For the Bioregional Assessment Programme, a GW is developed to probabilistically estimate the hydrological change due to coal resource development in the . The model provides the change in – groundwater flux that is integrated in the surface water model, AWRA-L, which is reported in companion product 2.6.1 for the Galilee subregion ().
The simulations indicate that the maximum in the upper Permian coal measures extends far into the Galilee Basin, with probabilities of exceeding 5 m drawdown in excess of 30% 50 km west of the coal mines. The Rewan Group acts as a regional seal that impedes upwards propagation of drawdown from upper Permian coal measures into the overlying Clematis Group and Eromanga Basin.
The Cenozoic cover and alluvial sediments are modelled as laterally infinite and continuous. As illustrated by the analysis, drawdowns in this hydrostratigraphic unit are controlled by the direct of water from this unit and to a much lesser extent by the extraction of water from the upper Permian coal measures. Drawdowns are specified as smaller or equal to 10 m. The probability of exceeding 0.2 m drawdown generally drops below 5% from about 25 km from the edge of the mine footprints.
Simulated drawdowns in the Clematis Group are the result of propagation of drawdown from the Cenozoic aquifer layer, which requires the system to be laterally continuous between the mines and the Clematis Group outcrop area.
The change in surface water – groundwater flux includes the change in to the Belyando River and the evapotranspiration by vegetation. The maximum change is less than 1% of the baseflow estimated for the Belyando River, estimated in companion product 2.1-2.2 for the Galilee subregion (). In companion product 2.6.1 for the Galilee subregion () this change in surface water – groundwater flux is integrated with the total streamflow to estimate the change in selected aspects of the hydrograph, summarised in .
Companion product 3-4 () for the Galilee subregion reports on, and to, and arising from the simulated changes in groundwater and surface water reported in this product and in companion product 2.6.1 for the Galilee subregion ().
The greatest potential in reducing the predictive lies in improved characterisation of the surface water – groundwater interaction and the Cenozoic and alluvial aquifer systems. Further development of the numerical MODFLOW model (as outlined in Turvey et al., 2015), including its integration into a probabilistic framework, has great potential to improve the current predictions.
Product Finalisation date
- 22.214.171.124 Methods
- 126.96.36.199 Review of existing models
- 188.8.131.52.1 Alpha and Kevin's Corner model review
- 184.108.40.206.2 Carmichael model review
- 220.127.116.11.3 China First model review
- 18.104.22.168.4 China Stone model review
- 22.214.171.124.5 South Galilee model review
- 126.96.36.199.6 Galilee Basin hydrogeological model review
- 188.8.131.52.7 Suitability of existing groundwater models
- 184.108.40.206 Model development
- 220.127.116.11 Boundary and initial conditions
- 18.104.22.168 Implementation of the coal resource development pathway
- 22.214.171.124 Parameterisation
- 126.96.36.199 Observations and predictions
- 188.8.131.52 Uncertainty analysis
- 184.108.40.206 Limitations and conclusions
- Currency of scientific results
- Contributors to the Technical Programme
- About this technical product