Shag Rock Reserve

Deans HeadThe road is currently protected from geotechnical hazards by ballasted shipping containers. These shipping containers will be removed once the geotechnical works are completed. The road will return to its previous layout and this will improve safety for cyclists and drivers.

The works at Clifton Hill and Deans Head will be overlapped to get through the work as quickly as possible and reduce ongoing disruption for residents.

Geohazard mitigation

Cliff collapse is a risk along most sections of the road. Clifton Hill is a Class II mass movement (landslide) area (where any further mass movement may damage homes and affect infrastructure, but lives are not thought to be at risk) and Deans Head is a Class I mass movement area (where further mass movement could pose a risk to live, homes and infrastructure.)

To reduce the risk to road users around Clifton Hill, the mitigation solution includes rock deconstruction, bolting and meshing. For Deans Head, the mitigation solution to reduce the risk to road users will include the removal of unstable soil, rock deconstruction and a bench.

Benching is cutting into the natural rock slope to create flat platforms within the rock. Benching is used to control rockfall on steep ground and cliffs as the platforms catch any rockfall from the rock cutting above. The benches can be created either with blasting or machinery.

Mitigation works at Deans Head will be carried out as part of the demolition works in the residential Red Zone on Deans Head. LINZ will manage the works at Deans Head. Clifton Hill works willl be carried out by Fulton Hogan.

Works are underway at Shag Rock Reserve to remove building debris from the cliff collapse debris in Shag Rock Reserve.

360 degree view of the geotechnical risk mitigation works at Deans Head

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Updates and more information

Works notices have been issued to communities in the surrounding areas.

If you would like to receive email updates on the project, please email your name and address details to with the subject header ‘Slcorridor updates’.

We will also be keeping community and residents’ groups in your area informed of any developments on the project, and paper copies of any updates will be available to take home from the Lyttelton Service Centre (15 London Street, Lyttelton) and The Sumner Hub (57 Nayland Street, Sumner).