More than 40 people attended a meeting on Monday evening at Hinakura Hall to hear experts discuss available options for the failed road into the valley.
Five different possibilities for the route from Martinborough were presented to locals – costing as much as $11 million and taking as long as three years to complete.
David Stewart, principal geotechnical engineer and engineering geologist at consulting firm WSP Opus, described how a progressive landslide has caused Hinakura Rd to collapse over the past two years.
“The landslide is about 500 metres long from top to bottom and roughly about 100 metres wide.
“In June 2020, it moved about three to four metres, and then on two to three other occasions, it moved similar amounts.”
Stewart said South Wairarapa District Council [SWDC] had been able to manage the road on the basis the slip would move a few metres and then stop – until
a catastrophic event in June last year.
“Over a period of a week, it moved 90 metres. It went from three or four metres three or four times and then suddenly changed behaviour and moved 90 metres. At the time we were thinking we could put some drainage in, but when this happened, it was too big a thing to fix [ in that way].”
Instruments currently monitoring parts of the slip show that areas are moving intermittently but one key area has not moved at all since last June.
The road has been impassable since the June event, with locals currently using a makeshift track over private farmland above the area of the slip. The track was open only to limited access by 4 x 4 vehicles, leaving one alternate route through Admiral Rd for stock and other heavy-duty vehicles.
The first option Stewart laid out for fixing the broken road – described in an accompanying report as “the current preferred option” – involves building a route that completely bypasses the slip zone and connects back to Hinakura Rd to the east.
This option is expected to cost between $10 and $11 million and take about a year to complete after extensive preparatory work.
Other options include: using part of the existing temporary track, which would then reroute around the slip; constructing a new road through the existing slip; constructing a new road through part of the slip;
and permanently closing Hinakura Rd and using a new alternate route through Admiral Rd and Clifton Grove.
Stewart said that although building through the slip would be cheaper and faster, costing about $1 million, it would also be at a higher
risk of a future failure.
Meeting attendees were strongly opposed to closing the road and were keen for the chosen option to provide a rapid resolution to their roading woes, while also providing more than a temporary solution.
Farmer Don McCleary described the conundrum faced by locals when he noted that, while the faster rebuild option is attractive in the short term, it would probably only be temporary, leaving people vulnerable in the future.
Valley residents will consider the options provided and communicate with SWDC officials over the coming weeks.
SWDC is expected to consider the community feedback and then make a decision about roading options at a future meeting.
