Thames Barrier

Auszug aus der Greenwich England Seite:
"The Thames Barrier has been described as the eighth wonder of the world. It is certainly a very impressive work of engineering. High water level at London Bridge has risen about two and a half feet per century, due to the melting of the polar ice caps and the activities of Man. However, the main possible cause of flooding in the London area is surge tides. [...]

In 1953 a particularly disastrous flood occurred. Over 300 people drowned and about 160,000 acres on Canvey Island, near the mouth of the Thames, were covered in sea water. The government appointed a committee to look at the flood problem. One of the recommendations was that a barrier be erected across the Thames. [...]

It was decided that openings only 200 feet wide, the same as Tower Bridge, would be sufficient, and the site of the barrier could be further upstream than originally envisaged. Finally, work on building the barrier started in 1974. It was designed for the Greater London Council by Rendel, Palmer and Tritton, and was officially opened by H.M. Queen Elizabeth II on 8 May 1984. The 1716 feet width of the river is divided by nine reinforced concrete piers, to form six openings for shipping and four other openings. The piers are founded on solid chalk, over 50 feet below the level of the river. The four largest steel gates are 200 feet wide and weigh 1500 tonnes each."

Darren Johnson, Green Party member for the London Assembly zum 21. Jahrestag der Eroeffnung im Mai 2005:
"The barrier has been extremely important in terms of protecting London but is being used more and more. In the previous five years the barrier has been used 55 times but in the five years before that it was used 12 times. There are questions as to how long it's going to be viable with the threat of climate change and the rising sea levels."

Do the maths.
And check the flood map.

Comments

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