Pondless waterfalls are a perfect idea for those who want to add the motion and sound of a pond to their garden or landscaping but don't want the added maintenance of taking care of the pool of the pond. Along with that, a pondless waterfall is easier to design, easier to build, and can take up a lot less space than an average pond and waterfall.
The idea behind a pondless waterfall and the way it works is by replacing the actual pool with a small underground pump housing and filter. It is then covered with a layer of gravel over a filter or screen that will allow the water to flow freely into the pump housing. From there the water is pumped back up to the top of the waterfall through underground hoses where it starts its journey all over again.
As for maintenance and clean up, leaves and debris can be raked or blown off the top of the pump housing gravel rather than having to net, sift, or even drain the pond. For yards with a lot of trees that create a lot of leaves, this is a huge plus. And for yards with a lot of sun where algae may become a problem, a pondless waterfall will keep you from having a pond pool area that becomes overgrown with algae. Cleaning the waterfall will be just a periodic shut down and clean.
Of course, if you're wanting fish in the garden, you'll need a pool area with plenty of water for them to grow and thrive rather than a pondless waterfall.