122.—(1) In this section—

the word “mill” includes any factory, machine, building or other work by or for which water is taken or used for any purpose, but does not include any work for the generation, by means of hydraulic power, of electricity, for distribution and supply to the public;

the expression “wheel sluices”, in relation to a mill, means the sluices which admit water to the wheels of such mill.

(2) The following provisions shall apply in relation to every mill which derives its supply of water from a salmon river—

(a) in case there is a fish pass in the dam belonging to the mill, the wheel sluices and the waste gates or over-falls shall be kept shut,—

(i) for twenty-four consecutive hours in each week between the hour of 6 o'clock p.m. on Saturday and the hour of 6 o'clock a.m. on the next following Monday, and

(ii) during any other period when the mill is not being worked;

(b) in case there is no fish pass in the dam belonging to the mill and the waste gate on the upstream side of the wheel sluices is erected in a channel suitable for the passage of fish, the wheel sluices shall be kept shut and the said waste gate kept open—

(i) for twenty-four consecutive hours in each week between the hour of 6 o'clock p.m. on Saturday and the hour of 6 o'clock a.m. on the next following Monday, and

(ii) during any other period when the mill is not being worked;

(c) if the provisions of paragraph (a) or paragraph (b) of this subsection are not complied with, the occupier of the mill shall be guilty of an offence under this section and shall be liable on summary conviction thereof to a fine of not less than three pounds and not more than ten pounds.

(3) Where the occupier of a mill is charged with an offence under this section, it shall be a good defence to prove that compliance with paragraph (a) or paragraph (b) (whichever is applicable) of subsection (2) of this section would in any way have injuriously interfered with the machinery or water power of the mill.