Water tumbling out of rock is a small drama in a backyard. Whether you create a waterfall to edge a fish pond or to vanish into a hidden reservoir, the sight and sound of moving water provides good chi energy and a lively water feature. A rock wall waterfall calls for modest sleight of hand and a good submersible pump. It can be built easily by an amateur but the fine-tuning of the rock arrangement and aesthetics of the falls will soon turn the architect into a connoisseur.
Site the waterfall close to the power and water sources for easy access. A pondless waterfall will be over a screened, below-ground reservoir with the submersible pump in it. A waterfall that aerates a pond will sit on the edge of the pond.
Determine the height of the top fall and take that information with you when you buy the pump. The size pump will be determined by how much work it has to do. Place the pump in the pond or underground basin.
Dig a shallow trench from the pump to the power outlet; set PVC pipe in the trench and run the power cord through it. Test to be sure it works and cover the trench.
Set a few cement blocks where the rock pile will be. Disguise their sharp angles with some soil – pack it around loosely and don't overwork this part. The real look of the falls comes later. Cover the hill with a pond liner to keep the water from seeping into the ground around the rocks and being absorbed. Be sure the pond liner reaches to the edge of the pond or down to the screen over the hidden reservoir.
Run the hose or pipe that delivers water from the pump to the top of the cement block hill. Now begin to place the rocks and small boulders around the pond liner. Build the vertical structure fairly straight on the front, waterfall side, so it forms a wall. Angle it slightly out toward the bottom for stability. Set some flat, protruding stones in it at various heights for the water to tumble and sheet over. If the falls drops into a pond, leave the last flat sheeting rock protruding enough so that water slipping over it falls directly into the pond from some height.
Keep arranging the stones for the fall, hiding and securing the hose or pipe with stones, until the waterfall looks the way you want it. Test as you go to see how the water falls from various points. Camouflage the pond liner completely with stones and shift rocks so that the water doesn't run off to one side and trickle into the reservoir without creating a fall.
Plant ground cover like Irish moss and other low, flowering greenery in the spaces between rocks and around the base of the falls. Landscape behind the rock wall waterfall with running bamboo in containers or tall ornamental grasses to emphasize the vertical construction of the rocks and the falling water.