503Interpretation

1. In this Part, unless the context otherwise requires,—

   council means a territorial authority

   district means the district of a territorial authority

   drainage area means any area constituted under this Part for land drainage purposes

   drainage channel or channel means every passage or channel on or under the ground through which water flows, continuously or otherwise, and which—but does not include a navigable river, a water race as defined in section 422, or a drain as defined in section 441 or section 471

   1. immediately before the commencement of this Part was a drainage channel under the control, as such, of any council; or
   2. is constructed by the council as a drainage channel after the commencement of this Part; or
   3. is vested in the council as a drainage channel;—

   land drainage works means works of any sort for the drainage of land in the district (being works vested in the council or acquired or constructed or operated by or under the control of the council under this Part), including drainage channels for receiving water in its natural flow on or from any hills or other lands, and works diverting or damming the same to prevent its overflow on to any other lands at a lower level, as well as drainage channels for carrying off water from any land.