I used to trap gophers for my grandpa when I was a kid. Here is what I did.
Go down to the local farm supply store and buy a few trap, wire or light chain and spike or tent stakes. Find a mound and clear the dir off and save the dirt. poke around and find the soft spot. Determine which way the hole is going. Take a shovel full of dirt out directly over the tunnel, not from the side. Clear the hole. Set and insert the trap.
Cover the hole with a board. 1/4" thick X 12" square is sufficient. Cover the board with the dirt and seal the hole up. Use more dirt if needed. Come back the next day and feed your cats with the gophers. If you find your hole is plugged with dirt it wasn't seald tight enough. Don't be afraid to set the trap again in the same hole. I'v taken as many as 10 out of one hole. If you don't get one on the second set of the hole, move on to the next. It won't be long until you have thinned out the population. If you catch one that is still alive, Don't handle it with bare hands. Their teeth are sharp enough to cut through leather gloves.
I hope this helps you out and maybe get the kids involved.
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