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Case study

Sustainable drainage helps residential project out of tight spot

10 January 2024

Contractor M & J Evans used Wavin’s AquaCell NG attenuation system to provide robust rainwater management for a new Bellway Homes development where space was at a premium.

Sustainable drainage helps residential project out of tight spot
Wavin's AquaCell NextGen (NG) attenuation tank at the Bellway Homes development site. Image credit: Wavin

When Bellway Homes needed a sustainable rainwater management solution that could be installed efficiently in a tight space, groundworks and civil engineering contractor M & J Evans was tasked with finding it.

Having worked with Wavin for a number of years, the contractor opted for the manufacturer’s new modular AquaCell NextGen (NG) attenuation tanks for the 100+-home site.

A perfect storm

Climate change is increasing the frequency of extreme rainfall events.

This piles on pressure on drainage infrastructure and puts emphasis on rainwater management in new developments.

It’s in this context that new legislation – Schedule 3 of the Water Management Act – is set to mandate the use of sustainable drainage systems (SuDS) in new developments.

These systems are intended to take the pressure off public drainage infrastructure by more closely mirroring the natural water cycle.

They store water and release it back into the environment at a controlled rate that doesn’t overwhelm sewers.

Attenuation tanks – underground tanks that store rainwater – are a crucial element of SuDS, but they’re often large, bulky systems that need to be installed at the outset of a project.

This has the potential to be a logistical headache in sites in more built-up environments where space to work can be in short supply.

From a site safety perspective, reducing clutter onsite is a further consideration.

It’s something that countless more developers will come across as they begin to work with SuDS on a regular basis following the arrival of Schedule 3 later this year.

Innovative design for seamless installation

For this project, space onsite was in very short supply and it had to support many contractors working simultaneously.

When it came to installation, space to manoeuvre wasn’t the only challenge.

A particularly frost-bitten week saw temperatures plunge to -7oC during the five-day installation window, restricting the amount of time that contractors could operate each day.

M & J Evans worked with Wavin to identify AquaCell NG as an attenuation system designed to work in this tricky environment and allow efficient installation that wouldn’t delay the rest of the project.


AquaCell NG attenuation tanks have a stackable design. Image credit: Wavin
AquaCell NG attenuation tanks have a stackable design. Image credit: Wavin

The slimline, stackable design meant it could be delivered in fewer trips and stored in a much smaller surface area once it arrived.

The entire 560m3 stock of product was delivered in just three lorry loads and could be stored without causing problems on an already crowded site.

No delays

Installation features of AquaCell NG attenuation tanks. Image credit: Wavin
Installation features of AquaCell NG attenuation tanks. Image credit: Wavin

At the installation stage, the push-fit design and integrated connectors came into their own.

The tank was designed for quick and easy installation without compromising on durability, and the team managed to install everything within three days so there was no delay to the rest of the project.

Adam Newsome, contracts manager at M & J Evans, said: “The little details on the tanks show that installation was clearly a priority in the design process, like a circular guide on top of each tank to ensure correct orientation first-time around, and hand grips on the side of the unit – all contributing to a more seamless installation.”

A sustainable solution

Developers up and down the country (and around the world) are working to reduce their emissions and Bellway Homes is no exception.

The built environment makes up almost half of global carbon emissions, so the industry needs to lead the charge if economies are going to hit fast-approaching net zero targets.

This means leaving no stone unturned in the effort to reduce environmental impact, including in the specification process.

This was front-of-mind when M & J Evans chose the AquaCell NG attenuation tank.

Made from 100% recycled materials and able to be 100% recycled at the end of its life, AquaCell allowed Bellway Homes to access all the benefits of sustainable drainage without adding to its carbon footprint.

Wavin AquaCell NG attenuation tank onsite. Image credit: Wavin
Wavin AquaCell NG attenuation tank onsite. Image credit: Wavin

Likewise, because the stackable design allows the tank to be delivered in fewer trips, this reduced logistics related CO2 emissions.

This is a significant benefit for housebuilders who are looking at supply chain sustainability, contributing to a more environmentally-friendly build overall.

Future-proof housing

The final result of the project was a development that complies with upcoming sustainable drainage legislation.

Also, one that will be resilient to more extreme weather for decades to come.

SuDS will soon be a key part of the planning and approvals processes for the vast majority of new developments.

But it doesn’t have to be a headache for housebuilders, even when they’re working in more challenging conditions.

Innovative and intuitive designs make installation simple and efficient so that work can move on quickly.

The latest SuDS technology should be viewed as an opportunity to create more robust homes without delaying builds.

For more information on Wavin’s AquaCell NG, visit:

  • Martin Lambley, global urban climate resilience product manager at Wavin