3.2.4 Assessing potential impacts for landscape classes and assets

The approach for assessing potential impacts to landscape classes and water-dependent assets is discussed in companion submethodology M10 (as listed in Table 1) for analysing impacts and risks (Henderson et al., 2017). The zone of potential hydrological change focuses the attention of the analysis on areas where there may be changes in surface water and/or groundwater that are attributable to additional coal resource development.

The principal focus of BAs is water-dependent assets that are nominated by the community. These assets may have a variety of values, including ecological, sociocultural and economic values. The water-dependent asset register (companion product 1.3 for the Maranoa-Balonne-Condamine subregion (Mitchell et al., 2015) and Bioregional Assessment Programme, Dataset 8) provides a simple and authoritative listing of the assets within the assessment extent. The register is a compilation of assets identified in natural resource management databases and Commonwealth and state databases, and through the Maranoa-Balonne-Condamine assets workshop. The identified assets were assessed by the Assessment team for fitness for BA purpose, location within the assessment extent and water dependency. Assets that satisfy the requirements were considered in the impact and risk analysis reported in this product.

Landscape classification discretised the heterogeneous landscape into a manageable number of landscape classes for the impact and risk analysis. Landscape classes represent key surface ecosystems that have broadly similar physical, biological and hydrological characteristics. They are used to reduce the complexity inherent in assessing impacts on a large number of water-dependent assets by focusing on the hydrological drivers and interactions relevant to a regional-scale assessment. The landscape classes provide a meaningful scale for understanding potential ecosystem impacts and communicating them through their more aggregated system-level view. The landscape classification for the Maranoa-Balonne-Condamine subregion is described in companion product 2.3 (Holland et al., 2016) and the methodology that underpins it is described in companion submethodology M05 (as listed in Table 1) for developing a conceptual model of causal pathways (Henderson et al., 2016).

Potential hydrological changes were assessed by overlaying the extent of a landscape class or asset on the zone of potential hydrological change due to additional coal resource development. For the landscape classes or assets that lie outside the zone, hydrological changes (and hence impacts) are very unlikely, and were thus ruled out in terms of further assessment. Section 3.4.2 identifies landscape classes in the Maranoa-Balonne-Condamine subregion that were ruled out on this basis.

Where an asset or landscape class wholly or partially intersects the zone of potential hydrological change, there is the potential for impact. This does not mean there will be an impact, but rather, based on the magnitude of the hydrological change, the possibility of an impact cannot be ruled out and further investigation is required. The nature of the water dependency of the landscape class can be important for informing the Assessment. For example, if the water dependence of a landscape class is unrelated to groundwater access, such as woodland vegetation that do not access groundwater, then it is possible to rule out the landscape class from further consideration because it is unlikely to be impacted.

The zone of potential hydrological change defined for the regional watertable was used to assess potential impacts to key surface ecosystems (landscape classes (except springs), economic assets (except groundwater bores), ecological and sociocultural assets). To assess potential impacts to springs and groundwater bores that access deeper geological layers, the zone of potential hydrological change was defined for the deeper geological layers.

Potential impacts are reported in Section 3.4 for landscape classes and in Section 3 .5 for assets.

In addition, impact profiles for landscape classes and assets are available at www.bioregionalassessments.gov.au. Each profile summarises the hydrological changes and potential impacts that pertain to that landscape class or asset (e.g. groundwater drawdown in the ‘Floodplain remnant vegetation’ landscape class in the zone of potential hydrological change). Users can aggregate and consider potential impacts for their own scale of interest.

Users can also explore the results for landscape classes and assets using a map-based interface at www.bioregionalassessments.gov.au/explorer/MBC/landscapes and www.bioregionalassessments.gov.au/explorer/MBC/assets.