While a large, stacked, stone waterfall may be your heart's desire, unless you have a large backyard with a naturally steep incline, it will be difficult to construct one. You can still build a smaller stone waterfall with only a couple of flat, stone slabs. Placed vertically and staggered, the slabs will provide enough height to create a small backyard waterfall, that is perfectly sized to suit your needs.
While you can prop your slabs up to create a gentle slope, one of the benefits of a stone slab waterfall is you can easily create a small waterfall that is still dramatic. The higher the slab for the falling water is placed, the higher the waterfall. As the water falls over the edge of the slab, it will create a veil of water that can be either narrow or wide, depending on your preferences. As it hits the pool of water or stone slab below, it produces a soothing splashing sound. Properly placing and anchoring your stone slabs will reduce water waste as well as provide a sturdy, long-lasting waterfall.
Purchase a pre-built waterfall structure from a garden center or build your own out of wood and wire. A wooden structure with a built-in vertical “fall” or drop is not difficult to build. Once designed and built, the rocks can be supported around the structure using a mix of mortar, polyurethane foam and gopher wire. The structure design requires flat surfaces large enough to hold your stone slabs, as well as being large enough for you to put the water pump and run tubing through but still conceal the otherwise unsightly items.
Because the stone slabs are the primary focal points of the waterfall structure, put them firmly in position first, before positioning the other rocks. Before deciding on the final placement, test out what the waterfall will look like by running the pump. Put waterproof polyurethane foam at the bottom and base of the stone slabs to keep them firmly in place, as well as prevent water from being trapped under the rocks and damaging the structure. You can cover the rest of the structure with the rocks you want, covering the foam base of the slabs as well as all wooden parts.
If you decide against building a pond in your backyard, a 5 gallon container can be used instead to make a disappearing waterfall. Place it so it captures the falling water from the second stone slab. Use a heavy-duty submersible water pump to pump the water from the pond or container back up to the top of the waterfall. Cover the pump and container with wire and rocks to disguise the appearance. Changing the pump pressure will also affect how the water flows and whether it strikes the bottom slab.