Radical $3 million transformation for damaged Christchurch cliff Deans Head
Christchurch's Deans Head is about to undergo a radical transformation to make the earthquake-damaged cliff safe.
Up to 63,000 cubic metres of soil and rock, enough to fill 25 Olympic-sized swimming pools, will be removed from the cliff face, which housed about 18 red-zoned homes.
Land Information New Zealand (Linz) has gained a resource consent to conduct the work, which will start within the next two months and is expected to take a year to complete.
Up to half the soil and rock could be placed at the neighbouring Shag Rock Reserve, where a 3 metre-high, 300m-long bund is being placed along the roadside. The total cost of the two projects was about $3 million.
Shipping containers, stacked two high, were put at the bottom of Deans Head following the 2011 earthquakes when it was discovered the risk of falling rocks was unacceptably high. The containers would be removed once the work had been completed.
Consent documents said the work was essential to mitigate the risk posed to road users, but it would not come without casualties. Lizards and a rare moth living on Deans Head would most likely not survive the work, the documents said.
Independent commissioner David Collins said the lizards could not be rescued from the site because of safety issues, but the lizard habitat would be reinstated on the slope and Shag Rock Reserve once the work was completed. It was also proposed to relocate portions of a rock wall directly above Main Rd to Shag Rock Reserve to give the moths a greater chance of survival.
Collins said the work would leave behind a raw hillside of undulating newly-exposed rock and patches of soil on natural benches.
"The change will be a significant one in my view and will be such for some time."
He acknowledged the site would be naturalised over time with planting and could contribute an enhanced sense of naturalness to the headland.
Collins said the land was already undergoing a significant change in appearance with the removal of buildings, retaining walls and driveways.
The Norfolk pines on the ridge line would go.
The road would remain open to two-way traffic, but lanes would be reduced from 3.5m to 2.75m and a speed limit of 30kmh put in place.
Sumner Community Residents' Association spokesman Darrell Latham said the work on Deans Head would be very obvious to begin with, but he hoped that would only be short term before the landscaping took effect.
"The residents accept there will be disruption but by the same token, the sooner it's over and the sooner life returns to normal, the better. Certainly for local businesses it will be a good day when things return to normal."