As one of the world’s largest movable flood barriers in the world, the Thames Barrier already qualifies for a high class status, but its elegant stainless steel clad exterior has ensured it also become one of London’s most iconic structures.
But beyond its appearance is a vital piece of infrastructure that is well designed for a serious job. The Thames Estuary is particularly vulnerable to flooding for several reasons. Geography plays its part as the south eastern corner of the British Isles is slowly tilting downwards and sea levels are rising. As a result, the high tide in central London is rising at a possible rate of 750mm per century.
In addition, when an area of low pressure - perhaps hundreds of kilometres across - moves eastwards across the Atlantic towards the British Isles, it raises the level of seawater beneath it by up to a third of a metre. If sustained past the north of Scotland and then down into the shallow basin of the North Sea, this can threaten extremely high surge tides in the Thames Estuary of up to 4m that head towards London. Surges coinciding with a spring tide or floodwater from upstream makes the possibility of flooding very real.
Which is where the barrier comes in, the idea for which gained momentum in 1953 when more than 300 people died after extreme weather combined with the tide to create a storm surge that flooded the east coast of England. In November 2007 another storm surge began sweeping inland causing damage and chaos down the east coast towards London.
“You could see it could be a replica of what happened in 1953,” Environment Agency Thames tidal flood risk manager Andy Batchelor told NCE in 2009. “But we had that great feeling that over 50 years on we have better forecasting and warning systems. But if the barrier and its associated defences weren’t there, it could have been a repeat.”
The Thames Barrier is the largest component of a bigger scheme, which includes other barriers at Barking and the King George V docks, as well as 195km of flood walls upstream and downstream.
But it is the star player and is this year celebrating 30 years since first becoming operational - although it was formally opened by the Queen in 1982. And despite being designed to last until 2030, thanks to a rigorous maintenance and great engineering it is now conceivable that it could still play a part in protecting London from flooding into the 22nd century.