Queenstown Lakes District Council principal monitoring and enforcement officer Anthony Hall said council staff spent yesterday at the Lakeside Rd Marina Terrace Apartments construction site with the developer, Multiplied Investment Partners, and geotechnical experts hired by the company.
Multiplied Investment Partners spokesman Matt Tuck confirmed the landslip occurred because the site became destabilised as a result of removing vegetation and waterlogged soil.
‘‘As part of our site investigation prior to commencing works, our consultants and contractors drilled and profiled over 100 locations across the site,’’ he said.
‘‘The top 1200-1500mm has been of concern, and while the site held up well in the significant rainfall earlier in the week, some localised works has caused an area of the site to weaken and slip.’’
The alarm was raised on Thursday night by a passing motorist who contacted the company when he saw water on the road coming from the construction site.
About 9pm mud started ‘‘creeping’’ about a metre an hour across the road, stopping just short of Lake Wanaka about 3am.
Mr Tuck said crews worked through Thursday night, ‘‘de-watering’’ the site and stabilising the slip.
Mr Hall said the developers were waiting for instructions from Geosolve about when the slip was safe to be removed and Lakeside Rd could be reopened. Diversions are in place.
The lakeside pedestrian walkway had also been closed as a precaution.Marina Terrace Apartments project manager Jason Buehler said drones had been flying over the site during the morning and the company was awaiting the results of the survey.
He said the site was full of underground springs but they could be effectively managed with a de-watering programme.
Queenstown Lakes deputy mayor Calum MacLeod visited the site several times during the day. ‘‘This was always going to be a challenging development on a challenging site but I hope that this is just a minor blip.’’
Otago regional councillor Ella Lawton said her main concern was ‘‘if this could happen once, could another landslip happen again?’’.
She questioned the long-term stability of the land and risk of the development withstanding an earthquake or a similar major event. Neighbour Scott Anderson has lived at 61 Lakeside Rd for the past year and watched the development site being cleared of tea trees and flax.
‘‘It used to be a tea tree swamp with flax before they whipped everything off and turned it into a quagmire. There’s water all through the site, springs everywhere. You only have to walk six feet out there and you sink down to your knees.’’
Mr Hall said along with council contractors, Downer and Veolia, the QLDC was in regular communication with the developers to monitor the clean-up operation and to ensure there was no detrimental effect to the lake, immediate environment and council services.
He said representatives from the Otago Regional Council had advised there was no adverse effect from the slip on the lake, and QLDC chief engineer Ulrich Glasner also confirmed that council water infrastructure was unaffected.
Lakeside Rd in Wanaka remains closed today as engineers and contractors work to stabilise the site where a large landslip came down from blocking the road.
As of yet there is not time line for the removal of the slip and the reopening of the road to both vehicles and pedestrians.
