Pond-free features, where a pond or waterfall recirculates from an underground reservoir, have become very popular because they are easier to build and maintain than fish ponds. The Pond-free basin is a hole lined with EPDM rubber to make it waterproof, filled with water matrix boxes called Eco-Blox that can support thousands of pounds.
This weight-bearing reservoir can be hidden under gravel, lawn, pavers – you can even build waterfalls right on top of it! The water in Eco-Blox basins stays clean and clear, so maintenance is much simpler. Pond-free water features are generally safer too, because there’s no way for anyone to fall in.
With the great popularity of these features, we receive many questions. One of the main questions we get at Atlantic is “How many Eco-Blox do I need?”
Here’s how to figure that out.
First, find the volume of water needed to fill the stream and falls to overflowing.
Usually about 3” in the whole stream will do. Measuring everything in feet makes things easier, so convert 3” to a quarter of a foot. For a 6-foot by 2-foot stream:
Length x Width x 0.25 feet = 6’ x 2’ x 0.25’ = 3 cubic feet
We’ll want 3 times as much water in the reservoir as we need, so the level will only drop by a third when we turn the system on before it starts recirculating:
3 cubic feet x 3 = 9 cubic foot reservoir
Finally, we’ll divide by 4.3 cubic feet, the number of cubic feet in an Eco-Blox:
9 cubic feet ÷ 4.3 cubic feet/Eco-Blox = 2.1 Eco-Blox
With the addition of a Pump Vault to house and protect the pump, as well as providing a little extra water volume, 2 Eco-Blox will be perfect!
Now that you know how many Eco-Blox you’ll need for your next project, check out our video on how assemble one.
About the Author:
Demi has been in water garden construction since 1986. As Atlantic’s Director of Product Information, if he’s not building water features, he’s writing or talking about them. If you have a design or construction question, he’s the one to ask.