Pondless Waterfalls and Streams:
Pondless Waterfalls are a bit of a misnomer. The waterfall and or stream will cascade or meander into a small body of water "Pond" but the "Pond" can have no water visible like the water is disappearing into a riverbed, or the "Pond" can have several inches of water so it resembles a tranditional pond. A Pondless Waterfall is not for you if you wish to have fish in your water feature. But if you do not envision having fish and want a low maintenance water feature, then a Pondless Waterfall/stream may be an option to consider. If you are concerned about deep water, children near the water feature, a Pondless Waterfall is also a good option.
How does it Work?
The primary difference between a traditional pond and a Pondless Waterfall design is that with a Pondless Waterfall design, the pond hole is excavated, and reservior cubes are installed below so it provides water retention (underground cistern) and it is covered with stones and rocks so it is not visible, but provides water capacity. The "Pond" can be designed so it still has a limited depth of water which is nice if you still wish to see water in the reservoir area. The limited water depth also attrack birds for bathing.
Some samples are shown below.