Modelling the impacts of future coal mining and coal seam gas extraction on river flows: A methodological framework

This manuscript outlines a methodological framework for modelling the hydrological impacts of future coal mining and coal seam gas extraction. Such impacts potentially include changes to both high flow and low flow characteristics such as total volume, high flow rate and frequency, low flow rate and frequency, and cease to flow frequency. In particular, the manuscript proposes a methodology that is suitable for the prediction of cumulative impacts from multiple coal resource developments and for making such predictions at multiple locations in the landscape. The proposed methodology is framed in terms of a structured uncertainty analysis to provide information on the likelihood and potential ranges of various impacts. The approach can be applied under a wide range of data availability, even when there is little to no observed data, whilst additional data can easily be incorporated to better constrain the results. The assessments thus derived can provide regulators with crucial objective information on the potential social, economic, environmental and ecological risks of future developments. Whilst discussed here in terms of coal resource development, this methodology has the potential to be readily adapted and applied to a range of extractive industries, including but not limited to minerals and other sources of unconventional gas. As it stands, the methodology does not explicitly consider impacts on water quality, but could be extended to include this if required.