An interesting announcement by NZTA today that the preferred alignment for the Waterview Connection motorway link has changed again – and quite significantly so.Here’s the full press release from NZTA:

Fewer affected homes and less disruption for revised Western Ring Route

Design improvements for the Waterview Connection section of Auckland’s Western Ring Route will require fewer houses and significantly reduce disruption to residents and commuters on Great North Road.

The NZ Transport Agency Board has confirmed a final alignment for SH20 from Mt Roskill to the Northwestern Motorway that will reduce the number of houses affected to 205 compared to the 365 estimated in May when the combined surface tunnel option was announced.

Of the 205, 140 are already owned by NZTA. Of the 65 residential properties still to be acquired 27 are newly affected, because of the revised alignment and resulting revisions to the rail designation in the Alan Wood Reserve area. It is anticipated that only three of these houses will need to be removed when the corridor is developed, with the remainder requiring partial land purchase from the rear of the section.

Board chairman Brian Roche says a concerted effort to develop project design to minimise community impacts combined with a better understanding of local geology had allowed the NZTA to shorten the SH20 route while making the tunnelled section deeper and longer.

“This refinement to the combined surface-tunnel route means the tunnels will be continuous from where they go underground in Alan Wood Reserve to where they rise to the surface to meet SH16 at Waterview Park. It will eliminate the previous gap between the two tunnelled sections.

“Building the tunnels further east without a gap between them can be completed within the original project budget and is the most cost effective option for constructing this section while also responding well to community concerns with the previous proposal.”

“Keeping the tunnels deeper means they can be extended further north which significantly reduces disruption on Great North Rd. Only a short length of surface construction will be required to allow the tunnel to cross underneath. All of this will help to reduce community effects,” he said.

In addition to the reduced surface property effects, the need to purchase underground land from residential properties above the tunnels reduces slightly from 111 to 105. The changes to the alignment mean that about 60 of these properties are newly affected.

Mr Roche said the board had decided against including a central interchange at New North Road because it would contravene accepted safety standards for traffic merging, remove more housing and open space and increase traffic through Avondale.

The NZTA is working closely with Auckland City to replace council land required for the project and upgrade facilities to allow for increased use. Improved linkages for the community are also planned through pedestrian and cycle bridges that will better connect local reserves.

Mr Roche said that while the Board was pleased that the new alignment would go a long way to addressing community concerns, they remained keenly aware of the impact on affected residents and property owners.

“Completing the Western Ring Route is crucial for New Zealand’s economic development, but we recognise that the concerns of affected communities are real, and we are committed to continuing to work with them as the project is progressed.”

The design development for both SH20 and the SH16 improvements from St Lukes to Te Atatu will be shared with the community at a project expo planned for late February 2010.

Construction on the project is likely to start in mid to late 2011 with an anticipated completion date in the 2015/16 financial year.

Here’s a map showing the difference between the two alignments:

The new alignment supposedly will affect less houses, and certainly will reduce impacts on Great North Road during construction. It appears to involve a significantly longer tunnel than the previous option, with the length of the full tunnel getting somewhat close to the length of the tunnel in the original, pre-May announcement. There are certainly some positives, some negatives and some as yet unknown outcomes from this change of alignment.


  • As stated above, this route will affect fewer houses. This is particularly the case along Great North Road, where the previous alignment involved huge effects on properties along this road through Waterview.
  • The length of the tunnel has been increased, and there’s no messy portal halfway between two tunnels.
  • The impacts along Great North Road will be far less significant than in the previous option.


  • Now that Great North Road isn’t being touched, I think it’s very very unlikely we’ll see NZTA sending much money towards Auckland City Council for the previously mooted bus lane upgrades.
  • Cost. It’s hard to imagine how this option can cost the same as the May 2009 option.
  • Potential effects on open space land through Phyllis Street reserve (is the motorway a bored tunnel there or cut and cover?)
  • Potential effects on Oakley Creek. Once again this depends on whether the motorway is a bored tunnel or cut and cover.


  • As noted above, it’s not really that well known whether the motorway is a bored tunnel or cut and cover. This will have a huge impact on the level of effect it has on Phyllis Street Reserve and Oakley Creek. It will also have a huge effect on the cost of the project.

Subject to confirmation that the whole tunnel will now be bored/driven (as opposed to cut and cover), I think that this change is a positive step and the new alignment will have reduced effects on the community and on the environment. Now if only they could underground the motorway through Allan Wood Reserve we’d be back to where we started.

How on earth did that extra tunnel through Allan Wood Reserve end up being the difference between a $1.4 billion price tag and a $2.77 billion price tag? Something strange is going on.

Fewer affected homes and less disruption for revised Western Ring Route

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  1. If NZTA doesn’t come up with the money then the Auckland Council needs to find the money themselves I guess, they’ll have close to 6 years to squabble over it before the motorway opens and GT. Nth Road will need to be ‘fixed’.

    I find it slightly opportunist to include the proposed railway line in the map too, giving the illusion to some that a railway line is in the mix when it’s clearly not.

  2. Going by what was said on Morning Report this morning, apparently the changes were made possible by favourable geological conditions “making it easier to go deeper than expected”. So hopefully that means bored tunnel not cut and cover. The resident spoken to said that a lot of test holes had been drilled.

  3. @Jeremy – the question is, how hard will it now be to build the line, I imagine that transit would have planned for the rail to be at ground level however with when it is built it will also need to go under new north road to avoid traffic issues. I wonder if they have left enough room for this to happen.

  4. I think it is a bored tunnel too, which is very good. It would be nice to see some cross-sections though.

    I really wonder how this option can be the same price.

  5. @Matt they could do a grade seperation of New North Rd, Hendon and the line, with the line staying at the current ground level, I don’t see any other way as the line couldn’t even get close to getting back up to meet the NAL otherwise…

  6. Looks like a good outcome, but still leaves a lot to be desired to be honest. We can kiss goodbye to two parks and I hope they do some serious noise proofing in the bits going through people’s backyards.

  7. And let’s not forget the price of this would build the CBD rail tunnel. Add in the price of the SH16 upgrades and we would be close to having airport rail too.

  8. This peice really does need to be completed and the cost of doing so is only ever going to increase with time so we need to bite the bullet at some point and it might as well be now. I am happy as long as they have done what is required to future proof the thing so it doesn’t need doing again in 20 years and that at a future date ontrack can put a double tracked line without any issues. (really ontrack needs to put pressure on the government to get funding freed up to do this at the same time.

    Also any reason why it won’t start being built till mid to late 2011, that is another 1.5 years away

  9. I posed the question some time ago as to why the motorway did not continue under Heron Park and then swing right to meet up with the motorway. This route would need virtually no houses to be demolished and no interference with Gt North Roads housing. there would be a significant amount of fill needed to reclaim the required land but after all this has already previously been done for the NW Motorway and as the inner harbour area between Rosebank Rd and the Motorway is slowly being reclaimed from the sea, it would not be a major issue.

  10. @John Dalley. I’m not familiar with this area, but I note the bit of sea that you’re suggest be reclaimed has the words “marine reserve” on it in the graphic above. I’d say that would make it extremely difficult, probably more so than going through houses.

  11. John, LG. I also though that a tunnel to Heron Park then a causeway across the mudflats would have been cheaper and easier, particularly as it means the motorway to motorway interchange can be built on an open section rather than on top of the existing waterview interchange.

    This was considered as the AR1 alignment and was the prefered option of the ARC, but it was discounted due to cost and the fact it provided a less direct route from the CBD to the airport (so much for the ‘western bypass’ eh, turns out they are actually just building another radial motorway to the city). But I wonder how that cost stacks up now against these tunnel options?

  12. LG. In about 20 years or so, that “Marine Reserve” is going to become dry land as the NW Motorway has blocked the flow into that area and as can be seen, both sides of the motorway are steadily filling in.
    I would venture to suggest that i would much rather see extra monies spent reclaiming the necessary land to go this route than have them demolish a couple of hundred houses and decimate this part of the city.

  13. I’ve just had a look at the AR1 route, and that actually ran along the length of the Rosebank peninsula’s edge, taking in quite a stretch of properties along the way. I wonder if they have ever looked at a causway aross the estuary?

  14. From memory the surface level Rosebank option cost more than the full tunnel Waterview option. I think that, and its significant environmental effects, ruled it out quite early.

  15. I suspect that opportunistic or not, the indicative map demonstrates NZTA’s real inability to even think about rail: Avondale station is indicated as being located where it was until this time a year ago. Says it all, really.

  16. @commuter – as the current station is only temporary it is probably relevant to put the station on that will exist when this is built. In saying that the actual location of the new station is below the legend so it is probably a case of better to show it nearby rather than not at all.

  17. The original costing for the long tunnels included half a billion for financing as a PPP. Not sure how that worked but it didn’t seem like apples with apples.

    Also they have been doing a lot of design development and investigations as far as I am aware, so saving may have been found.

  18. Yes Matthew the inclusion/exclusion of financing costs has had some rather dodgy effects on the costing.

    It is interesting to hear that a “road-header” rather than a “tunnel boring machine” will be used for this project. Road-headers are cheaper, but much much slower. This means the construction period could be quite lengthy indeed.

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