2.6.2.1 Methods

Summary

A regional numerical MODFLOW groundwater model was developed to assess the impacts of the additional coal resource development on water-dependent assets within and surrounding the extents of the additional coal resource development in the Clarence-Moreton bioregion. The impact is quantified as the change in predefined hydrological response variables, namely, drawdown due to additional coal resource development (additional drawdown), year of maximum change, and surface water – groundwater flux at a number of locations. The changes in these variables are presented probabilistically using a formal uncertainty analysis method. The groundwater model was coupled with the Australian Water Resources Assessment (AWRA) landscape model (AWRA-L) to assess the indirect impacts of the additional coal resource development on hydrological variables associated with surface water systems through baseflow changes as a result of coal seam gas (CSG) extraction.