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 be potentially impacted by changes in the groundwater or surface water regime due to coal resource development were identified. While the vast majority of the assets will be clearly 'water dependent' in the general sense of the phrase (e.g. groundwater bores, rivers and wetlands), there is a small group of assets that could be affected but are not as readily identified as being ‘water dependent’. Examples of these assets include historic buildings that may be potentially subject to added inundation or salinity impacts, or Indigenous assets that may be more difficult to access due to changes in the water regime.

It is important to emphasise that BAs consider the potential impact to the habitat of species not the individual species per se. However, it is necessary to present species-based information to best reflect the available data; but implicit in this is the focus on habitat.

The water dependency of threatened species assets or habitats was assessed by a review of the habitat requirements for each species. In most cases profiles from the Species Profile and Threats Database (SPRAT; Department of the Environment, 2012; Australian Government Department of the Environment, Dataset 10) were examined. The water dependence of each species-related asset was ranked as being ‘likely’, ‘possible’, ‘unlikely’ or ‘unsure’. Assets listed as ‘likely’ are those with a clear and demonstrated link to aquatic ecosystems, (e.g. aquatic species). Assets listed as ‘possible’ may have some overlap with habitats that may be water dependent (e.g. species that may visit riparian areas). Assets listed as ‘unlikely’ show no water dependence in habitat requirements.

Species listed under NSW’s Threatened Species and Conservation Act 1995 for areas covering the former Namoi and Border Rivers-Gwydir CMAs were considered for inclusion in the asset database. However, there is currently insufficient habitat modelling information to make definitive determinations of:

  • their occurrence within the PAE
  • habitat requirements occurring within the PAE.

Similarly, listed aquatic species from Table 17 of Welsh et al. (2014) are included in the asset database.

As there was no available spatial information related to the distribution of assets associated with species and their associated habitats, they are recognised as being ‘potential’ assets but require further investigations before they can be included in the water‑dependent asset register.

A preliminary assessment of the water dependency of vegetation assets was made using the following rules:

  • Riparian vegetation was assumed to be water dependent (attributed as ‘likely’).
  • Vegetation assets that intersect with the maximum floodplain extent were assumed to be water dependent (attributed as ‘likely’).
  • Vegetation assets outside the maximum floodplain extent mapping, where groundwater was less than 10 m from the surface were assumed to be water dependent (attributed as ‘likely’).
  • Vegetation assets derived from the ‘Groundwater-dependent ecosystem’ class with a known groundwater dependency derived from previous field work or a high potential for groundwater dependency were assumed to be groundwater dependent (attributed as ‘likely’). Assets with a moderate potential for groundwater dependency were attributed as possible. Vegetation assets sourced from the Atlas of groundwater dependent ecosystems (Bureau of Meteorology, 2012) with a low probability for groundwater dependence were given an attribution of ‘unlikely’.

All assets in the ‘Surface water feature’ and ‘Groundwater feature (subsurface)’ classes of the asset database were assumed to be water‑dependent assets and attributed as ‘likely’.

Assets attributed as ‘likely’ or ‘possible’ are considered further in the bioregional assessment and flagged as ‘yes’ with respect to water dependency in the asset database; assets attributed as ‘unlikely’ are flagged as ‘no’ in the asset database and are not considered further in the bioregional assessment.

Once water dependence was determined, and the decisions recorded in the asset database, a preliminary version of the water‑dependent asset register was generated from the asset database. The preliminary version of the water‑dependent asset register, with associated maps and data, was presented to experts and organisations with local knowledge at a workshop in Gunnedah in July 2014 for comment and feedback. Further economic assets were identified: water licences that do not require a works approval and therefore do not include a specific location and surface water storages used for flood plain harvesting. These additional economic assets are further discussed in Section No additional ecological or sociocultural assets were suggested by the attendees.

The characteristics of the groups of water‑dependent assets identified in the Namoi subregion, 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.

The water‑dependent asset register is a simple and authoritative listing of the names of the assets that will be included in other components of the BA; all the spatial and other data associated with each asset (including for each element) is stored in the asset database. Other BA components are described in the BA methodology (Barrett et al., 2013) and the pending companion submethodologies including M03 (as listed in Table 1) for assigning receptors to water-dependent assets.

Last updated:
6 December 2018