Several factors contributed to the slip on Route 52. PHOTOS/SUPPLIED
Tararua slip still sliding
Wet weather, saturated ground, an earthquake, a fire and logging create a slippery situation on Route 52
Residents should not hold their breath for a quick, permanent fix to Route 52 as the road continues to rapidly deteriorate.
Route 52, east of Eketahuna, was the main road between Alfredton and Pongaroa and was partially wiped out by the slip over a week and a half ago.
About 60 metres of the road was completely engulfed.
Tararua Alliance delivery manager Matt Erard said the land had not stopped moving.
“There’s a pretty large landslide on the move, we estimate there’s 50,000m3 within the movement itself
About 4100m3 of slip material had been transported by contractors to landowners who had offered fill-sites.
Erard said an earthquake near Castlepoint on September 7 contributed to the slump.
“The earthquake wouldn’t have helped, and the unusually wet season wouldn’t have helped.
“There was also logging activity and a fire that went up the cliff face. Someone planted trees to try and stabilise the bank and a fire went up it taking out essentially one-third of the trees.
“But the biggest thing is groundwater.”
A temporary road had been established by contractors over the past few days.
However opening the track was reliant on the weather.
“We’d like to get this open in the next one to two weeks, but it’s really hard to put an active timeframe on it at this point
“But the likelihood is we’ll open it up to four-wheel drive access only, to try and assist the locals.”
Erard said he was working with Geotech and design engineers on plans for when the ground dried up and work on a permanent fix could begin. Plans included controlling and cutting off underground aquifers to stop land movement and building a retaining wall to stabilise the area.
Tararua Mayor Tracey Collis said plans were moving forward to find a solution for the road.
“I went out on site on Monday afternoon and got reports from the team on the site.
“I may be jumping the gun here, but when we had an issue on the Pongaroa to Alfredton road a couple of years ago, a bit closer to Eketahuna, we got that cleared pretty quickly.
However, Collis said a thunderstorm rolling in on Wednesday raised concerns over rainfall worsening the slip.
“As that storm rolled in we had alarm bells going off. A lot of rain in that area would have been a concern.
Collis said that although Tararua had several slips affecting its roading network, the difference with this one was the amount of land movement.
“It’s certainly a very large site. Just to see how far down the hill that road is and the sheer volume of wet clay puts it in proportion.
“And when you’re down there you can certainly see that – it’s very saturated.”
An alternative route along Rimu Rd was available however a safety assessment had determined the road was unsafe for heavy vehicles.
Instead, heavy vehicles were advised to use State Highway 2 and cut across to head east.
The council was unable to say how many people were affected.