Council is recommending a new option for the renewal of the Paekākāriki seawall but public feedback is needed first.
The current option is a full replacement of the seawall, about 1km long, built with concrete and rear raised rock revetment, designed to a 50 year life, with work taking two years.
However, the estimated cost had increased from $17.7 million in 2018, when council first consulted on the seawall, and is now projected to be $27m.
The increased cost, according to the Draft Long-Term Plan, was due to a number of factors including roading projects in the region making rock a scarce resource and putting significant pressure on market rates; finding a contractor could be challenge; and the works were a greater construction risk.
On the upside though resource and building consents were already in place.
But a building a seawall in timber, which is a like-for-like replacement, and what the plan recommends, would only cost $17m.
It would be built to a higher specification than the current seawall with longer more deeply-set posts and palings, have improved beach access, and while the timber option had a shorter life span, at 25 years, it could last longer, as the current seawall had.
The work would be simpler, lower risk, give certainty of delivery, and there were many contractors, including local ones, with the right expertise.
And it would be delivered as a five-year programme with the contractor delivering it in stages during the best time of the year.
Infrastructure services group manager Sean Mallon said the current seawall has been in place for 38 years and deteriorated to the point where it had needed regular maintenance over the years.
"On average in recent years we have been spending about $100,000 per year on repairs to the seawall."
Council was committed to replacing the seawall "to ensure it continues to effectively protect The Parade and other public infrastructure".
"However, the cost of the proposed concrete and rock option have increased substantially since 2018 and, while we acknowledge the huge amount of time the volunteer design group, the Paekākāriki Community Board and the wider Paekākāriki community invested in helping us to arrive at a preferred concept for the seawall, it would be remiss of us not explore other options for renewing the seawall at a more reasonable cost to the district at this time.
"The alternative proposal could also be staged over several years which would help with managing the financial impact of what is still a significant investment.
"Affordability will be a key consideration in any decision that is reached.
"The council needs to balance the community's aspirations with the need to apply a fair and consistent approach to coastal management across the district while continuing to operate within its financial means."
Mallon said council had explored other funding options for replacing the seawall.
"This includes responding to the Crown Infrastructure Partners request for proposal for shovel-ready infrastructure projects in May last year which was unsuccessful."
He said it was important to stress that no decisions had been made at this stage.
"Options for replacing the seawall, this includes sticking with the concrete and rock wall option, will be consulted on as part of our 2021-41 Long-Term Plan process from April 7 to May 15.
"We encourage Paekākāriki residents to take the time to consider the replacement options for the seawall when the consultation document becomes available and to have their say."