made by the project groups, their targets, their
working method and also a number of clear
examples have been given.
An experimental discharge programme for the
Volkerak sluices
A special working group has proposed to
improve the prognoses for the salt/fresh water
distribution around and afterthe year 1985. For
this purpose it proposed that the discharge of
fresh water via the inlet sluice in the Volkerak
should be increased up to 100 m3/sec. during a
certain period of time. Possibly this measure
will become effective as of November 1st, 1979.
Momentarily the discharge amounts to
50 m3/sec. The doubling of the discharge will, in
any case, clearly show its impact on the salt
water distribution along the stretch
Krammer-Volkerak. The experience gained can
be used asaguidelinefor the testing of the
calculation models used for these studies.
The calibration of the mathematical model
Rand-Delta II
For some years, research into the
water-movement in the Delta area has been
done by means of bi-dimensional models. The
first model of this particular type consisted of a
flow net of nearly 3,000 grids.
During the preliminary investigation for the
construction of the barrier it became clear that
grids with a finer tracework were needed over a
larger area. Currently the model RD-II is used
which has a trace-work of 800 meters and a
sea-ward edge which remains outside the
barrier's influence. Next, there is the model
Scheldes, which only comprises the estuary,
but which has a finer trace-work: the mutual
distance between the grids is 400 m.
Furtherfollows a description of the calibration of
the models. For operational usage computer
time is hired in Los Angeles (USA).
The 'Punt van Goeree' in the Grevelingenmeer
The recreation area 'De Punt' situated
in the western section of the Grevelingenmeer
forms part of the facilities that are laid out
according to the 'New Environmental Design for
the Grevelingen-basin' of 1975.
By zoning the area, possibilities have been
created for both the intensive and extensive
recreation. The intensive part joins up to the
Brouwersdam and is made easily accessible for
motoring tourists. The shore recreation will be
concentrated on two places where parking lots
are built; tourists will find sandy beaches there.
The quiet inner area will be protected from view
by sand-dunes.
The 'Schelphoek' in the Veerse Meer
Step by step provisions are being made in the
Veerse Meer to give shape to the recreational
function of this water. The 'Schelphoek' has
been earmarked to enhance the possibilities for
the aquatic sports - in the neighbourhood lies
the large yacht-harbour of Wolphaartsdijk.
Beaches have been laid out, care has been taken
that the water is deep enough, a landing stage
has been built and three islets have been
created. Part of the project, meant for the
extensive recreation, has not been adapted for
yachting; the shore has been planted with
shrubs and trees to allow for the evolution of a
varied wooded area.
New developments to appraise the quality of
the water
After several years of specially inventory -
research into the water-quality in the Delta area,
interest is growing for a more detailed study.
The large scale measuring programmes render
it necessary to accelerate the input procedures.
Therefore instruments have been made that,
while the measuring vessel is running, measure
the depth, the temperature, the conduction, the
concentration of oxygen, the acidity and
fluorescence of the water. Registration and
calculation instruments complete the
apparatus. A big advantage of this new technic
is for example, that the measuring vessel during
its run can continue to observe and measure the
flow of ebb and flood in the estuary.
Site information in the Delta area
Especially as the realization of the storm-surge
barrier in the Oosterschelde has begun now,
much interest is shown in the Delta works. A
team of 10 persons leads excursions to the
works, gives lectures and assists with the
organization of exhibitions. There are two
exhibitions in the Delta region, i.e.: one at
Stellendam which is primarily focused on the
near-lying Haringvliet and the other, on the
dam-section Geul, which specializes in
information and exhibits regarding the
storm-surge barrier. From this exposition one
can get an excellent overall view of the works in
the Oosterschelde.
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