If you have a garden pond and want to add the sound of cascading water, a waterfall is one option you can incorporate. Waterfalls can be created by a fountain or by a stream that falls into the pond. One popular method for constructing a waterfall is to use a pre-formed liner made of rigid PVC tubing.
Dig a trench that extends from the edge of the pond to the point where you want to place the lip of the waterfall.
Hook up PVC tubing to the outflow valve of a pond pump. Place the pump in the bottom of the pond. Lay the tubing along the bottom of the trench and run the tubing to where the waterfall will begin.
Place a pre-formed PVC waterfall liner over the trench so the lip of one end overlaps the edge of the pond and the edge of the hose extends out from the edge of the liner. Lift up the edge of the waterfall liner and fill the gap between it and the bottom of the trench with sand for added support.
Cover the sides of the liner with landscaping rocks to hide the edges. Fill the liner with pea-sized gravel to hide it.
Lay landscaping rocks over the liner to give the waterfall texture and to hide the mouth of the hose. Turn on the pump to ensure the water flows into the pond. Add extra water to the pond to help with any displacement created by the waterfall.