Outdoor Animal Control - Chipmunk Problem

I have a chipmunk infestation problem. they are coming in the back section of my house which is pole construction. They are burrowing under the wainscot and up into my house. I cannot get to to the crawlspace in this part of the house. I would like to install either a metal barrier or dig a trench and fill with gravel. is this worthwhile and if so how deep do I need to go? if not practical, do you have any other suggestions?

Chipmunk infestation beneath or inside structure can be devastating. They can chew through wires, cables, and pipes. Tunneling can lead to cracks and destruction. Chipmunks carry fleas and which can infest home and pets. Snakes feed on chipmunks and can inhabit tunnels. Thus, snake infestation may become a problem.
Trapping is the recommended control. Set live traps near holes. Bait with peanutbutter. There are battery operated electronic traps that electrocute chipmunks. Repellents may provide some success, but these need to be reapplied.

Chipmunk tunnels can be two or more feet deep. A trench can be dug around the structure and metal mesh (hardware cloth) installed and attached to structure to prevent chipmunks from burrowing beneath structure. Areas inside the structure should be opened up and damage assessed. Chewed wires can lead to house fire. Feces and urine harbor disease. Affected areas need to be cleaned up and disinfected. Affected insulation should be replaced.