What about desalinization?
The time for California to get on with massive desalinization plant building was a decade or more ago, when the levels in Lake Mead were already dropping, and massive subsidence in the Central Valley was already a fact of life. Yes, they should still do it, but now they will be playing catchup and won’t avoid some of the problems they could now be avoiding. They didn’t want to pay for it then, and they’ll pay more for it now.