Catchment and water resource modelling are important tools for understanding current and future catchment processes, water requirements and assessing the effectiveness of management activities.  Generally, however, the two platforms are developed separately and rarely ‘talk’ to each other. The requirements of the ACT Government to improve their understanding of water quality, land use change, water resources and basin plan requirements within key ACT subcatchments as well as the wider Upper Murrumbidgee, were best answered through a combination of catchment and water resource modelling (Source platform).  The development of both models in conjunction with each other allowed for benefits of each modelling platform to be incorporated into the other. For example, flow routing calibrated in Source Rivers was applied to the Source catchments model to further improve flow calibration, and vice versa, the rainfall runoff parameters calibrated within Source catchments were used to infill gaps in the gauge record used as input into water resource model. This paper describes the benefits, limitations and potential future applications of combining catchment and water resource modelling.