Where the land described in application (or such an application as adjusted or amended pursuant to subsection (b) or (c) of this section), was on that date withdrawn, reserved, or classified for powersite or power-project purposes, notwithstanding such withdrawal, reservation, or classification the described land shall be deemed vacant, unappropriated, and unreserved within the meaning of the Acts referred to in subsection (a)(1) of this section, and, as such, shall be subject to adjudication or approval pursuant to the terms of this section: Provided, however, That if the described land is included as part of a project licensed under part I of the Federal Power Act of June 10, 1920 (
41 Stat. 24), as amended [
16 U.S.C.
791a et seq.], or is presently utilized for purposes of generating or transmitting electrical power or for any other project authorized by Act of Congress, the foregoing provision shall not apply and the application shall be adjudicated pursuant to the appropriate Act: Provided further, That where the applicant commenced occupancy of the land after its withdrawal or classification for powersite purposes, the entry shall be made subject to the right of reentry provided the United States by section 24 of the Federal Power Act, as amended [
16 U.S.C.
818]: Provided further, That any right of reentry reserved in a patent pursuant to this section shall expire twenty years after the effective date of this Act if at that time the land involved is not subject to a license or an application for a license under part I of the Federal Power Act, as amended, or actually utilized or being developed for a purpose authorized by that Act, as amended [
16 U.S.C.
791a et seq.] or other Act of Congress.