Assessing water dependence

Once the assets were compiled into the asset database and checked for inclusion in the PAE, they were assessed for water dependence. All assets in the asset list that may have been potentially impacted by changes in the groundwater or surface water regime due to coal resource development were identified. Although most of these assets were clearly water dependent (e.g. bores, rivers, wetlands), there were some that were less readily identifiable as ‘water dependent’. Examples of these assets include species distributions that may use habitats associated with water dependency amongst other habitats that are not water dependent, or Indigenous assets that may be more difficult to access due to changes in the water regime.

All economic assets were assumed to be water dependent. Sociocultural assets were assessed by their vicinity to water features. That is, an intersection was run between the sociocultural assets and streams and groundwater-dependent ecosystems (GDEs). If a surface water feature or GDE intersected (i.e. overlaps at least some of the same geographic area) with the asset, it was considered to be water dependent.

The ecological assets were assessed through common knowledge (e.g. if the asset was a surface water feature, such as a river), literature searches and spatial intersections through Geographic Information Systems (GIS) software. All assets in the ‘Surface water feature’ and ‘Groundwater feature (subsurface)’ subgroups were assumed to be water dependent (Section 1.3.4).

The water dependency of threatened species assets were assessed through their habitats rather than the species per se. This was because the BAs consider the potential impact on an asset (or the habitat of an asset if it is a species distribution) as a result of groundwater or surface water changes due to coal resource development (Mount et al., 2015). In most cases, profiles from the NSW species profiles (NSW Environment and Heritage, 2013) were accessed for information on species’ habitat. The information on the Species Profile and Threats Database (SPRAT) (Australian Government Department of the Environment, Dataset 7) and the Queensland Government’s WetlandInfo website (DEHP, 2014a) were also examined. The water dependence of the habitat for each species-related asset was ranked as being ‘likely’ if habitat features were consistent with demonstrated water dependency, ‘possible’ if habitat features were consistent with water dependency or ‘unlikely’ if habitat features were not consistent with demonstrated water dependency. Assets with ‘habitat features consistent with demonstrated water dependency’ were those with a clear and demonstrated link to aquatic ecosystems (e.g. aquatic species). Assets with ‘habitat features consistent with water dependency’ may have had some overlaps with habitats that were water dependent (e.g. habitat may have included riparian areas) so links were possible but difficult to prove. Assets listed with ‘habitat features not consistent with water dependency’ showed no water dependence in habitat requirements.

Only threatened species with modelled habitat data were included in the asset database. Therefore, a number of threatened species with known water dependency were not included, particularly the aquatic species. Negotiations have been underway to access models of these data from the relevant agencies. The data will be included in future products.

Water dependency of vegetation assets were assessed using the following rules:

  • Riparian vegetation were assumed to be water dependent.
  • Vegetation assets that intersected with local GDE data (NSW Department of Primary Industry (Office of Water), Dataset 14; DEHP, 2014b) and wetland data (NSW Office of Environment and Heritage 2001; DEHP, 2014c) were assumed to be water dependent.
  • All vegetation assets in the ‘Groundwater-dependent ecosystem’ class (Section 1.3.2) with a known groundwater dependency derived from previous field work or a high potential for groundwater dependency were assumed to be groundwater dependent and attributed as ‘likely’. Assets with a moderate potential for groundwater dependency were attributed as ‘possible’.

All vegetation assets that intersected with drainage lines that have some surface groundwater dependency (GDE lines) were considered water dependent. A preliminary version of the asset data register was created, with associated decisions on water dependence. The preliminary version, with associated maps and data, was presented to experts and organisations with local knowledge for comment and feedback at two workshops: Lismore in December 2014 for the NSW assets and Brisbane in January 2015 for the Queensland assets. As a result, further assets were added to the asset register and assessed for water dependence accordingly.

The characteristics of the groups of water‑dependent assets identified in the Clarence-Moreton bioregion, and the reasons for their inclusion or exclusion from the water‑dependent asset register, are described in Section 1.3.2, Section 1.3.3 and Section 1.3.4.

Last updated:
28 September 2018