Thames Water has appointed Arup and Binnies (Arup Binnies joint venture) as its Technical Partner to lead development proposals for a vital new reservoir near Abingdon, in Oxfordshire.
The UK’s largest water company is working on the SESRO project (South East Strategic Reservoir Option), which – if approved – will provide a secure water supply to 15 million customers in the Thames Water, Southern Water and Affinity Water catchments from 2040.
Without the reservoir, the South East’s future water supply is at risk due to population growth and climate change.
Thames Water forecasts that across London and the Thames Valley, it will need an extra one billion litres of water every day by 2050, with two million more people expected to live in London and the Thames Valley.
The appointment follows a comprehensive procurement exercise, where Thames Water shortlisted Technical Partners with extensive experience in developing and supporting large complex infrastructure projects in the current UK planning environment.
The Arup Binnies joint venture brings world-class expertise in major infrastructure. Separately, both organisations have supported the design and construction of London’s Thames Tideway Tunnel and are playing a pivotal role in the design of the Fens and Lincs Reservoirs.
The companies will work alongside Thames Water’s SRO team to deliver technical services in engineering design, environmental assessment, planning, and land access and acquisition.
Should Thames Water secure government approval for SESRO, as part of its draft Water Resource Management Plan, Arup Binnies joint venture will play a crucial role in ensuring the company is ready to submit a Development Consent Order (DCO) for the reservoir in 2026. If granted, construction is forecast to begin in 2029 with SESRO planned to begin operating in 2040.
Mohit Farmah, Head of Procurement and Supply Chain at Thames Water said, “We are delighted to announce the appointment of Arup Binnies joint venture as our new Technical Partner for SESRO. This supply chain of technical experts with global reach will ensure our reservoir proposals are not only compliant with the Planning Act 2008 but are also developed to a world-class standard.
“SESRO is a nationally significant infrastructure project that has a crucial role to play in the health and wellbeing of 15 million people, the economy and the environment. I have every confidence this partnership will help us to secure that future.”
Paula Walsh, Chair of Arup in the UK, India, Middle East and Africa, said, “Being part of Thames Water’s bold new vision to improve water resilience is a fantastic opportunity to make a positive difference in support of secure and sustainable water solutions. Delivering major water infrastructure projects, such as reservoirs, presents significant complexity and challenges.
“Together with Binnies, we look forward to drawing on our diverse water engineering experience to create nature-led designs that benefit local communities and the environment.”
Scott Aitken, Managing Director, Binnies, added: “The Arup Binnies joint venture is delighted to support Thames Water with the South East Strategic Reservoir Option (SESRO) to build a new reservoir which will secure and enhance water resources in the South East and London region. Our team provides a strategic, comprehensive, and adaptive approach for executing large infrastructure projects that creates enduring legacies for future generations. We are committed to fostering positive change and building a sustainable future for communities across the region.”
Progress so far
The company reports ‘significant’ progress with the proposals, including a great response to its public consultation, which ended in August.
Ground investigations, embankment trials and environmental studies are already underway at the proposed site, ahead of the application for development consent in 2026.
It is estimated that around 45 million cubic metres (45 Mm3) of material will be excavated and moved to build the reservoir’s embankment structures, which range in height between approximately 15 and 25 metres. The majority of the earthworks are expected to be carried out across six main summer working seasons (March to October).
Thames Water’s supply chain and procurement team is also in the process of engaging interested businesses to outline the broad range of contract opportunities that will stem from the proposed construction programme.
