Phantom Ranch, the only lodge within the Grand Canyon, has drawn adventurers and dignitaries, including Theodore Roosevelt, for more than a century.

© Craig Sanderson, via Associated Press

The uncertainty stretches across seven U.S. states, tribal nations and Mexico.

Under the Bureau of Reclamation's plan, California, Nevada and Arizona will collectively reduce water use by 1.25 million acre-feet annually for the next two years, with the possibility of larger cuts depending on conditions.