acres, as generally depicted on the map, which shall be known as the Belmont Mountains Wilderness . (4) Saddle mountain centennial wilderness Certain public land in Maricopa County, Arizona, comprising approximately 24,200 acres, as generally depicted on the map, which shall be known as the Saddle Mountain Centennial Wilderness . (5) Gila bend wilderness Certain public land in Maricopa County, Arizona, comprising approximately 68,800 acres, as generally depicted on the map, which shall be known as the Gila Bend Wilderness . (6) Sonoran desert national monument wilderness Certain public land in Maricopa County, Arizona, within the Sonoran Desert National Monument, comprising approximately 128,300 acres, as generally depicted on the map, which shall be known as the Sonoran Desert National Monument Wilderness . (b) Administration of wilderness Subject to valid existing rights, the Wilderness Areas designated by this Act shall be managed by the Secretary in accordance with the Wilderness Act ( 16 U.S.C. 1131 et seq.) and this Act, except that— (1) any reference in the Wilderness Act to the effective date of that Act shall be considered to be a reference to the date of enactment of this Act