Storm tides and coastal protection on the German North Sea shore

Guest post by Michael Palmer

The North Sea is the shelf sea between Great Britain in the West and continental Europe in the East and South. It has strong tidal movements, and is prone to storm surges that occur when northwesterly winds whip the sea against the continental coast. The most severe surges tend to arise when storms combine with spring tides, during which the sun, moon and earth are all lined up to maximize the gravitational pull on the water. The coastal people have long fought and laboured to protect their lives and their land from the elements. Their history should be of interest to anyone worrying about the best way to adapt to “climate change” or “extreme weather”.

I first encountered the North Sea in 1971, when my parents took all of their six children to spend the summer with relatives on the small North Frisian island of Pellworm. This island is located in the Wadden Sea, off the west coast of Schleswig-Holstein, Germany’s northernmost province.

combined-map-1000Map of the North Sea and adjoining countries (left), and blow-up of Pellworm and its surroundings.

The Wadden Sea is an area of coastal shelf so shallow that the sea floor becomes exposed during every tide of ebb. For several hours, the sea retreats by some 10 kilometers or more, and it then becomes possible to walk across the mudflats from one island to the next. Such walks might be a little scary and sometimes outright dangerous, for the next island may be hours away; the mudflats can turn from firm to swampy quite abruptly, and into some areas, one should not venture without a local guide. However, these walks were also fun; one could catch little fish, crabs and other creatures that were trapped in little pools and puddles left behind by the retreating water.

15515107

A walk across the Wadden Sea (ripped off from someone’s blog). Original soundtrack and smell not available, but both can easily be recreated using a plumber’s helper and a clogged lavatory.

But what I found even more fascinating were the shards and bricks, the teeth and bones, upon which we occasionally stumbled several kilometers from the shore. I learned that these were the remnants of settlements whose inhabitants had perished in a great flood in 1634, and that an earlier flood had taken even more lives and land in 1362. Indeed, these two floods had been only the locally most devastating ones in a long series of storm tides. My father then told us that only nine years earlier, in 1962, a storm tide had killed more than 300 people in the city of Hamburg, where he then used to live and study, and that he had helped to collect the drenched bodies in the aftermath.

mejer-1000.jpg Above: Historical map of Pellworm and its surroundings. This map was drawn in 1652, that is, shortly after the great flood from 1634. The island named “Nortstrandt”, in the center of the image, is no more; the larger of its two remnants, on the left, now forms the island of Pellworm. The areas that surround the islands, shaded with criss-crossed lines, are the mudflats of the Wadden Sea; they presumably were solid ground prior to the great flood of 1362.

These stories of danger and disaster formed a stark contrast to the serene summer landscape, with sheep grazing and dozing right next to gentle waves. However, that the threat was real was plain from the aspect of the coastline fortifications. The entire island of Pellworm, and the continental shoreline as well, were protected by a dike seven meters high. Grass-covered, it had a fairly shallow profile towards the sea, although more steep close to the crown. On the island, this dike had just barely withstood the flood of 1962, and improvements were already underway; in some places, the dike had been elevated another one or two meters and also been given an even shallower and more regular profile, so as to minimize the impact of the onrushing storm waves. Indeed, these new dikes would prove their worth in the even higher flood of 1976; all failures in that flood occured in segments where this modernization had not yet been completed.

seedeiche

Modern sea dike on Pellworm (left, source), and historical illustration of a sea dike (source). The very shallow profile of the modern dike minimizes the impact of onrushing storm waves; it also belies the height of the structure, which approaches 10 m. In the photograph, it is ebb tide, and the sea has receded beyond the horizon.

The shoreline was also decorated with breakwaters built from wooden poles and brushwood, which served to slow the tidal movement, promote the deposition of sand and mud, and ultimately reclaim land from the Wadden sea. The process of land reclamation could be seen in its various stages. Saltwort settled on freshly risen banks and aided in their further growth and stabilization. Drainage trenches were dug, and the excavated mud used to further elevate the banks in between, which then became overgrown with grass; the trenches eventually became filled in by further mud deposition to form a continuous area of elevated marsh land. In many places, reclaimed marshes had been surrounded with new sea dikes and turned into farm land.

A little further behind the new sea dike, older dikes were still visible; and the older they were, the lower, steeper and less adequate they seemed. Yet, even these older dikes were still being maintained, and where roads cut through them, wooden barriers were on hand with which to close the gaps in emergencies. Moreover, these dikes were hundreds of years old, and considering that they had been erected by hand, they actually were quite impressive in their own right.

From all this, it was quite clear that coastal protection was, and for a long time had been, taken very seriously. This is also illustrated by historical records, which show how even since the middle ages, dike construction has deeply affected the lives of the hardy Frisians who have been living along the sea shore throughout written history. In those early days, Frisian men were supposed not to travel any further from their homes than allowed them to return the same day, so that they might be ready to defend their land both from the floods and the “heathens” (that is, the Vikings). Every landowner was assigned a stretch of dike for maintenance, in proportion to the size of his land; and an elected Deichgraf (literally, “dike earl”) made sure that this maintenance was properly performed. If a landowner failed to maintain his dike, his property was forfeited and fell to the next person willing to assume those duties; if a person wantonly or negligently caused damage to the dike, their limbs or lives were forfeited as well.

While dike construction and maintenance was initially a local concern, it gradually came to be organized on a larger scale. The observation that dikes time and again failed before the floods, as well as increasing centralization of political power, likely both contributed to this development. Only with this larger scale organization did it become possible to tackle the enclosure of newly reclaimed marshland. Such a project had to be completed in one summer, since the new dike had to be completed before the onset of the next stormy winter season. For one historical construction project, which was carried out about 400 years ago, it has been estimated that more than 500 men toiled for 7 months, 6 days per week, and 14 hours per day, to move 500,000 cubic meters of soil for the erection of 6 kilometers of new dike. (This was hard work. The black, alluvial soil of the marsh land is exceptionally dense and heavy; teams of four Belgian horses used to be put before a single plow share on this soil.) Once the earthwork had been completed, the new dike had to be covered with sods of turf, which were fastened to the soil with rye straw; the straw was poked into the soil with several hundred stitches on each square meter.

The engineers who oversaw such projects came very often from the Netherlands. Holland is even more crucially dependent on its coastal defences, since so much of it lies below regular sea level, and the Dutch have always been the acknowledged pioneers and masters of the trade. Indeed, the modern coastal dikes and bulwarks of Holland, from the Zuiderzee works to the Eastern Scheldt dam, are not just impressive but downright magnificent. Bulwarks have been built across the many river arms of the Rhine delta, so as to prevent the surging sea water from pressing into the rivers and flooding the settlements upstream. (Indeed, this is what happened in Hamburg in 1962; that city is 50 km upstream from the estuary of the Elbe river and had not been considered in grave danger from the North Sea storm tides.) Construction of these bulwarks was begun after a disastrous flood in 1953, which broke through the dikes in 89 places and killed more than 1500 people in the country.

Maybe some reader from Holland will find it worth their time to pitch in with a more thorough and substantial description of Dutch coastal management than I could give.

While the floods of 1953 and 1962 claimed approximately 2500 casualties—apart from Holland, England and Belgium were also significantly affected in 1953—the highest flood on record, at least as far as the German coast is concerned, actually occurred in 1976. Nevertheless, damage was minor; clearly, the new construction that had been motivated by those to recent floods worked as planned to protect the coast and its people. With even further enhancements having been made since, nowadays even exceptionally strong storm surges have become uneventful and barely even make the national news anymore.

When I first came from Germany to North America, I was struck by the absence, or near absence, of coastal defences in New York and many other places. How could people have been so imprudent? It may simply have arisen as a consequence of immigration—most immigrants to those places probably came from landlocked places in Europe, and therefore lacked the sense of danger that has become second nature to the indigenous people of the North Sea coast.

So is there a moral to this story? Maybe this one: When confronted with rising seas, don’t belabor “extreme weather”—instead, get in touch with some Dutch engineers ASAP.

Thanks for reading.

Michael Palmer

Department of Chemistry
University of Waterloo
Waterloo, Ontario

42 thoughts on “Storm tides and coastal protection on the German North Sea shore

  1. Defense lawyers on call?

    Seems to me this has a lot to do with pressure on land, Germany is an old country whereas America is recent and huge. Definitely odd when you find a country behaving very differently from what you thought was normal.

  2. More like impudent, the funny thing is that we fix these problems with money printed on German presses.

  3. The problem is that hominids of this era, on the NA continent, at the very least, do not have such tribal memories. They might very well have to experience it for themselves. One might perhaps be statistically more solvent quoting Sirocko, et al, 2005, “A late Eemian aridity pulse in central Europe during the last glacial inception”, nature, vol. 436, 11 August 2005, doi:10.1038/nature03905, pp 833-836:

    “Investigating the processes that led to the end of the last interglacial period is relevant for understanding how our ongoing interglacial will end, which has been a matter of much debate…

    “The onset of the LEAP occurred within less than two decades, demonstrating the existence of a sharp threshold, which must be near 416 Wm2, which is the 65oN July insolation for 118 kyr BP (ref. 9). This value is only slightly below today’s value of 428 Wm2. Insolation will remain at this level slightly above the inception for the next 4,000 years before it then increases again.”

    But that is more than 140 characters methinks (Fail)………

  4. In Canada and the U.S., should winter snowfalls become more frequent and deeper, inland flooding in the northern states of the midwest wlll aslo become more frequent. In Minot and Fargo North Dakota, the “dikes” are formed from many sandbags, filled and put in place by students and many volunteers.

  5. “Kiel Canal has been sadly neglected over the past two decades. I’m pleased that I was able to fight for the necessary funding for the fifth lock chamber in Brunsbüttel and that the public tender is now under way. The next step is to submit a time schedule and plan of measures for Kiel Canal as a whole.”

    http://www.dredgingtoday.com/2013/04/11/germany-to-strengthen-maritime-economy/

    If I had time I would look for parallels between economic decline and neglect of great infrastructure. That Europe’s ‘great powerhouse’ has let the Kiel Canal fall into disrepair (it is the world’s busiest by far) tells a sorry tale. And as for shutting down its nuclear industry, you can only wonder at the process of decay.

  6. Steve, living in Germany I can tell you the problem is not money, it is misinformed “Green” politics. “Green” propagandists, their misinformation and sometimes outright untruths to young people are the cause of the shut down of nuclear, and the prevention of the building of new ‘normal’ power stations. They also want to increase taxes to 49% to fund “ecological renewal” – whatever that means – and there are fools who will still vote for them, mainly young, professional and well educated, but totally lacking any grasp of reality.

    I have the perfect solution. Round up all “Greens” and make them live in the areas prone to extreme weather on a regular basis. No “mod con”, just the tools our forefathers used to defend themselves. How “Green” is that?

  7. The Germans will need more coastal protection since they are building more evil Coal power stations, which as we know will cause the sea level to rise by 50 meters or more [/sarc].

    Sorry for the frivolous comment, but after a couple of hours reading the latest AGW dribble on the web, it is difficult to be serious.

  8. Thanks Michael Palmer for a really interesting read. One of the many things I like about WUWT is the occasional “off the beaten” path article that is nevertheless of considerable relevance to the central issue of climate change.

  9. “noaaprogrammer” wrote (April 28, 2013 at 9:11 pm):

    In Canada and the U.S., should winter snowfalls become more frequent and deeper, inland flooding in the northern states of the midwest wlll aslo become more frequent. In Minot and Fargo North Dakota, the “dikes” are formed from many sandbags, filled and put in place by students and many volunteers.

    It is important to note that Minot and Fargo are on the Red River, which has the unusual characteristic (for a Northern Hemisphere river) of flowing north, where it eventually drains into Manitoba, Canada’s Lake Winnipeg. If southern North Dakota warms up earlier than usual and/or more rapidly than usual in the spring, large volumes of melt water will begin their journey downriver (i.e., north) while the lower reaches of the river in northern North Dakota and southern Manitoba are still frozen.

    When spring comes earlier than usual and/or warmer than usual to southern North Dakota, the risk of flooding is greatly increased along the length of the Red River. This is true whether or not there’s been higher-than-usual snowfall. (Of course, adding more snow can make a bad situation worse.)

  10. What happens to the water collected from heavy rain? Do they have (huge) pumping systems?
    Presumably there must be duplicates.

  11. Nice story! I am living near the Dutch border, not far from where the water did come with the 1953 flood disaster. I have some remembrances of it with water everywhere and on a distance a few roofs and a church tower above it. The Dutch and Belgians indeed learned from it and reinforced the dikes for a once in 1000 years spring tide storm surge. Mostly by shortening the necessary protection by closing several waterways with open dams that can be closed at storm surges. That are the delta works, which are very impressive to see:

    http://en.wikipedia.org/wiki/Delta_Works

    With the engineering knowledge built up by these works, Dutch engineers now are helping Bangladesh to built their defences against hurricanes and river flooding and they advised New Orleans after Katrina. If the latter will do something with that advice, that is another question…

    I have always some grin if somebody warns for the influence of global warming on a “dangerous” increase in sea level: the lowest point in The Netherlands is some 12 meter below average sea level. A firm NW storm at spring tide adds some 10-12 meters to that. Why would one be afraid of some 0.5 meter extra from sea level in the next 100 years? Time enough to increase dike height with a few meters if necessary at all…

  12. Great story. The sheer height and volume of seawater involved in these tidal and storm surges certainly puts the whimpering about possible sea level rises of a metre or two over many years into perspective.

    Can anyone give an update on what has been happening to reinforce New Orleans post Katrina?

  13. In his “Origins of the British”, Dr Stephen Oppenheimer traces the resettlement of England, which began approximately 10k YP, at a time when there was no North Sea or Irish Sea. English ancestors were able to walk from Portugal to Ireland without every stepping on current Spain, France or England. His book traces the genetic migrations in response to geologic changes. The Flandrian Transgression, app 6k YP caused massive rise in sea level world wide and created the islands of Ireland and the UK.

    In his exhaustive work “Underworld”, Graham Hancock pursues the origins of civilization beyond the current meme, 7k YP Mesopotamia myth with proof of coastal cities repeatedly inundated by rising seas since the start of the Holocene. The Seven Pagodas, at Mahabalipuram, off the eastern coast of India, show stone temples in stages down to 440 ft below current sea level. Such submerged coastal settlements exist world wide, as do local origin, biblical type flood myths.

    Only human hubris allows you to think that humans did then, or do now, or will in the future control sea level. The Holocene extinction saw the loss of 45 species of very large mammals from North America, including mammoths, mastodons, 900 pound saber toothed tigers and 400 pound dire wolves. Also extinct was the Clovis man, who had migrated from Europe. This migration was likely by foot and small boats, along the then continuous North Atlantic ice shelf. It is over-funded government hubris to blame Earth changes on a single parameter, benign, three atom gas. It is folly to let cloistered Climatologists dictate the conditions of Earth changes.

  14. After being berated by a warmist for not caring about the plight of the poor in countries like Bangladesh, I confused him completely by explaining why that country, far from being washed into the sea, was actually growing at a steady rate. Even if sea level rises, a bit ingenuity and investment would mean that instead of continuing to expand outwards it could grow upwards and stay ahead of the threat.

  15. Britain beefed up its North Sea defences – eventually – after the 1953 floods. One key element was The Thames Barrier, first in a state to be used in the 1982/1983 flood season. It was closed against what turned out to be a modest surge in January/February 1983. Due to fairly generous allowance for sea level rise/sinking of land* in SE England, it is currently expected to serve without major modification to the end of this century.

    *Tectonic plate recovery after thawing (and therefore removal of loading) of last ice sheets on North England & Scotland.

  16. Colonial,
    Actually Minot, ND straddles the Souris or Mouse River just down stream of the junction of the Des Lacs and Souris in Burlington, ND both of which (towns and rivers) are prone to flooding for the reasons you provided. The Souris in this area is now inadequately diked, but maps from the 1800s show areas that are now developed as river bottom hay meadows and park land, which is what it should have remained, but people needed to live close to the transportation artery provided by the Burlington Northern Railroad. Unfortunately the city fathers didn’t have the foresight to hire BN’s Engineers to protect low lying areas.

  17. The Gray Monk says:
    April 28, 2013 at 11:20 pm

    I hear you Mr Monk. My inlaws live in Kiel. They are stunned by the news that the canal would have to be closed to certain categories of ship for some time. It is the lifeblood/pride and joy of that corner of Germany.

    http://www.spiegel.de/international/germany/repairs-force-sudden-closure-of-vital-german-kiel-canal-shipping-lane-a-887759.html

    But even then I can’t convince them of the folly of the wind turbines that increasinly pollute the skyline and drain money away from truly useful infrastructure. They have some notion that they are generating energy to power BMW in Munich.

    There is some hope though as one or two of the family teenagers show a fliker of rebellion.

  18. The tidal bulge pulls on the moon, decreasing the speed of its orbit and causing it to drift farther away.

  19. Ferdinand Engelbeen: April 29, 2013 at 1:06 am
    “Time enough to increase dike height with a few meters…”

    who is going to pay that?

  20. maarten says:
    April 29, 2013 at 4:41 am

    who is going to pay that?

    The inhabitants, as good as they have paid the Delta works which are already in use. I have given my fair share, by working in The Netherlands for some 34 years and paying taxes there…

    BTW, the new plans for this and next century of the Delta Commission were based on exaggerated “projections” of the future sea level rise (several meters) from PIK, the notorious Potsdam Institute für Klimafolgenforschung, with Schellnhuber (advisor of Angela Merkel on climate change) and Rahmstorf as most visible exponents. The exaggerations were disputed by another German Institute (Geesthacht), where Hans von Storch is the main leading person.
    The report for the Delta Commission also was prepared under high influence of the concrete manufacturers, which have some interest in the results…

  21. Kevin M: I recall learning that the tidal bulge is always a bit ahead of the Moon (because the Earth rotates faster than the Moon orbits), and thus the gravitational tug of the tidal bulge accelerates the Moon, which acceleration causes the Moon to move further from the Earth thereby preserving net angular momentum within the system.

  22. ***
    When I first came from Germany to North America, I was struck by the absence, or near absence, of coastal defences in New York and many other places. How could people have been so imprudent?
    ***

    Seems people have regressed. The Jamestown, VA settlers from England knew to go well inland from the sea and find a protected, defensible, well-above water-level location for their settlement.

  23. Making New Orleans dryer is not necessarily a solution. New Orleans is basically made up of islands floating in silt. Enclosing the “land” and pumping out the water makes the land sink, so the dikes become less effective over time.

  24. When I first came from Germany to North America, I was struck by the absence, or near absence, of coastal defences in New York and many other places. How could people have been so imprudent?

    The land of the eastern US is sand, lots of sand. I live in North Carolina and the barrier islands known as the Outer Banks are beautiful, but constantly shifting. Bodie Island lighthouse was on an island and not far from the ocean. Today, it is no longer an island and a good distance away from the ocean. (It was also recently restored and you can now climb the lighthouse.) When you drive south there is a place called Oregon Inlet, so called because a ship named Oregon discovered it after a hurricane. But the currents constantly try to fill the inlet in. Further south is Cape Hatteras which had to be moved because it was in danger of falling into the ocean. And so it goes, a hurricane forms an inlet and erode the sand, the currents file the sand back in, repeat. And that is just the barrier islands.

    In the southern part of North Carolina, just south of Wilmington at the mouth of the Cape Fear river is Fort Fisher. During the American Civil War, Fort Fisher protected ships leaving Wilmington and was right at the ocean. Today it is about 1/2 mile from the ocean.

    The land is beautiful. People pay more to live next to the ocean. They know the risks because insurance companies will not insure property next to the ocean here. They know the risks and are willing or can afford to take them. We don’t have protection from the ocean because the land is never static and because people pay extra for the privilege to be there.

  25. maarten says:
    April 29, 2013 at 4:41 am

    “who is going to pay that?

    Being of a certain age, I can remember actor Walter Matthews appearing in a series of commercials for Fram Oil Filters as one of the mechanics who told auto owners, “You can pay me now. — Or pay me later.”

  26. Jeff says:
    April 29, 2013 at 6:16 am

    Making New Orleans dryer is not necessarily a solution. New Orleans is basically made up of islands floating in silt. Enclosing the “land” and pumping out the water makes the land sink, so the dikes become less effective over time.

    It is a mixture of defences: the main problem with Katrina was the flooding from behind: the storm surge pushed the water up the river and flooded the river side dikes. By making an open, but closable dam, still river water can go out at low tides, but with storm surges + spring tides, one can close the dam. Further defences are small islands before the coast that slows down storm surges and flood plains to move excess water away from the river (as would have helped New York against their recent flooding) and double dikes at the most important places, directly in front of the storm waves.

    The main question is if the cost of defences is not more than the cost of relocation of all inhabitants and building a new town on a safer location. For The Netherlands and Flanders (South of The Netherlands, with Antwerp as largest town), that is no question: most industry and people are situated near the sea and sea-arms/rivers because of the huge harbours and worldwide import and export of goods. The same for New York. I am not that sure about New Orleans…

  27. Thanks to Michael Palmer for an interesting post.
    Regarding the 2005 Katrina storm surge at New Orleans, it was known for many decades that the dikes (called levees, in the French manner) at Lake Ponchatrain were vulnerable to a severe hurricane. It was a game of hurricane roulette and the inevitable finally happened. The authorities are to blame for the disaster.

  28. Thanks Mr Palmer, very interesting stuff. I imagine those screaming loudest about sea level rise would be reluctant to put in 14 hour days six days a week to bolster their nearest storm defences.

    This belief that rising seas are the fault of Evil humans and that we can control the movement of the seas by keeping more coal and oil in terra firma is very King Cnut. He also felt he had some power over the rising seas back in the Mediaeval Warm Period. Dare I suggest there seem to be an awful lot of Cnuts among environmentalists…

    • Sorry Keith, my understanding of King Canute is the exact opposite of yours.
      When Canute succeeded to (or more likely, took) the English throne, his courtiers fell over themselves to tell him what a wonderful King he was. In fact he was a Viking warrior, and his eventual realms included, in modern terms, Scandinavia and England. To settle the matter of his alleged powers (his courtiers said his greatness included the power to control the sea) he ordered that his throne be carried down to the seas edge, and then he took up position in it. It is amusing to imagine, from our 21st century viewpoint, all of those courtiers, arranged around their King, still singing his praises, as he announced that he was going to stop the tide coming in. Then he formally ordered the sea not to return. So he sat in his throne, at the seas edge, and slowly, at the speed of tides, the water returned and surrounded the throne, and it’s occupant. Presumably the courtiers all retreated, or perhaps they were afraid to do so until the King did so, the record doesn’t say.
      He had made his point, which was, although King, with great powers over his subjects, he was still but a man. Only God had the power to control the sea.
      Latter-day Canutes are not the environmentalists, who aspire to control nature, but the sceptics, who know they cannot.

  29. Keith, the story about king Canute seems somewhat controversial – somewhere I read that he wanted to convince his most awestruck admirers that he could, in fact, not command the waves.
    Thanks everyone for your comments, and in particular to Ferdinand for his contributions and insights. New Orleans, with its location on swampy, low-lying ground, is not so unlike the coastal cities in the Netherlands, I would imagine. Still, it might be even more difficult to guard against hurricanes than North Sea storm tides, because hurricanes strike more locally but also with even stronger gales and higher surges – have I got that right?

  30. Michael Palmer says: April 29, 2013 at 9:44 am:

    New Orleans, with its location on swampy, low-lying ground, is not so unlike the coastal cities in the Netherlands, I would imagine. Still, it might be even more difficult to guard against hurricanes than North Sea storm tides, because hurricanes strike more locally but also with even stronger gales and higher surges – have I got that right?
    <<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>
    Storm surge during hurricanes depends on their force- some have higher wind speeds than others. Katrina was an usually powerful storm. On the entire Gulf Coast, there are no protective structures such as on the North Sea shores, except very locally, like New Orleans, which is at or below sea level. Sea walls built on the strands, as at Galveston, may reach 12-15 feet above water. There are hardly tides on the Gulf Coast, so no spring tides. People take their chances with storms and build on the strandline. People flee inland when hurricanes threaten. In 1906 Galveston was utterly destroyed with over 6,000 deaths during one storm. Nothing like that since. People simply run.

  31. Michael Palmer says:
    April 29, 2013 at 9:44 am

    Still, it might be even more difficult to guard against hurricanes than North Sea storm tides, because hurricanes strike more locally but also with even stronger gales and higher surges – have I got that right?

    Much depends of the geography of the coast: both The Netherlands and New Orleans have lots of mud/sands before the coast and little depth, so that breaks already some of the highest waves. But The Netherlands are at the end of the North Sea funnel, where waters are swept much higher with a NW storm + spring tide as was the case for the 1953 flood and was the case for New York with Sandy. That is less the case for New Orleans, which lies on a much more even coast. On the other side, hurricanes give far more wind speed. Katrina caused about 9 m surging with its highest levels around Biloxy and surroundings in Mississippi, not directly around New Orleans, where it was 5-6 meters at the seaside and about 4 meters in Lake Pontchatrain. The Netherlands surge in 1953 was about 4.5 meter above average sea level + the maximum wave height, which was going over the height of the dikes of that moment, ultimately breaking the dikes at a lot of places.

  32. Arcadis to study flood defence scenarios for New York City

    http://www.dutchwatersector.com/news/news/2013/04/arcadis-to-study-flood-defence-scenarios-for-new-york-city/

    Some history on Water Boards, the oldest democratic institutions in The Netherlands, still virtual independent from local and central government:

    http://en.wikipedia.org/wiki/Water_board_(The_Netherlands)

    (A good habit never dies: the verb “polderen” is used when government, employers and unions try to find common grounds for closing deals on economic affairs. Just as it is done for ages by water boards about “keeping the feet dry”).
    Tax revenues of the 25 water boards totalled 2 billion euro’s (2008), mainly for maintenance.
    Households in polders pay upto 100 euro/year, polder land owners pay 0,05% of the commercial value.

  33. Peter Melia says:
    April 29, 2013 at 12:44 am
    What happens to the water collected from heavy rain? Do they have (huge) pumping systems?
    Presumably there must be duplicates.” Yes, the entire flat land is covered with a grid of canals to absorb the surplus in water. The water level in the canals is controlled by a network of pumping stations. At first the Dutch used windmills to turn big lakes into land. For this purpose they first build a dike around the lakes and a ring canal connected to the sea. The mills were build on top of the dikes. During the steam age the windmills were replaced with huge pumps propelled by steam engines like Cruqius which is now a museum. Today electric pumps are used although for emergency purposes and back up we still have an old steam propelled pumping station in use. http://en.wikipedia.org/wiki/Cruquius,_North_Holland

  34. In the London underground the stations near the thames have watertight doors, I don’t think they have been tested because of the embankments and the thames barrier, the NY metro, nothing but then they have the feds to pick up the tab. Arrogant NY sure are must be run by democrats!!

  35. Thanks Michael and Rosarugosa – you’re absolutely right. I should’ve known that the perceived modern-day ‘consensus’ of the story is bass-ackwards ;-)

    Whenever one sees reference to Cnut in pop culture (certainly in the UK), it’s regarding him as being so arrogant as to believe he could control the tides. As you say, a little digging shows that he was proving the opposite point.

    The McKibbenites may not be Cnuts, but…

  36. “Who is going to pay that” ?

    Well, all citizens in the Netherlands owning houses pay for it via a regional tax called “waterschapsbelasting”.

    I pay around 300 to 400 euros yearly; my house is around two times the average value of houses in the Netherlands, so most households will pay around 150 to 200 euros per year; the “waterschapsbelasting” is based on the value of the real estate. It varies a little bit according to how many seadikes or river dikes there are to be maintained in the region.
    The really large projects (like the “Deltawerken”) are paid out of the central government’s general budget.
    I’m not a collectivist, but this is one of the exepctions where it absolutely pays off to organize the defences against the water collectively. And my house is located four meters below sea level in a polder called Flevoland which also happens to be the largest artificial island in the world. So it is logical that you have to contribute something to maintain the polder.

    I consider the 400 euros a small price to pay for what is effectively much better insurance coverage than what any insurance company could possibly offer me. If our dikes were badly maintained, the insurance company would probably not be able to offer any insurance coverage at all, because the risk is far too large.
    We learned this the hard way again in the nineties, when we had some river floodings (river Rhine and Maas/Meuse) and insurance companies were seriously considering to withdraw flood coverage from the home insurance. The river dikes have been improved tremendously since then. Also the rivers have been given more room to flood in certain river bank areas with no or little housing, causing the river levels to rise less is case of floodings.

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