It makes sense that waterfalls and rock gardens would go hand-in-hand. If you look on the bottom of a stream or along any natural waterfall, you will see that the bed surface is made of rocks. Anywhere water flows, it picks up smaller particles such as dirt and sand, leaving behind heavy particles such as stone and rock. In the process, it usually wears stone smooth. When incorporating a waterfall into your rock garden, the trick is to make it look as natural as possible.
Lay out the course of your waterfall using a garden hose. Your waterfall may be built into a hillside, or dry-stacked in a compact area. But it must contain a catch-basin that is recessed into the ground.
Spray around the garden hose to mark the boundaries of your waterfall.
Dig out the catch basin using a shovel. Transfer this dirt to the top of the waterfall course to build up the height of the waterfall.
Dig a channel down the course of the waterfall to direct the flow of water.
Measure the length and width of the waterfall and catch basin. Then cut the PVC underliner and liner so that they are slightly longer than the waterfall and basin, and twice as wide.
Pour a layer of sand over the bottom of the waterfall channel and catch basin. Wet the sand slightly with a water hose, and smooth it with a shovel.
Spread the underliner over the sand base and smooth out any wrinkles. Then spread the PVC liner over the top of the underliner. Again, smooth out any wrinkles.
Measure the length of the waterfall. Select a pond pump that is rated powerful enough to lift water that distance.
Hook the PVC tubing into the pond pump. Place the pond pump into the pump housing and place it at the bottom of the catch basin. The pump housing will keep the pump free of debris. Pull the end of the PVC tubing and the electrical cord out of the basin.
Pour pea-sized gravel into the catch basin to fill it completely.
Place landscaping rocks along the edges of the waterfall and the basin. Pour pea gravel into the waterfall to hide the liner.
Place landscaping rocks into the waterfall channel to create natural falls and places for the water to run around.
Place landscaping plants around the edges of the waterfall and catch basin.
Arrange the PVC tubing so that the water from the pump spills out of the tubing at the mouth of the waterfall. Hide the mouth of the tubing between landscaping rocks. Hide the length of the tubing under landscaping plants.