You try emptying dirty water into the hole, remembering that he will have an entrance and an exit. They abhor flooding. Woodchucks usually have a platform nest about half-way above the bottom of the main burrow. This could be a nesting female, something else to consider. They like protected sites on slopes the best and like skunks, once established they regard themselves as permanent residents.
And if you are going to move (her) it needs to be done with a tenderheart trap, soon. That burrow is going to get BIG, fast.