The Remutaka Hill Rd. PHOTO/JADE CVETKOV
Motorists travelling the Remutaka Hill Rd should prepare for more slips this winter.
The only direct route between Wairarapa and Wellington is prone to slips during the colder, wetter months, and already half of last winter’s total rainfall of 277mm has fallen this month.
But it is unlikely it will ever reach the state of the Manawatu Gorge road, now closed permanently after huge slips last April.
The New Zealand Transport Agency said there were 30 minor slips, including nine rock falls, on the Remutaka Hill Rd last winter.
Contractors were called out to about 13 slips to clear debris but none resulted in major traffic disruptions.
NZTA regional transport system manager Mark Owen said the majority of last winter’s slips were during or after significant rainfall events.
This year, a damp autumn has been followed by a “reasonably wet winter” so far, Owen said.
The wet weather had contributed to the handful of minor slips in recent weeks, he said.
Last week, early morning commuters were confronted by a slip on the Featherston side, which Owen described as “wasn’t that big”.
Like most slips on the hill, last week’s was on a tight corner which made it challenging for contractors to get access, he said.
The Manawatu Gorge slip which permanently closed State Highway 3, was quite different to the Remutaka Hill, Owen said.
The gorge slip was significant due to the hill towering above the road, but the Remutaka Hill was different as the road was closer to the hillside and was prone to small slips due to the topography, he said.
The Remutaka Hill is subject to two types of slips: under-slips and over-slips.
Last week’s slips were an example of a “minor” over-slips, where a manageable amount material falls on to the road.
NZTA has also identified several high risk areas of under-slips – which cause large drop-outs of the hillside – but given the length and nature of the hill road, these cannot be dealt with all at once.
On the Featherston side of the hill, “a few sites” had been identified as ‘needing improvements’ and funding had been approved for the removal of loose rock.
Four additional sites also need improvements with funding being sought, Owen said.