Limitations lie in some parameters and the implementation of some stresses, such as localized and evapotranspiration, in the model. relevant inputs, such as and river stage, over the three reporting periods only reflect changes due to a single varying climate signal. Thus, the in the climate signal is not taken into account in the current analysis. In order to improve model stability and reduce model runtime for a feasible analysis, evapotranspiration was not explicitly simulated in the groundwater model. The estimated recharge component may compensate for the ignorance of evapotranspiration to some extent. Only the perennial reaches of the streams within the model domain were simulated directly using the River Package in MODFLOW. This simplification may underestimate stream recharge to the . The dual-phase flow process near CSG was not modelled in the current project. Previous studies have shown that the omitting of dual-phase flow overestimates , especially for prediction near CSG wells, depending on hydraulic properties, development plans and simulation time. For example, reported a drawdown overproduction of 15 m at a distance of 7 km from the well extraction centre at a simulation time of 20 years within the targeted coal seam in their model. The Assessment team believe that storage change due to CSG development is also overestimated to some extent, although the impact on water balance analysis was not directly investigated in these studies. In addition, assumptions, limitations and gaps listed in companion products 2.6.1 (surface water numerical modelling) and 2.6.2 (groundwater numerical modelling) for the also have an impact on water balance analysis.
Product Finalisation date
- 2.5.1 Methods
- 2.5.2 The water balances
- Contributors to the Technical Programme
- About this technical product