Planned reservoir to south of Oxford, near Abingdon

The Abingdon reservoir could cost up to £2.2bn to build and would supply water to 15m people across the South East.

Consultants Arup and Binnies were appointed joint venture technical partners this summer with Costain securing a deal to start clay compaction trials to understand the ground conditions at the site.

Costain will deliver three test embankments, each around 50m long, 20m wide, and up to 3m high, using the same plant and methodology as the proposed reservoir embankments

The fieldwork programme will help to inform an application for development consent in 2026.

Indicative designs and an interim masterplan for the new reservoir, which has a capacity of up to 150m cu m and a surface area of 7km^2,  are now out to public consultation.

If Development Consent is granted in 2028, construction is expected to start in 2029 for opening in 2040.

The scale of opportunity for earthworks firms and heavy plant machinery is significant.

An estimated 45million cu m of material will be excavated and moved to build the reservoir’s embankment structures, which rise to 15m and 25m

The majority of the earthworks are expected to be carried out across six main summer working seasons (March to October).

Mohit Farmah, head of procurement and supply chain at Thames Water, said: “Early engagement will ensure we have a pipeline of interested companies in place and ready to bid for contracts as soon as they are released.”

As an initial step, companies with an interest in delivering the proposed earthworks programme are invited to complete a short market sounding questionnaire.

Click for market briefing report, and the accompanying questionnaire can be found here.

Thames Water is seeking responses by the 30 August.