Source: New Zealand Transport Agency
Deep into a hillside north of Gisborne, nearly 3 kilometres of new underground drains are reshaping the way water moves through one of Tairāwhiti’s most landslide-prone road corridors.
Landslides have long been a challenge on State Highway 2 (SH2) through Otoko Hill due to the nature of the terrain, but Cyclone Gabrielle intensified the problem, triggering multiple slips that disrupted travel.
The Transport Rebuild East Coast (TREC) alliance, on behalf of NZ Transport Agency Waka Kotahi, has been working, since June 2024, on a programme of works across 11 sites at Otoko Hill. The last site, Site K, has now finished, with final road marking and checks complete.
Site K includes 976 metres of drainage: 691 metres of bored horizontal drains (long drainage pipes) drilled up to 60 metres deep into the hillside (that’s almost the length of two netball courts) and 285 metres of counterfort drains (deep trenches).
TREC project manager Richard Bayley says the Otoko Hill recovery work will help stabilise slopes around the highway.
“The underground drains intercept groundwater at multiple depths and ease pressure inside the hillside around the highway, helping to reduce future movement.”
“Drivers may not notice the changes as they pass, but the work through Otoko Hill means fewer landslides and a more resilient highway that will help keep communities, whānau, freight, and emergency services connected in future weather events.”
Mr Bayley said local contractors and hapu kaitiaki have played key roles in restoring the route after Cyclone Gabrielle.
“Otoko Hill’s recovery was a team effort, from the contractors who delivered the mahi on the ground, to the hapū kaitiaki and cultural monitors who guided the TREC team with care for the whenua. Their combined expertise helped stabilise this challenging corridor.”
“A huge thanks must go to our partners for their dedication, and to drivers who stayed patient while we got the job done.
“People who regularly travel through Otoko Hill will have seen the progress the team is making in improving this once vulnerable route and we’re very grateful for their support and patience.”
