De ground beneath Amsterdam and the surrounding area
is composed of alternating layers of sand, clay and peat. The sand was
deposited by rivers that flowed here 2.5 million years ago. During the ice ages
several layers of peat and sand blown in of the barren tundra were deposited on
the river sand. After this the main influence came from water (both the sea and
rivers and shallow lakes) that deposited clay. On this clay peat bogs and fens developed.
Originally these bogs and fens grew above sea level and
were dissected by streams and rivers that flowed into the Almere (a large lake
in the middle of what is now the Netherland). What was to become Waterland lay
above the inlet called IJ and Amstelland lay to the south. The area was
sparsely populated until around 1000 AD. Older centres of habitation are to be
found on the higher ground -on sand- furthers west (Kennemerland) and southeast
(Gooiland). Cultivation of the peatlands starts in the eleventh century.
Waterland had been cultivated around 1300. In Amstelland this took longer due
to the competition between the Earls of Holland and the Lords of Amestelle who
served as bailiffs for the Bishops of Utrecht. Holland tried to expand at the
expense of Utrecht by conquering the peatlands along the Amstel river. Waterland
with its many small lakes was aptly named and lay within Holland just south of
Friesland and originally also included the Zaanstreek (along the river Zaan) and
the Schermer and Purmer (two large lakes).
Both Amstelland and Waterland were cultivated in a
similar way by digging ditches at a right angle to a natural stream (Amstel or
Zaan) or a man-made drainage channel (called wetering) to drain the peat and
make it possible to plow the land. The direct consequence of draining the
peatland is that it starts collapsing on itself thus sinking the ground. In
combination with rising sea levels growing crops became impossible from the
thirteenth century onwards. Also low earth banks had to be raised to protect
the sinking land from flooding by the sea and also the former rivers. As a
result of the sinking of the land the naturally low lying rivers slowly got
raised above the level of the adjoining fields. This meant that on both sides
of the river banks were raised and behind them ditches were dug to act as
reservoirs from which the water was pumped by wind power into the watercourses
that had become in effect drainage channels (boezemwater). Thus the landscape
was inverted and so-called binnenpolders (land polders) were created.
In both Waterland and Amstelland we find polders as
they are most commonly understood by foreigners: drained lakes. Such
droogmakerijen (literally: made to be dry land) included both natural lakes as
well as so-called veenplassen, large expanses of water that arose as a result
of the extraction of peat for fuel. The lake-polders often have a rounded shape
and were created by surrounding the lake with a large dike with a drainage
channel (ringsloot) encircling it. A central ditch drains the new land that was
once the lake floor. If the lake is very large several of such ditches were
needed.
The floods that created the Zuiderzee created a need for better flood defenses. Thus a sea
dike was built along the IJ and the Zuiderzee shores. To close these dikes all
natural streams had to be dammed. Only
think of Zaandam, Monnikendam, Edam, Volendam, Durgerdam, Uitdam, Diemerdam,
Nieuwendam and Amsterdam. Mostly these dams took the shape of large lock gates with
a sluice to keep the waterways open for shipping. Where no lock was created a
so-called Overtoom (portage) was constructed for hauling ships across a dike.
Examples can be found near Zaandam (Westzaner Overtoom and Oostzaansche
Overtoom) and in Amsterdam(Vaartsche Overtoom).
Ensuing floods enlarged existing lakes and created new
ones as a result of a breach in the sea dike. The Buikslotermeer, Beemster,
Diemermeer and Bijlmermeer are examples of such lakes. The Amstel river used to
end at the Diemermeer. The present river that flows into the IJ at Amsterdam
was created by digging a drainage channel from the lake to a small inlet on the
IJ that was later dammed. The straight channel can still be recognised and also
gave rise to the alternative name for the Diemermeer as Watergraafsmeer.
Watergraaf literally means dug out channel.
An overview of the landscape of polders surrounding
Amsterdam. Of the former lakes the year of impoldering is listed. In the
Zaanstreek the polders are large and consist of a western and eastern section
in the case of Polder Westzaan (1) and Polder Oostzaan (2). The Polder Ilperveld (3) and Polder Landsmeer (4)
don't have this feature. The Waterlandsche Polder (5) includes all the land
within the sea dike.On the edge we find the Polder Buiksloot (6) and Grote
Blauwe Polder (7). North of the Diemermeer we find the Overamstelpolder (8). Diemen
lies in the Diemerpolder (9). Beyond the river Diemen we find the
Gemeenschapspolder (10) and Aetsveldsche Polder (11). Along the rivers Angstel
and Gein lie the Polder Baambrugge (12), Broekzijdsche Polder (13) and Polder
Gein and Gaasp (14). Next to the Bijlemermeer we find the Polder Oost Bijlmer
(15), Laanderpolder (17), Duivendrechtsche Polder (18) and Venserpolder (19). South of Ouderkerk lies the striking
Polder de Ronde Hoep (16). North of the Amstelveensche Polder we find the
Buitenveldertsche Polder (20), Stadspolder (21) and Riekerpolder (22). Around
the Slotermeer we find the Gecombineerde Sloter en Middenveldsche Polders (23),
the Osdorperpolder (24), Spieringhornerpolder (25) and Overbraker Polder (26).
The
Zaanstreek is one of the oldest industrial areas in
Western Europe. Once the Western part of Waterland it is now seen as distinct. As
a result of the greater thickness of the peat layer the ground sank more and is
therefore characterized by very wet and narrow strips of grasland between
ditches. Zaandam was once subsidiary of both Oostzaan and Westzaan but grew
from the 16th century onwards into the industrial satellite of Amsterdam
catering for both shipyards and the whaling fleet as well as wood mills and
food production. Hundreds of windmills stood on either side of the Zaan river.
At its height in 1700 around 600 windmills were in use. Nowhere else was
industrial activity concentrated in such a small area. The area was well known
for its weaving mills, sail making, paper making, tobacco, paint production,
candle factories, snuff production, cocoa roosting, chocolate making, starch and bluing factories, sawing mills, bark
mills, rope-making, smokehouses, cooperies, metalworking, whale oil
distilleries, bulk trading and meat trade.
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