Harbour plans dredge up opposition

Plans by Port Otago to scale back how much silt will be removed during channel-deepening means all of the work can be done by the port company's own dredge New Era, pictured at the Kitchener St slipway. Photo by Stephen Jaquiery.

• Regional council supportive, but with specific conditions
• Opponents concerned at effects of disposal 

Port otago is about to unveil changes to its contentious proposal to deepen and widen 13km of the shipping channel from Port Chalmers to Taiaroa Head, scaling back from the disposal of 7.2 million cubic metres of silt and sand out at sea to 2.5 million cubic metres.

Of the 195 individuals, groups and businesses who have made submissions on the proposal, 75%, or 148, are against the proposal.

Well over 100 submitters - a mix of those for and against - wanting to be heard and prompting the need for a three-week hearing; starting on April 4.

While Port Otago will still seek the same resource consents it originally applied for in May last year, it has extended the time frame of completing the work from a two-to-15-year programme out to about 20 years.

Both scenarios ultimately allow for the removal of a total 7.2 million cubic metres of spoil.

The project was initially budgeted at $80 million to $100 million for full deepening and widening to 15m deep, but Port Otago is scaling back the work into two stages, from dredging from the existing 13m deep to 15m, and instead going to 14m, costing an estimated $12 million to $20 million.

Subject to the hearing commissioners granting consent, dredging work could begin within months.

Initially, it would amount to about 500,000cu m of silt/sand being removed and dumped at sea over each of the next three years.

Port Otago has estimated that during the past 145 years, 34 million cubic metres of spoil has been dredged from the harbour channels.

The change in the plan, while it might allay some concerns submitters had, was not related to the extent of submissions, Port Otago's chief executive Geoff Plunket said, but to giant container shipping operator Maersk, which is Port Otago's largest customer.

Maersk said in February it now planned to incrementally phase in ships larger than the present 4100-container carriers, moving towards 4500- to 5000-carriers in coming years, as opposed to visits of ships of 6000 containers or more, which many in the industry had been expecting to occur sooner, rather than later.

Mr Plunket said deepening from 13m to 14m meant very little of the channel sides would have to be dredged, but taking another metre to 15m deep would mean dredging and changing the profile and sides of the channel.

The company was still seeking the same consent, over a 20-year period, to eventually deepen to 15m, because of the likelihood container ships will eventually get bigger.

"Given that certainty, at some stage in the future we will need to go to 15m deep . . . not in 10 years, but within 20 years time," Mr Plunket predicted.

However, given the proximity of the channel near the Aramoana salt marshes and the potential effects on recreational fishermen and sportspeople, surfing beaches and avian and aquatic wildlife, it is expected submitters will continue to express their environmental concerns, regardless of Port Otago's time-frame.

For many submitters, the effects of disposal are of most concern.