I am new to this site thanks to the creatures that are taking over my yard-I need help!

I have a smallish yard, have lawn, half wooded hill covered in shrubs, trees and junipers. Recently had several rose bushes and nandina blow over in a storm, when we removed them I saw that they had basically separated from the roots, right at the ground-hmmm? Some kind of animal? Well, most of the hill is spongy feeling, but hard to find any holes as it is covered in mulch, pine straw and plants. The yard is starting to feel spongy now also. Hubby has seen a hole or two in the grass. We had decided we have voles, and then just yesterday he has seen several chipmunks in the yard and among the plantings. So I guess my question is: is it possible the chipmunks are causing all this damage, or do we likely have TWO infestations in our yard. FWIW, we have seen pretty large droppings in the garage and basement. I do NOT want the critters taking up residence in my house! After reading these forums all day yesterday, I am ready to build a swimming pool, but has anyone used this method for voles as well?

Thanks for reading my LONG plight and for any advice available.