25-year dredging consent secured

A seagull accompanies Port Otago's tug Arihi and barge Hapuka as they head down Otago Harbour yesterday. Photo: Gerard O'Brien
A seagull accompanies Port Otago's tug Arihi and barge Hapuka as they head down Otago Harbour yesterday. Photo: Gerard O'Brien
Port Otago's $650,000 split hopper barge Hapuka had its first day at work yesterday, taking spoil from upper-harbour dredging for dumping at sea.

Port Otago received its latest Environment Court dredging consent earlier this month and now has all necessary consents in place covering maintenance and development dredging for the next 20-25 years.

Port Otago's outgoing chief executive, Geoff Plunket, said granting of the 25-year consent for the harbour channel would allow Port Otago to cater for the increasingly larger ships visiting New Zealand.

''Port Otago also recently secured a 20-year consent to deepen the channel to 15m, an integral part of the company's Next Generation programme,'' Mr Plunket said.

The Next Generation project had required a new offshore disposal site, in addition to the three disposal grounds for inshore dredging, including Heywards, Aramoana and Shelly Beach, he said.

The dredging spoil would be an efficient source of nourishment for the beaches next to the sites, including beaches further north along the coast from Blueskin Bay, Mr Plunket said.

Bought from a Queensland company in August 2015, to

work alongside Port Otago's hopper dredge New Era, the unmanned Hapuka carried a half load yesterday, Port Otago manager of marine and infrastructure Sean Bolt said.

''We really just wanted to see how she towed, familiarisation, so it was a half load,'' he said.

The rudderless 50.4m-long Hapuka can carry up to 650cum of spoil, weighing up to 1000 tonnes. The hull's hopper doors are opened by remote control.

Aside from some seal repairs, maintenance and painting, Hapuka had been unable to work until now because it had to gain several Maritime New Zealand certificates, and also wait for the resource consents to be finalised, Mr Bolt said.

He did not rule out the contracting out of New Era and Hapuka to other ports ''some time in the future'', but both would work in the upper harbour for at least three months, before assisting later with the multipurpose berth extension at Port Chalmers.

''There's solid work for the Arihi and Hapuka for the next couple of years,'' Mr Bolt said of further lower-channel dredging towards Taiaroa Head.

The $15million multipurpose berth extension will add 140m of wharf to the existing 300m, using steel piles capped by reinforced concrete, to better accommodate vessels longer than 280m.

Also to attract larger vessels, the first phase of Port Otago's Next Generation dredging project has been completed, to a depth of 13.5m. Phase two is to be completed to a depth of 14m.

The overall cost of channel and berth deepening and extra warehousing is about $30million.

While the $6million, Turkish-built 18.7m tug Arihi works with Port Otago's other tugs Otago and Taiaroa, its primarily role is with dredging operations.


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