catamaran lowers the piers while being afloat.
The catamaran will be moored alongside a
mooring pontoon. This pontoon is equipped
with an installation to remove the sand from the
place where the pier is to be placed. The
catamaran will have its own limited propulsion,
in order to be able to manoeuvre in the
construction-site by itself. Model tests have
shown that the pier hangs sufficiently stable in
the tackles even without a guide frame due to its
heavy weight.
The Oosterschelde behind the storm-surge
barrier
In September 1977 the Steering Committee
Oosterschelde was inaugurated and charged
with the planning of the Oosterschelde area
after 1985. This committee made an inventory
of the problems it has to deal with, proposed a
provisional management and indicated the
direction in which further research needs to be
done.
The main policy can be defined as maintaining
and strengthening the ecological function of the
Oosterschelde. Nevertheless regulations must
be made to recognise other interests: interests
of the fishing industry in the first place, but then
also some recreational and shipping interests.
For the time being the facilities for the aquatic
sports are allowed to increase by 1500 berth for
yachts.
Capacity of the discharge medium for the
Zoommeer
The fresh water Zoommeer, situated in the most
eastern part of the Oosterschelde, needs a
discharging sluice atthe south-end of the lake in
order to control both level and quality of the
water. This sluice discharges on the
Westerschelde. Between the Zoommeer and the
sluice a canal must be dredged across
Zuid-Beveland. By means of calculations and
model tests it was endeavoured to determine the
capacity of the canal and the sluice. Four
alternative plans were suggested. The
Committee for the Compartimentation of the
Oosterschelde advised a sluice capacity of 150
m3/s, with a connecting canal of an initial
discharge capacity of 100 m3/s, which, if
necessary, can be increased later on.
Storage of dredged material from the discharge
medium of the Zoommeer
Due tot the excavation of the connecting canal
between the Zoommeer and the discharge
sluice near the Westerschelde 5,5 million m3
dredged material comes out which is of no use,
so that a dump place has to be found.
A project team examined nine possible
locations for the dump places. The team comes
to the conclusion that at present only a partial
decision can be made. Anyhow, several dump
places will have to be used together. Filling up a
pit in the future Zoommeer itself has been
considered, besides expansion of the sand
depot Molen plaat as well as the partial filling up
of a channel in the Westerschelde, and possibly
the construction of saltings north of the
Oesterdam.
Vegetation developments on the Slikken van
Flakkee
Since 1972 landscape ecological research has
been executed on the Slikken van Flakkee, an
area outside the dike in the stagnant salt
Grevelingenmeer. It includes a.o. research into
the vegetation developments on the saltings and
mudflats of this area. The successive changes are
described which took place in the vegetation
since the tidal movement came to a halt by the
closing of the Brouwersdam. The process of
succession of vegetations has not stopped yet,
but it is noticeably slowing down.
Strengthening of the dikes in Friesland
The seadikes in Friesland are also raised to a
height prescribed by the Delta Act. In 1978 the
7 km long stretch between the ferry-quay at
Holwerd and't Schoor was finished. The new
crest height is slightly over MSL 8 m. In
general the work progressed smoothly,
although some problems arose during sand
dredging in the Waddenzee.
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