Bubble rocks* are becoming more popular, especially for gardeners who don't want to have a pond, but do want a water feature. Bubble rocks are easy to construct over a weekend, and usually involve using a liner. However, if you have any type of container such as a plastic barrel, old bathtub, etc., they work just as well. This past week, I converted a small ornamental pond I have had for many years into a bubble rock. It took just a few hours, once I had all of the materials, and cost well under $200. The original pond was constructed over 20 years ago using a farm supply store water trough. Now that I have two larger ornamental ponds, I wanted to re-use the small one that we enjoy from our breakfast nook.
*In this area, we call them bubble rocks, but I've heard them called bubblers, and other names. They are a variation of pondless waterfalls.