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) |
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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. Two extensions were constructed between 2007 and 2010.