At a point in time where industry is still building its understanding of the unconventional gas resources in the Beetaloo GBA region, distinct characteristics of any future development, and potential impacts on water and the environment, cannot be known. Using a causal network to assess impacts ( Section 3.1 ) helps to address some of this uncertainty and increase understanding of the potential implications of development. However, knowledge gaps do remain. These range from overarching knowledge gaps about the resource development through to specific knowledge gaps about aspects of activities, stressors, processes and endpoints, and the links between them.
Overarching knowledge gaps
The overarching knowledge gaps relate to the lack of certainty about what a future resource development entails and the associated impacts to water and the environment, particularly at a local scale. The aspects of resource development where there are significant knowledge gaps are:
- The scale, location and timing of future development. Economic viability for industry dictates that the scale must warrant the level of infrastructure investment required to connect the resource to market (such as production of hundreds of terajoules per day with hundreds of wells over the development lifetime). Location will influence the environmental, economic, cultural and social values with which development potentially interacts. The timing of future development influences rate-dependent potential impacts, such as water use and rates of vegetation removal.
- The characteristics and impacts of drilling and hydraulic fracturing activities that are ultimately used in a development. These technologies will depend on the nature of the resource and the decisions made by operators. The overall footprint of the development and amount of water used will be influenced by the development approach.
- Future interactions with other industries. High-resolution quantitative information on both the state of the environment and the processes acting on the landscape is needed to assess interactions with other drivers of system change (for example, agriculture, tourism, infrastructure development and climate change), which are not in scope for this assessment.
- How thresholds of material change will be altered due to any modification to the environment and ecological processes due to climate change.
Other aspects of the impact assessment where there are overarching knowledge gaps relate to the baseline for environmental values. The current understanding of all aspects of the ecosystems of the Beetaloo GBA region is limited; for example, which native species occur in the Beetaloo GBA region, where and how they use the area, and how these species respond to and interact with each other, invasive species and other potential stressors. These knowledge gaps will be partly addressed by the baseline ecological and groundwater information that is being collected by the Northern Territory Government’s Strategic Regional Environmental and Baseline Assessment program.
The nature of these overarching knowledge gaps primarily relates to the specifics of future development. Most, if not all, gaps will be addressed via project-specific environmental impact assessments required by the Environmental Assessment Act 1982 (NT). The causal network and causal pathways, along with the knowledge gaps identified, may provide useful input into the terms of reference for these.
Specific knowledge gaps
Specific knowledge gaps are recorded in the descriptions of the nodes and links of the causal network. The evaluation of each link in a causal pathway is based on best available data and knowledge. There are cause-and-effect relationships in the network for which the knowledge base is limited. This can pertain to limited data on the cause-and-effect relationship itself, its direction, the existence of any potential ‘tipping points’ for thresholds where the relationship suddenly alters markedly, the definition of material change, or the availability or effectiveness of mitigation strategies. This uncertainty is captured in the confidence score assigned to each link (‘low’, ‘medium’ or ‘high’), as well as the confidence in the existence of the link, its materiality and the effectiveness of mitigation methods (‘high’ or ‘low’), reflecting the knowledge base underpinning the evaluation
Specific knowledge gaps relating to extraction of unconventional gas resources include the following:
- It is not known what chemicals will be used in future petroleum activities as the technology in this area develops. There are also aspects of ecotoxicity and the fate of chemicals in the environment that are not fully understood. As more knowledge becomes available more sophisticated approaches to understanding potential impacts of chemicals could be used than the conservative modelling used in this assessment.
- Information on how a single spill at a local scale impacts a protected matter over a large scale (for example species’ population persistence and fitness or wetland health). New data and information may potentially change thresholds of material change for species or functional groups of species.
There are also specific knowledge gaps related to the understanding of ecological processes and how sensitive they are to the stressors that may be imposed on them by resource development activities. They include:
- Understanding of the occurrence and distribution for water, environment, and protected matters endpoints in the Beetaloo GBA region. From a biodiversity perspective, the region is one of the least surveyed in Australia. The Beetaloo GBA region Strategic Regional Environmental and Baseline Assessment studies should provide much of this baseline information.
- The characteristics of groundwater resources below the Cambrian Limestone Aquifer are not well understood. Improving this knowledge will assist in understanding its suitability as a water supply and for any potential connections between these groundwater resources and the Cambrian Limestone Aquifer.
- Habitat requirements of species, including activities (for example, breeding and foraging), are not fully understood. The impact of seemingly minor stressors (for example, noise and light pollution) on suitability of critical habitat for specific species is not known in the Beetaloo GBA region. Additional knowledge would allow nuanced assessment of the impacts of these stressors on critical habitat.
- Estimates of the population size of species in the Beetaloo GBA region and how that varies seasonally, interannually and over time. This is baseline information that will assist in determining potential impact from future resource development activities. Demographic data have been identified as being an important knowledge gap for Gouldian finch and Gulf snapping turtle.
- The reliance of certain species on surface water, how much and when, and the water quality required.
- Understanding of the potential impacts of changes in fire regime resulting from a future unconventional gas resource development. A better understanding of optimum fire management, particularly for Gouldian finch, crested shrike-tit (northern) and greater bilby is required.
- The role of artificial water sources from unconventional gas resource development in increasing predation by invasive carnivores. The key questions are whether predation by introduced carnivores is a threat for each species and, if so, whether this threat is facilitated by the presence of artificial water sources and what are the options for mitigation.
While the assessment is designed to be structured, robust and transparent, there are limitations for both the methodology and assumptions made by the assessment team, including representation of the following:
- Non-linear effects or time-varying cause-and-effect relationships that capture theboom-and-bust dynamics of a region. It is a complicated exercise to represent the complex reality of ecological and hydrological systems in a directional acyclic graph (the graphical causal network, Figure 6 ). One of the most challenging aspects is that feedback loops cannot be represented. Feedback loops are an essential feature of complex natural systems. When represented in a graph, however, it is no longer possible to unequivocally establish causal pathways between starting and ending nodes.
- Adverse impacts and benefits. In line with guidelines under the EPBC Act (Commonwealth of Australia, 2013a), where an action may have both adverse and beneficial impacts, only adverse impacts are assessed. However, positive effects are also evident. For example, while new roads in a landscape may increase bushfires due to an increased likelihood of accidental ignition, roads can also act as firebreaks, limiting the spread of bushfires. To determine net benefits of an action, a more quantitative estimate of the likelihood and magnitude of positive and negative effects is needed.
- Ecological, economic and/or social values to be protected. Environmental values are represented in the assessment by key ecological and hydrological systems in the Beetaloo GBA region. The 6 protected fauna listed under territory or national legislation were prioritised for assessment based on the importance of the Beetaloo GBA region to the continued persistence of each species. However, while the assessment takes a values-based perspective, more detailed assessment of potential impacts on cultural heritage values are beyond the scope of the GBA Program and are not directly represented in the causal network.
- Cumulative impacts of multiple stressors from multiple industries. Future studies could extend the causal network to other industries, such as pastoralism or tourism, to assess the impacts of multiple activities and stressors on processes and endpoints. A quantitative assessment of the magnitude and likelihood of cumulative impacts is not possible without detailed baseline and future development scenarios.
- Ecological processes and interactions. Links between activities, stressors, processes and endpoints are unable to capture all of the nuance of more detailed ecological conceptual models, which may cause unintended assessment outcomes.
Product Finalisation date
- At a glance
- Explore this assessment
- Executive summary
- 1 About the assessment
- 2 About the region
- 3 Causal network for the Beetaloo GBA region
- 4 Assessment results
- 5 Additional studies
- 6 Monitoring
- 7 Conclusion
- Contributors to the Program