Quake-proofing Karori Tunnel: Expect delays
Karori tunnel is being upgraded.
Wellington City Council is spending $1.9 million on earthquake strengthening Wellington's oldest tunnel.
Temporary traffic lights have been installed at both ends of the tunnel, in preparation for the work.
City councillor Andy Foster, who holds the transport portfolio, said the work would be likely to cause significant disruptions.
"The barrel of the tunnel itself is deemed fine from an earthquake risk point of view," he said.
"Peak-hour traffic won't be affected. But from 9.30am till about 3.30pm it will go down to one lane."
It was a "balancing act" to make sure traffic and work demands were met, he said.
"There will be significant disruption. It could potentially last up to nine months."
The first part of the work would consist of tying back the two portals, or entrances, into the rocks.
The two portals were not safe and would likely collapse in a big shake, Mr Foster said.
The second part of the work would be to reinforce the bank on the city side of the tunnel.
"A large retaining wall is being put up there.
"The bank has been progressively collapsing, and it will collapse at some point."
The $1.9m project was already in the council's budget, and the work would be partly funded by NZ Transport Agency, he said.