Towards integrated modelling in the Murray-Darling Basin

The Murray-Darling Basin is characterised by low but highly variable rainfall and surface runoff and a high level of surface water use. Regulation has altered the stream flow pattern dramatically, affecting river dependent ecosystems. Responsibility for land and water management is fragmented, producing varying (and sometimes disparate) policies, management, and modelling approaches. The Murray-Darling Basin Commission coordinates common strategies to cap further stream flow diversion, improve river ecology, and address stream salinity, nutrient pollution and algal blooms. Several risks to future water resources have been identified. Climate change and farm dam development are the most important, but others include reforestation, bushfire recovery, groundwater extraction, irrigation water management, and perhaps changed cropping patterns and a developing water trade market. The processes underlying these risks often interact, affect ecosystems and economies in different ways, and have implications for several strategies and policies. Therefore, a capacity for integrated assessment or a ‘systems approach’ is needed. In this paper, we describe the characteristics of the system we model, some of the questions we want to answer, issues encountered in developing an integrated modelling framework, and a roadmap for further development.