Summaries
Progress in the BARCON project
The work group BARCON, which is at present
engaged amongst other things in preparing a
note on 'Management of the Storm Surge
Barrier', consists of a number of sub-groups
involved in specific aspects of the policies to be
implemented on the Oosterschelde barrier.
These include for example the organisation of
the controls and the training of skilled workers
in this field, safety precautions, environment
and fishery and other related aspects. The work
of these sub-groups is further enlarged upon
and the organisational structure is explained.
Finally the studies on operational management
and especially the way in which a decision is
reached on the closing of the barrier are dealt
with.
Hydro- and Meteo-assistance in laying out the
foundation mattresses
It is largely weather conditions which determine
whether planned operations forthe construction
of the Oosterschelde barrier can proceed. This
is why the Hydro- Meteo-Centre issues a
statement three times a day on prevailing
hydraulic conditions in the area of operation.
Such predictions can only be considered
precise as long as conditions in the closure
gaps remain reasonably alike. This was still the
case while the mattresses were being laid out.
One concrete example is discussed in which
the laying out of an upper mat had to be
postponed three times. The role of the current
measuring co-ordinator on board the 'Cardium'
is important in last minute decision making.
Operational hydraulic assistance in laying out
the foundation mats
The foundation mattresses for the
Oosterschelde barrier are laid out by the
workship 'Cardium'. A number of the
proceedings which have to be carried out are
susceptible to the current which meant that
reliable data on current, speeds and current
direction were necessary. This was mainly
taken care of by the Zierikzee hydraulic
engineering department, and could only be
realised by calling in the assistance of collegial
services.
This article deals mainly with the measuring
equipment used to gather data on the current,
the sand transport and the state of the already
laid out mattresses. This consisted of a Pump
Filter Sampler, and acoustic sand transport
meter and a sidelooking Sonar.
Sand concentration predictions
Only a small layer of sand can be tolerated in
between the mattresses and between a mattres
and a pier during the construction of the
Oosterschelde barrier. It is therefore of
importance to be able to predict the amount of
sand deposited after the last cleaning up
operations.
A computer model has been developed for this
purpose which can predict the sand
concentration at any given moment and at
each spot in the axis of the storm surge barrier,
when the current and water level predictions
are known.
However the mathematical explanations of the
mechanisms involved are insufficient. It is only
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