3. Where the abstraction, diversion and use will, in the opinion of the Department of the Environment—N.I.
(a)substantially reduce the flow of water in any waterway, that Department shall in the authorisation specify the extent to which and the circumstances in which water may be taken;
(b)substantially reduce the level of water in any waterway, that Department shall in the authorisation either—
(i)specify the extent to which and the circumstances in which water may be taken; or
(ii)specify the quantity of compensation water to be provided by the person;
(c)impound any waterway, that Department shall in the authorisation specify the quantity of compensation water to be provided by the person.