna and flora. Floodwaters support terrestrial vegetation, fill lakes and recharge shallow groundwater. The floodplain supports an agricultural grazing industry worth $65 million per year with single large floods increasing the value by up to $150 million.
Disturbance from unconventional gas resource development is of ‘potential concern’ in up to 30% of floodplain areas. Obstruction to overland flow, a potential impact to water (described earlier), is of ‘potential concern’ for up to 6% of floodplain vegetation due to changes to flooding extent. This has potential to impact on agricultural productivity and the condition of protected areas including the Channel Country Strategic Environmental Area and Coongie Lakes.
Dryland ecosystems in the Cooper GBA region are arid and are solely reliant on rainfall to meet their water needs, receiving a very low mean annual rainfall of 217 mm/year and evaporation in excess of 1700 mm/year. They include inland dunefields, undulating country on fine grained sedimentary rocks, tablelands and duricrusts, loamy and sandy plains, and clay plains. Dryland vegetation is relatively undisturbed and covers close to 90,000 km 2 (about 69%), of which approximately 23% overlies areas prospective for unconventional gas resources.
Despite being very arid, the region is diverse with approximately 70 regional ecosystem types in Queensland and 28 in South Australia. Dryland vegetation communities include chenopod shrublands, Mitchell grass tussock grasslands, hummock grass dominated by spinifex and Acacia dominated woodlands and shrublands. They support protected fauna, including the kowari found in the Sturt Stony Desert and yellow-footed rock-wallaby found in the tablelands and duricrusts. The night parrot is thought to use unburnt spinifex for roosting and breeding.
Soil compaction could increase habitat degradation, fragmentation and loss and soil erosion and is of ‘potential concern’ in 20% of the agricultural grazing and 23% of the dryland areas. Mitigation strategies for soil compaction are well understood but knowledge on soil erosion is limited.
Potential impacts on protected fauna and flora
The Cooper GBA region is biodiverse. The boom-and-bust ecology is a driver of regional biodiversity including over 2,000 known species. The region’s relatively intact landscape and stable vegetation communities support high biodiversity. The Cooper GBA region provides potential habitat for 68 species protected under state or national legislation. The assessment prioritised 12 species (4 birds, 3 mammals and 5 plants) based on the importance of the Cooper GBA region to each species. Many species are culturally significant, for example, the iconic river red gum stabilises rivers banks, provides habitat for birds and animals and has long provided food, timber and medicines for Indigenous peoples.
Future unconventional gas resource development is estimated to increase the existing conventional oil and gas development footprint in the Cooper GBA region by 27 km 2. This footprint underestimates ecological impact as expansion of linear networks (roads, fences, seismic lines) facilitates the spread of invasive plants and animals. Invasive species may amplify competition and predation, lead to changes in fire regimes, degrade habitat and change ecological communities. Regional diversity is strongly influenced by these broad landscape impacts to sensitive communities and threatened species.
Mitigation and management of invasive species is best achieved via coordinated industry-wide approaches that work with existing land managers and NRM programs including whole of life-cycle planning and risk management. Dedicated invasive species officers, and raising awareness of workers and contractors are key monitoring and mitigation options. There is medium to high confidence that competition and predation can be effectively managed and mitigated using existing controls, although current data and knowledge is limited in the Cooper GBA region.
Unconventional gas resource development could amplify threatening processes that are already impacting biodiversity in the Cooper GBA region. This includes habitat degradation, fragmentation and loss; competition and predation by invasive species; and ecosystem burning, which are of ‘potential concern’ in 25 to 30% of the Cooper GBA region.
Potential impacts to floodplain inundation and soil or surface water contamination (discussed above) are of ‘potential concern’ for protected species. Vegetation removal and spread of invasive species can degrade habitat important for protected species. Predation by cats and foxes and competition for resources with feral herbivores are threatening processes for protected fauna species. Changes to fire regimes potentially impact all protected species.
Noise and light pollution can have significant impacts on all animal taxa and are not currently recognised as key threatening processes for protected species. Both impacts are assessed as of ‘potential concern’ in 25% of the Cooper GBA region. Noise and light pollution may be of particular concern to cryptic or nocturnal species. Potential impacts can be mitigated by minimising the extent and location of new facilities, roads and pipelines and by ensuring rapid and effective remediation of disturbed sites as well as follow up monitoring.
Compliance with approval conditions and protocols in existing state and Commonwealth regulatory frameworks is needed to ensure that potential impacts can be mitigated. Priorities identified by the assessment for future management, mitigation and monitoring at the surface are direct impacts within the development area and indirect impacts that could spread beyond development areas. Current protections and management are focused on direct impacts due to disturbance in the development area.
Indirect impacts can spread beyond development areas into surface waters (accidental release and overland flow obstruction), or change ecological interactions (artificial water sources, invasive plants and invasive predators) and functions (dust generation and operation of industrial machinery). Management of indirect impacts requires regional-scale approaches coordinated across governments, industry, land managers and communities.
Product Finalisation date
- At a glance
- Explore this assessment
- Executive summary
- 1 About the assessment
- 2 About the region
- 3 Assessment, mitigation and monitoring
- 4 Potential impacts on water
- 5 Potential impacts on the environment
- 6 Potential impacts on protected fauna and flora
- 7 Conclusion
- Contributors to the Program