Resource consent application
Ports of Auckland have applied for resource consent and requested public notification to deepen the Waitematā Navigation Channel.
Auckland's population is growing fast, with a million more people expected to live here by 2050. More people means more demand for the products we all buy from overseas, which means more containerised imports and – because of economies of scale – bigger ships.
Ports of Auckland has to be ready to handle this growth
The largest container ships we handle at the moment carry up to 5,000 twenty-foot containers (TEU). Shipping lines want to bring 6-7,000 TEU ships here in the next 2-3 years and in future we will need to host 'New Panamax' ships that can carry around 12,000 TEU.
The shallowest parts of the channel are 12.5m deep at low tide, whereas 6-7,000 TEU ships have a draft of 14m and New Panamax ships have a draft of 15.2m.
Keeping dredging to a minimum
To keep dredging to a minimum, we will use tidal windows. Tidal windows are in common use in other New Zealand ports, and simply mean that deeper draft ships enter or leave port when the tide is high enough. To create a suitable tidal window for New Panamax ships to access port safely we will need a channel which is 14m deep on the straights and 14.2m deep on the bends. As it takes around 15 hours to unload and load a container ship, our berth will be dredged to 15.5 metres so ships can stay through a full tide cycle.
Ports of Auckland will use a mechanical dredge – a digger on a barge – to deepen the channel. The digger will have a long arm to reach down to the seabed to scoop out the bottom material. The bed of the channel is mostly soft material like marine muds, mudstones and some sandstone and gritstone, which can be removed by a digger. No blasting is required.
Managing environmental impact
The current channel is a highly modified environment which has been dredged many times. As a result we already know a great deal about how dredging impacts the environment. Regardless, we have undertaken a wide range of studies to examine the likely impact of this new dredging campaign. This includes work on navigation & safety, wave & current impacts, biosecurity and more.
Ports of Auckland have applied for consent to dredge the Waitematā Navigation channel in two stages:
• Stage 1 for 6-7,000 TEU vessels
• Stage 2 for New Panamax vessels
Ports of Auckland have requested that this consent application be publically notified. The detailed consent information is available on the Auckland Council website.