Transport Rebuild East Coast (TREC) is preparing to begin further drainage and slope stability improvements on State Highway 35 at Kopuaroa Hill, north of Tokomaru Bay.

From Monday (10 August), crews will begin a project to stabilise the slope and upgrade drainage covering a 1.5 kilometre section of SH35. Four new culverts will also be installed across the road to help move water away from the slopes.

During the work, people travelling through the area should expect delays of 5 to 10 minutes, with one-way stop/go traffic management in place, Monday to Friday, 6am to 6pm while work is underway.

At all other times the road will be open to two lanes, with temporary lower speeds in place.

Work is expected to be completed by Christmas.

Drainage improvements

During work, crews will be installing almost 60 horizontal drains, extending approximately 100 metres into the hillside from road level, to help reduce groundwater pressure and improve slope stability. New rock-lined roadside drains will be installed to better manage surface water.