Tunnel options surface but with a pricey tag

Solutions to Auckland's road traffic congestion could lie underground, reports BERNARD ORSMAN.

Tunnels are being promoted as an alternative to covering Auckland with more motorways.

One answer to a second harbour crossing, spanning Hobson Bay with a highway and increasing the Victoria Park flyover from four to six lanes is to go underground.

When plans for a bridge or a tunnel under the Waitemata Harbour are made public this year there will be options for tunnel connections to the Northwestern and Southwestern Motorways.

The Avondale leg of State Highway 20 will also have tunnel options.

And thought is going into building a cross-city tunnel from Britomart Place to Fanshawe St to connect the eastern highway to the Northern Motorway.

Environmental, cultural and community damage from new motorways is driving the tunnel plans, albeit at much greater cost, says an Auckland City Council report.

Auckland City Mayor John Banks campaigned on the promise to investigate a tunnel under Hobson Bay, ignoring critics who said it was "cloud cuckoo-land stuff".

That tunnel, costed at about $1 billion, does not look likely, but that has not stopped council staff resurrecting an old plan to build a similarly priced cross-city tunnel to connect the highway at the city end with the Northern Motorway.

A cross-city tunnel has just been opened in Sydney at a cost of $770 million.

The latest project proposed in Auckland is to build a trench or tunnel beneath Victoria Park.

Next month, Transit will seek public comment on four options to widen the 2.5km approach to the harbour bridge from the Wellington St overbridge.

The cheapest option, costing $70 million to $110 million, is to widen or build a new viaduct and widen the approaches to the bridge to four lanes and a shoulder northbound and five lanes and a shoulder southbound.

Putting the motorway in a trench through Victoria Park would cost between $220 million and $250 million, and a partial or full tunnel under Victoria Park between $150 million and $290 million.

A fourth option, promoted by the St Marys Bay Association, to tunnel under Victoria Park and straighten the approach to the harbour bridge, would cost between $350 million and $430 million.

Wayne McDonald, Transit New Zealand regional manager for Auckland, said yesterday that he could probably get money to widen the approaches to the harbour bridge above ground.

But the only other obvious funding source for the more expensive tunnel options was Infrastructure Auckland.

The local funding agency has $90 million set aside over five years for spending on roads and $75 million for innovative transport solutions.

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