I was going to DM you but figured someone else might be in a similar bind - So, I've got a walkout basement, with retaining walls. I don't mow the slope with the 'chuck den and it's got some low woody brush on it. What I'm picturing you're recommending is digging out the top few inches of topsoil 18-24" away from my retaining wall, laying my barrier flat on top of the freshly-bared soil, and burying it. So the barrier is horizontal, disregarding the slope of the terrain. Am I understanding you right? Is 18-24" far enough to keep woodchucks away? I thought their burrows were dozens of yards long.