Tim Draper has an interesting idea. Make it into six new states.

Just looking them over, I’d say that Jefferson would be very similar to Oregon, North California would probably lean Republican, despite all the Democrats in Marin, Central CA would be heavily Republican, Silicon Valley and West California would almost certainly be Democrat, and South California would be Republican. I’d say, at worse, that it would be six new Senators of each party, though it would actually only be four new Democrats, since they’d lose the two from the current monstrosity. But the Central Valley would finally have some senators willing to fight for them and their water needs.