The Electricity (Northern Ireland) Order 1992

5.  In deciding whether to give the authorisation or in specifying the quantity of any compensation water to be provided under the authorisation, the Department of the Environment shall have regard to all the circumstances of the particular case, including—

(a) the interest of public health;

(b) the character of the waterway, and the flow, or as the case may be the level, of water in it;

(c) the extent to which the waterway is, or may in future be, used for industrial purposes or for the purposes of any public undertaking or for fisheries, water supply, agriculture, transport and navigation; and

(d) the effect on land drainage or on any canal or inland navigation of any alteration in the flow or level of water in the waterway,

and shall secure, so far as practicable, the protection of the rights of riparian owners and of other owners of land or fishings.