For wild and scenic rivers flowing through federal lands, how does the comprehensive management plan (CRMP) relate to the river-administering agency’s unit-wide management plan (e.g., BLM RMP, NPS's GMP, FWS's CCP, USFS's RMP)?

The requirements specified for a CRMP in Section 3(d)(1) are most often developed through a separate-in-time planning process. This can result in either an amendment to the direction in the agency’s unit-wide plan o a stand-alone plan, depending on agency practices. For designated rivers that are separate NPS units, the CRMP is the General Management Plan (e.g., St. Croix National Scenic Riverway).

Source
Interagency Wild & Scenic Rivers Council