Review launched after Whanganui Port hits $4.2m dredging and contamination hurdles

Port chairman Mark Petersen says work on Wharf 3 will be completed in April or May.

Removing contaminated materials from Whanganui Port’s redevelopment has led to unbudgeted expenditure of $4.2 million.

An independent review of the entire project is now underway, due to the extra cost, dredging issues and health and safety risks.

Port chairman Mark Petersen told the Whanganui District Council’s council-controlled organisations and economic growth committee that contamination was predominantly asbestos-related.

The port is a subsidiary of the council.

“We still have a substantive pile of contamination behind the area where Wharf 3 is going, but we have an agreement with Q-West [Boat Builders] and the contractor that it will be sealed underground,” Petersen said.

Another pile at the site had been removed, “most of which had to go to Bonny Glenn [landfill site near Turakina]”.

Petersen said there was another contaminated site behind Wharf 2 but the intention was not to disturb it.

“The key is to ensure it is encapsulated and there is an impervious protective barrier.”

Petersen’s report to the committee said three flood events in the Taumarunui catchment between July and October last year resulted in substantial volumes of silt, logs, and debris coming down the Whanganui River.

That created unsafe operating conditions and the initial dredging contractor, West Coast Dredging, was unable to safely stabilise its Kawatiri boat following the first flood event, the report said.

“Johnson Brothers was subsequently engaged and completed the dredging required to enable EV1 [electric ferry built by Q-West Boat Builders] to undertake tidal sea trials.

“They are now contracted to dredge the channel to 3.0 metres chart datum during the first half of 2026.”

He told the committee that close to 6cu m of silt came down the river every year, along with “a fair amount of debris”.

Because of the difficulties the project was facing, the port had engaged Peter Leslie of PDL Consulting to undertake an independent review, Petersen said.

The review could include issues caused by a hole in the wall enclosing the harbour basin, he said.

Speaking to the Chronicle in 2024, Petersen said “the port [authority] in its past life” decided to create the hole so the river would flow through and take material with it.

“That hasn’t worked very well, it would be fair to say,” he said.

“It’s caused a lot of scouring but it’s also delivered us silt from up the river, and it is a very silt-laden river.”

Leslie will present draft findings at a council workshop on March 24.

The port project is being completed in three phases, with the first being a vessel hardstand and concrete structures over the water to carry Q-West’s mobile boat hoist.

Renewing Wharf 3, originally scheduled to be completed last, began in June 2025.

Petersen told the committee Wharf 3 would be finished in April or May.

His report said Whanganui contractor Emmetts Civil Construction was pricing work for four options for Wharf 2 - 190-metre wharf and 140m wharf configurations, each at design depths of 5.5m and 6m.

“The port board will not be in a position to award the Wharf 2 contract until the independent project review is completed and the council has considered and approved the resulting recommendations.”

It was anticipated Wharf 2 would be completed towards the end of 2027.

The council’s work is part of the port revitalisation project Te Pūwaha, which includes iwi, Whanganui District Council, Whanganui Port, Horizons Regional Council, Q-West Boat Builders, Te Mata Pūau and the Whanganui District Employment Training Trust.

Mike Tweed is a multimedia journalist at the Whanganui Chronicle. Since starting in March 2020, he has dabbled in everything from sport to music. At present his focus is local government, primarily Whanganui District Council.