Dutch Can Teach U.S. About Controlling Floods
November 15, 2012
By Andrew Higgins, International Herald Tribune
High-tech defenses help, but so do the daily rounds of the muskrat hunters.
Entrusted with ensuring that the central Netherlands never suffers a calamity like the one visited on New York by Hurricane Sandy, Willem Van Dijk, guardian of the dikes in Flevoland Province, sends out an 11-man team each morning to combat a grave menace to the world`s most advanced network of storm defenses.
Their mission is to kill muskrats. Using metal cages and spring- traps baited with carrots, Flevoland`s rodent hunters provide a low- tech but vital service in an elaborate and highly effective defensive system that ranges from flood-control techniques first developed in the Middle Ages to futuristic steel structures that, operated by computers, move to block storm surges when water levels rise too high.
In recent days, the peerless expertise and centuries of experience of the Dutch in battling water have been widely hailed in the United States as offering lessons for how New York and other cities might better protect people and property from flooding.
But Dutch officials and hydrology experts who have examined the contrasting systems of the two nations say that replicating Dutch successes would require a radical reshaping of the U.S. approach to vulnerable coastal areas and disaster prevention.
Disaster relief generally takes precedence over disaster avoidance in the United States, said Wim Kuijken, the Dutch delta commissioner, who is responsible for overall water-control policy. "The U.S. is excellent at disaster management," he said, but "working to avoid disaster is completely different from working after a disaster."
The Netherlands does not have hurricanes but does suffer ferocious storms that hurtle in from the northwest, funneled toward the Dutch coast across the North Sea. Centuries of living so close to the edge have cultivated a keen awareness of the consequences of flooding and the need to prevent them in a country where two-thirds of the population, including most residents of Amsterdam, Rotterdam and The Hague, live on flood-prone land, much of it below sea level.
"We know that if things go wrong, we pay for decades," Mr. Kuijken said. As a result, he said, the Netherlands has been able to mobilize enormous resources to anticipate and minimize the risk of flooding.
For most of their history, the Dutch held back water in land that began as a large peat swamp by creating an elaborate mosaic of dikes, which, put together today, would stretch for about 50,000 miles. After serious floods in 1916 and 1953, however, it was decided that constantly building, raising and reinforcing dikes was no longer feasible, particularly in densely populated areas.
This led to a series of huge dam projects to seal off flood- prone river estuaries and inlets from the sea. This shortened the coastline and sharply reduced the land area exposed to storm surges. On waterways that could be not be sealed because of heavy shipping traffic, like the estuary leading to Rotterdam`s port, movable barriers were erected instead.
In response to the 1953 floods, which killed more than 1,800 people, the state laid down strict new rules, ordering that flood defenses be made strong enough to resist a storm so severe that, according to computer projections, it would occur only once every 10,000 years.
If a dike breaks in Flevoland, a province nearly 12 feet below sea level that is made up entirely of land reclaimed from the sea, it would take just 48 hours for it to be submerged, Mr. Van Dijk said. Dike maintenance includes killing muskrats because they weaken the levees by burrowing deep into them to create nesting chambers.
"We either kill the rats or the water kills us," said Peter Glas, president of the Dutch Association of Regional Water Authorities. Those elected local bodies trace their roots to the 13th century and are empowered to levy taxes.
Each year, the Dutch government spends about EUR 1 billion, or nearly $1.3 billion, on water control, and the local water boards spend hundreds of millions more. Mr. Kuijken, the delta commissioner, said the heavy investment involved a careful cost- benefit calculation.
Capital investment on mammoth construction projects has added further billions to the total bill. The Delta Works, a construction program begun after the 1953 flood, cost the equivalent of EUR 10 billion and took more than four decades to complete. The Maelantkering, a movable storm surge barrier near Rotterdam that is twice as long as the Eiffel Tower is tall, was finished in 1997 and has been used only once, in November 2007, to block a storm surge.
Bas Jonkman, professor of hydraulic engineering at the Delft University of Technology, gave a presentation at National Hydrology Day meetings comparing flood disasters around the world: the Netherlands in 1953, New Orleans in 2005, northern Japan in 2011 and New York`s recent trauma. Since 1953, Dutch defenses have mostly held firm, though a near-disaster in the early 1990s led to the evacuation of 250,000 people and nearly as many cows and pigs.
Because of Dutch successes, Mr. Jonkman said in a later interview, "we have to go abroad to see how flood management systems respond in extreme situations." New York, he added, is particularly interesting because of its dense population and geographical similarities with the Netherlands.
The Dutch response to New York`s damage, he said, "would be to build big barriers," but a better and cheaper answer may lie in "local solutions like flood-proof entrances" to subway stations and parking garages. "You need to be careful not to just copy Dutch solutions," he added.
In the last century, these consisted largely of huge efforts like dams and other projects begun after 1953. Flevoland is the result of an earlier building blitz that followed the 1916 flood. A 30- kilometer-long dam sealed off the Zuiderzee, an extension of the North Sea, turning its northern part into a freshwater lake and its southern part into Flevoland.
Mr. Kuijken, the delta commissioner, said Dutch thinking today puts a priority on ways "to enlarge defenses in a natural way." The state, for example, is investing in Room for Rivers, a plan that aims to ease flooding by giving waterways space to move and even overflow. Last year the country spent about EUR 75 million to dump 20 million cubic meters of sand -- enough to fill more than 8,000 Olympic swimming pools -- off the coast north of Rotterdam to promote the formation of protective sandbars.
For New York, Arcadis, a big engineering consulting company, is proposing a movable barrier across the Narrows, which separates Upper New York Bay from the Atlantic Ocean. "The big challenge in the U.S. is how you get a big pot of money in place for an entire region," said Mathijs van Ledden, an Arcadis official.
Not everyone in the Netherlands shares the passion for eliminating risk. Residents of Uitdam, a small town in the north, recently protested plans by the local water board to raise the height of dikes, complaining that this would destroy their view of an adjacent lake. And in Flevoland, Mr. van Dijk said he got regular complaints from animal rights activists that killing muskrats was cruel and unnecessary.
Jacko Westerndorp, a muskrat hunter who cruises around the province each day in a Ford Ranger loaded with carrots, waterproof gear and traps, has little time for such concerns.
"We have to do this work," he said. "If the water comes, we all drown."
(C) 2012 International Herald Tribune.
Story image: A dike under the Bovenkerkerweg in Amstelveen, the Netherlands. Courtesy of Martin D and Wikimedia Commons
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