Wanaka wakes up to large mudslide

A large mudslide that has blocked a Wanaka road was caused by vegetation and waterlogged soil being removed from a building site.

Multiplied Investment Partners spokesman Matt Tuck said a passing motorist notified the company of water across the road from the Marina Terrace building site at 65 Lakeside Rd last night.

He said a slow-moving mudslide moving about a metre an hour began at about 9pm and did not stop until 3am today.

The road remained closed this afternoon after the mudslide. Photo: Kerrie Waterworth

"The top 1200-1500mm of soil on the site 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," Mr Tuck said.

The Queenstown Lakes District Council this afternoon said officials were on site and they, along with contractors Downer and Veolia, were in communication with the developers to monitor the clean-up operation. 

In a statement, the QLDC said the developer had confirmed the landslide was due to the site becoming destabilised as a result of removing vegetation and waterlogged soil.

QLDC Principal Monitoring and Enforcement Officer Anthony Hall said: ''We’ve been advised that GeoSolve engineers are onsite directing the operation. The developers are awaiting instructions from GeoSolve as to when the landslide can be removed and the road re-opened."

"We are continuing to monitor progress and the road remains closed. We’re unable to confirm at this stage when the road will reopen which will happen as soon as it is safe and practicable. Diversions are in place and as a precaution the lakeside pedestrian walkway has also been closed." 

A slip on the Marina Terrace construction site on Lakeside Rd overnight has blocked the road to all traffic. Photo: Kerrie Waterworth

"The developer is currently continuing to draw down the groundwater level on site and they report that this has stabilised the slip with no additional movement noted since 3.00am. Once this dewatering is completed a slope stability analysis will be undertaken to confirm that the remedial works have provided sufficient increase in stability and reduce risk to Lakeside Road."

The council said it had been advised there was no adverse effect from the slip on the lake.