The Department of Forestry¹ is hereby authorized, in its discretion, to grant the right to occupy and use any portions of the State forests for use as sites for dams, other water obstructions, reservoirs, canals, pipe lines, and other water conduits, for supplying water otherwise than for steam condensation. Every such grant shall be on such terms, conditions, and stipulations as the department shall deem necessary for the protection of the present and future interests of the Commonwealth and its people, and suitable for affording a reasonable opportunity for a fair return on the actual investment, prudently made, on the faith of such grant.