Mitigation of, or adaptation to, dryland salinity will require large-scale changes in land and water use. Analysis of the problem requires the simultaneous observation of hydrological processes, which drive salinisation, and economic conditions, which influence the decisions of land managers. Given the long-term nature of the salinity problem, the time lags involved and the very large number of possible land-use combinations for a particular catchment, it is necessary to resort to modelling as a decision tool and for policy analysis . This paper presents suggestions for combining hydrology and economic models . A simple model of a catchment is developed and used to identify minimum data requirements. Questions regarding model design and implementation are raised and the advantages and disadvantages of different approaches are discussed.