Brian Rudman: Transit turns on charm

COMMENT

Over the past few days, state road builder Transit New Zealand has been out selling its plans for a new more environmentally-friendly way of getting State Highway 20 around the Mt Roskill cone.

The charm offensive has included visits to the Auckland Volcanic Cones Society, Department of Conservation, the Conservation Board and the Auckland City Council. The message is that the redesign complies with the spirit and intent of the recently unearthed 1915 act of Parliament, passed nearly 90 years ago to prevent further destruction of Auckland's unique volcanic cones.

Remarkably, Transit says it can do what it previously claimed was impossible, by the simple act of moving the southern edge of the six- lane carriageway 3m to the north and narrowing the central median strip, a reduction made possible by recent advances in crash barrier design. Also helping is the decision to raise the bed of the motorway 1m.

To separate the highway from busy Dominion Rd and Mays Rd, it has to run in a deep trench under the two existing roads and along the side of the mountain. At Dominion Rd, immediately to the east of the mountain, the road surface was to be 6m under the bridge. The redesign reduces this to 5.1m.

A combination of the raised road bed and the shift north has resulted in the controversial 11m high vertical retaining wall on Mt Roskill's north face being replaced by a 40 degree grass slope, which is a key requirement of the 1915 act.

Not surprisingly, the cones society, which has fought a long and lonely battle to save this, and Auckland's other cones from further destruction, is wary of getting over-excited about what are, at this stage, just an artist's impressions.

Using simple geometry, they worry that the carriageway would have to be moved some 9m or 10m further north rather than the proposed 3m, to achieve the claimed 40 degree slope.

Spokesman Greg Smith wants an independent engineer to check the arithmetic and suggests one of the various public bodies charged with protecting this mountain - DoC, for one, or the Auckland City Council, which as trustee for the Winstone Reserve, which includes the mountain, has special obligations - should pay this bill.

It's hard to disagree with Mr Smith on this point and I'd add another, that DoC and the ACC owe it to the mountain as penance for their previous neglect of their guardianship responsibilities.

Neither body is willing, at this stage, to agree to Mr Smith's request, saying they are waiting on further details from Transit before deciding on their next moves.

There's no doubt that from the artist's impression, the mountain has regained a semblance of its old dignity. It now has a slope down to the motorway approximating that found elsewhere on Auckland's cones.

On the other hand, it still is an artificial solution. What we're still going to have is a huge motorway trench, cut into the side of the mountain and its adjacent flow plane, 5.1m below the level of the surrounding terrain. The bottom half of the 40 degree slope Transit is now offering to create was, in fact, once part of a buried lava flow.

So what we're now being offered is not Mt Roskill bypassed, but Mt Roskill recreated. Recreated in a shape more sympathetic to its fellow cones, for sure, than what was earlier on offer, but still artificial.

That is the dilemma facing the champions of the volcanoes. Celebrate the part-victory that is on offer - one that until the miraculous rediscovery of the 1915 act a few months back was unimaginable - or hold out for more.

Cones society spokesman Greg Smith worries that even the 3m proposal might not be what it seems.

"I still have to be convinced they can do it by tweaking and raising and shifting and whatever.

"Thinking in terms of world heritage status, it doesn't make sense if in one sentence you're talking world heritage and the next minute your chopping a little bit away. If they're world heritage you should back away from them."

The next step is for Transit to come up with more detailed plans. Crucial to a fast resolution for the road builders is that they persuade Auckland City regulators that the proposed alterations to the plans already approved by the council involve only minor changes.

If they get the council nod, they can avoid the possibility of protracted new hearings. They also need the approval of DoC.

Which means that for once, DoC and the council have the whip hand. Over this whole saga, these two bodies have been appalling custodians of this unique cone.

Now they're in situation where Transit really needs their approval, if only to get an awful lot of egg off its face.

The least they can do is ensure the new plans genuinely meet the 1915 act requirements. Of course, if they were truly repentant custodians, they could turn the notch up a twist or two as well.