I'm having a similar problem with raccoon only I'm using a 22. That doesn't do the job as fast as you might think esp with a less than ideal shot. Plus I have to be concerned with the bullet flying back at me or somewhere else.

I think a bigger tank of water is your best bet. Carbon dioxide is painless but you need a big source and a tight enclosure. Can't think of much else that would be quick, painless, and totally safe.

We had some wily ones this year (and they look so rolly polly.) Rat poison at the entrance to their holes did them in though. It'll take a couple of doses.

I have a burrow (on my neighbor property) 25 ft from my unfenced garden (I also have two fenced ones). The garden is a salad garden, including a number of chard plants, which in my experience are favored by GH, but it is untouched. He used to come in, while I was busy with other projects, but not anymore.

All it takes is a $20 electric fence, and two wires around the perimeter, one two inches above the raised beds rim, and another 4 inches higher. The paths are blocked by bricks, so that the GH has to touch the wire to get in. I don't kill anything.

You can build a water box and line it with black plastic. put a few feeder goldfish inside to eat the mosquito larvae. feeder goldfish are dollar a dozen.

Rubbermaid makes a 100 gallon heavy duty water trough that should work. it will probably fit inside. Rubbermaid Poly Stock Tank 100 Gallon

they make other sizes also.

Here is a link that might be useful: stock tank

Relocating them would just be passing the problem on to someone else. An air gun is pretty light weight for groundhogs. They're tough varmints. If that's all you have try to put the shot right where the skull joins the backbone.
I'm really surprised you caught more than one. They're not dummies and usually learn a trap is dangerous as soon as you catch the first one.
If you ask around you might find someone willing to take them off your hands. They're mighty good eating. I've eaten quite a few.

I've purchased gas bombs made for this exact purchase. You locate the burrow, make sure there is only one way in/out, light the fuse and place it inside as far as you can. Then block the exit with a rock. Have lots of rags on hand and block the spots where you see the gas escaping. It has worked for me on all but the most extensive burrows.

Get a 22 rifle and some hollow points & keep the gun in a car, shed or garage, if the wife doesn't want one in the house.

Or, send her out with the air gun.

GH's aren't my most favorite critter, by a long shot...I do shoot them. Even a 22 hollow point isn't an instant death. They are tuff critters. I always make sure they die as quickly as possible, no matter how many bullets it takes.

I prefer to use the 12 ga. shot gun. It is MUCH more deadly, but...one needs to be in the correct range. Not always possible.

I could never drown anything.

Ground Hog hides make excellent old time banjo heads. Extra pocket money?

Here is a link that might be useful: Appalachian Banjo

Reading that reminds me that strips of groundhog hides were once thought to be the best for shoelaces. Very tough hides.

Another good method (and painless too) for dispatching with ground hogs, once they're in a live trap, is to build a box just the right size into which one can set the trap and cover it. The box should have a hole on each end, in which one can connect a hose, run from the exhaust of a car or riding lawn mower. With the critter in the trap, and the trap in the box, with the exhaust running through it all, the wood chuck will go to sleep and be dead in minutes.

George
Tahlequah, OK

Hi George - why 2 holes in the gas chamber? Wouldn't the second hole let the exhaust escape?

You can check with your local animal shelter. Some of them will take trapped varmits and put them humanely to sleep.

You have to ask what they do with the critters, though, because some shelters have a release program and pass the varmits off to be someone else's problem--- maybe even bringing the creature, now trap wise, back to your neighborhood.

zach,

without the second hole, gas flow would be impeded. Besides, carbon monoxide kills in fairly low concentrations.

FWIW, gassing by CO is much less traumatic than gassing by CO2. Carbon dioxide asphyxiation induces an instinctive panic reaction. But CO2 is much safer to work with than CO, so animal shelters use it...

I use dry ice (CO2). built a box that was air tight on the bottom, but the lid does not seat tight. As the dry ice melts the co2 settles to the bottom forcing the air/oxygen up and out around the lid.

My friend has a business raising rats and mice as food for reptiles etc. They kill thousands each month with CO2. There is no panic reaction from those critters. In about 30 seconds they fall "asleep" as if nothing happened.

I like the dry ice idea. All you'd need is a big tight cardboard box to set your trap into.

So... Can you put the dry ice in the burrow? Or even better, run a pipe from the mower exhaust into the burrow? I have a very intrusive GH under my front porch around to under a shallow deck and have a hard time reaching anything but one entrance. I tried to crawl under the porch to fix a dryer vent and the ground began to collapse due to the tunnels. Once the GH is killed, how do you collapse the burrows to prevent re-entry?