(a) In determining whether the proposed hydroelectric project is best adapted to a comprehensive plan under section (10)(a)(1) of the Federal Power Act for improving or developing a waterway, the Commission will consider the extent to which the project is consistent with a comprehensive plan (where one exists) for improving, developing, or conserving a waterway or waterways affected by the project that is prepared by:

(1) An agency established pursuant to Federal law that has the authority to prepare such a plan, or

(2) A state agency, of the state in which the facility is or will be located, authorized to conduct such planning pursuant to state law.

(b) The Commission will treat as a state or Federal comprehensive plan a plan that:

(1) Is a comprehensive study of one or more of the beneficial uses of a waterway or waterways;

(2) Includes a description of the standards applied, the data relied upon, and the methodology used in preparing the plan; and

(3) Is filed with the Secretary of the Commission.