Children walk to school across broken Hinakura Rd. PHOTO/SUE TEODORO

New plan to fix Hinakura

SUE TEODORO
sue.teodoro@age.co.nz

After months of waiting, a plan is within reach to fix Hinakura Rd outside Martinborough, with an expert saying the problem is not like the Manawatu Gorge.

After heavy rain in June, a large part of the narrow rural road slumped down the hill. The road was closed to vehicles for days. Children walked across the failing road to meet their school bus. Stock was unable to get out and supplies could not get in. The only alternate route, Admiral Rd, was also closed.

Residents said the damage started the year before, but the South Wairarapa District Council had not taken advantage of warm, dry summer months to fix the road. Last week David Boone from Greater Wellington Regional Council presented a report to the assets and services committee of the district council setting out a three-stage plan to fix the badly damaged road.

He said the damage could be managed. Unlike the Manawatu Gorge Rd, a workable, affordable solution was preferable to relocating the entire road.

“That slip in the Gorge was a catastrophic mass movement hard rock event. This is much more of a slow earth flow type issue which is far easier to manage.

“The option we are talking about, [for Hinakura Rd] with drainage control and vegetation management over time, can be quite successful.”

Boone said shifting the road using a structural solution would cost millions and was not worth considering with a remediation plan in place.

The regional council would fund 50 per cent of the cost, with the district council paying the balance.

The report described the damage as ‘an active landslide’ approximately 450m long and 100m wide, which was prone to movement and instability following heavy rain.

Boone thought it unlikely work could start until an alternate site for a nearby reservoir had been found.

He said finding the alternate water source as a first step was critical, so the affected landowner had a water supply in place before the other work started.

Some activity would need fine weather and he thought the whole programme would take from 10 to 12 months.

Mayor Alex Beijen said he would like a meeting with residents of the valley when it was possible.

“We now have all the information and a plan going forward that would make a meeting more productive.”

Boone outlined a three-stage sequential management plan.

“It has a few parts and they all need to be done together. It’s important to know we can’t pick and choose which bits of the recommendations to implement.”

Boone said the dam uphill from the road was contributing to the problem, but was not the full problem.

“The first part of the recommendation involves finding an alternative site for that reservoir.”

The second phase was managing water runoff from the hillside.

The third phase was vegetation control, including removing trees and new planting.



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