Te Ahu a Turanga: Manawatū Tararua Highway project

Three geotechnical rigs are operating, drilling boreholes ranging from 10 to 70 metres deep.

More than a third of ground investigations along the road alignment for the Manawatū Tararua Highway project has been completed, the NZ Transport Agency says.

The proposed new route will connect the Manawatū, Tararua District, Hawke's Bay and northern Wairarapa, replacing the closed State Highway 3 Manawatū Gorge route.

"This is important work to understand the properties of the soil and rock to determine the most appropriate methods for the cuts and fills needed to construct the highway.

"Three geotechnical rigs are operating, drilling boreholes ranging from 10 to 70 metres deep. More than 500m of vertical drilling has been completed to date, along with 43 test pits to a depth of up to 4m. The test pits assess the near-surface materials to determine what can be re-used or removed during construction."

The span of the new bridge over the Manawatū River will exceed 300 metres.

Notice of Requirement and consents

NZTA is continuing with work to resolve outstanding appeals to the Notice of Requirement for the transport corridor designation, while at the same time finalising its resource consent applications.

Designation and consent are required before construction can commence.

Design and construction

Over the past six months, the project's design team has completed the concept design and is working closely with the construction team to finalise the building programme.

• The project involves 40 major culverts ranging in size and length from 10m to 180m, required earthworks exceed 5.5 million cubic metres. The project includes the construction of nine large stormwater treatment wetlands.
• The main types of soils over the project include mudstone, conglomerate and alluvium.
• The span of the new bridge over the Manawatū River will exceed 300 metres.
• There are currently 10 ecologists on the project completing stream and habitat assessments to support the upcoming resource consent application.