HAURATON’s crate system, DRAINFIX BLOC HD, was specified as the attenuation solution for a new residential development in Bungay, Norfolk.
The development of three houses required the installation of two attenuation tanks, the first (5.5m x 8m x 0.8m) positioned under a drive and the other (3m x 11m x 0.8m) in soft ground to be landscaped with vegetation. Though the project itself sits in Flood Zone 1, there is significant risk of flooding in the village and surrounding area. Therefore, the need to manage surface water as close to where it falls as possible (in-line with the principles of Sustainable Urban Drainage Systems (SuDS)) was all-the-more critical.
Each tank consisted of a double layer of crates laid into an impermeable geomembrane. The membrane was sealed around the tank with tape and the tank was then wrapped in a protective fleece, before being covered to ensure effective distribution of the anticipated surface load.
David Moore, owner of installing contractor DS Moore Building and Groundworks, said “This was our first time working with the DRAINFIX BLOC HD system and the team found it easy and intuitive to work with. We appreciated the closed crates, ready-specced for structural stability, as they reduced the labour time involved in constructing the tanks.”
Why Retention?
Retention systems temporarily store excess rainwater and release it slowly into drainage networks and natural waterways. This controlled discharge reduces peak flows, prevents sewer overload, and mitigates flooding. By holding back runoff during heavy rainfall, retention systems help prevent erosion, protect water quality, and stabilise downstream water levels. They play a crucial role in managing stormwater sustainably, especially in areas where infiltration is limited due to soil or site conditions.
With the soil in the local area of the project having high clay content and therefore low permeability, conditions were best suited to the use of a retention system vs infiltration.
About DRAINFIX BLOC HD
DRAINFIX BLOC HD is HAURATON’s dual-crate system, designed for easy construction and efficient transportation. The closed outer crates are used to quickly create the outer boundary of the structure - with no need for separate face plates or end panels - and provide exceptional rigidity and protection during backfilling. Meanwhile, the open inner crates offer a 75% increase in transportation efficiency, stacking neatly for compact transport and reduced carbon footprint.
DRAINFIX BLOC HD has a large storage capacity (383.2 litres) with 95.8% voids and is made of 100% recycled polypropylene. The crates are also PVC free and can be fully recycled following lifetime use. The system can be used for both retention and infiltration projects, paired respectively with an impermeable geomembrane or permeable geotextile of choice. It can be configured to suit any project scale or footprint and easily expanded retrospectively in all directions to meet varying storage requirements.
In the case of this residential project, DRAINFIX BLOC HD has enabled the developer (a local businessman) to reinforce his commitment to his local community by ensuring that rainwater is managed responsibly and sustainably on-site.
