may cause a F1screen or F1screens of such form and dimensions as F7it may determine to be placed and maintained, at the F8expense of the appropriate agency, at a suitable place in any watercourse, mill race, cut, leat, conduit or other channel for conveying water for any purpose from any waters frequented by salmon or migratory trout; and

may cause any watercourse, mill race, cut, leat, conduit or other channel in which a F1screen is placed under this section to be widened or deepened at the F9expense of the appropriate agency so far as may be necessary to compensate for the diminution of any flow of water caused by the placing of the F1screen, or shall take some other means to prevent the flow of water being prejudicially diminished or otherwise injured.

injures any such F1screen; or

removed any such F1screen or part of any such F1screen, except during any period of the year during which under a byelaw F1screens need not be maintained; or

opens any such F1screen improperly; or

permits any such F1screen to be injured, or removed, except as aforesaid, or improperly opened;

affect the liability under this Act of any person to place and maintain a F1screen; or

authorise a F1screen to be so placed or maintained during any period of the year during which under a byelaw F1screens need not be maintained; or

authorise any F1screen to be placed or maintained so as to obstruct any conduit or channel used for navigation or in any way interfere with the effective working of any mill;