GP’s statement you quoted is entirely inaccurate. The natural state of California’s Central Valley is a wetland, which is how settlers found it in the 1800s, full of swamps, fish, deer, and lakes. And then they set to the work of draining all of the swamps so they could grow things there. It’s an unnatural desertification, and if the dams and waterworks were removed, it would return to the marshland. Even now, the rice grown near Sacramento is grown in land that is periodically flooded by the river.
That's not really accurate. Much of California is Mediterranean climate, including all of Sacramento county. Yes, there's some desert in California, but most of the agriculture happens elsewhere; but it depends on what you mean by 'almost a desert', a lot of the central valley is classified as arid and that's where a lot of the agriculture happens. A lot of people also live in (different) arid parts of California though, maybe they should move to where fresh water is easier to access :P
Also, the terrain means it's relatively easy to move water from the north around the central valley, but difficult to move it from the north or central valley to the greater LA area. Elsewhere in the thread, people claim water is fungible, and it mostly is, but location is important, and moving water in Bakersfield to Los Angeles is non trivial.
https://en.wikipedia.org/wiki/Climate_of_California#/media/F...