Christchurch City Council and NZ Transport Agency are working to re-open Sumner Road, from Evans Pass to Lyttelton. The critical roading link has been closed since the February 2011 Earthquake, due to earthquake damage and the risk from geohazards.
The re-opening of the road will help limit night-time closures of the Lyttelton Tunnel and provide better access for the harbourside community of Lyttelton.
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 reopening of Sumner Road has moved a significant step closer, with the start of geotechnical risk mitigation works around Crater Rim Bluffs.
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 2019.
The geotechnical risk mitigation works will mean some changes to public access in the area around Sumner Road, and the harbour below.
The area for the proposed work extends from approximately 100 metres from the Evans Pass layby down to Double Gully. It includes the Crater Rim Bluffs and the slopes below these, the Battery Point Bluffs, the road cuttings, and Double Gully to the west of the Crater Rim Bluffs.
For public safety, a gate has been installed across the junction of Sumner and Summit Road, limiting access to the lookout.
While the work is taking place, heavy vehicles will use the lookout area and carpark at the top of Sumner Road as a turning point and staging area, making it unsuitable for public access.
A walking track across Crater Hill will remain open and provide access to recreational areas.
All areas not accessible to the public will be fenced off, but for your safety, when walking or cycling in the area, please take care, follow the directions on all signage and do not cross safety barriers, as there will be high hazard work taking place nearby.
Locals should also be aware of a marine exclusion zone that will be put in place. For public safety and to manage the risk from rockfall, the Harbourmaster will mark Gollans Bay off with buoys. While the geotechnical risk mitigation works are being carried out and there is blasting on the bluffs to remove and deconstruct loose rock the area will remain closed to all members of the public. The exclusion zone is shown in red in the map.
If you have any questions about the project or the marine exclusion zone please contact the project team on 0508 MCD COMMS (0800 623 266)
The proposed project methodology has had rigorous professional and technical investigation and peer review by a multi-disciplinary team including planners, engineers, geologists, landscape architects, construction and operations consultants, and ecologists.
The team has considered potential effects during construction and in the long term. These include disruption to plant and wildlife; erosion; stormwater runoff; nuisance, noise and dust effects; landscape impacts; impacts on walkers and mountain bikers using the Crater Rim paths and many more. The project team has developed strategies for avoiding, remedying and mitigating these effects. Conservation work includes native restoration planting and gecko translocation.
Native lizards (skinks and geckos) live in many places on the Port Hills/Banks Peninsula area. Five different types of lizards live in the Port Hills/Banks Peninsula area. There are two gecko species (Canterbury Gecko and Jewelled Gecko) and three skink species (Central Canterbury Spotted Skink, Common Skink and McCann’s Skink). The Council is working with the Department of Conservation to reduce the impact on lizards and their habitats from the work needed to fix earthquake damaged sites and reduce the risk of rockfall on the Port Hills.
Rockfall risk remediation takes place to ensure peoples’ safety and to prevent damage to the road below. It is a process to reduce or remove the risk of future rockfall and is carried out by experts.
The work to reopen Sumner Road between Evans Pass and Lyttelton requires major rockfall risk remediation work to stabilise the Crater Rim Bluffs and adjacent rocky areas.
Rockfall risk remediation affects lizards living in the area. Some lizards face permanent habitat loss, injury or death, although the Council has looked to reduce the impact as far as we can. Work on the Sumner-Lyttelton road will have the most effect on the Canterbury Gecko because it lives in the rocky Crater Rim bluffs.
The amount of rock removed from the area will be kept to a minimum and we will try to avoid key habitats, for example the areas where Canterbury Geckos live communally. Before work starts, as many lizards as possible have been captured from accessible areas and released in safe areas. Skinks have been released in suitable tussock grassland nearby. Canterbury Geckos have been caught and released at Riccarton Bush to start a new population there. Riccarton Bush has 7.8 hectares of forest surrounded by a state-of-the-art fence that keeps out predators (mice, rats and cats).
The geckos have been caught by specially-trained rope access technicians working with a herpetologist (a person who specialises in working with reptiles and amphibians). Some have been caught in live traps and some caught by hand once rocks are removed. Some geckos have also been gently coaxed out of their crevices.
We will not return them to the Port Hills site because they will no longer have the vital resources on which they depend, including deep, narrow rock cracks that keep them safe from predators and readily available food sources (plant berries and insects).
Works started in late 2015 and the road is expected to be open in 2019.
Ahead of any work, works notices will be issued to communities in the surrounding areas, emailed to e-newsletter subscribers and put up on this page.
If you would like to receive email updates on the project, please email your name and address details to firstname.lastname@example.org with the subject header ‘Slcorridor updates’.