The Australian landscape is characterised by floods and droughts, so that the form, flow patterns and structure of our rivers reflect the full range of discharge patterns from perennial to intermittent, through to ephemeral. However, legislative descriptions of 'river' are derived from a Eurocentric perspective. In New South Wales, the definition of a river is provided in the Rivers and Foreshores Improvement Act (1948) and the partially implemented Water Management Act (2000). The Rivers and Foreshores Improvement Act implies that a bona fide river should have perennial and intermittent flow. This is quite atypical of many lower order river systems in New South Wales which are normally ephemeral. Herein lies the issue. Development on or adjacent to a river is subject to specific restrictions. As a consequence, numerous disputes regarding the nature and definition of a 'watercourse' have arisen in both the Australian High Court and the NSW Land and Environment Court. This paper considers the utility of the legislative definition of 'river' and 'watercourse' with respect to a range of geomorphological parameters, human perceptions of, and relationships to, these vital natural resources.