Is knocking down sea walls the answer to Britain's coastal flood defence? Director Jonathan Clay explains more:
Growing up in Ipswich I was taught about the Great Flood of 1953 when more than 300 people died along the east coast of England. But it wasn't until I heard the personal testimonies of Dick Harman and Malcolm MacGregor while making Flooded Britain that I understood its true horrors. These survivors believe it is going to happen again, and this time, because more people are living on what were once the floodplains of the North Sea, the disaster will be many times greater.
Of course, the chances of a huge tide breaking through our defences and flooding towns and villages are very small - our sea walls are much better now than in 1953. But if predictions for global warming are correct and the frequency and intensity of big storms increases, the chance of a massive "surge tide", large enough to break through our defences might be higher than many people realise.
Another 1953?
Regardless of global warming, Dick and Malcolm believe there is another cause for concern. In 1953 large areas of northern Holland and Lincolnshire were flooded before the surge tide reached Essex and the Thames where the devastation was greatest. With improved walls along the North Sea's northern shores, surge tides can no longer spread sideways and it is possible that even more water might be funnelled south along the East Anglian coast. This would place even greater pressure on the Essex sea walls than in 1953.
Thankfully, something is being done to address the problem. Mark Dixon, who was a project manager for the Environment Agency and now works for DEFRA, is in the process of taking sea walls down. That may sound crazy but there is logic behind it.
New theory
Much of the land the sea walls currently protect is uninhabited farmland. Mark hopes that if some of these areas are allowed to flood, they will act like a pressure-relief valve during a storm tide. As the water is allowed to expand sideways onto its former floodplain, the tide is reduced in height, lowering the risk that seawater will flood over the walls that are protecting places where people live.
Mark's theory is now being tested at Abbott's Hall Farm - an Essex Wildlife Trust site on the Blackwater Estuary. In October 2002, five holes were made in the sea wall allowing the farmland to flood and salt marsh to grow once more. Now the site is being carefully monitored to see whether schemes like this one also have the potential, not only to recreate a natural habitat, but to reduce the risk of coastal flooding.
Could this prevent the recurrence of a disaster like the floods that claimed so many lives in 1953?
Read the interview with Mark Dixon
