Underwater excavation to begin at Napier Port's new wharf

Dredging set to begin at Napier Port's new 6 Wharf this week. Photo / Warren Buckland

Underwater excavation is set to start at Napier Port's new wharf this week.

The port is on track to start dredging for 6 Wharf, taking the port a step closer to finishing it by the end of 2022.

The new 6 Wharf will allow the port to reduce congestion and welcome more and larger ships.

Dredging is a process that uses a specialised ship to remove sediment and rock in a harbour and deposit it to a disposal site.

Napier Port infrastructure services general manager Michel de Vos said a backhoe dredge (GPK), operated by Heron Construction, arrived from Lyttleton on Monday, with work set to commence this week.

"The community will be able to see the GPK in the harbour for the next 18 months or so," he said.

"Some dredge plume may be visible as Heron goes about their work. This is sediment from the seafloor and is a normal part of the dredging process."

To build the wharf, Napier Port will need to excavate around 1.3 million cubic metres of material from underneath the wharf, the swinging basin and the shipping channel.

Napier Port is monitoring water quality in real-time to ensure the dredging doesn't harm the marine environment.

"We'll be alerted immediately by our monitoring buoys at Pania Reef if turbidity (water quality) is above expected levels and will adapt our operations, or stop, until conditions mean it's safe to resume," de Vos said.

All vessels not associated with the dredging operation are asked to stay 50 metres away from the dredge.

The Port will deposit most of the dredged material at a consented site 5 kilometres east of the port.

Napier Port has secured resource consents for five stages of dredging, but is only undertaking stage one dredging for now.