Hey Sue, I remembered a trick for woodchucks that works and might work for ground squirrels as well. Used(scooped free of poop) cat litter gets dumped down their hole and they will abandon it, if they cannot cordon of that section and dig another entrance. I also knew someone who caught their neighbor taking a dump down a groundhog hole! At least that is what he said he was doing...
The baby woodchucks are out on there own now and one tried to move into my carrot patch, eating as he dug his first short little hole. He was very lucky to not be home when I served my eviction notice with a grub hoe!