What is the process to amend a segment division of a wild and scenic river?

The need to amend a segment division should be identified as a management concern/public issue during the planning process and considered in establishment of the initial boundary. The proposed amendment associated with establishment of initial boundaries must be undertaken with full public input and disclosure and is often completed during development of the comprehensive river management plan (CRMP) as a basis to make a recommendation to Congress to amend the Wild & Scenic Rivers Act.

The river-administering agency can only recommend such a change to Congress. A subsequent amendment to the Wild & Scenic Rivers Act would be drafted by the agency after notice of the initial boundary or amended boundary is published in the Federal Register and the 90-day congressional review period has concluded.

Source
Interagency Wild & Scenic Rivers Council