Most likely a woodchuck. The young of the year are going off on their own at this season. They are diurnal so if you keep an eye on the burrow you should eventually get a look at it. I've been told that they are fairly easy to live trap, using apples or cantaloupe for bait, but I've never tried it myself. A suitable trap will cost you about fifty dollars. But watch and wait a bit and see if the animal does more damage.

sounds like a ground hog to me.

I had one burrow under a detached garage. When I started dumping the cat's litter box around it, he moved out and back into the woods.

oooo.
I have 4 cats' worth of cat litter.

I was going to say ground hog, too.
I have rabbits creating warrens in the middle of the yard. The holes are about that big, too!

Yep, groundhog/woodchuck. I've never dealt with one IN my garden, but I've heard those castor-oil based mole repellents that you water in to the soil also work on groundhogs.

It looks like you have edible crops there, so be sure anything you use is safe for use around those. Some repellents are not to be used on or near edible crops.

You may have to fence your garden, extending some welded wire or chicken wire below ground for about 18". Rather than digging a trench, it usually works to just lay the fencing horizontally just below the soil surface.

Thoroughly used cat litter. I tried all kinds of things, stinky cats are the best! Pour the litter as far down into the hole as you can, and then block the top with something heavy, so that they only way for the groundhog to remove the cat litter is to carry it out its other exit (don't worry... it has one). They don't like to do that....