43 CFR § 423.60 - How special use areas are designated.
(1) Establish special use areas within Reclamation facilities, lands, or waterbodies for application of reasonable schedules of visiting hours; public use limits; and other conditions, restrictions, allowances, or prohibitions on particular uses or activities that vary from the provisions of subpart C of this part 423, except § 423.28; and
(2) From time to time revise the boundaries of a previously designated special use area and revise or terminate previously imposed schedules of visiting hours; public use limits; and other conditions, restrictions, allowances, or prohibitions on a use or activity.
(1) The protection of public health and safety;
(2) The protection and preservation of cultural and natural resources;
(3) The protection of environmental and scenic values, scientific research, the security of Reclamation facilities, the avoidance of conflict among visitor use activities; or
(4) Other reasons in the public interest.
(c) An authorized official establishing a special use area must document in writing the determination described in paragraph (b) of this section. Such documentation must occur before the action, except in emergencies or situations of immediate need as described in § 423.61(c), in which case the documentation is required within 30 days after the date of the action. Reclamation will make documents produced under this section available to the public upon request except where such disclosure could compromise national or facility security, or human safety.