Geotech works begin towards re-opening Sumner Road

Posted on 30th September 16

The reopening of Sumner Road moved a significant step closer today, with a blessing and planting to mark the start of geotechnical risk mitigation works around Crater Rim Bluffs.

Sumner Road from Evans Pass to Lyttelton has been closed since the February 2011 Earthquake, due to earthquake damage and the risk posed by geohazards including rockfall, cliff collapse and landslides.

The Sumner Road reopening project, jointly funded by NZ Transport Agency and Christchurch City Council, will see this important roading link opened again.

Sumner Road is one of four projects within the Sumner-Lyttelton Corridor programme, which aims to mitigate geohazard risks to road users and return the road corridor between the Sumner side of the causeway and Lyttelton to its pre-quake level of service.

The work to mitigate the geohazard risks around Crater Rim Bluffs at the top of Sumner Road, is the first stage in works to re-open Sumner Road, and will be undertaken by McConnell Dowell, partnering with Beca, Doug Hood Mining and Geovert.

Works will include source rock deconstruction by scaling the upper reaches of the Crater Rims Bluffs, with a 400 metre long, 15 metre wide catch bench constructed at the base of the bluffs to protect the road below from rockfall.

A rock bund will also be constructed in Double Gully to the west of the Crater Rim Bluffs to capture rockfall from the bluffs. The bund will be several metres high and 50 metres long, and covered with basalt cobbles to reflect the basalt stone walls in the area.

To minimise environmental impacts and reduce cost, the existing road will now be used as a ‘haul road’ for transporting excess rock from the excavation of the bench, and structural repairs will be completed under the existing road. Using the existing road rather than constructing a separate haul road also makes a start on the repair work required to return the road to two-lane use.

Once the geotechnical risk mitigation work is completed, the next stage of work will begin, investigating the extent of the damage to retaining walls along the road. The road will then be repaired and reinstated. At this stage, it’s expected that the road will reopen in 2018.

Christchurch Mayor Lianne Dalziel said the re-opening of Sumner Road will play a crucial role in the region’s earthquake recovery, and exemplifies our commitment to building the city’s resilience.

“Sumner Road is such an important place to Cantabrians – economically as the link between Lyttelton Port and the city, as the connection between Lyttelton and Sumner communities and also as hugely popular recreational space with tourists and cyclists. It’s really exciting to be heading into this phase of work, and see us closer to being able to travel this road once again.”

The Transport Agency’s Southern Regional Director Jim Harland says with this work starting, the community will start to see great progress in getting Sumner Road re-opened. “This is a lifeline route for Christchurch, and so critical in supporting the economic wellbeing of not only Canterbury but the whole South Island. This is recognised by the Transport Agency’s 83 per cent funding of the work as part of the earthquake recovery programme. He says the re-opening of Sumner Road will help in limiting night-time closures of Lyttelton Tunnel and provide better access for the harbourside community.

Work on the other three Sumner Lyttelton Corridor projects – Moa Bone Point, Wakefield Avenue and Shag Rock Reserve, is progressing well, with the shipping containers protecting the road from rockfall able to be removed from Moa Bone Point late last month.