Critics say motorway should go under, not through, the bush

By MATHEW DEARNALEY

Transit NZ will face pressure at hearings starting today for the country's first toll motorway to tunnel rather than slice through native bush.

The road builder wants the hearings before commissioners in Orewa to dwell simply on whether it should be allowed to charge tolls on the long-awaited extension of the Northern Motorway to Puhoi, emphasising that it already has full environmental consents.

Although it disclosed last week that it was still investigating "a range of possible enhancements" for the project, regional manager Wayne McDonald said the toll hearings would not be an opportunity to revisit environmental issues.

Even so, critics claim measures prescribed by the Environment Court in 2000 are insufficient to satisfy an environmental sustainability requirement of the new Land Transport Management Act - needed for the project to win Government approval as a toll road.

The court ruled then that a more efficient and safer motorway outweighed the significance of its harmful environmental effects.

But Transit is promoting tolls as a way of affording superior environmental measures, and promises further consultation if there are changes in that direction.

Any more consultation will have to fit into a tight deadline for Transit to persuade Transport Minister Pete Hodgson that tolls have enough local support for road-building to start in December.

If it fails to win approval by then, the Environment Court threatens to order closure of the link road between the end of the existing motorway and Orewa, worsening holiday weekend road chaos by forcing all traffic to revert to driving through Silverdale.

Tolls have been the focus of most of 620 written submissions, which are evenly split for and against charging motorists $1.80c a trip along the 7.5km road extension.

Orewa residents appear more opposed than others, fearing tolls will keep pushing traffic their way for a free ride along the coastal highway, frustrating the town's hope of remodelling itself as a chic beach and business centre.

Some accuse Transit of "blackmailing" them into accepting tolls as the only way to provide what they say was promised years ago, to be paid for from fuel taxes.

Transit is gaining stronger support further north, from motorists and community leaders who say the toll is a cheap price for time savings and a safer route.

But residents of bushclad Johnsons Hill above Waiwera are finding support from independent engineers and the Royal Forest and Bird Protection Society for a claim that tolls cannot be justified without environmental improvements to the $300 million project.

They want Transit to tunnel under the hill rather than carve a 57m chunk out of it - deeper than the length of an Olympic swimming pool - to receive traffic from a 620m viaduct across the Waiwera River before the motorway finishes on an interchange above the Puhoi Valley.

The bridge will cross the river at one of its widest points, above an island believed to contain a Maori burial ground.

Auckland engineer Peter Riley, an expert in rock mechanics who says he supports a motorway extension in principle, argues that a tunnel would avoid severing an important bush corridor from Wenderholm Regional Park and solve major design problems for the interchange.

"The viaduct will dominate the entire [Waiwera] valley and that interchange is going to be an absolute mission," he told the Herald.

"It is going to be prodigiously expensive because it perches on the side of an unstable hill which plunges down into the Puhoi Estuary."

Mr Riley, former chairman of the NZ Society on Large Dams, believed a tunnel would cost no more - probably less - than a viaduct and hill cut that would leave a giant scar in place of coastal podocarp forest and a notable kauri tree visible to southbound traffic.

Resident Armie Armstrong said that what was now a magical place, luxuriant in bush and birdlife, would be overwhelmed by a structure almost as large as the Auckland Harbour Bridge.

He said the proposed cut was almost as deep as one rejected in 1993 as environmentally unacceptable.

A tunnel would have been an obvious solution, one which Auckland Regional Council hearings commissioners urged Transit to investigate, he said.

A Transit spokeswoman said the agency was not ready to comment further on environmental options such as a tunnel, apart from the fact that it was investigating possible enhancements.

Forest and Bird spokesman David Pattemore said a tunnel would be "vastly superior" to such a large cut in the bush, which he feared might, among other things, deter the movement inland of North Island robins reintroduced to Wenderholm in 1999.

He tempered his concern with praise for Transit for a planned 240m "eco-viaduct" over an arm of the Otanerua Stream above Hatfields Beach, high enough to let native birds and other wildlife pass beneath.

But Manu Waiata watercare group secretary Dr Wendy Pond said two other tributaries of the Otanerua as well as the more ecologically diverse Nukumea and Westhoe catchments further south needed similar protection rather than culverts which fish could not swim through.

She accused Transit of laying culverts along the Westhoe Stream well before gaining approval for a toll road, structures that were too long and narrow for kokopu - New Zealand's largest native fish - to swim up to complete their life cycle.

Alternative route

Transit's plan: The Orewa-Puhoi motorway to cut 57m through bushclad Johnsons Hill to receive traffic from a 620m viaduct across the Waiwera River.

Critics' proposal: A tunnel through the hill to avoid scarring the coastal podocarp forest and to solve major design problems.