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Authors: Brian Fagan

Tags: #The Past, #Present, #and Future of Rising Sea Levels

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On January 31, 1953, an extratropical cyclone with winds of 145 kilometers per hour developed off northern Scotland.
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The storm swept into the North Sea. A huge storm surge dashed down Britain’s east coast, up the Thames, then across to the Netherlands. Great waves breached dikes and seawalls on the English side in more than twelve hundred places. Forty-six thousand cattle drowned; more than 64,750 hectares of farmland became salt contaminated and useless for many years; over 25,000 houses were damaged or destroyed in villages and towns. Remarkably, only 307 people died, thanks to heroic rescue efforts, but the economic effects were enormous. During the war years, no one had maintained the coastal sea defenses. The storm was a wake-up call. More than fifteen thousand workers, including British and American soldiers with heavy equipment, rushed to repair the damage before the next spring tide in mid-February. Fortunately, London avoided flooding by mere centimeters. The tide level at London Bridge in the heart of the city was nearly two meters above the highest ever recorded. Only a little water flowed over the London embankments. Dike breaks farther downstream had flooded the neighboring countryside and lowered the water level.

The lowest parts of the Netherlands in Zeeland and the southern part of South Holland withered under the onslaught of floodwaters from catastrophic dike breaches. Here, too, the sea defenses suffered from the neglect of the war years, as well as from a sense of security resulting
from a lack of serious flooding since 1916. Now the coast paid the price of neglect. Sea levels crested between 3.6 and 4.2 meters above normal and inundated as much as 4,100 square kilometers in short order. As the waters approached, families climbed onto their rooftops, but to no avail. At least 1,800 people died, and 70,000 flood victims required evacuation. Once the sea had flooded Zeeland and most of South Holland, the floodwaters dashed against a major dike, which protected a still-dry Rotterdam and more than three million people in North Holland. Part of the unreinforced dike gave way. The mayor of Nieuwerkerk requisitioned a riverboat and ordered its skipper to close the hole with its hull. Providentially, the barge turned sideward into the gap and acted like a floodgate, saving thousands of hectares from inundation.

When the surge waters finally receded, the destruction was truly catastrophic. In Zeeland alone, the dike breaches were over three kilometers wide. Thirty-nine kilometers of dike were heavily damaged. As recovery efforts got under way with the help of thirty thousand volunteers working on the dikes, the government formed the Delta Committee to make recommendations for the future. Dam construction to close estuary mouths accelerated in the years that followed under a huge project known as the Delta Works.
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One estuary in the Eastern Scheldt remains open. Following protests from environmental and fisheries groups, the Oosterscheldekering (Eastern Scheldt storm surge barrier) joined an eleven-kilometer gap between two islands, the largest and most ambitious of the thirteen dams that form the Delta Works. Huge sluice-like gates installed in a four-kilometer length of the barrier remain open except when the sea level rises three meters above the regular, specified height, a legally mandated figure. The Oosterscheldekering officially opened on November 5, 1987, exactly 467 years after St. Felix’s flood of 1530 inundated a huge tract of land upstream of the barrier. An inscription on the artificial island that forms part of the barrier reads: “Here the tide is ruled, by the wind, the moon and us.” The cost was staggering: 2.5 billion euros, well over 3.6 billion dollars.

One final project remained, the construction of a huge storm surge barrier for the Nieuwe Waterweg to protect Rotterdam. Two huge curved steel doors provide protection during surges, remaining submerged out of the way most of the time so that ships can pass. The barrier, opened in 1997, protects a million people from inundation.

Figure 14.3
The Eastern Scheldt storm surge barrier. Flickr.com/Fotografie Siebe Swart.

When completed, the Delta Works reduced coastal sea defense levees by seven hundred kilometers and allowed much better regulation of water for agricultural purposes. The sea defense works are a delicate balance between safety, economic factors, and the environment, but with no compromise on protection. But there is far more to coastal protection than just seawalls and levees, the latter tending to fence in rivers and cause them to flow more rapidly. The Scheldt River provides an example of what the future holds.

The Scheldt estuary has caused political controversy between the Netherlands and Flanders since the sixteenth century, mainly over competition between Antwerp and Rotterdam. The Scheldt Estuary Development Project (ProSes), set up in 2002, aims at fostering more sustainable development throughout the Scheldt estuary in the light of ever-changing sea defenses and future environmental changes to the river further in
land. The Scheldt estuary is one of the few remaining European river mouths that encompasses everything from fresh- to saltwater tidal areas and includes the largest brackish marshes in western Europe.
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The challenges of planning for the future are extremely complex, for there are many stakeholders. A river channel of at least 13.1 meters deep for the enormous container ships of the future is needed to keep Antwerp’s port competitive, located as it is at the hub of rail and highway networks to the heart of Europe. Farmers are reluctant to give up valuable hectares for flood basins in an area where agricultural land is in short supply. Important commercial and recreational fisheries need protection, while recreational boaters have a right to sheltered water away from shipping lanes. Each group of stakeholders in the region has valid needs and concerns, quite apart from the pressing urgencies of nature conservation in an estuary where the area of shallows and saltwater marshes has shrunk dramatically in recent centuries as a result of land reclamation and urban development. Above all, there is the issue of safety, a need for protection from rising sea levels and the catastrophic sea surges that coincide with strong northwesterly storms and high tides. The 1953 disaster was the catalyst for a new chapter in flood control work throughout the Low Countries. In Flanders, another major flood in 1976 that inundated parts of Antwerp and Ghent also prompted long-term planning for flood protection as far into the future as 2030.

As far as Flanders is concerned, the process of developing their long-term plans, known as a whole as the Sigma Plan, was, and still is, thwart with tension, especially over proposals to transform agricultural land into artificial floodplain as part of a sophisticated plans for controlled flood management. Some of the flood areas require the compulsory purchase of six hundred hectares or more of cropland by the government from the farmers. Belgium suffers from a shortage of open space for recreation, so the flood control areas are being created not only as potentially inundated basins but also as nature preserves and recreational areas with hiking trails and bike paths. The engineers chose the flood areas with great care, then lowered the height of the riverside levees, thereby allowing water generated by very high tides or storm surges to flow over them into the low-lying area behind them. A much higher dike at the inshore
extremity of the flood basin reaches a height of seven meters or so, while drains in the riverside levees allow floodwater to escape when the tide falls. The entire project not only creates flood control basins but also restores estuary environments that will thrive into the long-term future, when local populations are considerably higher. At present, flood control basins can provide protection against 70- to 180-year storm surges, but the long-term planning continues. Every aspect of the construction and completed projects is subject to constant monitoring of soil nutrients and water quality, as well as changing vegetation and animal populations. So tight is the control that even the sand and mud raised by ship channel dredgers is dumped in carefully specified areas to prevent damage to marshlands.

The Sigma Plan combines coastal protection with attempts to steer and store storm surge and tidal waters in carefully controlled ways, while at the same time paying careful attention to commercial, environmental, and human needs. All of this requires enormous sums and a long-term commitment to flood and coastal protection that worries as much about the development of Antwerp’s waterfront as it does about ports, fisheries, and farmlands. Everything looks far into the future; construction and monitoring continues steadily, with no illusions as to the difficulty of balancing modern industrial needs against those of people and the environment. Such approaches, expensive and long-term as they are, offer hope not only to those who live by the banks of the Scheldt, but also in other estuary lands, which may be able to adopt some of the lessons learned—if the funding can be found to help them achieve results.

WHATEVER THE SUCCESSES inland, one can never escape the unpredictable future. Today, the Netherlands sea defenses are the strongest they have ever been, but the work never stops, as new calculations reveal hitherto unsuspected weak spots. The defenses are continually being strengthened and raised to meet a huge safety margin, equivalent to that of a flood on a scale that would occur only once every ten thousand years for the western, and most densely populated, parts of the country. A criterion for floods that occur once every four thousand years applies
to less populated areas. Every five years, the authorities test the primary flood defenses against these norms. The results can be sobering. In 2010, about 800 kilometers of a total dike length of 3,500 kilometers failed to meet the norm, which is becoming ever stricter as research on wave action and sea level rise continues.

Have the Dutch mastered rising sea levels? The specter of humanly caused global warming looms. In 2008, the Dutch State Committee for Durable Coast Development, established in response to the Hurricane Katrina disaster in the United States, attempted to answer a fundamental question: Could people continue to live in the coastal zones under the most extreme scenarios? For example, they estimated large sea level rises of 1.3 meters by 2100 and 4 meters by 2200, much higher than other estimates. The committee members recommended measures that would cost about a billion euros (over $1.4 billion) a year. They urged a tenfold increase in safety norms, the strengthening of dikes, and intensified sand replacement to build up coastal beaches. In addition, they suggested lakes in the southwest be used as river water retention basins, at the same time raising the water level in the Ijsselmeer to provide additional freshwater. In response, the government set up a Delta Fund and a Delta Programme that provides not only long-term funding but also a mechanism for individuals, communities, and special interest groups to be involved in an integrated approach that addresses both local and national issues. At the same time, many cities and towns are moving ahead with their own plans as part of the scheme. Rotterdam is trying to make itself sea-surge-proof by 2025, including provisions for a neighborhood of environmentally friendly houseboats, a prototype for the long-term future.

Most coastal villages in the Netherlands have no view of the ocean. The sea hides behind great ramparts that are as high as thirteen meters and up to forty-six meters deep. A steep climb to the top lets you see the North Sea crashing against reinforced concrete and stone. Look behind you and you realize at once just how vulnerable coastal cities, towns, and villages are in a densely populated country of which over half is below sea level. Widening and raising dikes will be an uphill battle against the North Sea, but there is no debate about the need to prepare
for the long-term effects of the rising sea levels, increased storminess, and surging rivers predicted for the future. Large-scale engineering is a way of life in the Netherlands. Every year the Dutch spend billions of dollars on infrastructure and sea defenses, on raised seawalls and river dikes, and also on heightened quays in major ports. They invest in massive water barriers and ever-larger pumping stations—all to keep the nation’s feet dry.

Defending the Netherlands from the North Sea requires long-term thinking, enormous sums of money that have to be planned for in advance, and a forward-looking strategy for the distant future that allows for more rapid climatic change than may in fact occur. Every plan, every study, every investment has one purpose—long-term security for future generations. There is no room for skepticism about global warming or future climate change along a coastline where 60 percent of the country is below sea level. Fortunately, the Netherlands can afford such long-term thinking. However, the question remains. Can the government and its people really ensure long-term safety? There is talk of planning for 125,000-year norms. But, as observers have pointed out, the 125,000-year event could occur tomorrow, without warning, and one has to be ready for it.

The Dutch and Belgians are sober, dispassionate planners and engineers, who are looking for long-term solutions. They are fortunate to have the resources to develop state-of-the-art armor for their coasts and estuaries. However, the scale of engineering and infrastructure needed for long-term success is so gargantuan that it may defeat us. Can we really rule the tides? The Dutch seem to think so, but only the distant future will prove them right or wrong. In the case of the wealthy, advanced Low Countries, the chances of success are as good as they can get. The same cannot be said of other parts of the world where millions of people live at the mercy of the ocean.

BOOK: The Attacking Ocean
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