Background and context

Receptor impact modelling attempts to capture the direct, indirect and cumulative impacts of coal seam gas (CSG) and coal mining development on the ecosystems within the defined landscape classes. The aim of receptor impact modelling is to convert the potentially abstract information about hydrological changes into predictions about impacts on values (risk assessment endpoints) that ideally stakeholders care about and can more readily understand and interpret. The receptor impact models should therefore support community discussion and decision making about acceptable levels of development.

The causal pathways that describe how coal resource development can lead to changes in hydrology are identified in companion product 2.3 for the Hunter subregion (Dawes et al., 2018). The receptor impact models represent the subsequent pathways, which relate changes in hydrological response variables to potential impacts on water-dependent landscape classes and assets within the zone of potential hydrological change.

To better understand the potential impacts of coal resource development on water resources and water-dependent assets such as wetlands and groundwater bores, receptor impact modelling for BAs deals with two potential futures:

  • baseline coal resource development (baseline), a future that includes all coal mines and CSG fields that are commercially producing as of December 2012
  • coal resource development pathway (CRDP), a future that includes all coal mines and CSG fields that are in the baseline as well as those that are expected to begin commercial production after December 2012.

The difference in results between CRDP and baseline is the change that is primarily reported in a BA. This change is due to the additional coal resource development – all coal mines and CSG fields, including expansions of baseline operations that are expected to begin commercial production after December 2012. In receptor impact modelling, however, the critical change is the difference between average groundwater and surface water conditions in the reference period (1983 to 2012), and their predicted average conditions under the baseline and the CRDP in the short term (2013 to 2042) and longer term (2073 to 2102).

This product presents the receptor impact modelling for the Hunter subregion. The modelling is described in detail in companion submethodology M08 (as listed in Table 1) for receptor impact modelling (Hosack et al., 2018). Section of this document describes how this methodology is applied to the Hunter subregion.

The following terms are used throughout the receptor impact model products to describe the modelling process and its results:

  • hydrological response variable – a hydrological characteristic of the system (for example, drawdown or the annual flow volume) that potentially changes due to coal resource development (see companion submethodology M07 (as listed in Table 1) for groundwater modelling (Crosbie et al., 2016) and companion submethodology M06 (as listed in Table 1) for surface water modelling (Viney, 2016)).
  • receptor impact variable – a characteristic of the system that, according to the conceptual modelling, potentially changes due to changes in hydrological response variables (for example, condition of the breeding habitat for a given species, or biomass of river red gums)
  • receptor impact model – a receptor impact model predicts a relationship between a receptor impact variable (for example annual mean percent canopy cover of woody riparian vegetation), and one or more hydrological response variables (for example, dmax, maximum groundwater drawdown due to additional coal resource development).
Last updated:
18 January 2019
Thumbnail of the Hunter subregion

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