On 31 January, the Netherlands marked the 70th anniversary of the North Sea flood of 1953, which claimed 1,836 lives, including ten of my relatives, and prompted billions to be spent on the nation’s flood defences.
The flood was also the biggest natural disaster to befall the UK, where a total of 326 lives were lost along with several hundred more at sea.
Seven decades on, how did the UK react to this terrible event? And, going forward, will we be able to protect ourselves from rising sea levels and river flooding brought about by a warmer, more storm-prone climate?
The 1953 flood was the culmination of annual spring tides coinciding with a deep pressure system and gale force winds. The resulting storm surge of 3-5m breached inadequate sea wall defences in 1,200 places and flooded estuaries along the east coast. The disaster prompted a range of sea defences, in the form of walls, dykes, embankments, and a coastal flood warning system. Topping it off was the Thames Barrier, completed in 1982, to protect the floodplain upon which much of Greater London is built.
The coastal defences, which prevented a recurrence of a 1953-scale flood, are coming to the end of their life, putting at risk homes and infrastructure built behind them since the 1960s.
Some serious decisions on protecting communities from sea level rise and coastal erosion need to be made. The difference between the UK and Netherlands is that Dutch politicians regard flooding as an existential threat to the nation given that 60 percent of the country is at risk. In the UK it’s around 15 percent with lower funding to match. Cost is only one issue though.
Will people feel comfortable living behind big defences? How will nature be impacted?
For the UK there is no single silver bullet – only sensible trade-offs between cost, benefits, impact and risk. For instance, building ever higher walls may not always be the sensible thing to do as we cannot predict with accuracy what the future holds. The best computer models are unreliable as currently we lack sufficient data points on which to base accurate predictions.
These trade-offs came to the fore in North Norfolk, where building hard sea defences to protect the Bacton Gas Terminal and several coastal villages was considered unacceptable – as it would only move the problem of coastal erosion further down the coast.
This knotty problem was solved through innovation, inspired by the Dutch Zandmotor project. It involved creating a new 6-kilometre-long, 7-metre-high beach – equivalent to a Wembley Stadium full of sand – to protect the Terminal and feed the villages’ beaches. This £22 million sandscaping project granted a 20-30 year reprieve. Enough time for politicians, townsfolk, and planners to make decisions about the future of the communities. It also saved the Gas Terminal, which is responsible for about one-third of the UK’s gas supply.
Nature-based defences
Floodgates, barriers, flood warning systems, and community awareness, all have a place in the dictionary of flood management. Perhaps less well known are nature-based solutions. For example, when it comes to river flooding, by encouraging wetland habitats up-river, it’s possible to solve multiple issues at once by dissipating and slowing the flow of water while improving biodiversity.
Another nature-based solution is to introduce beavers. Their building of dams and canals, slows down the flow of water and boosts populations of fish, amphibians, and other wildlife.
A study by Exeter University into beavers living in the tributaries of the River Otter in East Devon, saw a family of beavers construct six dams upstream of the flood-prone village of East Budleigh. The beaver dams slowed the flow of water and reduced levels through the village during peak flood events.
Although nature-based solutions may be found wanting during a major flood event, their role in alleviating regular once-a-year river flooding should not be underestimated.
Coalition of the willing
Whether it’s sand, beavers or walls, flood defences work best when there is a willing coalition focused on the problem and looking for opportunities. The best results occur when national agencies, local authorities, at-risk communities, landowners, conservation groups, and businesses work together. By focusing on the problem, understanding different needs and business models, it’s easier to architect a solution that delivers multiple benefits while satisfying different agendas. It is also the best way to attract multiple sources of funding.
Going Dutch
Contrary to popular belief, the UK has a well-tuned system for managing flood risk. But to be really canny it should capitalise on innovations already bankrolled by the Dutch. This only works if these innovations are adapted to the local setting. Such innovations include sandscaping, development of new software tools and methods for partnering, high performance sluice gates: all innovative techniques tried and tested on real-life projects.
By way of example, a sea defence technique, developed at more than €10 million to protect the Dutch coast from 1:10,000 per year storms, is in use at Stolford, Somerset. It removes the need for high, expensive, and unsightly rock defences by using a field of champagne cork-shaped concrete blocks positioned on the seaward side of an embankment. Storm waves flow over the structure and enter a network of cavities between the blocks that absorb wave energy. The high-density concrete blocks are designed to move slightly, keeping the structure in place purely through weight and friction. Walking along the beach it’s nearly invisible.
Despite benefiting from Dutch ingenuity, flood management remains a notoriously complex issue. It requires expertise, engineering, and sound judgement. But what shapes it most are political, budgetary, and social considerations. Floods like the North Sea flood of 1953 gripped the national psyche. It focused minds.
As we come to terms with the effects of climate change, tough decisions will have to be taken where to draw the line, particularly in relation to coastal flooding and erosion. It is good to see government support the development of approaches to help communities adapt to coastal change, with relocation inland an option. The question will be what’s practical to defend and what’s not? Finding the answer requires level heads and more than a dose of courage.
