Dia 1

1
The Closure Dike.
2
The Afsluitdijk (English Closure Dike) is a
major dike in the Netherlands, constructed
between 1927 and 1933 and running from Den Oever
on Wieringen in North Holland province, to the
village of Zurich in Friesland province, over a
length of 32 km (20 miles) and a width of 90 m,
at an initial height of 7.25 m above sea-level.
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It is a fundamental part of the larger Zuiderzee
Works, damming off the Zuiderzee, a salt water
inlet of the North Sea and turning it into the
fresh water lake of the IJsselmeer.
4
Previous experiences had demonstrated that till
(boulder clay), rather than just sand or clay,
was the best primary material for a structure
like the Afsluitdijk, with the added benefit
that till was in plentiful supply in the area it
could be retrieved in large quantities by simply
dredging it from the bottom of the Zuiderzee.
Work started at four points on both sides of
the mainland and on two specially made
construction-islands (Kornwerderzand and
Breezand) along the line of the future dike.
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Original plans for the works date back to the
seventeenth century, but it was not until a
severe flood struck in 1916, that the
Dutch parliament finally agreed. At this time
Cornelis Lely (after whom Lelystad is named) was
minister of transport and water management. He
had always been an advocate of the plan and now
had a chance to have the plan executed. The
single biggest structure in the project was a 32
km long dam, the Afsluitdijk ('closure dike'),
protecting the Dutch from the North Sea.
Cornelis Lely
6
But to test the waters the small Amsteldiepdijk
was built first to connect the island of
Wieringen to the North Holland mainland. Its
construction lasted four years and proved to be
a valuable learning experience for the much
larger Afsluitdijk. When the Afsluitdijk was
finished in 1932, the Zuiderzee was completely
dammed off and from then on would be called the
IJsselmeer. Total cost of the dam was about 700
million (2004 equivalent).
7
After damming off the sea, the next step involved
creating new land, new polders. This was achieved
by damming off portions of the IJsselmeer, and
then pumping all the water out. The first polder,
Wieringermeer, was dammed in 1929 and fully
drained in 1930. The third, the Noordoostpolder,
was not fully drained until 1942 and played a
vital role for the Dutch Underground resistance
during World War II, as the fresh polder offered
numerous hiding places.
8
After the war, work was started on draining the
Flevolands, a massive project totalling almost
1000 km². This area is now home to Lelystad and
Almere the latter is the fastest growing city in
the Netherlands (in part because of its
proximity to Amsterdam).
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Another large polder was planned in the
Markermeer, creation of which was heavily debated
until plans were officially abandoned in the
early 2000s. A new province, Flevoland, was
created out of the Noordoostpolder and the
Flevolands in 1986, thereby completing the Works.
10
This newly created land has led to a great change
of identity for towns like Lemmer, Vollenhove,
Blokzijl, the former islands of Urk and
Schokland, Wieringen and others. Kuinre suffered
from the change specifically because it was cut
off completely from open water.
11
In 1916 the dikes at several places along the
Zuiderzee (the current IJsselmeer) broke under
the stress put on them by a winter storm, and the
land behind them was flooded as had often
happened in previous centuries. This particular
flooding,however, provided the decisive impetus
to implement the existing plans to tame the
Zuiderzee. The concept of making the Zuiderzee
more docile had first originated in the
seventeenth century, but the ambitious solutions
sought then were not possible given the
technology of the time.
12
The Zuiderzee Works in the Netherlands turned the
dangerous Zuiderzee, a shallow inlet of the
North Sea, into the tame IJsselmeer, and created
1650 km² of land.
13
A new study, commissioned after doubts had arisen
over the financial feasibility of the project,
recommended that work should not only continue,
but should be accelerated. It was therefore
decided to start the next two major projects at
the same time, in 1927. The most important of
these would be the main dam, the Afsluitdijk
(Closure-dike), running from Den Oever on
Wieringen to the village of Zurich in Frisia
(Dutch Friesland) over a length of 32 km and a
width of 90 m, at an initial height of 7.25 m
above sea-level and an incline of 25.
14
Landsat photo of the IJsselmeer and surroundings.
The difference between the old land (dominantly
green), and the new lands (gained from the sea,
dominantly purple) is striking. Compare with the
figure above.
15
F1-coureur Robert Doornbos with a Formule 1 car
over the Closure Dike with 326 km pro hour.
16
1982 Afsluitdijk "De Steenzetter"
50 Years Closure Dike.
Roelof.