Subsidence probe continues

This Wimbledon Close property is understood to be the worst affected by subsidence.

The engineer that council commissioned to investigate subsidence on a badly affected section in Wimbledon Close is the director of the company that undertook the original soil testing in the Thornton Estate subdivision.

The subdivision borders a swampy reserve, with several properties in the area affected by subsidence of varying degrees.

Mark Mitchell is the director of Geocon Soil Testing Ltd, the company which undertook soil investigations for the several sections in Wimbledon Close ahead of the residential development in 2006.

Mr Mitchell was commissioned earlier this year to provide a geotechnical assessment for site remediation of ground settlement for what is believed to be the worst affected property in the area.

The house, like others nearby, sits on deeply driven piles to ensure its stability in the soft peat soil. However, the underground services are being compromised as they get dragged down with the sinking soil. There are regular electricity outages which means the owners are regularly without power, and their pump-operated sewerage system can't be used until power is restored. Gas mains regularly trip, which shuts down their gas-powered hot water. The piles are exposed as the soil sinks beneath them.

The section is a boggy mess. Where there used to be gardens is now flooding which rarely drains away.

Earlier this month, council's building control manager Phil Saunders told Hamilton News that council had commissioned an engineer to look at two sections in Wimbeldon Close who could give advice as to what residents could do to "mitigate their ongoing issues".

"One of the reasons we went off and got some careful engineering advice was so we could update residents affected in terms of how they can mitigate it in future."

Mr Saunders said the report indicated that the two worst-affected sections in Wimbledon Close could expect to continue to subside up to 50mm a year for the next three years "and then it will settle down. That's the best engineering advice we can get".

Councillor Dave Macpherson said, of particular concern, was that Mr Saunders had advised him and the property owners that this was an independent report.

"Phil also advised that council had approached the original engineers and not received a response, when in fact the original engineers were the same as the company he had asked for the 'independent' report from."

COUNCIL'S RESPONSE

Hamilton News asked to interview city planning and environmental services general manager Brian Croad about the Mr Macpherson's concerns.

Instead, council provided this response from its building control manager Phil Saunders:

"In relation to the land subsidence issues, we have since made contact with property owners in the area to give them the opportunity to discuss with us any issues they may have.

"We are happy to meet with any property owners who have concerns and we will offer advice and support to mitigate the issues.

"So far, we have had six property owners come back to us and we have met with them to discuss their properties.

"We encourage any property owners in the area who have questions to contact us on 07 838 6699."