Currently environmental water managers have limited capacity to consider ecosystem water requirements, and rely instead on the water requirements of key indicator species whose water requirements are both better understood and are believed to act as a reliable surrogate for ecosystem water requirements. The MDB EWKR project, by examining key ecosystem components (vegetation, fish, waterbirds and food webs) and the interdependencies among them, seeks to improve our capacity to predict ecosystem responses to environmental flows. Historically, researchers have focused on the development of detailed models that in some instances have been converted into Decision Support Tools. Adoption of these models has been relatively limited due to a number of issues; leaving managers without transparent of defensible means of either making trade-offs among watering priorities or ensuring that ecosystems are capable of sustaining their priority values (e.g. waterbirds, large native fish). Rather than develop a large complex model, the Murray-Darling Basin Knowledge and Research (MDB EWKR) Project is seeking to develop frameworks that will guide the application of both existing and new models to the task of predicting ecosystem responses to environmental flows. The MDB EWKR project will seek to develop one framework for consideration of landscape scale responses to flow regimes and a second to consider ecosystem responses to individual flows. It is hoped that this approach will increase the utility of existing knowledge in supporting decision making by providing a framework by which relevant information can be identified, adapted and applied to a greater variety of systems and situations.