CentrePort confirms seabed contamination

CENTREPORT has confirmed ‘‘low levels’’ of contamination in seabed sediment it plans to remove near the Thorndon Container Wharf as part of its programme to deepen the shipping channel in Wellington Harbour.

The project, which requires resource consents, would involve deepening two sections of the shipping channel, at the harbour entrance and berth, to accommodate ships with a draught of up to 14.5 metres.

Currently, the shipping channel can accommodate ships with draughts of up to 11.5 metres.

CentrePort chief executive Blair O’Keeffe said the contamination was due to runoff from the city’s stormwater system. When the material was removed it could be placed on the seabed close to the port.

‘‘The reason for this is the placement area, like the deepening area, is used for shipping activity so is likely to be similar in terms of ecology and sediment characteristics.’’

However, O’Keeffe said recent testing had confirmed that there was no contaminated sediment in the harbour entrance channel where the bulk of the material – up to 8.6 million cubic metres – could be removed and dumped at a site several kilometres out in Cook Strait.

When CentrePort applied for resource consent to deepen an area near the container wharf in 2002, concerns were raised that the sediment near the container wharfs contained pollutants including DDT.

At the time, independent commissioners turned down CentrePort’s proposal to dump the material in the inner harbour because of its DDT contamination.

O’Keeffe said the company is investigating the effects of the project as part of its for resource consents.

With a deeper channel, the port would be able to receive ships carrying up to 8000 containers, instead of the existing 4500 capacity.

It would take an estimated 10 to 20 weeks to complete the work.

‘‘CentrePort is committed to ensuring the environmental, social and cultural sustainability of Wellington Harbour,’’ O’Keeffe said.

Wellington Mayor Celia WadeBrown said the proposal would ‘‘keep the productive economy of central New Zealand directly linked to global markets’’.

A consent application is expected to be lodged in mid-2015.

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