In 1971 Dr HJ Firth wrote - 'the Murray- Darling system, in addition to being the greatest river Basin in the land, is one of the greatest and most complex problems of resource conservation and management. &quote; If you can't measure it you can't manage it! If you don't know how it functions you can't manage it! If the laws, institutions and governance arrangements act as barriers then you can't manage it! If you don't understand the relationships between the many human and natural resource components of a catchment, then management interventions may have unintended consequences! If people don't know what to do don't care or won't act then change cannot be managed If you reflect on these five statements it is possible to begin to comprehend the inherent risks and opportunities we face in managing our national heritage - the Murray Darling Basin. Perhaps the first being that while we all want a healthy Basin, we can rarely agree on how much data and understanding is required, what the appropriate institutional arrangements might be and what mechanisms and incentives should be employed to motivate individuals to change!