Building a rock waterfall is not as difficult as it may seem and makes for a really appealing feature in any yard. Teamed with lush vegetation and a gold fish or two, your new rock waterfall will be the envy of the street. A waterfall can be built out of real rocks or fake rocks--it depends on your taste and preferences. Set aside a couple of days to do the work so you can be more relaxed and enjoy the experience.
Dig a catchment pond for the waterfall approximately 2 feet deep and as wide as you like, a minimum 2 feet across. On the side of the catchment pond where you want the waterfall to be, dig out a small shelf, 1 foot deep and large enough to house the pump.
Line the catchment pond and shelf with pond liner. Place the pump in the shelf and attach the pump hose. Run the hose and power cord away from the pond. Place a stone over the top of the shelf. The stone needs to be large enough to sit over the sides of the shelf creating an enclosure for the pump. The hose should be unhindered by the rock.
Line the pond with river stones, and then use the rocks to start building up your waterfall. Lay flat, larger rocks laterally at the base. Thread the hose up through the middle of the developing waterfall. Place smaller rocks as you get higher—don't exceed approximately 2 feet high.
Cut the hose off at the top of the waterfall once you are happy with the formation. If you want to achieve a waterfall that is spread out, attach the waterfall spreader to the end of the hose, otherwise it will be more like a bubbling spring waterfall.
Fill the gaps between the rocks with self-expanding foam, also called "black pond foam," so that the water is forced to traverse the outside of the rocks as a waterfall. Let the foam cure as per the stipulated time on the manufacturer's instructions.
Fill the catchment pond with water, then plug in the pump and turn it on. The pump will propel water up through the concealed hose and out the top of the rock waterfall in a cyclic fashion.