; (2) a watershed that supplies a public drinking water system; (3) the habitat of a threatened, endangered, or sensitive fish or wildlife species, or species of conservation concern; or (4) a watershed for which the Secretary has completed a watershed protection and restoration action plan pursuant to section 304 of the Healthy Forests Restoration Act ( 16 U.S.C. 6543 ). (f) National forest system Except with respect to a project carried out on a watershed for which the Secretary has a cooperative agreement under section 323 of the Department of the Interior and Related Agencies Appropriations Act, 1999 ( 16 U.S.C. 1011a ), each project carried out under this section shall be on a National Forest System road or trail. (g) Identification of minimum road systems Not later than 3 years after the date of enactment of this section, the Secretary shall identify, for each unit of the National Forest System, the minimum road system and unneeded roads in accordance with section 212.5(b) of title 36, Code of Federal Regulations (as in effect on the date of enactment of this Act). (h) Unneeded roads The Secretary shall decommission any roads identified as unneeded under subsection (g) as soon as practicable after making the identification under that subsection. (i) Review; revision The Secretary shall review, and may revise, an identification made under subsection (g) for a unit of the National Forest System during a revision of the land and resource management plan applicable to that unit. (j) Authorization of appropriations There is authorized to be appropriated to carry out this section $100,000,000 for each of fiscal years 2020 through 2030. .