A closer watch needs to be kept on the St Clair sea wall
until Dunedin city councillors decide what long-term fix - if
any - is needed, a report suggests.
The report, by council maintenance engineer Peter Standring,
will be considered by councillors, who are set to begin
deliberating on the draft budget for 2014-15 from today.
Mr Standring's report suggested the council should allocate
$95,000 to pay for an interim risk management plan for the
battered St Clair sea wall.
The plan would allow council staff to keep a closer eye on
the wall, looking for further signs of deterioration, until
longer-term options could be considered at next year's
long-term plan budget discussions.
The risk management plan would include weekly visual
inspections, fortnightly sand level surveys and six-monthly
surveys checking for signs the sea wall could be settling or
moving, Mr Standring's report said.
As well, the sea wall's panels would be inspected for signs
of deterioration every year, and rocks at the foot of the
wall would be checked and rearranged every six months, he
The council would also be ready to react to any signs of
problems arising from the inspections, and would draw up an
emergency contingency plan should a partial failure of the
sea wall or rock revetment occur, he said.
The interim approach would cost the council at least $95,000,
but could rise by up to $160,000, to $255,000, if all
identified risks became a reality, Mr Standring warned.
That included the anticipated $100,000 cost to the council if
the emergency contingency plan needed to be put into action,
The recommendation came after a series of severe storms in
May last year stripped sand from the beach, resulting in the
appearance of sinkholes along the Esplanade at St Clair.
The council has since spent $680,000 on emergency remedial
work and reinstating temporary access to the beach, while
commissioning Opus International Consultants to study
possible long-term solutions to the problem.
Mr Standring said the council was only at stage one of a
four-stage approach to rectifying problems at St Clair, but
Opus had identified ''conceptual options'' to be considered
in more detail.
Those options ranged from continuing the existing approach of
reactive repairs and maintenance, to changing the existing
sea wall to building an offshore groyne to help protect the
beach and sea wall.
Each option had a range of adverse effects, and would require
a resource consent, and should be considered in more detail
as part of next year's long-term plan hearings, he suggested.
A report on the need for further studies into long-term
options for the sea wall was expected to be ready for
councillors to consider in two to four months, he said.
In the meantime, he recommended councillors agree to the
interim risk management plan, with the $95,000 cost to be
paid for by drawing on $130,000 in unspent transportation
operational funding from 2013-14.
The additional costs of up to $160,000, if risks became a
reality, could be covered by delaying some footpath renewal
work, even though that approach was not sustainable and
''should be avoided if possible'', he noted.