Global warming poses flood threat to Dutch
Copyright 1999, Reuters, All Rights ReservedFor hundreds of years, the dikes, dunes and ditches that crisscross the Netherlands have helped the Dutch succeed where King Canute failed. But experts say the lowlands cannot hold back the tide forever.
Global warming, accompanied by torrential rain and rising seas, could bring catastrophic floods to the Netherlands in the next millennium. Sea levels will rise by 24 inches in the next century, compared with an average of eight inches a century over the past 1,000 years, according to some forecasts.
This, coupled with predictions of monsoon-type rains, is worrying the Netherlands, where two-thirds of the population of almost 16 million already live below sea level.
"Environmental experts predict global warming will bring drier summers and wetter winters with extreme rainfall," said Jacob Hugo van der Vliet, chairman of one of the 63 regional water boards responsible for water management. "The rivers will have to drain more water and that means problems since we are at the end of the catchment area (in continental Europe)."
In 1953, catastrophic flooding killed 1,850 people in the Netherlands. On the night of Jan. 31, the dikes between the raging North Sea and the southern province of Zeeland proved too weak to hold back freak high tides and gale-force winds.
Surging waters submerged a large area of land, affecting thousands of homes and farms and forcing many people to take refuge on their roofs until they could be rescued. Of 72,000 evacuees, 10,000 still had no home nine months later.
The disaster led to the Delta Project to build dams to regulate sea levels around Zeeland's peninsulas and reinforce dikes. Zeeland has not suffered a severe flood since.
Rhine biggest threat today
The mighty River Rhine, cutting across northern Europe from the snow-laden Alps to the North Sea, poses the gravest threat to the Netherlands. This became clear in February 1995 when water levels along the key shipping route rose to 20 feet above normal, raising fears its banks would burst and forcing 250,000 people to flee their homes.
In the end the last wall of winter dikes held firm. Van der Vliet said the problem arose when the first line of defense, the summer dikes, overflowed, submerging the plains between the summer and winter dikes.
The floods caught thousands napping. Lulled into a false sense of security by many flood-free years, they thought it was safe to settle between the summer and winter defenses. City councils had pursued a policy of reinforcing the summer dikes in order to allow construction in the basin, though this reduced the river's drainage area. "Sometimes we need a flood to wake us up," Van der Vliet said.
After the 1995 floods, parliament passed an emergency law to strengthen 360 miles of dikes before the end of 2000, copying the 1953 Delta Plan. But experts warn that strengthening the dikes could ultimately increase the danger.
"The higher you build the dikes, the bigger the catastrophe when they break," said Van der Vliet. "When the tide is high, the water level is already five meters (15 feet) above land."
In addition, the Netherlands is sinking along an axis that runs from the southwest to the northeast. By 2050 land north of the line, already below sea level, will have fallen another 16 inches. Cities such as Amsterdam and Rotterdam, with solid foundations, should stay above water, but they could become islands if the dikes break.
Taking a step back
After heavy rains in September of last year, the government decided more had to be done and founded the advisory committee Water Management in the 21st Century (WB21). The committee will present possible solutions in the middle of next year.
"We can and did control the water to a large extent. We narrowed the river beds by using the flood plains for farming and even for urban expansion," said WB21 Project Manager Jan Hoeks. "But when it rains very hard there is not enough room for water storage and it accumulates in the low areas."
The committee is not seeking solutions in modern water management techniques such as raising dikes or increasing pumping capacity. "We have to take a step backward and give more room to water and to the rivers," Hoeks said.
While maintaining dikes along the coastline, the committee favors giving the flood plains back to the rivers. "Building is out of the question," Hoeks said.
It also says the authorities must set aside large areas to store excess flood water. This could pose the biggest challenge of all for policymakers as farmers, homeowners and local lobby groups are determined to keep their land.
"We have a lot of knowledge of water management in the Netherlands. Technically we can calculate how much land should be set aside for storage. But it will take quite some work to make this land available as there are still a lot of financial, legal and environmental problems to solve," Hoeks said.
Maybe the prospect of wet feet in the next millennium will provide the incentive the Dutch need.