December 2020
Construction is underway and most of the preliminary preparatory work has been completed.
Borehole drilling started – seven pile foundations for retaining wall number 2 are completed. This work is expected to be finalised by August 2021.
The site will be closed on from Tuesday 22 December 2020 for the Christmas holidays, and resumes on Monday 11 January 2021.
Ngaio Gorge Road is open for two-way traffic during the site closure period and will be down to one lane when construction work resumes.
Project Programme Milestones
| Project stage |
Planned work |
Period |
| Stage 1 |
Construction of three reinforced concrete retaining walls on the loser side of the road. |
October 2020 to September 2021 |
| Stage 2 |
Stabilisation of the two slip sites, including installation of rock anchors, netting, and MSE bund at the main slip area. Installation of an attenuation fence, anchoring, and drapery at lower slip area.
|
October 2021 to May 2022 |
| Stage 3 |
Road upgrades, including new/upgraded stormwater infrastructure, street lighting, provision of parking spaces, and improvements to the footpath and uphill cycle lane. |
June 2022 to October 2022 |
About the project
As part of the Council’s programme of work to improve safety and accessibility of major transport routes we are committed to fixing the Ngaio Gorge slip.
Construction work is scheduled to get underway from 12 October 2020 and will give priority to the construction of three retaining walls to realign the road. Once that is completed the Council is to continue stabilising the lower and upper slip sites and remove the concrete barriers and shipping containers.
The project cost is $11m including professional fees.
Impact on traffic and residents
The road will be down to one lane for the duration of the construction and will be controlled by traffic signals.
There will be impacts on traffic while the work is underway. We will monitor traffic flows, particularly during the morning and evening commuter peaks to minimise the impact on people’s journey times.
Work hours
Crews will be working between 7am to 6pm, Monday to Saturday from 12 October 2020 until October 2022.
Alternative routes
We encourage people to use alternative routes such as the Ngauranga Gorge or Onslow Road to help ease congestion during busy times.
There are good options for public transport in this area. Please check Metlink timetable for options.
Cyclists
Cyclists will be most affected in the early stage of the project when they are travelling uphill. Safety has to be the number one priority so we will need cyclists to dismount and push their bike through the pedestrian areas of the site, particularly when travelling uphill.
Trelissick Park users
Trelissick Park will remain open during this time. The upper entrance at Trelissick Park will remain open during the project. Later on - the lower site entrance will open.
Parking for people going for a walk in the area will not be available closer to the site to ensure safe passage for pedestrians and vehicles passing through.
Pedestrians
Pedestrian access will be provided throughout the project period.
Environmental considerations
An Environmental management plan has been developed to avoid contaminant into the stream below.
Also we have a Lizard Management Plan in place with the Department of Conservation to ensure safe relocation of all lizards in the area.
More information
If you have any questions about the Ngaio Gorge Slope Stabilisation Project please call 04 499 4444 or email us at info@wcc.govt.nz.