New breakwater for the Whitianga Marina

11 Jan 2022

New breakwater for the Whitianga Marina

 

Multi-million dollar contracts have been signed to replace the existing rock armoured breakwater at the Whitianga Marina, which will mean berths for an additional 30 large boats. It is part of an ongoing strategy of future-proofing the marina for years ahead and comes hot on the heels of the completion of a major project installing new fuel docks only a few months back.

Work on the seawall replacement is due to start at the end of next month or early March, and is hoped to be finished by next Christmas. While the new wall will enable the marina, which currently has 201 berths, to accommodate an additional 30 of the largest pleasure craft in New Zealand, the marina will still only occupy the same space as before and is not encroaching into the estuary.

In addition, the wall will have a 3m wide strip on the top for a public walkway along its 220m length.

Thousands of tons of rocks from the existing wall will be gifted to Thames-Coromandel District Council as part of the resource consent for the new wall and are expected to be used elsewhere on the Coromandel in the future. 

As with the fuel docks development, which involved many months’ work, Whitianga Marina manager, Dave Munday, was reluctant to put a figure on the cost of constructing the new breakwater. “You could say it will be in the millions of dollars,” he said. “It is a very big project and it is going to bring huge economic benefit to Whitianga, I am 100 per cent sure of that.

“It is going to bring bigger boats - some of the biggest top-end boats around - and lots of people. Truly, it is going to be amazing and it follows on from our recently-completed fuel docks project. This is a huge investment for the marina and for Whitianga, and just like the fuel docks, it helps us future-proof the marina for years to come.”

Project manager, Lorenzo Canal from engineering project management consultancy Urban Solutions, said that the contract to construct the new steel and precast concrete panel breakwater had gone to Heron Construction from Auckland, one of the largest and most experienced marine contractors in the country. “We have now got the green light and the project has actually started,” he said.

Lorenzo said the new berths had been presold, enabling the new wall construction to progress beyond the resource consent stage. “The green light has come with the [Whitianga Marina Society] committee’s approval to proceed and berth holders paying deposits down, which has allowed the project to go ahead,” he said.

Lorenzo and his team had also moved rapidly to secure huge supplies of materials for the new breakwater, particularly steel, amid global bottlenecks and soaring prices. Steel piles, measuring 1m in diameter and 12m in length, will be spaced at 4.5m intervals along the 220m stretch of wall. “We have mitigated the risk of the cost of steel escalating by locking in the price before Christmas last year,” Lorenzo said.

The existing seawall, which had been there since the marina was built in 1995, occupied a lot of space within the marina. “A couple of years ago, the Whitianga Marina secured resource consent to occupy the same space, but in a more economical way with a vertical breakwater on the outside of the existing marina footprint, and to accommodate about 30 extra boats, mainly 18 to 20m in length,” Lorenzo said.

The existing rock armoured wall would be removed altogether to be replaced by the new vertical breakwater while the floor of the marina would be dredged to accommodate the new boats, nine in 20m berths and the rest in 18m berths. “This is catering for the new size of boats that seem to be coming onto the market and there is a real shortage throughout New Zealand of 18 to 20m berths,” Lorenzo said.

While many marinas around the country had 12 to 14m berths, boatowners were moving towards buying “bigger and bigger boats”.

Lorenzo said that the project went out to competitive tender and Heron came up with a design which offered best value for money, a reasonably short construction duration and good functionality to maximize berthage. He said that the Marina Society committee had worked closely with Ngati Hei kaumatua, Joe Davis, on the project. “For the precast panels on the outside of the breakwater, we are working with local iwi and artist James Webster on an iwi narrative, and they will be integrating a Maori design into the structure,” Lorenzo said. “There is a really strong relationship between iwi and the marina, and the design will reflect that.”

Referring to the walkway on top of the new seawall, Lorenzo said it would be a good addition to the paths and walks around Whitianga, and would give members of the public the opportunity to see some splendid craft up close.

Rocks from the existing wall will be carted away for storage for use some time in the future. “They are not going to be dumped, they are a useful resource and will be used locally,” Lorenzo said.

He reiterated Dave’s view of the value of the project to Whitianga. “It is going to have quite significant benefits for Whitianga by bringing in fairly large recreational boats so close to the town centre,” Lorenzo said.

Dave indicated that local contractors would also be involved in the construction of the new breakwater.

Work is scheduled mainly for the winter months to cause as little disruption as possible around town from truck movements, Lorenzo said. However, there would be no disruption to boating or the new fuel docks from construction of the new sea wall.

 

Pictured: A diagram showing the new Whitianga Marina breakwater and berths for 30 additional 18m to 20m boats.