We've seen chipmunks and their burrows in our front yard and we were willing to ignore them till today. We just discovered a burrow entrance right up against the brick steps leading up to our front door. This is an area where we just had a French drain installed to correct drainage problems, and it's covered with sand, so it's easy to burrow into. They may also be burrowing underneath the steps for all I know. We're worried their tunnels and burrows might weaken the ground and cause structural problems in our walkway or steps.
We don't really want to eliminate the chipmunks, but we really need to prevent them from burrowing in this particular area. I tried putting some stones over the burrow entrance, but they've already moved the stones away. I was thinking of putting mothballs into the tunnel, or pouring ammonia down it in hopes that they'd move to another spot.
Suggestions? I've thought of live trapping and relocating them, but that would be a last resort. And we're in a suburban area, so shooting would not be an option even if we did want to eliminate them (which we don't).