How to Build a Concrete Waterfall in Pond
A waterfall can be constructed at the same time as a pond, or one can be added to an existing pond. In either case, the pond edge should be perfectly level and raised enough above grade so that ground water cannot run into it. A waterfall can be constructed on flat ground or into the side of a hill. In either situation, these same instructions apply.
Before building your waterfall, you will need a solid foundation to support the weight of the concrete block and waterfall rocks. Next to your pond, pour a concrete slab equal in size to the length and width of the waterfall you plan to build. For smaller waterfalls a large patio stone may be used. If your pond is already in place, do not pour the concrete on top of the liner at the edge of your pond. The concrete slab should be approximately 6″ thick and the surface should be level. This will help the waterfall remain level and also prevent portions of it from settling unevenly. Also, the top surface of the concrete should be about 2″ higher than the pond edge which will keep the weight of the waterfall rocks off the edge of the pond.
After the concrete slab has dried (approximately 24 hours), use concrete block to construct a three-sided or curved wall along the sides and back edge of the concrete slab. The height of the back of this wall should match the height of the waterfall you plan to build, and the sides step down towards the pond.
It is important to line the whole area with 45 mil rubber pond liner to prevent any water loss from behind the waterfall. Use pond underlayment under the rubber liner to protect it from any sharp edges on the concrete slab and block wall.
To determine the size of the piece of liner needed for your waterfall, consider the height, width and depth of your planned waterfall.
Width = side to side, from outer block edge to outer block edge.
Depth = from the front of the waterfall to the back of the block wall.
Height = from the top of the foundation to the top of the block wall.
For the first measurement of the liner, add the width plus two times the height plus two feet (one-foot overlap on each side).
For the second measurement, add the height plus the depth plus two feet (one-foot overlap in the back and one foot to hang down in the pond).
Please consult an Aquatic & Garden Decor staff member to confirm your calculations before the liner is cut.
For Example:
Concrete Block Wall Size: 4′ width, 2′ depth, 2′ height
1st dimension: 4′ + (2′ x 2′) + 2′ = 10′
2nd dimension: 2′ + 2′ + 2′ = 6'
Therefore, the dimension of Rubber Liner Needed: 10′ x 6′
If you are building your pond and waterfall at the same time, one larger piece of liner may be used for both.
How to Build a Concrete Waterfall in Pond
Source: https://aquaticgarden.com/resources/waterfall-construction/