Holland:Rising sea levels have forced the Netherlands, a world leader in flood defence technologies, to take stock, writes Jamie Smythin Ameide.
Standing on top of the dyke at Ameide, Joop (70) and Barend (82) swap stories about the river Lek, which snakes past their village in the southern Netherlands. The two old friends remember the last big flood in 1953, when tens of millions of litres of water poured over the land. Almost 2,000 people died when water levels rose by more than five metres during a violent storm and surged over Dutch sea and river defences.
"The water was up and it was the springtide. It came just a metre below this dyke that time," remembers Joop, who points down affectionately towards the gigantic concrete structure that protected Ameide's 3,000 inhabitants from the flood.
"The dyke has been here since 1269 and is very strong. I have faith in our technology to protect us."
The Dutch are used to living with the threat of catastrophic floods. A quarter of the country lies below sea level and for more than 2,000 years people have built dykes and intricate flood plains to guard against storm surges from the North Sea and rivers bursting their banks. But scientists are warning that rising sea levels and violent storms prompted by climate change could tip the balance against their flood defences.
"There are three dangers: sea levels rising due to melting of the Arctic ice cap; rising river levels due to more precipitation and the possibility of superstorms," says Rob van Dorland, climatologist at the Royal Netherlands Meteorological Institute.
A recent report published by the institute predicts sea level rises of between 35cm (14in) and 85cm (33in) by 2100 and up to 2.5m by 2300 on the Dutch coast. If this combines with the more powerful and longer storms that climatologists are predicting because of climate change our water defences won't be able to cope, says van Dorland, who believes that massive state investment is needed to adapt to changing weather patterns.
In Ameide the dyke is already being reinforced and heightened to cope with the rising water levels in the Lek during winter and spring. The din of mechanical diggers is almost unbearable in Jan De Wit's house, which is perched on the lip of the dyke.
"My house now sits almost a metre below the top of the dyke but it used to sit well above it," says De Wit, a teacher who is also a volunteer dyke monitor. He has signed up to check the structure of the massive dyke during flooding to check for subsidence.
He recounts the last occasion that he needed to monitor the dyke in a major flood. "It was in 1995 when the Lek threatened to pour over the dyke. Hundreds of thousands of people across the Netherlands were evacuated during the flood, although Ameide was not affected as the flood waters never breached its dyke," says De Wit.
But the Netherlands' traditional reliance on dykes to hold back floods is now being questioned.
There are more than 3,500km (2,175 miles) of dykes and 16,495km (10,250 miles) of levees to protect the coast. Complaints by locals, concerned at the increasing size of flood defences and concerns about the cost of upgrading the defences led the Dutch cabinet last year to propose a new spatial planning policy.
"This change involves the idea that the Netherlands will have to make more frequent concessions," says Karin van Rooijen, spokeswoman for the Dutch ministry of public works and water. "We will have to relinquish open space to water, and not take back existing open spaces, in order to curb the growing risk of disaster due to flooding." The strategy aims to create more space for rivers and lower high water levels by deepening the forelands of rivers, displacing dykes further inland and enlarging existing flood plains. Reinforcement of dykes is included only if other measures are too expensive or inadequate, according to the plan, which will cost at least €2.1 billion.
The strategy is likely to prove controversial as it could involve the displacement of tens of thousands of people who live on flood plains. But the government insists there is no alternative.
"Only by relinquishing our space can we set things right; if this is not done in a timely manner, water will sooner or later reclaim the space on its own, perhaps in a dramatic manner," says van Rooijen.
But while the threat of flooding is posing a headache for policymakers, Dutch firms, which are the recognised world leaders in defence technologies, are stepping up efforts to export their expertise overseas. Less than an hour's drive away from Ameide in the village of Maasbommel, the Dutch firm Dura Vermeer is pioneering a "floating home" concept that it believes it can sell abroad.
It has built 14 floating homes and 36 amphibious houses, which are designed to float on flood waters. At low water level the houses rest on concrete foundations. They are tethered to flexible mooring posts that cushion the swell of the water and prevent them floating off.
"It is Dura Vermeer's answer to the tense relationship between the growing need of land for housing and the need to preserve flood plains and retention areas in the Netherlands," says the company, which has already shown the houses to public officials from New Orleans, which was devastated by flooding in August 2005.
The 65sq m colourfully painted homes sell for about €260,000. One owner, Mieke Boots, said: "We bought this as an investment and come here to stay every weekend. It is wonderful living on water, although it can be a bit noisy when it is windy."
Dutch firms are already supplying technology and expertise to water construction projects in Japan, Dubai and China, according to SenterNovem, a government agency that provides public funds to companies carrying out innovative research in the field.
"The Netherlands is a highly dense country but we also have climate change bringing extra difficulties of more rain and higher sea levels. So we have to create flood plains but also use the land for housing," says Pyter Hiemstra of SenterNovem.
"Now we can sell our expertise overseas to other countries affected by climate change."