How to build a waterfall.
Visit some natural waterfalls or at least look at photos. Observe the water, and look at the way in which it flows over the rocks and terrain naturally.
The design of your falls will depend on the layout of your terrain, pump and pipe size, length of water flow from pump to falls, and pond size. It’s important to keep the elements of your water feature in scale. If you have a small pond, have an appropriate sized falls and vice-versa.
One of the most common mistakes results from the desire for a tall waterfall at a level building site. Large amounts of soil are imported to build the falls up to a three or four foot height. Yes, you will achieve a dramatic waterfall, but the total effect will not look natural. Try not to let any part be overly dominate. A falls of just two feet will produce a very satisfactory effect both visually and audibly.
On a level site, with an “average” size pond of say 11 by 16 feet, the amount of soil needed to surround the biological filter and create the berm is just about equal to the amount of soil excavated from the pond, so it works out quite well. To further enhance or enlarge the berm, you may want to import a little more soil, large boulders or other features.
Be sure to use a wide liner under the falls and/or stream, this will allow for twists and turns in the course of the water and also contain splashing. A ten foot wide liner is recommended. Under-layment under the falls and stream liners is usually not required.
When your excavation is complete for the falls, and the liner is in place. Then begin to add your stone. This is the fun part, so try out several combinations and visualize how the water will flow.
When satisfied with your arrangement, use black waterfall foam to direct the water over the stone instead of under it. That is, stone that is directly in contact with the liner should sit on a bed of foam so the water goes around or over the stone instead of underneath it. Caution - the foam expands greatly…don’t use too much!
Building a waterfall can be extremely satisfying. Though you should give some time to preliminary research, you’ll learn most by actually building your water feature.