Several years ago I came across a beautiful display in a garden center which utilized a pot such as yours. The water bubbled over the top onto a gravel bed. I believe the container may have been filled with gravel or rocks.

I'm sending along a link to a wonderful site I had bookmarked, for it has some wonderful ideas for water features and you may find something in there that closely resembles what you're trying to do. Enjoy!

Here is a link that might be useful: Water feature ideas

gardenlady48 - I actually did this with a big pot about your size - at the time I was living in Palm Springs - dry/hot, so I wanted as much water as I could. I put several bricks in the bottom and placed the sprayer part of the fountain on that - it was about a ft tall with the head was just above water for bubbling effect. The pump goes at bottom. I also put a few water plants in to make it more interesting.

Since it was the desert, I kept it going year 'round. Not sure what you would do in snow country. I'm now in VA and and planning on doing what loomis suggested - just buy a plastic basin - lots of choices at big box store, bury in ground, cover with some tight metal mesh - sturdy enough to hold your big pot, plus put rocks on top that will cover the mesh (mesh will also be tight enough weave to prevent debris from getting inside water basin. Fill with water and it will overflow down sides through rocks to basin, where the pump will pump it back up.

My pot doesn't have a hole in the bottom, so black plastic hose would be visible, but I don't want to drill hole in the bottom just yet.