Abingdon Reservoir

Abingdon Reservoir
2023 Illustration by Thames Water of the conceptual design and location for a 150 Mm3 reservoir. [1]
Abingdon Reservoir
Location	Oxfordshire
Coordinates	51°38′04″N1°21′15″W / 51.63444°N 1.35417°W / 51.63444; -1.35417
Lake type	Bunded reservoir (Proposed)
Primary inflows	River Thames
Primary outflows	River Thames
Basin  countries	United Kingdom
Surface area	6.7 km2 (670 ha; 1,700 acres)
Average depth	22.4 m (73 ft)
Water volume	150 million cubic metres (150 billion litres; 33 billion imperial gallons; 0.15 cubic kilometres; 0.036 cubic miles)

The Abingdon Reservoir (also known as the South East Strategic Reservoir Option, or SESRO) is a long-term proposal for fresh water storage for the Home Counties. To be located south west of Abingdon, Oxfordshire in the mid-west of the Thames Basin, it is intended to help support water supply provision in the south-east of England. The proposals have been developed primarily by Thames Water, along with Southern Water and Affinity Water, as the reservoir is intended to serve all three company’s customers. ^[2]

Proposals

The proposal arose in 2006 by Thames Water. ^[3] In 2007 the Environment Agency opined that need for this was not proven. ^[4] Further arguments were put but the near-term-demand case was rejected in 2011. ^[5] In 2023, following a period of consultation, a revised version increased the proposal to 150 billion litres (150 million cubic metres; 33 billion imperial gallons). ^[6]

This would make Abingdon the second-largest reservoir in England by capacity, exceeded only by Kielder Water in Northumberland at 200 billion litres (200 million cubic metres; 44 billion imperial gallons), pushing Rutland Water into third place at 124 billion litres (124 million cubic metres; 27 billion imperial gallons). Across the whole of the UK, only seven Scottish lochs have greater freshwater storage by volume.

Additional storage capacity is expected to be needed by 2043 to cater to projected population growth in the Thames Basin. ^{[7] [8]}

In early 2025, Thames Water opened discussions with potential contractors about delivery of the reservoir, which would cost up to £2.2bn to build and would then supply water to 15m people across southeast England. Ground investigations were in progress to help inform an application for development consent in 2026. If the consent was granted, construction was expected to start in 2029 for opening in 2040. ^[9] Chancellor Rachel Reeves expressed her support for the scheme in a January 2025 speech as part of "nine new reservoirs [...] to improve our water infrastructure and provide a foundation for growth." ^[10]

A judicial review of the proposed project started on 25 June 2025, ^[11] but was dismissed in the High Court on 25 July 2025. ^[12]

Reasons for the construction

See also: Climate of the United Kingdom and Population of the United Kingdom

The main reason to build is that the South-East is facing significant seasonal water stress. Factors are the rain shadow behind the prevailing westerly winds and western hills. Eastern counties lack the rainfall of the west; their average annual rainfall being 500-750mm. The west receives around 1800-2800mm.

Average population density is higher in the eastern than western counties; London houses 13.5% of the UK's population. This is the greatest concentration of domestic water usage. Roughly 22% of water use is domestic; 75% is from all types of industry.^{[ citation needed ]}

Counter-arguments

GARD, or the 'Group Against Reservoir Development', have counter-arguments, local, national, and international comparators. ^[13]

• Thames Water have unambitious targets for leakages. ^[13]
• The reservoir will not be effective against long droughts. ^[14]
• As there is enough water to supply London now there can be in future using other, sustainable methods. ^[13]
• The reservoir will damage the ecosystem, impacting endangered and protected land-based invertebrates, water voles, bats and hedgehogs but benefitting more water-based bird life. ^[13]
• Construction of the reservoir will cause traffic congestion and pollution. ^[13]
• Local businesses, including a solar farm, will suffer economic loss. ^{[15] [13]}
• There will be a new, low, risk of flooding. ^[13]

References

1. "New reservoir in Abingdon | Water resources". Thames Water. Retrieved 2023-09-08.
2. "South East Strategic Reservoir Option (SESRO) – a new reservoir for the south east". Thames Water Resources Management Plan. 2024-01-29. Retrieved 2024-03-05.
3. Reservoir 'biggest in 25 years' - BBC News, 14 September 2006
4. "Need for reservoir 'not proven'". BBC News. 5 January 2007. Retrieved 30 August 2009.
5. "Abingdon £1bn reservoir plan rejected by government". BBC News. 4 March 2011. Retrieved 7 May 2018.
6. Inman, Phillip (2023-04-22). "Lake or mistake? The row over water firms, drought and Abingdon's new super-reservoir". The Observer. ISSN   0029-7712 . Retrieved 2023-09-12.
7. "Abingdon reservoir proposals questioned by Oxfordshire County Council". BBC News. 18 April 2018. Retrieved 7 May 2018.
8. "Abingdon Reservoir back on the cards!". CPRE. 19 February 2018. Archived from the original on 31 May 2018. Retrieved 7 May 2018.
9. Morby, Aaron (8 January 2025). "Thames Water bidders day for £2.2bn reservoir scheme". Construction Enquirer. Retrieved 8 January 2025.
10. "Reeves: I am going further and faster to kick start the economy". GOV.UK. 2025-01-29. Retrieved 2025-01-31.
11. Stein, Joshua (25 June 2025). "Judicial review into £2.2bn Abingdon reservoir due to start". Construction News. Retrieved 25 June 2025.
12. "Thames Water reservoir 'size of Gatwick Airport' one step closer to being built in Abingdon". ITV News. 25 July 2025. Retrieved 26 July 2025.
13. "GARD: Group Against Reservoir Development". GARD. Retrieved 16 July 2025.
14. GARD (21 August 2017). "GARD review of Resilience of the Abingdon reservoir in the event of droughts more severe than droughts of the 20th Century" (PDF). Group Against Reservoir Development. Retrieved 16 July 2025.
15. Bennett, Peter (19 December 2014). "Belectric and First Solar connect 46MW Oxfordshire solar farm". Solar Power Portal. Retrieved 16 July 2025.

External links

• Project homepage by Thames Water

51°38′04″N1°21′15″W / 51.63444°N 1.35417°W / 51.63444; -1.35417