We did something like this at my parents house a while ago. There were some kind of animals digging holes in front of the front porch, so we go these things at the hardware store call “Gopher Gernades” or something like that. They looked like sticks of dynamite and you light it and throw it in the hole, then you look for more smoke rising and plug those holes. Then you toss a couple more in once the holes are plugged and it should get rid of all of the gophers.