16 U.S. Code § 541d - Acquisition of property within the scenic-research area; consent of owner; substantial change in use or maintenance of property
Subject to the provisions of subsection (b) of this subsection, the Secretary is authorized to acquire lands, waters, or interests therein within the Area by donation, purchase, exchange, or otherwise.
Within all subareas of the Area except the estuary and associated wetlands subarea, the Secretary may not acquire any land or interest in land without the consent of the owner or owners so long as the owner or owners use such land for substantially the same purposes and in the same manner as it was used and maintained on June 1, 1974:
At least thirty days prior to any substantial change in the use or maintenance of any non-federally-owned land within the Area, the owner or owners of such land shall provide notice of such proposed change to the Secretary or his designee, in accordance with such guidelines as the Secretary may establish.
 So in original. Probably should be “section,”.