Anglian Water and its @one Alliance have begun construction on the AMP8 Storm Tank Programme, marking a pivotal moment in one of the most significant capital investment periods in the company’s history.
With £47 million committed to delivering 35 new storm tanks across the East of England, the programme builds directly on the success of AMP7, during which £96 million was invested to construct and upgrade 112 storm tanks across the region.
Taken together, the AMP7 and AMP8 programmes represent a step change in how stormwater is managed across one of the UK’s most environmentally sensitive and climate vulnerable regions. And against a backdrop of increasingly intense rainfall, ageing infrastructure and rising regulatory expectations, the need for resilient, well-designed stormwater storage has never been more acute.
The East of England presents a unique paradox for water companies. Despite being the driest region in the UK, it is also highly susceptible to flooding. Its flat topography, low-lying catchments and rapidly changing rainfall patterns mean that even short, intense storm events can place significant pressure on wastewater networks.
And many areas are served by combined sewer systems which, during extreme weather, can become overwhelmed. Without sufficient stormwater storage capacity, flows can exceed treatment capability, increasing the risk of storm overflows and environmental harm to rivers and coastal waters.
For Anglian Water & its @one Alliance, protecting these receiving environments is a critical priority. Local watercourses support sensitive habitats, agriculture, recreation and community wellbeing, while Water Recycling Centres (WRCs) are vital operational assets that must continue to perform safely and compliantly under peak conditions. And stormwater resilience, therefore, is not simply an engineering challenge; it is fundamental to environmental protection, public confidence and regulatory compliance.
So therefore, the storm tank programmes were developed to address these challenges head-on. By increasing the volume of stormwater that can be temporarily stored during heavy rainfall, the tanks reduce peak pressure on treatment processes. Once flows subside, stored stormwater can be returned for full treatment in a controlled manner, significantly reducing the likelihood of uncontrolled discharges.
During AMP7, Anglian Water invested more than £96 million to construct and upgrade 112 storm tanks across its operational region. Delivered by the @one Alliance, the programme delivered measurable benefits: reducing pollution risk, improving operational resilience and safeguarding local environments during periods of heavy rainfall.
A defining characteristic of AMP7 was its standardised yet adaptable delivery model. While no two sites were the same, each presenting unique constraints such as limited land availability, challenging ground conditions or complex hydraulics. This balance enabled efficiencies at scale while still tailoring solutions to local requirements.
Technical innovation played a central role. Above-ground glass-coated steel (GCS) tanks were widely adopted, designed using detailed hydraulic modelling to optimise capacity and performance. And in several locations, existing assets were repurposed to minimise new construction. At Cotton Valley WRC in Milton Keynes, for example, two primary settlement tanks were successfully converted into permanent storm tanks, reducing both capital cost and embodied carbon.
The AMP8 Storm Tank Programme takes this proven approach further. With construction already underway at multiple sites, the £47 million investment forms part of Anglian Water’s £11 billion AMP8 business plan, its largest ever capital delivery portfolio.
The 35 new storm tanks will play a critical role in managing stormwater surges during extreme weather events, reducing flood risk and preventing untreated wastewater from entering rivers and coastal waters. Collectively, they will significantly increase stormwater storage capacity across the region, supporting compliance with tightening environmental standards while delivering tangible environmental benefits.
Even better, to enable the safe construction of these tanks, key methodologies have been carefully selected to minimise any risk. Above-ground tanks are assembled from ground level upwards, significantly reducing working at height & detailed optioneering during the design phase has also ensured materials are reused and recycled wherever practicable, reducing waste and embodied carbon.
This emphasis on whole-life value, rather than lowest initial cost, reflects Anglian Water’s commitment to infrastructure that performs reliably for decades while minimising environmental impact.
The programme is being delivered by the award-winning @one Alliance, a long-established collaborative partnership comprising Anglian Water, Balfour Beatty, Barhale, Binnies, Mott MacDonald Bentley, MWH Treatment, Skanska and Sweco.
This integrated alliance model has consistently outperformed traditional delivery approaches, driving efficiencies, improving safety outcomes and enabling savings to be reinvested into further resilience measures.
And by bringing designers, constructors and Anglian Water operational teams together from the earliest stages, the alliance is able to resolve complex challenges quickly and deliver consistent, high-quality outcomes across a diverse portfolio of sites.
And as climate change intensifies rainfall patterns and regulatory expectations continue to evolve, proactive investment in stormwater infrastructure will be essential for water companies across the UK.
Through its AMP7 and AMP8 storm tank programmes, Anglian Water has & is demonstrating how targeted collaborative investment can deliver measurable benefits for the environment, customers and communities.
As a result, by strengthening resilience today, the company is helping to protect the East of England’s rivers, coastlines and communities for generations to come, setting a clear benchmark for effective, responsible stormwater management across the UK water industry.
