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.