The correct liner size for a Pondless Waterfall depends on the length and width of the stream, the height of the waterfalls, and the dimensions and depth of the underground reservoir.
Most Pondless Waterfalls require separate liner sections for the stream and the underground reservoir.
How to calculate the reservoir liner size
Measure the length, width, and depth of the underground water storage reservoir.
Use the following formulas:
- Liner length = Reservoir length + (2 × Reservoir depth)
- Liner width = Reservoir width + (2 × Reservoir depth)
Allow additional liner around the perimeter to secure the edges and accommodate the final rock placement.
Example:
For a reservoir measuring 8 ft (2.44 m) long, 6 ft (1.83 m) wide, and 2 ft (0.61 m) deep:
- Liner length: 8 + (2 × 2) = 12 ft (3.66 m)
- Liner width: 6 + (2 × 2) = 10 ft (3.05 m)
The calculated minimum is 12 × 10 ft (3.66 × 3.05 m), before adding extra material for securing the edges.
How to determine the stream liner size
Measure the stream's overall length and width, including the waterfall areas.
Aquascape provides the following general stream liner sizing guidelines:
- Streams shorter than 20 ft (6.1 m): Allow an additional 5 ft (1.52 m) of liner.
- Streams longer than 20 ft (6.1 m): Allow an additional 10 ft (3.05 m) of liner.
These allowances help accommodate waterfall drops, elevation changes, and liner positioning. The final liner size must also provide enough width to cover the stream bottom, sidewalls, and edges.
Important considerations
- Waterfall height: Taller waterfalls and multiple drops require additional liner.
- Stream curves: Winding streams may require a larger liner section than straight streams.
- Rock placement: Leave enough liner to extend behind the rocks along the stream edges.
- Reservoir size: Larger reservoirs or additional AquaBlox modules may require larger liner dimensions.
- Liner overlap: Where separate liner sections connect, allow sufficient material for a properly constructed overlap or seam.
Do not trim excess liner until the Pondless Waterfall is filled and operating, and the water is confirmed to remain inside the liner.
Aquascape recommends using 45 mil EPDM Pond Liner with protective underlayment for Pondless Waterfall construction.