- overlay analysis, whereby asset polygons (or lines or points) are intersected with a nominated to identify whether the asset is potentially subject to that hydrological change
- qualitative mathematical models derived from expert elicitation
- quantitative mathematical models (receptor impact models) derived from expert elicitation and based on the qualitative mathematical models.
Details of the compilation of the Gloucester () are reported in companion product 1.3 for the Gloucester subregion (). The spatial layers representing the mapped extents or potential extents of the water-dependent assets, which are used in the overlay analysis, are contained within the Gloucester subregion water-dependent assets database (Bioregional Assessment Programme, ).
As described in companion product 2.7 for the Gloucester subregion (), receptor impact models were developed for two in the ‘Riverine’ landscape group: ‘Perennial – gravel/cobble streams’ and ‘Intermittent – gravel/cobble streams’. Qualitative models were developed for the (GDE) landscape classes. Overlay analysis can identify assets that are unlikely to be impacted by or changes, based on the lack of intersection with the zone of potential hydrological change. The zone of potential hydrological change is defined in Section 3 .3.
The impact and risk analysis uses different estimates of hydrological change (5th, 50th (median) and 95th ) to give an indication of the of hydrological changes to different types of water-dependent assets present in the zone of potential hydrological change. The principal focus of the analysis is the median (50th percentile estimate). However, the 5th percentile is shown in order to rule out potential impacts as being while the 95th percentile can be used to show where hydrological changes (although not necessarily ecological impacts) are .
The analysis of and considers each group of water-dependent assets separately – ecological, economic and sociocultural. Each subgroup of ecological assets is described separately – ‘Surface water feature’, ‘Groundwater feature (subsurface)’ and ‘Vegetation’. To improve clarity, assets in the ‘Vegetation’ subgroup are further divided into two classes: ‘Groundwater-dependent ecosystem’ and ‘Habitat (potential species distribution)’. Economic assets are separated into two classes: ‘Groundwater management zone or area (surface area)’ and ‘Surface water management zone or area (surface area)’. Potential hydrological changes to all non-petroleum and gas bores in the zone of potential hydrological change are also considered. The intersection of sociocultural assets with the zone of potential hydrological change is then described, and potential for impact assessed.
The impact and risk analysis uses a combination of summary tables, maps of modelled hydrological change within assets, plots of cumulative asset extent and degree of modelled hydrological change, and narrative. The spatial extent and number of water-dependent assets means that not all assets can be mapped and assessed in this product. Potential impacts to individual assets can be visually explored at www.bioregionalassessments.gov.au/explorer/GLO/assets. Finally, this section describes impacts on and risks to assets due to potential hydrological changes for only that part of the (CRDP) that was able to be modelled. Section 3. 6 of this product provides commentary for that part of the that was not modelled (Gloucester Gas Project Stage 2 and beyond).
Product Finalisation date
- 3.1 Overview
- 3.2 Methods
- 3.3 Potential hydrological changes
- 3.4 Impacts on and risks to landscape classes
- 3.5 Impacts on and risks to water-dependent assets
- 3.6 Commentary for coal resource developments that were not modelled
- 3.7 Conclusion
- Contributors to the Technical Programme
- About this technical product