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BOC Immingham Dissolved Acetylene Project Environmental Statement: Vol. 2 Main Text
Mitigation Measures
Construction
9.94 With appropriate good working practices and the production and implementation of the CEMP, it is
expected that there will be no significant flood risk impacts during the construction phase of the
development. Therefore no specific mitigation measures are deemed necessary.
Operation
9.95 Flood risk will be managed through providing safe refuges above the breach water level within the
Generator Building; providing secondary flood protection to electrical equipment through water
tight doors; providing a flood warning system; safe evacuation routes; and evacuation procedures.
Consideration has been given to reducing the risk to buildings by providing flow paths which divert
flows away from the building. Surface water runoff will be managed through an appropriately
designed surface water drainage system and pumping station which outfalls into Middle Drain.
9.96 Thus, flood risk to, or resulting from, the operation of the Dissolved Acetylene Project is not
expected to be significant and specific additional mitigation measures are not proposed.
Residual Impact Assessment
9.97 Since no mitigation measures are proposed in relation to impacts associated with flooding the
significance of impacts during construction and throughout the operation of the site does not
change from that described above.
Recommendations
9.98 BOC should continue to liaise with the EA to ensure they are informed of any changes to the
standard of protection provided by the coastal defences and any changes to the flood warning
system provided.
9.99 BOC should continue to liaise with NELDB to ensure they are informed of any changes to the
standard of protection provided by the pumping station on Middle Drain.
Summary
9.100 An assessment of the flooding issues associated with the existing site and the construction and
operational phases of the proposed Dissolved Acetylene Facility has been completed.
9.101 There is no knowledge of flooding to the proposed development site to date from all potential
identified sources, including, tidal, fluvial, groundwater, surface water and sewer flooding.
9.102 The site is at high risk from tidal flooding but the site of the proposed Dissolved Acetylene Facility
is currently protected to at least a 1 in 1,000 year tidal (0.1% AEP) event by coastal defences.
During the construction and operation phases, the site has a residual risk from overtopping of the
defences during more extreme tidal events (above 0.1% AEP) and from a breach of the coastal
defences.
9.103 The risk from the breach of the coastal defences will be managed by providing a flood warning
system; safe evacuation routes; and evacuation procedures. During operation, safe refuges will be
provided at 6.61 and 8.88 mAOD (above the breach water level of 6.45 mAOD) within the
Generator Building and secondary flood protection to electrical equipment will be provided through
water tight doors. On this basis the tidal flood risk is considered to be negligible for both
construction and operation.
5100935.404 Environmental Statement August 2011 142