Increasing pressures on water resources and associated cuts in allocation currently threaten many irrigators in the Namoi River catchment. In particular, cuts to groundwater allocation in many zones are expected to have significant negative social and economic impacts. Changed access to off-allocation water has been seen by many in the catchment as one possibility for mediating the impacts of these cuts. This paper discusses water allocation problems in the Namoi River catchment and the way in which off-allocation water may be utilised under various management strategies. A conceptual framework for an integrated economic and hydrological model for considering these options is developed, and details of the economic module are presented.