I always meant to write an article on this, but never got around to it, so I'll put some of the basic parts here.
Ponds are very difficult to build here, short of concrete, which is difficult everywhere. We have the wrong kind of soil for earthen ponds, so that leaves preformed and liners. Both of them require that you remove all of the sharp rocks from your hole, which is impossible for us since we have better than 50% rock in the ground (ancient river bed).
The answer for us was the stock tank, which I've been using for many years in many other capacities. They come in all sizes, are easy and inexpensive (relative to the cost of pond liners and such) and don't puncture just because there's a few rocks underneath and around them. For this project I was looking for a small waterlily pond. It has to be deep for overwintering plants and fish (I don't heat it in the cold winters), and for thwarting the birds and wildlife that home in on unprotected fish, destroying the plants in the process. We chose a small, 100 Gallon Rubbermaid type--$50 at Ranch & Home.
These are freestanding, long lasting, and can be used to stash a pond anywhere you like, above ground or below. You can build a brick wall facade around it for a formal look, or frame it however you like.
