The qualitative uncertainty analysis in Section lists the major assumptions and model choices that form the basis of the probabilistic assessment of the impacts of coal resource development on groundwater model nodes in the Namoi subregion. Within the context of the goal of the Bioregional Assessment Programme, the Namoi subregion modelling team deemed these assumptions valid and acceptable. There is no guarantee, however, that these assumptions will hold or be acceptable to address any other water management questions in the subregion; therefore, the modelling team recommends not using these models for any other purpose without a formal assessment of the suitability of the conceptualisation, parameterisation and implementation for the changed objective.

Should these models be considered for any other purpose, there should be a formal re-evaluation of the suitability of the conceptual model and model assumptions, in line with the Australian groundwater modelling guidelines (Barnett et al., 2012). All model files and executables are available at www.bioregionalassessments.gov.au. It is recommended to contact the model development team for detailed information on the groundwater models.

The chain of models described in this product is designed to estimate impacts on a regional scale. This unfortunately means trade-offs are made in terms of local resolution of the model. Especially in the immediate vicinity of coal mines, the effect of coal mining activity will be largely dominated by local variations in geology and hydrogeology. The reliability of any predictions made by this model will be inferior to the reliability of predictions made by a local groundwater model that fully accounts for this level of detail.

The models are designed within a probabilistic framework. This implies there is not a single parameter combination that provides a ‘best fit’ to observations and a corresponding single set of predictions. Any evaluation or further use of both the parameter combinations used in the models or the predictions need to take into account the full posterior distributions reported in Section Input data, model files, (including the pre- and post-processing scripts and executables) and results are available at www.bioregionalassessments.gov.au.

The utmost care has been devoted to ensuring the results presented are in accordance with the conceptual understanding of the system and the stresses imposed on it. This is mostly done by targeted spot checks of model outputs and visual examination of the response of model outputs to varying parameter values. While these checks minimise the risk that artefacts have gone undetected, as in any modelling exercise of this scale, there is no guarantee that there are no artefacts of modelling included in the results.

Last updated:
6 December 2018
Thumbnail of the Namoi subregion

Product Finalisation date