The Australian Water Act 2007 defines watercourse as follows:
(a) means a river, creek or other natural watercourse (whether modified or not) in which water is contained or flows (whether permanently or from time to time); and
(i) a dam or reservoir that collects water flowing in a watercourse; and
(ii) a lake or wetland through which water flows; and
(iii) a channel into which the water of a watercourse has been diverted; and
(iv) part of a watercourse; and
(v) an estuary through which water flows.