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An essential new water supply for the South East 

What’s the solution?

To protect public water supplies during periods of drought, we're proposing a new reservoir to the south-west of Abingdon. 

Reservoirs are valuable because they provide a reliable source of water. They can also offer recreational opportunities, support wildlife habitats and support flood management. 

The new reservoir would be filled with water from the River Thames in winter, when there’s plenty of water. When river levels drop or demand for water increases, we'll release water from the reservoir back into the river. This will help the environment, protecting our most sensitive rivers. 

We've carried out technical assessments to determine the size of the proposed reservoir. We also consulted with regulators, stakeholders and customers. This research supported building the larger option, 150 million cubic metres (Mm3), rather than 100 Mm3. This is explained in our revised draft Water Resources Management Plan, published August 2023.

In June 2024, we launched a public consultation on the emerging design options and an interim master plan for the proposed new reservoir. You can find out more about our proposals on our website.

A map showing the proposed South East Strategic reservoir.

This illustration reflects the conceptual design for a 150 Mm3 reservoir.

Map key

  1. Proposed reservoir
  2. Reservoir embankment with pasture, hedgerows, woodland belts and copses
  3. Environmental bundling for noise and/or visual screening 
  4. Steventon to East Hanney road diversion
  5. Indicative replacement floodplain storage and associated wetland habitat 
  6. Corridor for future Wiltshire and Berkshire canal
  7. Alternative indicative locations for T2ST water treatment works and temporary compound
  8. Pumping station
  9. Western and eastern watercourse diversions and realignments
  10. Recreational lakes
  11. Main access road
  12. Wetland lagoons
  13. Conveyance tunnel (including emergency discharge)
  14. Intake and outfall on the River Thames
  15. Indicative location for railway sidings and material handling area during construction
  16. Indicative access location for water sports centre
  17. Floating islands
  18. Indicative minor car park with restricted access
  19. Main visitor car parking

Gate 2

Gate 1