The Thames Barrier: Engineering London’s Climate Resilience

If you follow the Thames’ meandering curve to the East, you will stumble across seven shell-like stainless steel structures spanning the width of the river between Charlton on the south bank and Silvertown on the north bank. At first glance, they might be mistaken as sculptures that you see as you walk along the Olympian Way. However, these structures are there for a reason: to protect the city from its river.

River Thames is London’s lifeline. On its bank, the city built its fortune. London became the capital of the British Empire and a Global City on the banks of Thames. However, London’s rise to power came at the cost of its river. The marshes were drained out to make way for Canary Wharf, and then the forests were chopped off. Rivers that once fed the Thames, became the next victim. When the needs of the burgeoning city weren’t fulfilled, the river itself was channelised and encroached upon. On the embankments of the Thames, Londoners found new ways of recreation and commerce, but the water lost its freeway. Result?

History of The Thames Barrier

In 1953, a combined storm surge in the North Sea and a high tide claimed nearly 300 lives and £50 million in damage, equivalent to £5 billion at today’s costs. If the tides were higher, an area almost the size of Birmingham would have been destroyed. 

Flooding on the Thames isn’t a recent phenomenon. It was as much a part of the city’s culture as the red buses and telephone booths. Charles Dickens and Samuel Pepys have written about Victorian London’s fear of the Thames bursting its banks. The North Sea flood of 1953, however, was a fresh reminder of the danger that the city was exposed to if prompt actions weren’t undertaken. London needed something more robust than just some old-fashioned sandbags or stone embankments. It needed something modern yet sustainable: a barrier with movable gates.

The response came almost 13 years later when Sir Hermann Bondi presented a feasibility report for the Thames Barrier. However, it wasn’t the first time a barrier was proposed across the river. In 1236, when London’s thriving port faced threats from the river’s natural tides, King Henry III ordered a chain of floating barriers to be built along the Thames. Constructed with timber piers locked with heavy iron chains, the barrier was stretched across the London Bridge. The wooden fences were later replaced by protective stone battlements where guarding soldiers could raise or lower the gates to allow water and ships to pass through.

The Thames Barrier, London’s Engineering Marvel

What separates the Thames Barrier from other engineering marvels is its combination of the latest technologies with practical mathematical modelling and aesthetic sensibilities. The 20 metres high rotating steel gates, weighing about 3,300 tons, are engineered upon an earlier concept by (Reginald) Charles Draper. The idea for this comes from a gas cooker’s rising valve. Shell-like stainless steel structures were conceptualised by Architect Roger Walters. If you observe them carefully, you can find uncanny resemblances with the tides, emerging and crashing into the Thames’ water. A closer look at the material reveals a gradual transition between a smooth finish and micro-crevice-free surface finish stainless steel. This provides resistance against wind corrosion and salt water.

Thames Barrier Environmental Impact

Besides being functional and visually appealing, the barrier exhibits exceptional structural capabilities. The barrier was estimated to remain functional until 2030. However, it is now estimated to outlive itself and protect London for another 50 years. Without the Thames Barrier, London’s flood defence would have to rely on embankment walls as high as the Victorian street lamps, thereby depriving Londoners of their river. The area between Whitechapel and Canary Wharf in the East to Southwark, Westminster and Chelsea would be submerged under flood water in absence of the barrier.

The Thames Barrier is the second largest of its kind structure, only next in size to the Oosterscheldekering Barrier in the Netherlands. However, like any other mega infrastructure, the barrier came at the cost of  £535m (£1.6 billion in today’s money). It took about 8 years to be fully functional. High investment and long construction time involved in the project also make one question, whether infrastructures like the Thames Barrier, are the only way to protect our cities. Or should we look for other solutions as the climate becomes more unpredictable?

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