In the subcommittee-approved bill, we had achieved a signal goal: the entire river was under the administration of NPS at Grand Canyon. From the Paria to the Grand Wash Cliffs, from shore to shore, there was to be one management. We did not know why the Hualapai did not contest this; perhaps they were too focussed on their dam. We did know that NPS did not like having the "slack-water" from mile 238.5 to the Grand Wash Cliffs in the Park, as a matter of their "professional assessment", a position repeated in a 6 Mar letter to McComb. It might make sense, NPS suggested, if the reservoir's water level were stabilized, a "highly unlikely" condition. So they talked of "creative management". However, the regional director rejected the plan of LMNRA assuming some of the management, since there had been strong public input for single management -- which may have meant that he remembered Goldwater's Dec 1972 statement of desire for unified administration. Eventually, though, the superintendents involved eroded this position in favor of Lake Mead NRA having an important say in the lower Canyon along with the Park. That remains true today, even as the reservoir level has dropped so far that it no longer reaches the Canyon itself. Moreover, NPS has pursued a policy of trying to work with the Hualapai on river matters, giving them a say rather than insisting on the boundary matter as primary. It could be argued that the 1975 Act godfathered what has evolved: joint use and rule-making in fact. Had the Grand Canyon Wilderness been created in the late 1970's, Congress could have settled the management issue more definitively depending whether it included the slack-water in the Wilderness, or left it out, or hedged it about with conditions.
What we can take comfort in, regardless of the not-always-easy administrative relations, is that the entire river is inside the Park boundary.