12 (vii) - Lord Howe Island Board

Board Meeting: May 2015
Agenda Number: 12 (vii)
File Ref: EV0001
Business Paper
Windy Point Erosion
In 1999, the Seabee wall was built to prevent coastal erosion in the area immediately to the
north of the runway. In 2011, following erosion of the end of the Seabee wall, a short section
of sand filled geotextile wall was constructed to reduce the potential for damage to the
Seabee wall.
In September 2014, the Board endorsed the Coastal Hazard Definition and Coastal
Management Study for Lord Howe Island. The report recommends a number of immediate
and potential management actions to manage erosion and recession risks.
In mid March 2015, the Board submitted a grant application to the Office of Environment &
Heritage under their Coastal Management Program for $105,000 as part of a $140,000, two
year Sediment Tracing Study within the Lagoon. The outcome of the grant application is
expected before the end of the financial year.
A number of concerns have been raised with Board staff regarding accelerated erosion at
the end of the sand filled bag wall, which has resulted in slumping of some of the bags. The
area immediately north of the sand filled bag wall has regressed more than 5m since the wall
was completed in 2011.
Board staff have received a proposal from Haskoning (authors of the Coastal Hazard Study)
to undertake detailed design of a rock wall to protect the most critical section of the beach
scarp located just north of the sand filled bag wall. The cost of $14,000 is considered
reasonable and the 6 week timeframe is acceptable.
Options for rock sourcing have also been considered and include rock at Little Island and
rock imported from the mainland using empty barges to be brought back to the Island in July
\ August to remove the plant and equipment used in the runway project.
It is recommended that the Board note the above information.
Prepared __________________ Andrew Logan
Manager, Infrastructure & Engineering
Endorsed __________________ Penny Holloway
Chief Executive Officer