2.6.2 Groundwater numerical modelling

The products on groundwater numerical modelling present potential changes in groundwater due to coal resource development in bioregions or subregions. The products also describe uncertainties in model outputs.

Groundwater modelling predicts the difference between groundwater levels in two potential futures:

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

The difference in results for these possible futures is due to the additional coal resource development –all coal mines and coal seam gas fields, including expansions of baseline operations, that are expected to begin commercial production after December 2012.

Groundwater numerical models were chosen depending on data and model availability.

Relationship to other products

Results from groundwater modelling were used as inputs for receptor impact modelling (product 2.7), where resulting changes to key characteristics in the landscape or water-dependent assets were estimated.

Predictions from groundwater numerical modelling and receptor impact modelling are further considered in the impact and risk analysis (product 3-4), which examines the risks to, and potential impacts on, water resources and water-dependent assets of coal seam gas or coal mining developments.