The Australian government is undertaking a program of bioregional assessments (BAs) in order to better understand the potential impacts of coal seam gas (CSG) and large coal mining developments on water resources and water-related assets. The aim of the program is to strengthen the science underpinning decision making on CSG and large coal mining developments. A key component of this work is in providing credible, consistent estimates of the impact of CSG and coal mining developments on river flows. The aim of surface water modelling in bioregional assessments is to provide information on flow characteristics at locations in the stream networks that are relevant for key assets and receptors. In particular, the modelling needs to account for changes in flow regime that relate directly to the impacts of future coal mining and coal seam gas extraction. This paper reviews some of the candidate models for achieving these outcomes and outlines some of the practical considerations behind the resulting choice of modelling tools. AWRA-L and AWRA-R have been chosen as the modelling tools to generate these river flow responses. Fluxes from the landscape (predominantly surface runoff, interflow and baseflow) are modelled using AWRA-L. These fluxes are then accumulated and routed through the river network using AWRA-R.