Thames Water Ring Main

Thames Water Ring Main
Thames Water Ring Main
	Ring Main shaft and pump house at New River Head
Overview
Type	Urban water infrastructure
Status	Operational
Locale	Greater London
Construction Period	1988 - 1993, 2007 - 2010
Website	http://www.thameswater.co.uk
Owner	Thames Water
Technical
Tunnel length	80 km (50 mi)
Capacity	1.8 Gl/d (gigalitre / day)
Depth	10–65 m (33–213 ft)
Tunnel diameter	2.54–2.91 m (8.3–9.5 ft)
Cost of construction	£248m (initial construction)

The Thames Water Ring Main (TWRM, formerly the London Water Ring Main) is a system of approximately 80 km (50 mi) of concrete tunnels which transfer drinking water from water treatment works in the Thames and River Lea catchments for distribution within central London.

A major part of London's water supply infrastructure, the initial ring was constructed by Thames Water between 1988 and 1993 at a cost of £248 million (equivalent to £638 million in 2023), and when completed, it was the longest tunnel in the UK.^[2]^[3] Two extensions were constructed between 2007 and 2010.^[1]

^ ^a ^b Cite error: The named reference timelines was invoked but never defined (see the help page).
^ ^a ^b Bensted, I H (January 1994). "Historical Perspective and Corporate Overview". Proceedings of the Institution of Civil Engineers - Civil Engineering. 102 (6): 1–8. doi:10.1680/icien.1994.27264. ISSN 0965-089X. Retrieved 30 July 2022.
^ "London Ring Main turns 25". Thames Water. 15 November 2019. Retrieved 30 July 2022.

[timelines-1] Cite error: The named reference timelines was invoked but never defined (see the help page).

[Bensted94-2] Bensted, I H (January 1994). "Historical Perspective and Corporate Overview". Proceedings of the Institution of Civil Engineers - Civil Engineering. 102 (6): 1–8. doi:10.1680/icien.1994.27264. ISSN 0965-089X. Retrieved 30 July 2022.

[3] "London Ring Main turns 25". Thames Water. 15 November 2019. Retrieved 30 July 2022.

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