Developing causal pathways

The approach undertaken in the Hunter subregion closely follows the process laid out in the companion submethodology M05 (as listed in Table 1) for developing a conceptual model of causal pathways (Henderson et al., 2016).

The key system components, processes and interactions for the geology, hydrogeology and surface water of the subregion were synthesised based on contextual information provided in companion product 1.1 for the Hunter subregion (McVicar et al., 2015) and in conjunction with the development of the companion products for surface water modelling (companion product 2.6.1 (Zhang et al., 2018)), groundwater modelling (companion product 2.6.2 (Herron et al., 2018c) and water balance assessment (companion product 2.5 (Herron et al., 2018a)) for the Hunter subregion.

The geological conceptualisation is based on the geological model developed by the Assessment team for the Hunter subregion (see companion product 2.1-2.2 for the Hunter subregion (Herron et al., 2018b)). A landscape classification was chosen that reflects the water dependence of the main biophysical and human ecosystems of the subregion.

Coal mining has occurred within the Hunter subregion for more than a century. Existing (as of May 2015) and potential new coal resource developments in the Hunter subregion are detailed in companion product 1.2 for the Hunter subregion (Hodgkinson et al., 2015). The list of potential new developments (including expansions to existing operations) identified in this product were presented to the Independent Expert Scientific Committee on Coal Seam Gas and Large Coal Mining Development (IESC) in March 2015 and approved as the basis for defining the additional coal resource developments in the bioregional assessment (BA) for the Hunter subregion. This list was subsequently reviewed and discussed with representatives from mining companies with operations in the subregion at a workshop in Singleton in August 2015. Discussions were focused on knowledge gaps and uncertainties identified by the Assessment team. A revised list of additional coal resource developments was generated based on feedback obtained at the workshop and follow-up conversations with some mining companies.

There are no CSG developments currently operating, approved, or under consideration in the Hunter subregion.

A hazard analysis workshop for the Hunter subregion was undertaken in April 2015 with a small group of hydrological, geological and coal mining experts present from CSIRO, Geoscience Australia and the NSW Department of Primary Industries Water. The hazards were prioritised and subsequently aggregated by common impact causes to a reduced set of causal pathways for baseline and CRDP. No causal pathways or hazards associated with CSG developments are evaluated in this BA.

A conceptual modelling workshop for the Hunter subregion was held in Newcastle in August 2015 to socialise and discuss the modelling approach for the BA for the Hunter subregion with mining company, state agency and local government representatives. It was an opportunity to:

  • test the Assessment team’s regional-scale conceptual understanding of the Hunter subregion with local experts
  • present results from the hazard analysis and describe the approach to classifying hazards into the main causal pathway groups
  • explain how this conceptualisation of system components, processes and interactions is reflected in the numerical surface water and groundwater models
  • introduce the landscape classification approach for grouping water-dependent assets into hydrologically-similar ecosystem groupings, to simplify the impacts analysis
  • for each of the foregoing, provide external stakeholders with the opportunity to share their knowledge, comment on the Assessment team’s approach, raise issues of concern (e.g. representation of local-scale features in regional models) and respond to questions from the Assessment team.
Last updated:
18 January 2019