What are stormwater attenuation crates?

Posted by Callum Vallance-Poole, on June 24, 2024.

Rain Bloc Attenuation Crate

Stormwater attenuation crates, also known as soakaway crates or simply attenuation crates, are structures designed to be built up to create attenuation tanks. These tanks capture, store, and gradually release excess rainwater or runoff. These crates play a crucial role in mitigating the impact of heavy rainfall on urban environments by reducing flooding, minimising soil erosion, and preserving the integrity of drainage systems.

Effective stormwater management is essential for maintaining urban areas’ resilience and sustainability. With the increasing prevalence of extreme weather events and rapid urbanisation, the need for robust stormwater management solutions has never been greater. Stormwater attenuation crates offer a proactive approach to addressing these challenges, providing a versatile and sustainable means of managing stormwater runoff.

Functionality and Purpose of Attenuation Crates:

Attenuation crates serve as key components within modern stormwater management systems, offering a multifaceted approach to mitigating the impact of rainfall and runoff. These crates are designed to capture, store, and slowly release excess rainwater, thereby reducing the burden on drainage systems, minimising the risk of flooding, and promoting groundwater recharge.

Graf UK’s attenuation crates are engineered with precision and durability in mind. They feature a modular design that allows for seamless integration into diverse urban landscapes. These crates are made from 100% recycled plastic and offer a sustainable alternative to traditional stormwater management solutions.

Some key benefits of using attenuation crates for your stormwater management projects are:

  • Flood Risk Reduction: Attenuation crates capture and store rainwater, preventing localised flooding during heavy rainfall.
  • Drainage System Relief: Crates ease pressure on drainage systems by gradually releasing stored water, preventing overflow and erosion.
  • Groundwater Recharge: These crates promote groundwater replenishment by allowing rainwater to infiltrate the soil, supporting ecosystem health when used to build soakaway tanks.
  • Environmental Preservation: Attenuation crates preserve natural water cycles and minimise the need for costly infrastructure upgrades.
  • Space Optimisation: Their modular design maximises land use efficiency, making them ideal for urban areas with limited space.
  • Reduced Infrastructure Costs: Crates help save on infrastructure expenses by mitigating flood risks and minimising drainage system upgrades.
  • Minimal Maintenance: GRAF UK’s attenuation crates require little upkeep and have a service life of over 50 years, providing cost-effective and dependable stormwater management solutions.

Types and Variations of Stormwater Attenuation Crates

Stormwater attenuation crates represent a modern approach to managing urban runoff and flooding. These crates are part of a broader category of stormwater management systems designed to capture, store, and gradually release excess rainwater, preventing flooding and reducing the strain on drainage systems. Among the various options available, Graf UK offers a diverse range of attenuation crates to suit different project requirements.

At Graf UK, we have worked on developing a range of attenuation crates to suit every eventuality.

EcoBloc Flex:

  • Designed for deep applications subject to heavy traffic loadings.
  • Manufactured from recycled materials.
  • The EcoBloc Inspect Flex option is available for camera inspection and jetting.

EcoBloc Maxx:

  • Suitable for deeper applications with regular heavy traffic.
  • Stackable design minimises transport costs and storage space.
  • BBA (British Board of Agrément) certified for quality assurance.
  • Made entirely from 100% recycled plastic, demonstrating environmental responsibility.
  • Backed by a robust 5-year warranty for peace of mind.
  • Easy installation with up to 13 modules fitting on one base plate.

EcoBloc Light:

  • Intended for landscaped areas or restricted car parks.
  • One lorry can transport up to 2700 EcoBloc Light modules, reducing carbon emissions by 85% during transport.
  • Manufactured from 100% recycled plastic.


  • Designed for deep applications with regular heavy traffic.
  • Manufactured from 100% recycled plastic.
  • Ideal for small-scale soakaways.

Attenuation crate comparison

Several factors come into play when comparing GRAF UK’s attenuation crates with traditional stormwater management systems, including gravel infiltration ditches, concrete attenuation tanks, and traditional single-piece crates. While effective, gravel infiltration ditches require significant land area and are prone to sediment accumulation. Concrete attenuation tanks offer durability but can be costly to install and may require heavy machinery for transportation and placement.

In contrast, GRAF UK’s attenuation crates offer a modular design, allowing easy installation and customisation. Their lightweight nature makes them easy to handle and transport, making them ideal for projects with limited access or space constraints. GRAF UK’s crates are also designed for optimal space efficiency, maximising storage volume within a compact footprint.

Stormwater attenuation crates are vital components in modern stormwater management systems, offering practical solutions to mitigate the impact of heavy rainfall on urban environments. As urbanisation continues and extreme weather events become more frequent, the importance of robust stormwater management cannot be overstated.

GRAF UK’s attenuation crates stand out for their versatility, durability, and sustainability. Designed with precision engineering and manufactured from high-quality recycled materials, they offer a reliable and eco-friendly solution for managing stormwater runoff. With a service life of over 50 years and backed by warranties, GRAF UK’s crates provide long-term peace of mind.

Contact us today if you need help choosing which crate is best for your project. Our team at GRAF UK is here to assist you in finding the perfect stormwater management solution.