To live below sea level, ask Dutch
In the Netherlands, a system for holding back Mother Nature is a national priority that is suddenly of great interest to Americans. First of two parts.
By SUSAN TAYLOR MARTIN
Published November 6, 2005
[Times photo: Susan Taylor Martin]
Huge storm surge barriers at the entrance to the port of Rotterdam are part of a multilayered system to keep flood waters out of the Netherlands.
DELFT, Netherlands - More than half a century later, K. G. Bezuyen will never forget the night the North Sea swallowed part of his country.
Jan. 31, 1953. Bezuyen was 20, enjoying the weekend in a seaside village when a wicked gale sprang out of the northwest. He watched, amazed, as icy waves crashed over the road; no one had ever seen anything like it.
Farther south, the water surged inland for miles. Bezuyen's girlfriend rode the roof of her home to safety. Her parents died in the house, scratch marks high on the walls recording a doomed struggle to escape.
Until Hurricane Katrina swamped New Orleans last summer, the 1953 Netherlands disaster was the costliest storm flood on record. The toll: 1,835 people killed, many of them trapped asleep in their beds; more than 200,000 head of cattle drowned; 47,000 homes, factories and offices destroyed or damaged.
"It motivated me," says Bezuyen, who spent months aiding in the cleanup. He went on to become an engineer and helped design improvements to the Dutch flood defense system.
Today that system, the Delta Works, is considered the gold standard of flood prevention. Its crowning achievement - the massive storm surge barrier on the Eastern Scheldt River - has been called one of the seven wonders of the modern world.
In Katrina's wake, Americans are flocking to the Netherlands to see how lessons learned here might apply to New Orleans, another area that lies dangerously below sea level. Dutch engineers, meanwhile, have become sought-after experts in assessing what went wrong with New Orleans' flood defenses. While the final reports are not in, they came away with some sobering personal observations.
"It would be hubris to say that a well-designed structure could have withstood the fury of these hurricanes, but it was not state-of-the-art engineering," says Jurjen Battjes, a professor at Delft University of Technology. "Knowing, seeing what I did, I'm not surprised there was a failure."
After Katrina, Battjes was part of an international team dispatched to New Orleans by the American Society of Civil Engineers. Among the problems that struck him:
The city's flood barriers are a "haphazard" mix of concrete walls and earthen levees. Pilings beneath the walls were not deep enough to keep water from seeping underneath and scouring away the soil. The height of the barriers varies by several feet, creating weak points at which water, seeking the lowest level, poured across.
Battjes noticed something else: Flood prevention is not as high a priority in the United States as it is in the Netherlands.
"Being exposed to the dangers of the flood and its consequences is ingrained in the Dutch national soul. If you had such a breakthrough here, half the country would be at a standstill. I pity all those in New Orleans, but from a national point of view, the accepted level of risk there is much higher than the politically accepted level of risk here."
* * *
"God created the world and the Dutch created the Netherlands." It's a common saying, and not far from the truth.
Half of the Netherlands - a country twice the size of New Jersey - lies below sea level. Amsterdam's Schiphol Airport sits on what used to be a lake. The newest Dutch province, Flevoland, was uninhabitable until the 1980s; now it's home to 400,000 of the Netherlands' 16-million people.
When the last ice age ended 10,000 years ago, rising waters levels created the North Sea. The earliest settlers lived on shoreline ridges, followed by the Romans, who built the first dam, and monks, who protected their monasteries with the first true dikes. With the invention of the windmill 600 years ago, the Dutch were able to drain larger and larger areas.
The battle to hold back the sea has not always succeeded. Since 1000, there have been 113 serious floods. Moreover, the country is sinking while sea levels are expected to rise an estimated 4 inches to more than 3 feet over the next 100 years.
"In the long term, maybe we should give away our land to the sea, but a lot of people live here so that's not a solution," says Pieter van Gelder, a professor of hydraulic engineering at Delft University.
"The soil here is very soft - if it doesn't get flooded it will continue to sink at the same speed as the increase in water level, so there's a doubling effect. We will have to build stronger."
After the 1953 calamity, parliament approved the Delta Project. It involved sealing off many sea inlets and shortening the coastline by more than 400 miles.
There were environmental battles, especially over a proposed dam for the Eastern Scheldt River that would have destroyed the habitats of many bird and shellfish species. The government finally agreed to a 2-mile-long barrier with sliding gates that would prevent flooding but preserve the unique ecosystem.
The area near Rotterdam, one of the world's biggest ports, posed another challenge. Residents living along the New Waterway objected to reinforcing the dikes for fear historic buildings would be demolished. And the river couldn't be dammed because it would have blocked shipping to the port.
The government held a competition for the best design. The winner: two massive, curved gates that would swing shut only in event of extremely high water.
Six years and $450-million in the making, the Maaslant storm surge barrier was inaugurated in 1997 by Queen Beatrix and a fleet of powerboats trailing streams of red, white and blue smoke, the colors of the Dutch flag.
The gates have the world's largest hinges, and each gate is as long as the Eiffel Tower is high. The computer-controlled barrier is tested once a year - drawing thousands of spectators - but has never shut because of storm surge. The closest it came was during a nor'wester two years ago when water levels reached 9.8 feet or 299 centimeters - one centimeter, a third of an inch, shy of the automatic trigger point.
Even with completion of the Delta Project, the Netherlands was not completely safe, as 250,000 evacuees learned in 1995 when rivers in the southeast overflowed. "The Dutch sealed off the front door," a foreign newspaper commented, "only to find they were threatened from the back."
After that near disaster, hundreds of miles of dikes along the rivers were fortified and raised to almost 17 feet.
The Dutch defenses are currently designed to prevent the type of catastrophic flooding that occurs once every 1,250 years from rivers and once every 10,000 years from the sea. Dutch experts were surprised to learn the United States plans only for less serious flooding - that which occurs once every 50 or 100 years.
"In the nuclear industry, they use levels of one in a million years, but for floods, which are also very dangerous and cause a lot of damage, you should also protect yourself with those small probabilities of occurence," says Delft's Van Gelder.
A colleague, Henk Jan Verhagen, visited New Orleans before it was hit by Katrina, a Category 4 storm. He found it "very remarkable" that the Army Corps of Engineers couldn't tell him how safe the levees were.
"They said the dikes were built to withstand a Category 2 or 3 hurricane, but when I asked, "What's the probability you get a hurricane higher than 2 or 3?' they couldn't answer."
But, Verhagen adds, inadequate flood defenses are often due to political as well as technical factors. Even the Netherlands had become so complacent by 1953 that the chief engineer warned just a day before the terrible North Sea flood that the dikes were "no good at all."
"People get the idea that when a disaster happens long ago it will not happen again, so it's very low on the political agenda," Verhagen says. "Engineers in the U.S. are on a level to solve the problems (in New Orleans), but you need money and political support and when they are missing, it doesn't work."
As good as Dutch flood defenses now appear, experts say they have weak spots, especially along the coast where sand dunes are eroding. As climate change produces heavier amounts of rainfall, the risk of river flooding also increases.
In theory, there is almost no limit on how high or how wide dikes and New Orleans-style levees can go. But the more land they take up, they more apt they are to encroach on homes and businesses.
"Building a dike is relatively cheap and simple when you have space available," Verhagen says, "but they cost 10 to 100 times more in urban areas. I think we should be making plans to cope with sea-level rise, not investing in dikes now but realizing it could happen and save space."
As surprised as he was by New Orleans' flawed flood defenses, Verhagen was even more amazed on a visit to Florida. Unlike the Netherlands, where most of the coast is undeveloped and owned by the government, Florida's shoreline is covered with billions of dollars of private property within a few feet of sea level.
Some experts predict the seas could rise a meter, or 3.3 feet, over the next century. That would be worse for Floridians than for the Dutch, Verhagen says.
"When you're seven or eight meters below sea level, as we are, a meter doesn't make much difference. But in Florida, with a one meter rise, you're at sea level. We already have the infrastructure to protect ourselves, but it took us 100 years to build it."
Susan Taylor Martin can be contacted at firstname.lastname@example.org
COMIN G MONDAY
As the climate warms and sea levels rise, Dutch visionaries foresee their countrymen living in floating cities. The future of life in a flood zone is already on display in Holland.
[Last modified November 6, 2005, 02:26:28]
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