58Drainage and river authorities not to be harbour authorities for purposes of this Act if not possessing exceptional powers
For the purposes of this Act neither an internal drainage board (within the meaning of the Land Drainage Act 1930), a river board, a river authority, a river purification authority, a district board, an improvement committee, the Conservators of the River Thames nor the Lee Conservancy Catchment Board shall be taken to be a harbour authority if, apart from this provision, they would only be taken to be such by reason of the fact that river works powers or duties are vested in them; and any reference in this Act to functions of a harbour authority relating to a harbour shall be construed as not including a reference to such powers or duties.