Thames Barrier

[1] In 1954, the Waverley Committee, established to investigate the serious North Sea flood of 1953 which affected parts of the Thames Estuary and parts of London, recommended that "as an alternative to raising the banks, the possibility and cost of erecting a structure across the Thames which could be closed in a surge should be urgently investigated".

[3][page needed] In 1966, Sir Hermann Bondi was asked to take an independent view of the situation.

He strongly recommended that a barrier should be built in order to avoid the catastrophe of flooding central London, and a site was agreed at Woolwich.

The barrier was designed to provide a flood defence capable of resisting a once in 1000 year surge tide at a base date of 2030.

The barrier was designed by Rendel, Palmer and Tritton for the Greater London Council and the concept tested at the Hydraulics Research Station, Wallingford.

[1] The site at New Charlton was chosen because of the relative straightness of the banks, and because the underlying river chalk was strong enough to support the barrier.

[3][page needed] A separate contract for the gates and operating machinery was placed with the Davy Cleveland Barrier Consortium, formed by Davy McKee Ltd of Sheffield and Cleveland Bridge UK Ltd.[5][3][page needed] Work began at the barrier site in 1974 and progressed in two phases.

[6] The gates of the barrier were fabricated in sections at Cleveland Bridge's Darlington works and assembled at Port Clarence on the River Tees.

Delays to the civil works required changes to the construction and installation sequence, but commissioning was relatively uneventful and the first trial operation of all the gates together was carried out on 31 October 1982.

[citation needed] A Thames Barrier flood defence closure is triggered when a combination of high tides forecast in the North Sea and high river flows at the tidal limit at Teddington Lock indicate that water levels would exceed 16 feet (4.9 m) in central London.

[19] On 27 October 1997, the barrier was damaged when the dredger MV Sand Kite hit one of the piers in thick fog.

[20] The annual full test closure in 2012 was scheduled for 3 June to coincide with the Thames pageant celebrating the Diamond Jubilee of Elizabeth II.

Environment Agency said the pageant provided "a unique opportunity to test its design for a longer period than we would normally be able to", and performance under conditions of "a higher water level upstream than downstream"; also that the "more stable tidal conditions … in central London … will help the vessels taking part".

The barrier would incorporate turbines to generate renewable energy and include road and rail tunnels, providing connections from Essex to a major new Thames Estuary Airport on the Isle of Grain.

The Environment Agency was examining the Thames Barrier for its potential design life under climate change, with early indications being that subject to appropriate modification, the Thames Barrier would be capable of providing continued protection to London against rising sea levels.

Far view of the River Thames Flood Barrier
Diagram showing how the gates work, though the barrier actually rises further than this to allow water to "underspill" under the barrier in a controlled fashion