CentrePort is seeking resource consents so that it can accommodate container ships with draughts of up to 14.5 metres that are capable of carrying more than 6000 containers. Ships of this size will soon be heading to New Zealand. In order to accommodate these ships, CentrePort needs to deepen the current shipping channel through the harbour entrance to depths of between 16.5m and 17.2m below chart datum, and deepen the northern approach and berth at the Thorndon Container Wharf to a depth of up to 15.2m. No other deepening, including in the main harbour basin, is required.
CentrePort will seek to remove up to six million cubic metres from the harbour entrance, and 270,000 cubic metres from the berth and northern approach to Thorndon Container Wharf.
That depends on when shipping companies start bringing bigger ships to New Zealand. The Ports of Otago and Tauranga have already begun the work to deepen their shipping channels, with their Stage 1 projects to be completed later this year. It is likely that bigger vessels will begin arriving in New Zealand soon thereafter. We are seeking long term consents which will give us the flexibility to deepen the channel in response to the size of the ships actually visiting New Zealand.
The port is seeking long term consents which will give it the flexibility to deepen the channel in response to the size of the ships actually visiting New Zealand, so it is possible the work may be completed in a staged fashion. There is also a range of options for how the physical work itself will be carried out and this will depend on the size of the dredging vessel that is used. A larger dredge vessel would take just a few months, while a smaller vessel would dredge more slowly over the course of many months.
The type of materials to be dredged and the sea conditions mean that a Trailing Suction Hopper Dredge ("TSHD") is the most suitable dredge for the Project. A TSHD can work around shipping traffic in the channel. TSHDs are available in different sizes to suit the dredging works required. If hard ground is encountered a backhoe dredge will be used.
No. There will be no effect on wider harbour use, but navigation restrictions may apply in the immediate vicinity of the dredge vessel during the work to ensure safety. Ships will be able to come through the harbour entrance during the deepening work and this will be managed carefully by CentrePort and the Harbour Master.
Careful consideration and analysis led to the chosen placement ground for the dredge material off Fitzroy Bay. This is a refinement of an area for which CentrePort already has consents. The placement ground needed to be a location where there were minimal effects on ecology, bathymetry, shipping navigation, and bed material type. We needed to find an area based that: • Had a seabed which contained similar material to the seabed that is found through the harbour entrance; • Was suitably separated from customary, commercial and recreational fishing grounds, and marine reserves; • Where any dispersal of placed material by currents would not affect customary, commercial and recreational fishing grounds, and marine reserves; and • Was deep enough that the placed material was not disrupted and shifted by wave and wind energy, or impacted on the safe navigation of vessels. • Did not adversely affect coastal processes
Initially, some maintenance dredging may need to occur while the new channel slopes find an equilibrium. However, regular ongoing re-dredging of the channel is considered unlikely. The harbour entrance channel was last dredged in the 1960’s, and has maintained its depth without the need for re-dredging.
CentrePort has used a range of New Zealand and international experts to carry out in-depth investigations to optimise the proposed channel design and identify potential effects of the project. Matters investigated include: • dredging and disposal of the sediment; • marine ecology; • coastal processes; • consideration of potential effects on the Waiwhetu Aquifer; • noise; • sediment contamination; • heritage and maritime archaeology; • landscape; and • recreation. The draft assessment reports are on this website.
CentrePort knows that Wellington Harbour/Te Whanganui-a-Tara and Cook Strait are important areas for commercial, customary and recreational fisheries. Modelling indicates that dredging and disposal would have no adverse effects on fisheries such as crayfish, paua and fin fish. We are working with iwi and representatives from the commercial fishing industry to provide assurance for the valuable fishery in this area.
Our assessment show there would be low effects on the marine species relied on for recreational fishing and seafood harvesting.
Modelling suggests a deeper channel at the harbour entrance will increase wave action on the western shore of the harbour entrance, while wave action on the eastern shore will be reduced.
We know the harbour is a well used and loved marine recreation setting. Our investigations show there would be no short or long term affects caused by the project on these activities.
Our modelling suggests the deepening will lessen the amount of wave energy along the Eastbourne coast, which will result in a reduction in surfable days at breaks along this coast, such as ‘the Pipes’.
We have considered a wave focussing device or artificial reef, however our experts tell us that these will not be successful in that environment. What the port is doing is consulting with surfers and the Eastbourne community to identify initiatives to sustain overall surfing opportunities across the wider Wellington region. We are also considering how we can assist with other marine recreation activities in the Eastbourne area.
Effects on marine mammals would be low and management controls would be in place during dredging and disposal activity.
Wellington Harbour/Te Whanganui-a-Tara are home to many important bird species. There is a very low risk of a moderate effect on seabirds and CentrePort will put a lot of care into managing effects on seabirds.
The Waiwhetu Aquifer, which is located beneath the Hutt Valley and the Harbour, is an important resource in terms of the Wellington region's water supply. Consequently, significant analysis of the deepening’s effect on the aquifer has been undertaken. Multiple experts and agencies, including NIWA, Greater Wellington Regional Council and Wellington Water, have been involved. It is agreed that the project is likely to have a negligible effect on the aquifer. Monitoring and management controls would be in place during dredging and disposal activity.
An assessment of the potential noise impacts of the deepening work, under water and above water, was undertaken. Dredge vessels are typically no noisier than other types of ships that already operate in the harbour.
There is no contaminated sediment in the harbour entrance channel. Investigations show there are low levels of contamination of the seabed sediment near Thorndon Container Wharf, typical of the urban coastal environment. The contamination is due to runoff from the city’s stormwater system and shipping activity. This contaminated material is located at towards the top of the seabed. When the work is undertaken, this material will be moved first, placed in a deeper placement area close by, and will then be capped by the deeper material from the dredged area which contains less contaminated material. The proposed dredging at TCW and placement of that material in deeper water will decrease contaminant concentrations the dredged area, decrease most contaminant concentrations at the proposed placement area, and will result in less ongoing disturbance of contaminated sediment.
CentrePort has used a range of New Zealand and international exports to carry out in-depth investigations to optimise the proposed channel design and identify potential effects of the project. All the reports are available on this website. We have also provided a summary of each of these reports.
CentrePort will consider the feedback it receives and use that information to finalise its application.
We expect to lodge an application in early 2017.
We have a consultation process in place where we are keen to engage with interested parties through open days and face-to-face meetings. You can find information about our open days on our website. You can also contact us by calling 04 495 3800 or by emailing us at firstname.lastname@example.org. Once the application is lodged there will be an opportunity to make a formal submission on the application if you wish.
Once the application for resource consent has been lodged, it will be publicly notified by the consent authority, and submissions can then be made. Information on how submissions can be made will be provided as part of that process.