Since he was under a wooden 6x6 wooden deck next to the flower garden and tasty, succulent hostas and hydrangeas, I figured that I could hose him out. I turned on the hose, and I think that he quite enjoyed the shower. There is little half inch spaces between the 6x6 timbers, so I knew that I was nailing him with the spray of water, and he seemed to appreciate the built-in amenities. Stomping and sound failed to drive him out. It was time to turn into Chemical Ali and chase him out with a proprietary repellent formula. I will share it with you here.
I took two cups of household ammonia (don't inhale the fumes), and dumped it down the holes. I followed that with two cups of Woolite for darks. I did this at both entrances. Five minutes later, old groundhog made a beeline for the woods. This was last night. I saw him over at the neighbor's property this morning. I managed to stink him out from under the deck. Worked like a charm. I imagine it will work for skunks or any other pests. That household ammonia is powerful stuff, and whatever is in Woolite, clings to their fur and they hate it.
So this is a sure-fire groundhog repellent. If it works for you, send money. The hell with it, send me money anyway. It will make us both happy.