I have totally given up on control. Maybe one day I'll try an owl house. For now all I can do is try to protect the vulnerable plants with cages. There's a whole lot of gopher habitat around the planted areas here. The soil is very sandy so they can build elaborate underground networks. Traps are pretty cruel, in my opinion, except live traps, which I rely on for squirrels and mice. One of the problems with gophers (as opposed to ground squirrels, which we have too) is that they hide the entrances to their home, making it almost impossible to figure out or control where they live, without a whole lot of close inspection.
