Pond-Free 101

Chapter 9

The Water Matrix Block

The Water Matrix is a device borrowed from the storm water management and rainwater harvesting industries that creates modular, structural reservoirs underground to detain or retain water. These simple rectangular blocks have found great favor in the water garden industry because their capacity to handle great weight allows for the construction of water features right on top of the reservoir, creating pond-free features that can also work as hidden water storage tanks for irrigation, drainage, rain collection and/or storm water management – or all 5 at once!

Water Matrix blocks are as simple as they are effective. There are typically four long and four short sections that slide or snap together to form a rigid, reinforced rectangle that resists ground pressure and the weight of soil and rock surprisingly effectively. For example, the Atlantic Water Gardens Eco-Blox assembles and disassembles easily via slide locks and has a distributed load capacity of over seven tons! At 16” wide by 17.5” high by 27.5” wide, each Eco-Blox provides 31.5 gallons of water storage in 4.2 cubic feet of space, which translates to 96% void space available for water storage. For the contractor used to creating pond-free reservoirs backfilled with gravel, that void space is a great advantage, because it means that the whole hole is available for water storage. If the reservoir is filled with gravel, the hole needs to be three times bigger, because 2/3 of the hole will be stone, leaving only the spaces between the gravel for water storage, about 1/3 of the volume of the hole. Gravel backfill has fallen out of favor precisely because of the cost of digging three times the hole, moving three times the dirt, buying a much larger liner, paying for the gravel to backfill the hole and the labor to backfill it, not to mention the additional cleanup costs. Because they’re real cost and labor savers, it’s no wonder Water Matrices have become the industry standard for hidden reservoir construction.