BRABANT FIGHTS AGAINST WATER
Oosterschelde
Oosterschelde barrier
(Eastern Scheldt barrier)
The largest, most
expensive and difficult part of the Delta works was the construction of the
flood barrier Oosterschelde. This partly open barrier in the
Oosterschelde is considered to be "the eight's
world wonder".
First of all the plans
were different. It was the intention to close the Oosterschelde with a
"conventional " barrier
The works started in
April 1967. The workdock Schelphoek (Schouwen-Duivelland) en Sophia (North
Beveland) and the work island Roggenplaat (1969), Neeltje Jans ( 1970) and
Noordland (1971)were completed. After the construction of the connection
barriers between the work dock and work islands at the end of 1973 a total 5 out
of the 9 km wide Oosterschelde was
closed. What remained were three openings, Hammen,
Schaar van Roggenplaat en Roompot. The
intention was to closed them by using concrete blocs dumped by
cable car. The required twelve support towers for this cable car were
positioned during 1972.
But why did they change
the plans???. They changed under the influence and pressure of a large part of
the population who protested against the complete closure of the Oosterschelde.
The results of the protest activity under the name of " Oosterschelde Open"
was that all final activities were postponed in July 1974, awaiting the
final decision by the government.
A turbulent period
started the Oosterschelde problem as priority on the
political agenda. The final decision toke a long time.
Finally the government
decided not to build the conventional dam but a storm barrier with movable
gates. As a direct consequence during the winterperiod
1976-1977 the support towers for the cable car were taken down.
The new plan to construct
storm barrier existed of huge concrete pillars resting on the seabed of the
Oosterschelde . Between the pillars the steel movable gates were positioned
which can close the Oosterschelde completely during a storm surge. On the weir a
road is constructed of various different concrete elements.
The construction started
in 1978 from the work island Neeltje
Jans which could be reached from
Schouwen-duivelland by a temporary road bridge with a length of 2780 m . Next
was the construction of the
building dock where the concrete pillars could be fabricated.
In July 1981 orders were placed to constructed the steel
gates..
Also here they faced
problems. The gates were very heavy and so a strong foundation was required.. To
improve the resistance of the sand the sandy bottom was prepared for this
resistance up to a depth of 15 meters. The special constructed vessel Mytilus
was able to put long needles in the bottom. By vibration
the sand closed in and formed a prpoer foundation to withstand the
weights of the steel barriers. The treatment of the sand lasted from the
beginning of 1980 until the end of 1982.
After the sandy bottom
was prepared it had to be reinforced and levelled. A specially for this purpose
plant was constructed on the Neeltje Jans.
The plant produced artificial filled with a variety of shingles.
The mats were put in
position by two specialized vessels the "Cardium" and the "Dos.
1". In addition the stone and the asphalt dump barge " Jan Heijmans"
filled the gaps in between the mats with different type of stones. The mats are
positioned between November . '82
and June '84.
When the total carpet of
mats are ready the pillar can be positioned. For the construction of the pillars
a total number of three large 15
meters deep construction docks are available.. In April 1979 they
started with the construction of the first pillars in the building dock.
After having constructed all required pillars in 1983 the docks were flooded
allowing the special constructed lift vessel "Ostrea" to start with
the positioning of the pillars.
In Augustus 1983 the
first of the 65 pillars are put into position. Finally a total of 16 in the
North shutter hole, 17 in the middle shutter hole Schaar and 32 in the South
Shutter hole Roompot. The 66th pillar was just a spare one and wasn't used..
The
Oosterschelde kering
Finally the
day is there: On October 4 1986 the
Queen
of the Netherlands Beatrix the
storm barrier was officially put in service. Together with the Minister of
Transport and Public Works Miss Nelie
Kroes and the Director- General of Rijkswaterstaat Mr.
J. v. Dixhoorn she speaks
the historic words: "the storm barrier is closed . The delta
works are ready. Zeeland is safe."
On 1 January 1987 the
Delta Service hand over the storm barrier to Rijkswaterstaat of
Zeeland. The road on the weir was constructed later. On the fifth of
November 1987 Princes Juliana opens the road passage by normal traffic. In
July 1988 the last activities at the storm barrier are completed.
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