Rainwater Attenuation Systems

Attenuation systems store rainwater from storms until it can be safely released at a controlled rate, reducing peak flows and minimising flooding downstream.

The process of attenuation starts with a high storm water flow rate activating the flow control device. The flow control device will cause the storm water to back up in to the storage tank where it will be held temporarily. The flow control device will continue to discharge the storm water at the controlled rate after the storm has finished and until the storage has been emptied.

Environmental attenuation systems can be constructed from various materials. Two examples are detailed below:

Stormcell
The Stormcell system features individual modular cells that can be built up to form a load bearing tank structure of any shape or size to receive rainwater collected from the gutter system or surface drains ready to release in a set discharge limit.

Stormbloc
Stormbloc is similar to Stormcell but has the added feature of laterial flow, although typically stormbloc is used for infilltration applications.

For each of the above systems to work an impermeable membrane typically SC Membrane is required together with an SC2000 geotextile on top of the stormcell or stormbloc.