It was about a year ago I was dealing with a gopher problem. Flooding the hole does NOT work. Apparently, the little brats have burrows within the tunnels that sit higher, so while you're flooding, they just climb up, sit there and wait it out as water rushes by. All the water does is make the ground more unstable as now you have a too much water under dirt that has already been compromised by the gopher's tunnels.
It was also suggested I try carbon monoxide. I did that, I thought it worked because I hadn't seen the little sucker for a couple of days, but it came back.
Tried the old fashioned "whack a mole" method, but the little guys are quick and you only have to swing at them a few times before they disappear for hours.
I tried baited traps and they never caught him, but the ground in my front yard was becoming more unstable every day.
I finally decided poison was the way to go. So I went to Home Depot and got this:
http://www.backyardstyle.com/shop/in...-flypage-15445
I put some peanuts down the hole and within 24 hours there was a dead gopher in my flower bed next to one of his holes. The thing to keep in mind with the poison is that you need to discard the dead gopher ASAP because any animal that eats it could be killed by ingesting poison via the rodent. I wouldn't have used the poison in the backyard because my dog is there.
Gophers are more than a nuisance, they can cause real damage. My gopher had managed to crack some of the irigation pipes which I had to have replaced. He didn't make it to my concrete walkway, but some people aren't so lucky. The last thing you want is weakend ground under concrete, whether that's a walkway, porch or your foundation.