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The seawall that Auckland Council proposes to build for erosion protection on the northern portion of Orewa Beach has already run into headwinds, although the first public consultation doesn’t take place until the end of this month.
Legal action has been threatened by a group of beachfront residents, and members of the public, including a local engineer with experience in coastal projects, are demanding that Council staff consider alternatives.
Feedback after the plan, estimated to cost around $5 million, was revealed on Hibiscus Matters’ website on October 15, was critical of the wall and the fact that sand transfer will still be part of the mix.
The proposal for the 640m stretch of beach from Kohu Street to Marine View combines sections of masonry seawall, loose (but ‘engineered’) rock structures and a small area of restored dunes. It includes a 2m–2.5m shared pedestrian and cycleway and two new beach access points. Sand transfer from the southern end of the beach will continue if the proposed structures are built, acting as a sacrificial buffer against erosion.
This part of the beach is Council’s top priority because of the high risk of losing reserve land to erosion. It was severely damaged in a storm in 2013, threatening infrastructure such as the walkway. Council erected a ‘temporary’ rock wall that has been in place ever since.
Council’s coastal management services team manager, Paul Klinac, says that the design solutions proposed are a response to the way this section of the beach functions. He says that the plan protects the reserve and ensures access – both to private property, and for the public using the beach.
“If we don’t do anything, we will lose that section of reserve and the public won’t be able to walk along that section of the beach at high tide,” he says.
Cost is also a factor – sections of ‘rip rap’ wall, consisting of sloping sections of loose rock, are included because they dissipate wave energy, but also because they cost 3–4 times less than constructing a solid wall.
The masonry and riprap walls are supported with foundations that go lower than the depth of the most severe erosion to date and Mr Klinac says that sea level rise is factored in.
A restored dune system is proposed for in front of Kinloch Reserve.
Beachfront residents are being contacted by Council staff, but some have already put the matter in the hands of lawyers to ensure the community is involved in the decision making process.
The same legal team acted for residents five years ago when the former Rodney District Council proposed building a wall on this section of beach – that resource consent was declined.
Local and sports parks north manager, Martin van Jaarsveld, says the new design takes into account the reasons that were given for declining resource consent in 2010 and follows proven engineering practices and standards.
He says there are several key differences between the two designs. These include:
- The 2010 application proposed an untested combination of rock revetment and a cement stabilised sand toe. The current proposal is for either a rock revetment or grouted masonry wall.
- The 2010 proposal generated concern that it may not withstand a 1-in-100-year storm and would not prevent overtopping, without the need for extensive maintenance, as the height of the seawall was below that of the reserve. The current proposal has been designed to be stable for a 1-in-100-year storm and could be modified over time to take into account predicted sea level rise of at least 0.5m.
- To provide visual mitigation, the 2010 application included sand placement and dune planting over the seawall. The current proposal does not promote this level of visual mitigation.
Last month the Hibiscus & Bays Local Board endorsed the draft design so that it can go out for public consultation, as well as advocating for funding in the 2017 Annual Plan.
At that meeting, on October 21, local engineer Greg Shaw suggested that Council should consider cheaper options such as realigning the estuary mouth to recreate the channel that was there before it was altered in the 1950s. He said that a pedestrian/cycleway is not needed and that it is a natural process for reserve land to be eroded and replaced with sandy beach.
More feedback is expected at public open days, which begin this month. These will be held at Orewa Community Centre on Saturday, November 28, 1.30pm–3pm and Thursday, December 3, 3.30pm–5.45pm.
Local board chair Julia Parfitt suggests that residents seeking amendments to the draft design should come to the open days, so that any changes can be made before consent is sought.
Council expects to lodge a resource consent application in March and will request that it’s publicly notified so people can make formal submissions.
