Managing rainwater effectively has become a growing concern for homeowners, builders, and local authorities. Increasing urbanisation, more paved surfaces, and extreme weather patterns have placed significant pressure on existing drainage systems. One innovative and sustainable solution to these challenges is the use of soakaway crates, also known as attenuation crates or modular geocellular units. These structures are designed to manage surface water runoff by either infiltrating it back into the ground or storing it temporarily before controlled release.
What Are Soakaway Crates?
Soakaway crates are lightweight, modular plastic structures with a high void ratio—typically around 95%—which allows them to hold a large volume of water compared to their physical size. They are usually installed underground, wrapped in either a permeable geotextile (for infiltration systems) or an impermeable membrane (for attenuation systems).
- Infiltration systems: Water collected from roofs, driveways, or car parks is directed into the crates, where it slowly soaks into the surrounding soil, replenishing natural groundwater levels.
- Attenuation systems: When infiltration isn’t possible due to clay soils or high groundwater levels, the crates act as temporary storage. Water is then released gradually into the public drainage network, reducing peak flows that could otherwise cause flooding.
Why Are They Needed?
Traditional drainage systems rely heavily on directing rainwater quickly into sewers or rivers. However, with growing population density and more impermeable surfaces, these networks often struggle to cope with sudden surges of water during heavy rainfall. This results in flash flooding, property damage, and erosion of natural waterways.
Soakaway crates play a key role in Sustainable Drainage Systems (SuDS) by mimicking the natural water cycle. Instead of allowing rainfall to rush immediately into drains, they manage water at the source, holding it back and releasing it in a controlled manner. This reduces the risk of downstream flooding and helps communities meet environmental regulations.
