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Modelling the oceans: Using maths to predict floods

Published: 14 December 2018

On the night of Saturday 31 January 1953, the UK, Netherlands and Belgium suffered one of their worst floods in modern times. 

A lethal combination of high tides and a wind storm over the North Sea caused a tidal surge which overwhelmed coastal defences.

What could be done to stop this happening again?

The 1953 North Sea flood

A catastrophic North Sea tidal surge in January 1953 killed 2500 people and left tens of thousands homeless. In the UK alone, 160,000 acres of farmland were flooded, killing tens of thousands of animals. Additionally, 200 miles of railway lines, 24,000 homes, 200 major factories, twelve gasworks and two power stations were inundated along the coast.

Storm Surge Model – Storms and Floods Hit Europe © Easy Street Productions, LLC

In an emotional statement to Parliament the following Tuesday, Prime Minister Winston Churchill described the flooding as a ‘shocking and tragic disaster’, and pledged that all the resources of the State would be deployed to meet the emergency. Repairs eventually cost £1bn.

Saturday morning’s tide was not abnormal; but the evening tide was two hours earlier than predicted and maintained itself at a high level for several hours.

Sir Thomas Dugdale, Minister of Agriculture, in the House of Commons (2 February 1953)

Making model oceans

Canvey Island residents evacuating their homes after flooding, 1953 © Daily Herald Archive / Science Museum Group Collection
Rescue of an elderly couple trapped by Canvey Island floods, 1953

The flooding had not been caused by a higher-than-usual tide. Instead, it was caused by a tide that had occurred earlier than predicted and, driven by the howling wind, had remained high for longer than expected. 

Scientists needed a better understanding of the intricate interplay between gravity, weather and the shape of the oceans to better predict storm surges and the flooding they caused. To achieve this, they needed to model the oceans, both mathematically and physically.

Scientists had been making ocean and tide models for years. One, made by leading Victorian scientist William Thomson, predicted tides a year in advance after four hours of cranking its handle. But the complexity of storm surges meant that more power was needed.

Thomson's (Lord Kelvin) tide-predicting machine, 1876.

More information about this object

Decades later, in 1949, a 29-year-old Japanese ocean scientist at the Nagasaki Marine Observatory, Shizuo Ishiguro, began working on a project to apply electronics to storm surge prediction, enabling more complex modelling. Four years later, the North Sea Flood struck with its devastating force.

Shizuo Ishiguro's North Sea machine

Within six months of the devastating North Sea Flood, the UK government had begun investing heavily in ocean research.

As the UK’s oceanography community scrambled to accelerate its research into the North Sea and its deadly surges, the director of the National Institute of Oceanography in Surrey, George Deacon, scoured overseas institutes and conferences for promising talent. 

To work at this level of refinement requires much deeper penetration into the physical and mathematical complexities of the subject than could have been justified even a few years ago.

George Deacon, oceanographer (1969)

It was at an oceanography conference in Japan that Deacon met Shizuo Ishiguro and learned about his pioneering use of electronic models. Deacon was intrigued, telling the young scientist, ‘you must come and show us how to do it’.

In 1956, Ishiguro decided to continue his studies in Britain and moved to the institute in Surrey, where he made a six-foot-high electronic model of the North Sea.

Electronic storm surge model, invented and constructed by Shizuo Ishiguro at the National Institute of Oceanography.
Science Museum Group Collection More information about Electronic storm surge model, invented and constructed by Shizuo Ishiguro at the National Institute of Oceanography.

North Sea oil and gas

Ishiguro’s model contributed to a growing sophistication in the oceanography industry. It was used for several years and was continually modified and improved as new technologies became available. Its flexibility meant it could model any sea or ocean—it was just a case of changing the programme.

It also helped meet new challenges. Throughout the 1950s the North Sea came under increased scientific scrutiny as major reserves of oil and gas began to be discovered. In the 1960s, research efforts rocketed.

By 1967 the petrochemical industry had invested £100 million into oceanographic research, including waves, tides and weather effects. Mathematicians modelling the North Sea had never been in greater demand.

What became of the North Sea machine?

After Shizuo Ishiguro retired, he took his ocean model home, where it was housed in his garage to be tinkered with and modified.

Shizuo Ishiguro and his North Sea machine, black and white photograph © National Oceanography Centre Southampton
Ishiguro and his North Sea machine

But what can one do with an increasingly out-dated electronic model of the North Sea?

His son, the writer Kazuo Ishiguro, commented,

‘It was really heavy and looked like the inside of a Tardis. My father died in 2007 ... The fantastic news is that, last summer (2014), the Science Museum decided it was of historic interest. My mother was so relieved somebody was going to take it away’.

So this unique piece of mathematical history has been preserved forever.

As Winston Churchill had said in 1953, the North Sea Flood was a shocking and tragic disaster. But it launched a major programme of ocean research which has vastly improved our understanding of the ways oceans move and behave. This research continues to this day.

The Thames flood barrier

Model of a main pier of the Thames flood barrier

It was one thing to understand and predict ocean tides and surges. It was another to protect vulnerable communities from their potentially catastrophic effects.

During the 1953 North Sea Flood, which caused such devastation on both sides of the North Sea, central London was spared serious damage.

But the waters of the River Thames had lapped at the tops of river walls.

As Churchill made his speeches to Parliament in the days following the disaster, he was acutely aware—standing as he was just feet from the river’s edge—how close the capital had come to succumbing to the water.

Within months, experts appointed in the aftermath of the flood set out plans for an gigantic flood barrier across the Thames.

The Thames flood barrier Aleem Yousaf © CC BY-SA 2.0 Image source for The Thames flood barrier
The Thames flood barrier

Mathematicians in all disciplines got involved in planning a barrier across the River Thames. Some were tidal surge modellers. Others brought extensive knowledge of astronomy. Actuaries in the insurance industry provided crucial data on the probable cost to life and property of future flooding. Hydrodynamicists modelled water flow over the barrier’s gates. Aerodynamicists designed the huge engine houses rising above the water’s surface.

The barrier was eventually completed in 1982 and has protected London ever since.