I use to live on top of a hill that was infested with the varmints. We got a cat and soon he was chasing down the gophers. He killed all of our gophers and then cleared out the neighbor's yards.
If you're refering to a real gopher that lives in a hole in the ground and not a chipmunk, they're easy to get rid of.
Take a hose or a bucket of water and pour it into their hole and flush them out. Then do what you want with them.........