Mangahauini Gorge roadworks move to next phase

Work on Mangahauini Gorge, State Highway 35, is expected to be complete in August. Photo / Supplied

Part of State Highway 35 will be under single-lane traffic light management from next week as work on Mangahauini Gorge progresses to the next phase.

Crews working on the recovery project, between Tokomaru Bay and Te Puia Springs north of Gisborne, are strengthening river control structures that protect the highway during high river flow.

NZ Transport Agency Waka Kotahi (NZTA) in an update this morning said the next phase involves completing further stabilisation works along the gorge and managing river alignment to reduce erosion caused by the fast-moving water in the Mangahauini River.

“From next week through to August, when the project is expected to be completed, the road will operate under single‑lane traffic, controlled by 24/7 traffic lights," NZTA said.

“A 30km/h speed restriction will be in place, and delays of up to five minutes are likely.

“As works progress along the gorge, traffic will switch between the southbound and northbound lanes, but single‑lane access will remain in place for the full duration.

“When traffic shifts to the northbound lane, road users will be on the new road alignment, which is a big milestone for this project.”

NZTA said the staged changes would allow crews to safely access different parts of the embankment and river structures while keeping SH35 open for the community.

About half a kilometre of the riverbed will be shaped and lined with large concrete blocks to help contain the riverbed at its steepest and most destructive section, according to NZTA.

Around 1150 of the blocks have now been installed, with only 50 still to be delivered to the site.

This project is expected to be completed in August.

Culvert and drainage work will also begin 500 metres from the main Mangahauini site next week.

The road will be reduced to one lane under stop/go traffic management from Monday to Friday between 7am and 6pm.

The work is expected to take nine weeks to complete, depending on weather and ground conditions.