; and (C) 10 feet from any other roads. (b) Setback exceptions (1) Well-defined topographical barriers If, between the road and the boundary of a setback area described in paragraph (2) or (3) of subsection (a), there is a well-defined cliff edge, stream bank, or other topographical barrier, the Secretary shall use the barrier as the wilderness boundary. (2) Fences If, between the road and the boundary of a setback area specified in paragraph (2) or (3) of subsection (a), there is a fence running parallel to a road, the Secretary shall use the fence as the wilderness boundary if, in the opinion of the Secretary, doing so would result in a more manageable boundary. (3) Deviations from setback areas (A) Exclusion of disturbances from wilderness boundaries In cases where there is an existing livestock development, dispersed camping area, borrow pit, or similar disturbance within 100 feet of a road that forms part of a wilderness boundary, the Secretary may delineate the boundary so as to exclude the disturbance from the wilderness area. (B) Limitation on exclusion of disturbances The Secretary shall make a boundary adjustment under subparagraph (A) only if the Secretary determines that doing so is consistent with wilderness management goals. (C) Deviations restricted to minimum necessary Any deviation under this paragraph from the setbacks required under in paragraph (2) or (3) of subsection (a) shall be the minimum necessary to exclude the disturbance. (c) Delineation within setback area The Secretary may delineate a wilderness boundary at a location within a setback under paragraph (2) or (3) of subsection (a) if, as determined by the Secretary, the delineation would enhance wilderness management goals. 206. Livestock Within the wilderness areas designated under title I, the grazing of livestock authorized on the date of enactment of this Act shall be permitted to continue subject to such reasonable regulations and procedures as the Secretary considers necessary, as long as the regulations and procedures are