Unstable land closes Raumanga playground; high voltage lines at risk

Unstable ground conditions due to slumping land have forced the closure of a children's play area and could shift high voltage power lines, putting public safety at risk.

A power pole beside a children's play area on Dakota Pl in Raumanga was strengthened two weeks ago while another located on a large swathe of land being developed by former Whangārei mayor Stan Semenoff has shifted.

In March 2016, the Northland Regional Council issued Semenoff consent to undertake about 152,000cu m of cut and fill earthworks, including within the bed of an unnamed tributary of Limeburners' Creek.

Semenoff said he was unable to comment while he was awaiting technical reports from surveyors and civil and geotech engineers and monitoring the land area in question.

Manuka Pl resident Anthony Stringer and his wife are living in temporary accommodation after a Whangārei District Council engineer found extensive cracks in their house in late August.

Asphalt was put on a slumped roundabout directly across their property appeared to have sagged further, while parts of land being developed appeared to have slumped more than when the Stringers home was condemned.

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Northpower spokesman Steve MacMillan said power poles and high voltage lines in the area were affected.

"The land movement has caused one of the poles to shift. On August 30, we strengthened one power pole near the affected area and are monitoring it regularly and continuing to work on a permanent solution."

He said the final solution would depend on expert geotech advice which Northpower was currently working through.

"The nearby substation has an alternative electricity supply if we need it and if an outage occurred we have contingency plans in place to minimise the impact of an outage."

MacMillan said Northpower was working closely with the Whangārei District Council and other stakeholders and would continue to do so as public safety was its priority.

A digger was yesterday working closer to power lines on land being developed and a truck was parked not far away.

Both would have had access from the end of Lancaster Pl which is off Mt Pleasant Rd where the Northpower head office is located.

WDC general manager infrastructure Simon Weston said the decision was made to close the children's playground due to repairs needed to powerlines and would remain closed until it was safe to re-open.

"Like others, we are concerned the ground is still moving. We are monitoring the progression of the slip and the state of the road on Manuka Place. We will continue make repairs to the road as needed to ensure its safety.

"We are awaiting a report from the developer's engineers on what they are doing to stabilise this area, and we will review the report as soon as it is submitted to us as part of our standard subdivision consent process."

NRC water and waste monitoring manager Alison McHugh said since no work was happening on site, there was no need to put a stop-work order.

She said heavy machines were not having any impact on ground conditions as they were operating further down from the slumped areas.

McHugh said works outlined in the resource consent finished last year while remedial work Semenoff undertook after the Stringers' house was condemned finished last week.

An Earthquake Commission report last month found a combination of rain and earthworks led to structural damage the Stringer's property and slumped land around it.

However, the report was based on a visual assessment of the site only and pointed out that subsurface conditions may vary.