(1)In this Part—
“banks” means banks, walls or embankments adjoining or confining, or constructed for the purposes of or in connection with, any channel or sea front, and includes all land and water between the bank and low-watermark;
“drainage” includes—
defence against water, including sea water;
irrigation other than spray irrigation; and
warping;
“flood defence” means the drainage of land and the provision of flood warning systems;
“main river” (subject to section 137(4) below) means a watercourse shown as such on a main river map and includes any structure or appliance for controlling or regulating the flow of water into, in or out of the channel which—
is a structure or appliance situated in the channel or in any part of the banks of the channel; and
is not a structure or appliance vested in or controlled by an internal drainage board;
“watercourse” shall be construed as if for the words from “except” onwards in the definition in section 221(1) below there were substituted the words “except a public sewer”.
(2)If any question arises under this Part—
(a)whether any work is a drainage work in connection with a main river; or
(b)whether any proposed work will, if constructed, be such a drainage work,
the question shall be referred to one of the Ministers for decision or, if either of the parties so requires, to arbitration.
(3)Where any question is required under subsection (2) above to be referred to arbitration it shall be referred to the arbitration of a single arbitrator appointed—
(a)by agreement between the parties; or
(b)in default of agreement, by the President of the Institution of Civil Engineers, on the application of either party.
(4)Nothing in this Part shall affect the powers exercisable by the Authority under any local Act, as they existed immediately before the coming into force of this Act.