This section creates powers for any person authorised by the Department to enter land for the purposes of carrying out its functions under the Act. The power to enter land includes a power to enter buildings and other structures, integral to the functioning of the reservoir, by virtue of the definition of ‘land’ in the Interpretation Act (Northern Ireland) 1954. Subsection (1) specifies the land which may be entered and subsection (2) specifies the purposes for entry on to such land.