Helicopters will drop thousands of plants onto the steep slopes above Sumner Road as the final stages of a massive planting project gets under way this week.
Several thousand plants have already been planted on the slopes above the reconstructed road that links Sumner and Lyttelton, but another 15,000 still need to go in.
Some of those 15,000 plants will go in over the next few weeks. The remainder will be planted in May and June next year when nursery stocks have replenished.
Several tonnes of plants – a mix of native shrubs, trees, flaxes and tussocks - are being airlifted onto the slopes because the terrain where they will be planted is too steep to be accessed by vehicles.
“Teams will go in by foot to plant the plants. They’ll be digging in tricky terrain among the Crater Rim Bluffs above Sumner Road and using rope access in some areas. Their experience of the site, and techniques during previous work will be invaluable in managing the risks of this challenging job,’’ says Christchurch City Council Senior Project Manager Peter Bawden.
The plants will help to stabilise the slopes above Sumner Road as well as mitigate the impacts of the geotechnical work done to reduce the risk of rocks falling onto the road.
Sumner Road was badly damaged when tonnes of rock from the surrounding cliffs came tumbling down onto it in the February 2011 earthquake.
It took two and a half years to rebuild the road, but before the reconstruction work could begin, the Council and the NZ Transport Agency had to address the risk of further rocks falls.
Contractors blasted about 100,000 cubic metres of rock from the cliffs above the road. They also built a 407-metre long catch bench to intercept falling rocks and a 50-metre long, seven- metre high rock interception bund.
“The planting work will go some way towards restoring the ecological balance in the area and represents the final stage of this massive project,’’ Mr Bawden says.