Northland Tunnel waterproofing

From May to July 2020, we are waterproofing the Northland Tunnel.

The opening of the Northland Tunnel with no cars inside.

The Northland Tunnel is in very good structural condition, and had earthquake strengthening work completed in 2017. However, there is a longstanding issue with ground water seepage penetrating the internal barrel joints of the tunnel which results in the increase in maintenance costs.

To resolve the issue, we have contracted Concrete Solutions Ltd to apply a suitable waterproofing system to prevent seepage. We aim to complete the maintenance with minimal disruption to the local community. 

What we are doing

  • Applying a suitable waterproofing system to the tunnel to prevent seepage.
  • Repainting the interior tunnel barrel.
  • Applying an anti-graffiti coating to the interior of the tunnel. 

Progress so far

In 2017 we completed earthquake strengthening work on the Northland Tunnel entrances and adjacent retaining (wing) walls. The strengthening work reduced the risk of the banks above the tunnel slipping and potentially blocking the road and tunnel in the event of an earthquake. It is now more likely that the tunnel will be able to be used following an earthquake. 

In March 2020 the work was tendered and awarded to Concrete Solutions Ltd. Construction work on the tunnel was delayed in March 2020 due to the Covid-19 Level 4 lockdown where all construction work had to stop.

In accordance with Government guidelines work can now resume under Alert Level 2 and is expected to be completed in July 2020.  It is preferred that 2 metre distancing is applied and the contractor will also amend their Health & Safety plans to align with the requirements.

What to expect

Traffic changes

The tunnel will be closed to traffic and pedestrians between 12am and 5am for the week starting Sunday 17 May to Sunday 24 May
From Monday 25 May, the tunnel will be down to one lane controlled by traffic lights between 7am and 4pm

Pedestrian access

The footpath in the tunnel may be out of action at times, but an alternative safe route through the tunnel is being provided for pedestrians at all times. 

Other things 

  • While we always ask that people stay well clear of construction activity for everybody’s safety, there is an added need to keep your distance as we all observe physical distancing of two metre spacing in response to Covid-19 Alert Level 2. 
  • There will be cones and barriers, and surfaces may be uneven. If you are walking in this area, please take extra care to avoid potential trip hazards, particularly when it is dark. 
  • If you are expecting a courier, rideshare, taxi or trades-person to arrive when contractors are working, please let the contractor know and they will do their best to ensure they can reach your property. 
  • If the contractor is working on a day when your recycling or rubbish is usually collected, please put your bins out as normal and we will ensure that the collectors can get through. 
  • In the event of unsuitable weather or other unforeseen circumstances, the start date may be postponed and we will advise you of any changes as soon as possible. 

Background

Northland Tunnel links Northland with the central city and Karori. The tunnel was constructed in the 1923 with the first tram service eventually commencing on the 4 June 1929 after many years of ‘start-stop-start’ construction work.

It is a listed heritage object in the District Plan because of classical style arched opening entrances. The tunnel is in very good structural condition, and had earthquake strengthening works on the portal entrances completed in 2017.

Need help?

Jone Sumasafu – Civil/structures Project Engineer
Email: jone.sumasafu@wcc.govt.nz