I live on some acerage and we have problems with gophers every spring. We use traps, like
this one. Its pretty effective. Clean out the mound of dirt until the hole is actually exposed, set the trap and then lay some loose blades of grass over the hole to let filtered light in. If there is too much light they wont come up, but filtered they will come see whats up and bam.
If you have a large cat population in the area i strongly recommend attaching your traps to a piece of small rope and then trying the rope around a fence post or drive a tent stake and secure it to that. Otherwise, lazy cats will stop by to take your dying victim and liberate your 6 dollar trap in the process.