of the Oosterschelde barrier. To ascertain the
accuracy of the models the outcome has been
tested in one- and two-dimensional models.
The two-dimensional test (1 6) was performed
in the latest acquisition of the Delft Hydraulic
Laboratory, i.e. the 'Delta flume', the
test-section of which is 50 m. long en 9.5 m.
deep. These tests showed that the selected
design need not be adjusted as the safety
margin of the filter proved to be satisfactory.
The phasing and closing method of the
compartment dams
The moment of actual closure of the
compartment dams at the end of the
Oosterschelde is optional, i.e. they can be
closed before or after the partial closure of the
mouth of the Oosterschelde with a stormsurge
barrier. As to the closing-method: a choice can
be made for an instant closure with caissons or
a gradual closure with rubble or quarry stones
which could be dumped from a bridge, from
ships or from helicopters. A third sollution is
possible if one waits until the Oosterschelde
barrier is completed. Then the Philips Dam and
the Oester Dam could be sand-filled.
A happy medium has been found to reach the
ultimate decision. There are signs that by 1986,
in anticipation of the complete closure of the
compartment dams, the closure gap will be
narrowed, due to the fact that the sill beams of
the barrier will already be placed by 1985, thus
creating an earlier reduction of the tidal action
than originally expected. In the meantime, the
study into the final closure including the
possibility of a sand-fill closure, will continue.
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