6.5.1 Demobilisation
When the water level has receded below the opening level and the flood event is confirmed as
over, the demobilisation phase commences. The procedure for demobilisation, clean-up and
storage of demountable or temporary sections of the protection system should be outlined in
the flood protocol. Following laid down procedures and manufacturers guidelines for
dismantling the system, lifting and transporting them is important to avoid damage during the
process.
Once all removable parts have been dismantled or the barrier otherwise opened, they should
be properly cleaned, checked for damage and counted. Any recommended post-event oiling
or coating should also be carried out.
All permanent and moveable parts should be inspected and all damage recorded. Damaged
parts should then be separated and repaired or replaced as soon as possible after the event.
The lifting, transportation and storage should be carried out in accordance with laid down
procedures.
Some protection systems use materials such as aggregates or water as part of the protection
system. These should be completely removed from the systems before cleaning. Disposal of
aggregates should be carried out in accordance with current disposal guidelines. There is a
risk of contamination of aggregates that have had contact with flood water. The aggregates
should be examined and appropriate disposal methods to suit their post- event condition
should be followed.
On removal of all temporary or demountable parts from the line of protection, the area should
be cleaned up and returned to its pre-event state. This could involve removal of debris,
levelling of ground surface, opening of accesses and securing all permanent parts of the
system where public access or tampering is discouraged.
6.5.2 Performance Evaluation
As soon as practical after demobilisation of the system, collation of all relevant information
about the loading onto the barrier and its response should be carried out. Such information
could include the following:
! Predicted and actual flood level hydrograph
! Timing of the flood warning trigger or action level
! Records of seepage or damage
! Performance of protection system under loading
! Effectiveness of call-out system
! Time taken for all phases of mobilisation and operation
! Ease of erection, closure or damage repair
! Resource deployment
! Adequacy of storage, access and communications
! Demobilisation issues.
The above and other relevant issues should be reviewed with the emergency team in a
debriefing session. The objective is to compare the predicted performance of the protection
system and all related operational procedures with the actual performance, with the view to
identifying improvements or at the minimum validating the performance of the existing
protection system and flood protocol.As the need to erect or close temporary or demountable systems seldom occurs, there is a need
to carry out emergency drills. During such exercises the information highlighted above should
be reviewed and the flood protocol amended if necessary.