Brilliant idea! Seriously, I bet none of those people move to where you live and will instead stay and die of thirst!
Where do you think all those people are going to go when it goes dry? You can either prepare to take them in or have an adult discussion on how to not have to. I prefer the latter.
I really don't give a flip where they go. As long as we as a human race stop this nonsense of "we can bend mother nature to our will!" - No, ultimately you cannot. You live in a region that regularly sees droughts. You resist building power plants when you need them. And then when everything goes to shit and you have no power or water, suddenly everyone else has to come in and fix your broken state for you.
Look, the PNW supplies A LOT of the power to CA already, since we've got it coming out of our ears with hydro and wind power. This is DESPITE us blowing dams along the White Salmon river to allow Salmon to spawn upriver again. The last thing we need to do is pump water out of our ecosystem and further throw things off.
The adult discussion to have here isn't how to place a band aid on this gaping wound of absolute stupidity. The adult discussion is to say "Look, you can't live below sea level and expect to survive that long. You can't expect to have n * 100,000 live in a region that gets barely enough rain to support n number of people. The people in the areas of CA that are going to see a serious drought and not for the first time should see the writing on the wall.
But while we're at it, let's also help out by reducing the water you use: shut down water parks. Close golf courses. Ban all future swimming pools in residential zoned areas. Let the cost of water skyrocket and the free market will take over and people will leave. Or they'll die of thirst.
And given your name, you should be OK with those choices. People who live in desert regions and expect it to be acceptable and sustainable need to finally wake up. The whole "the world cannot support 7 billion people" realization needs to also come with this.