Wadden
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The Wadden is a coastal region stretching from the north-west of the Netherlands through Germany to the west of Denmark. It consists of the Wadden Sea, large parts of which fall dry during low tide, and the Wadden Islands (see below), a string of islands that shields this sea from the North Sea.
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[edit] Locations
Wadden coasts can be found all over the world in moderate climate zones. In tropical areas similar tidal areas are usually overgrown by mangrove forests. The biggest wadden area in the world is the aforementioned Wadden Sea. Other wadden areas can be found in Europe at sheltered places along the English Channel, Atlantic coast of France and the North Sea shore of England. Every other continent also have their sporadic wadden coasts, of which the largest are the ones near the Yellow Sea in Korea. Quite similar off the east coast of the U.S. are what is called the Outer Banks of North Carolina.
[edit] Prerequisites
There are a lot of prerequisites to be met for a wadden area to form, which is why this geological form is quite rare. Important is the availability of a shallow coastline which slows down the movement of water and enable the down wash of sand- and clay particles. When there is a very gradual increase of the sea level these strata can envelop an ever larger area. The height difference before the coast may be no more than one meter per kilometer while the difference between high and low tide has to be more than two meters. A wadden area nevertheless needs to be protected from strong sea currents. In the Wadden Sea the islands form this protective barrier.
[edit] Nature value
The extraordinary circumstances in a wadden area enable a very rich but also very fragile flora and fauna. The shallow water is relatively warm and rich with sea bed life. The wadden offer food and a resting place for birds and sea mammals. This is why environmentalists give the wadden area a high priority.
[edit] Origins
During the last ice age, which ended approximately 12,000 years ago, the sea level was about 60 meters below the current level. Due to melting of the ice caps the sea level rose and the water submerged the North Sea. The current coast line was reached approximately 7000 years ago. Due to the tides large quantities of sand were transported to the coast. This sand piled up near rocks and behind vegetation. There a large and unbroken line of dunes originated which extended all the way from contemporary Belgium to the mouth of the river Elbe, where now Hamburg lies.
Around the beginning of the era the increase of the sea level diminished. The sea had however already found its way through the dunes transformed the lower country behind to the current wadden plains. The continuous tidal currents wore gutters and this way the Wadden Islands arose.
[edit] Habitation
Long before the beginning of our era there were already humans inhabiting the Wadden area. Up to the eighth century after Christ most inhabitants live on ‘terpen’. The living conditions are bad, as this quote from Roman Pliny shows:
... what is nature and characterisations of living by people who live without trees or shrubs. We have indeed said that in the east, to the coasts of the ocean, a number of races in such needy conditions exist; but this also applies to the races of peoples which are called the large and small Ghaucen, which we have seen in the north. There, two times in each period of a day and a night, the ocean with a fast tide submerges an immense plain, thereby the hiding the secular fight of the Nature whether the area is sea or land. There this miserable race inhabits raised pieces ground or platforms, which they have moored by hand above the level of the highest known tide. Living in huts built on the chosen spots, they seem like sailors in ships if water covers the surrounding country, but like shipwrecked people when the tide has withdrawn itself, and around their huts they catch fish which tries to escape with the expiring tide. It is for them not possible keep herds and live on milk such as the surrounding tribes, they cannot even fight with wild animals, because all the bush country lies too far away. They braid ropes of zegge and biezen from the marshes with which they make nets to be able to catch fish, and they dig up mud with their hands and dry it more in wind than in the sun, and with soil as fuel they heat their food and their own bodies, frozen in northern wind. Their only drink comes from storing rain water in tanks front of their houses. And these are the races which, if they were now conquered by the Roman nation, say that they will fall into slavery! It is only too true: Destiny saves people as a punishment.
Around the year 1000 the construction of dikes is started. An important role is played by monks, among others those of the convent of Aduard. But even earlier already attempts are undertaken to control the sea. At the Frisian Peins (in the municipality Franeker) a 40 meters long stretch of dike has been discovered that supposedly descends from the first or second century before Christ.
In the late Middle Ages the bed calibration gets more and more form and the water nuisance decreases. As from the seventeenth century the dikes keep moving further outward due to land reclamation. The peak of this takes place in the nineteenth and twentieth centuries.
[edit] Conservation of the WestFrisian/Dutch coast
The dunes south of the Wadden Sea were also liable to this process, but man’s intervention prevented that the many storm surges changed the coast of the provinces North-Holland and Zuid-Holland into separate islands with wadden plains behind them. However, storm surges, around 1200, did break up the northern coast of Western Friesland into five island. Around 1600 four of these along the west coast had been again recovered, but Wieringen, to the south east of Texel, remained an island up to the 20th century.
[edit] Embankment of the wad
In Friesland and Groningen a lot of plans have been made to embank and drain the Wadden Sea. As a result the islands would become part of the mainland. Nature - and environmental movements have always been able to prevent this.
The only plan ever to be carried out was the construction of a dam from the Frisian Holwerd to Ameland, in 1872, on the then wantij which was not very successful. The dam already had so much storm damage shortly after construction started that already in 1882, the dam was given up. The dam has been almost entirely knocked off since that time, though there are, among other things to both ends, still some remainders to be found.
In the northern Wadden Sea building dams proves to be considerably simple. Nordstrand is now so much linked to the rampart by dikes that one can’t really call it an island anymore, and also Langeness, Oland, Nordstrandischmoor, Hamburger Hallig, Sylt and Rømø are all reachable by dams. Mandø is even reachable without a dam, by means of tidal road.
[edit] Development
[edit] Walking
The Wadden Islands are in continuous movement. The most important movement is the 'walking': the islands themselves are slowly but certainly moving from West to East. On the West side most of the islands disappear slowly in the sea and on the East side always larger sand-banks arise. This walking is also the cause is that most of the villages themselves are on the West side of their island. When they were founded generally they were situated in the center. In the course of the last centuries a lot of houses and even complete villages have already disappeared into the sea.
[edit] Hook shaping
The second movement is the hook shaping: along the sea breaches hookshaped sand ridges arise, which change form with the moving of the sea arm. By growth of these hooks new plates arise such as the Noorder - and Zuiderhaaks. Sometimes such a plate grows, originating where an island has been ‘walking’, and as a result of which that island recovers its lost area.
[edit] Types of ‘wadden coasts’
Research has shown that there are a limited number of possible types of wadden coasts. These depend on the circumstances on the spot, such as altitude of the tidal difference and average golf altitude.
In general it commonly applies that a large tidal difference in combination with a small golf altitude leads to a very ' open ' coast, without islands, with some sand plates and vast area with kwelders and wadplates.
When there is on the other talk of a large average golf altitude but a small tidal difference, a closed coast with very long islands (dozens km), with a lagoon with little to no wadplaten arises.
The following five categories wadden coasts are distinguished:
- type of 1: tide difference is dominant; no islands, vast kwelders and range plains
- type of 2: richels built by golves, sometimes ' primitive ' islands
- type of 3: many sea breaches and (short) islands
- type of 4: decreasing number of islands, longer islands
- type of 5: golf altitude is dominant; long joined tightly barriers
(Source: M.O. Hayes, Barrier island morphology ash a function or tidal and wave regime. In: S.P. Leatherman (ed) Barrier islands, from the Gulf or Saint Lawrence to the Gulf or Mexico, Academic Press, 1979.)
The average golf altitude near Rottum amounts to approximately 1 meter whereas the average tidal difference amounts to over 2 meters. Follows that the Dutch/German wadden coast fall into type of 3, characterised many (short) islands and many sea breaches.
[edit] Islands
[edit] Dutch Wadden Islands
(from West to East)
[edit] Inhabited
- Texel
- Vlieland
- Terschelling
- Ameland
- Schiermonnikoog
The Dutch islands have a surface of 405.2 km² and a total of 23,872 inhabitants.
[edit] Uninhabited
- Noorderhaaks
- Richel
- Griend
- Rif
- Engelsmanplaat
- Simonszand
- Rottumerplaat
- Rottumeroog
The names of all these places suggest this is the transition area between island and sand plate. Griend and Rottumeroog are generally considered as an island, the others are considered to disappear from time to time into the waves. The former island of Wieringen can be found at the top of noord-Holland, dead against the ‘Afsluitdijk’. (not mentioned on map).
[edit] German Wadden Islands
(from West to East and south to North)
[edit] Inhabited
- Borkum
- Juist
- Norderney
- Baltrum
- Langeoog
- Spiekeroog
- Wangerooge
- Neuwerk
- Pellworm
- Nordstrand (presently mainland)
- Inhabited Halligen
- Amrum
- Föhr
- Sylt
[edit] Uninhabited
- Lütje Hörn
- Kachelotplate
- Memmert
- Minsener-Oldoog
- Alte Mellum
- Grosser Knechtsand
- Nigehörn
- Scharhörn
- Trischen
- Süderoogsand
- Norderoogsand
- Japsand
- Uninhabited Halligen (Habel, Südfall, Norderoog)
The German islands have a surface of 448.52 km² and a total of 53,296 inhabitants. It is possible to make a boat excursion from several German Wadden Islands to the small rock island of Helgoland which is situated 70 kilometres from the coast line in the German Bend. It is no real Wadden Island, but there are strong cultural links with the Wadden area. For one a dialect of Northern-Frisian is spoken here.
Not all aforementioned island are officially considered to be Wadden. For the definition of an island a minimum of 160 hectares must no longer be submerged during average high water by the North Sea.
[edit] Danish Wadden Islands
(from South to North)
- Rømø
- Mandø
- Koresand
- Fanø
- Langli (uninhabited)
South of Rømø lay in the 20th century still the only Danish hallig, Jordsand, but in 1999, the last remains proved to be gone. North of Fanø the sand coast has been opened and closed numerous times in the course of history, but at the moment the coast line is closed, and forms a whole again save for two west coast fjords. The Danish islands have a total surface of 193.8 km² and a total of 4,173 inhabitants.
