There are lots of well-known ways to slow down rainfall to let it seep into the ground, things like terracing and berms. California does little of that, so when it does rain, it all just washes into the ocean and it's back to drought.
Good news, my California town makes terracing so difficult to do that it might as well be illegal. So when it rains there's rapid runoff into a creek that makes a beeline for the ocean.
It's really not that hard. Well, it takes time and labor. Beavers used to be the key to water retention in the ecosystem, but we hunted them to near extinction.
You can have some of the ones that live by me. They're quite the nuisance, and nobody wants to trap them for pelts anymore.
I'm pretty sure the colony that lives by me has been exporting them (given the number of babies and new dams I've seen) but they're not likely to cross the Rockies on their own.
Well, yes, you do need to erect fencing around the trees you don't want them to cut down, but beavers do greatly help create better water retention in the local environment.
