Flora and Fauna a focus at Auraki Stream on SH4


As the Auraki Stream road retreat project on State Highway 4 near Raetihi nears completion, dozens of school-aged children have helped with planting in the area.

In June 2015, major flooding in and around Whanganui caused substantial damage to parts of SH4 Parapara Road.

Since then Waka Kotahi NZ Transport Agency has completed work on a number of sites along SH4, and we have undertaken work at the site of a subsequent major slip at Te Oreore in 2019.

Auraki Stream road retreat is the final major repair site to be completed following the June 2015 major flooding event. More than 30 sites of damage in total required remediation from the 2015 weather event.

The Auraki Stream road retreat project has involved the relocation of a section of SH4 away from where a slip occurred into the Mangawhero River.  The new road has been moved up to 15 metres east of the old section of road.

Work on the Auraki Stream retreat began in December 2021.

In total, an estimated 11,000 plants will be planted in the area as part of the project.

Last Friday, to mark the progress of the project, children from local schools, Aberfeldy, Kakatahi School and Te Kura Kaupapa Māori o Ngāti Rangi joined with representatives of Waka Kotahi, Beca, Higgins and Mills Albert, and project partners Ngāti Rangi, Uenuku and Te Korowai o te Awaiti for the day.

Four year old Lucy was the youngest person onsite to help with planting.

Waka Kotahi senior project manager Malcolm Chiles says the project is progressing well with next steps involving chip sealing, followed by line marking, when the weather is fine.

Some other final works include guardrail installation, fencing, drainage work, planting and completing a small new wetland area away from the road.

In June, traffic was moved onto the southbound lane of the new section of road. Then last month, the road was opened to two lanes at night.

“I’m really proud of the work on this project. Working together with local iwi has been important to the success of the project to date and has led to some crucial and beneficial changes to the design of the project,” says Mr Chiles.

“For example, where we filled in a gully, instead of putting the stream underground through a 70m long culvert, the stream will take a more natural path and flow overland through large rocks and boulders.

“Another example is the type of planting we’re using in this project. Kererū are a common sight in the area and by planting a mixture of natives and fruiting trees, we’re hoping the species will flourish in the area.

“With new planting and including fish passage up Auraki Stream this our way of improving the health of the awa,” says Mr Chiles.

“The Auraki Stream road retreat project is part of the wider work on SH4 (see link below), to ensure the road remains safe for all users, and is resilient and future proofed. SH4 Parapara Road is a major trade corridor as well as a scenic tourist route and a route well used by locals.”

SH4 Whanganui to Raetihi repairs

Planting underway – the planting day begins.