3.1 Overview

Summary

The proposed future development of black coal resources in central Queensland’s Galilee Basin will potentially result in impacts on and risks to some water resources and water-dependent assets. Within the broader context of the bioregional assessment (BA) for the Galilee subregion, this product presents the main findings of the targeted BA impact and risk analysis. These efforts are focused mainly on an area near the central-eastern boundary of the subregion where the initial phase of coal mining is planned to occur. This multi-disciplinary investigation has been carried out to evaluate the possible regional-scale cumulative impacts on surface water and groundwater resources, and the potential risks posed to the many ecological, economic and sociocultural assets that rely on access to these water supplies.

The Galilee subregion encompasses a large swathe of outback central Queensland, covering an area slightly larger than the state of Victoria. The subregion boundary coincides with the geological Galilee Basin, although much of this basin is now buried by younger sedimentary cover. There have never previously been any commercially producing coal resource developments in the Galilee Basin. However, seven large-scale new coal mines are planned to begin operations over the next decade or so, targeting the central-eastern basin where the coal resources are relatively close to surface. Consequently, the key outcomes of this BA represent the first attempt to understand and quantify the potential combined effects of multiple coal resource developments on the extent, magnitude and timing of regional-scale hydrological impacts.

The Galilee subregion is ecologically diverse, supporting distinctive terrestrial and aquatic ecosystems including some species and communities that are of national and regional significance (e.g. it hosts seven ecological communities listed under the Commonwealth’s Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act)). Six major surface water catchments cover the Galilee subregion, and around two-thirds of the total drainage area flows inland towards Lake Eyre as part of either the Cooper Creek – Bulloo river basin or the Diamantina river basin. The subregion’s semi-arid to arid climate means that most streams are intermittent or ephemeral, with the timing and magnitude of streamflow commonly varying between the main river basins. Groundwater-fed springs provide important habitat and water supplies for many species, with most springs in the subregion sourced from aquifers of the Great Artesian Basin. There is a high degree of species endemism within many spring complexes of the Galilee subregion.

The area is sparsely populated, with fewer than 20,000 inhabitants mainly living in country towns such as Charleville, Blackall and Barcaldine. Most of the land within the subregion is used for dryland agriculture, mainly livestock grazing on native vegetation across large pastoral land holdings. There are several areas reserved for nature conservation, including the Diamantina and White Mountains national parks, and the Bimblebox Nature Refuge. Aside from pastoralism there are no other large-scale industrial activities in the subregion, although minor gas production occurs from the Gilmore Gas Field about 100 km south-west of Blackall, targeting a conventional hydrocarbon reservoir in the deeper geological Adavale Basin (underlying the Galilee Basin).

The impact and risk analysis for the BA for the Galilee subregion focuses mainly on the seven most advanced coal mining proposals identified in the coal resource development pathway (CRDP). From south to north, these are: South Galilee, China First, Alpha, Kevin’s Corner, Carmichael, China Stone and Hyde Park. The CRDP in the Galilee subregion also includes seven other less advanced coal mining projects and three pilot/exploration stage coal seam gas (CSG) developments. However, none of these projects could be evaluated through modelling in this BA due to lack of required data and information. Qualitative analysis of potential impacts of the non-modelled coal resource developments is provided in Section 3.6.

The cumulative hydrological changes due to the seven modelled coal mines were previously reported in companion products for the Galilee subregion on surface water and groundwater numerical modelling, which focused on quantifying changes in water quantity and availability. The probabilistic approach adopted for the BA modelling has enabled development of a zone of potential hydrological change in this product, outside of which water resources and water-dependent assets in the Galilee assessment extent are very unlikely (less than 5% chance) to be impacted (i.e. they are ‘ruled out’ of the analysis). Consequently, this assessment is focused on the zone of potential hydrological change, and is structured around the three broad system components that are in scope for the BA, namely the impacts on, and risks to, the hydrological systems, ecosystems (characterised in BAs using the landscape classification approach), and the relevant ecological, economic and sociocultural assets.