The second issue is global warming.
If you have any ideas on how to get the manpower necessary to perform 100+ years of backlogged forest maintenance spanning the entire west coast, or (better) how to fix global warming, I’d love to hear it.
Also, desalination at the scale necessary to meet California’s demands is beyond current technology (especially if it’s done without destroying the ocean ecosystem). Note that the central valley relies on irrigation, and is the bread basket of the US.