At best, it forms the CA/AZ border. the water rights for the Colorado river are a hot topic among those states and should be carefully managed.
Not the Mexican states, of course, they get shafted. It’s wild how they just divert the water right at the AZ/Mexico border lol.
I mean, the middle of the river is generally considered the border. All I’m pointing out here is that California isn’t really importing water if they’re getting it from a river that is at least partially part of California