Hi, Deb:
Sorry for the delayed response--we were on vacation!
Our pond designer included steps into the pond on 2 sides for easy entrance and exit. They also included a double liner (with some type of cushioning material in between) so that if the top layer got punctured by a sharp dog toe-nail, we didn't have an immediate leak. We have had to repair just a few puncture holes, but they are very easy to see because of the "bubble" that forms between the 2 liners when that happens. We have just a little gravel, or small rocks on the bottom to hold the liner down--no big rocks inside the pond. Obviously, we can see the liner on the bottom, but it's not as big deal for us.
We originally showed the dogs where the steps were, and they got very used to using them. Our golden in the photo was in the pond every day it wasn't frozen over--even in the winter!!! It was just deep enough for cooling off, but not large enough to swim in. They seemed happy enough.
Needless to say, we have no plants or fish in our pond--just golden retrievers
Linda