Cliffside houses checked for fall risk
Hills and Harbour
A group of unstable cliffside houses in the Port Hills red zone will be checked for the risk of collapse after the urgent demolition of a quake-damaged home.
Work tearing down the Redcliffs property finished yesterday after the house, clinging to a cliff above the main road to Sumner, came dangerously close to falling down.
Canterbury Earthquake Recovery Authority (Cera) Port Hills land clearance project manager Brenden Winder said between six and 12 properties needed to be checked for similar danger.
"It's only those houses on the edge of a cliff that we need to be concerned about, they'll have similar circumstances as this."
The properties were "scattered around the Port Hills red zone", he said.
"We're expecting no more will be in a situation like this but to be prudent we'll go and check those dozen or so houses."
Demolition of the Balmoral Lane property began on Monday night and a helicopter with monsoon bucket yesterday dropped water on the site to remove any loose debris at risk of falling onto the road or nearby properties.
Main Rd was closed until the demolition was finished.
Heavy rain and a recent flurry of aftershocks had nudged the house much closer to the cliff's edge.
More rain was expected over the next few days and weather forecasters predict above normal rainfall this winter.
Christchurch City Council Port Hills geotechnical adviser Don Macfarlane said continuous rain would be "testing" for cracked hillside land.
"Water is one of the main driving forces for land movement."
It got into the cracks, putting on pressure and softening the land, MacFarlane said.
Blue Skies weather forecaster Tony Trewinnard said this winter was expected to be cloudier than normal and it was "almost likely", rainfall would be above normal.
Rainfall in Canterbury was already above normal for May, which is typically the wettest month of the year for the region.
- © Fairfax NZ News