Attenuation & Soakaway Crates

Surface Water Drainage

Soakaway Crates, also known as Attenuation Crates, Storm Cells or Storm Crates, are interlocking crate systems that allow surface water to be stored and gradually released back to the ground or sewer network slowly. This slowed rate of discharge helps to avoid downstream flooding and the erosion of water ways due to heavy flows.

Soakaway Use - In soakaway schemes, the system is wrapped with a permeable membrane allowing water to be collected and slowly soak back into the ground through an infiltration process. Used in this way, the crate provides an underground void for the temporary storage of excess rainwater. Collected through pipes from the roof and/or road, the water can then be slowly infiltrated into the surrounding soil in line with the natural rate to avoid flooding and water-logged ground.

Attenuation Use - In an attenuation scheme, storm water is temporarily stored for a period of time before then being released back into a watercourse or sewer network. The storm water is collected and routed into the sewer the normal way but the use of flow controls allows a controlled volume to flow through into the main system. During a heavy rainfall, the rest of the excess water, which would be backing up at this point, is fed into the crate system where it is held until its ready to re-join the main system.

Whilst the risk of flooding cannot be prevented entirely, its effects can be reduced. Installing a soakaway crate system is one way of doing this as it can help to control the level of surface water, especially in areas prone to flooding or heavy rains.