Well it’s been a while since my last post on the Waterview Connection, and there have been a few interesting developments. So it’s probably worthwhile to give a bit of an update on what’s been going on recently. As I mentioned in my most recent post on the Waterview Connection, NZTA have released details of “the other two options” that they decided to not proceed with. I talked about those before (basically outlining how terrible they are), but to refresh the memory (and provide a better quality image), they’re included below:
What I find quite interesting is that option 3, which is what NZTA eventually chose to go with (talk about the biggest no brainer in the world), was originally proposed as a surface route, with the eventual tunnel underneath Avondale Heights merely being “additional mitigation”. I can imagine it would have been quite a challenge (both engineering wise and community opposition wise) to drive the motorway through this area at surface level, so it’s not really a surprise that the additional mitigation option was chosen.
Furthermore, even the stretch of motorway through Waterview was suggested to be built between Great North Road and the Oakley Creek, with the option of instead going underneath Great North Road another “additional mitigation” measure. Now I would agree that it’s pretty unlikely NZTA would have ever chosen to go with any option other than what they’ve finally chosen – as the effects of a surface level option through Avondale Heights would be pretty horrific, while both Options 1 and 2 have significant effects on property and open space in the area. In fact, option 2 is relatively similar to what was being proposed before 2006 (which was soundly rejected by the local community).
One of the most interesting aspects of the way in which NZTA have separated out the costs of the “additional mitigation” is how it gives us an idea about what extra things like a 1.2 km tunnel underneath Avondale Heights, in itself, actually costs. The same goes with the cut and cover tunnel that is to be constructed underneath Great North Road. In the case of the Great North Road tunnel, the cost is actually pretty amazingly low: only $38 million more than the cost of building the motorway adjacent to Great North Road at surface level instead. In the case of the 1.2 kilometre long bored tunnel underneath Avondale Heights, the cost of choosing to go with the tunnel rather than building the motorway at surface level is $212 million. Interestingly, the cost of doing a cut & cover tunnel under Avondale Heights was worked out at $260 million – more than the cost of a driven tunnel (and far more disruption). So no real surprise that the tunnel was chosen – $260 million seems well worth what the effects would otherwise be.
NZTA also analysed the cost of additional mitigation measures that they have decided not to proceed with: mainly those that relate to Allan Wood Reserve. Notwithstanding my opposition to the idea of spending $1.4 billion on another road when state highway traffic is actually declining, I do consider option 3, the one which has been chosen, actually creates a reasonable solution to the north of New North Road (especially if the small surface area between the two tunnels is ‘capped’ as seems likely). However, this is at the cost of effects on Allan Wood Reserve, which in my opinion are certainly the most significant effects of the current proposal. NZTA have analysed the price tag of additional mitigation options for Allan Wood Reserve, although none have been proposed. They are outlined below:
The costs are in millions of dollars, so it’s pretty clear where the “huge savings” of this proposal (compared to previous options explored by NZTA) have come from. When I discussed the possibility of building a trench through Allan Wood Reserve (the $359 million option) with an NZTA engineer a few weeks ago at an Open Day on the Waterview Connection, he explained that it was so cost-prohibitive because you would need to build the trench directly through a fairly significant lava flow: which means a lot of expensive and very difficult blasting and earthworks. The lava-flow runs between 1 metre and 10 metres below the surface level, and was actually one of the main reasons why NZTA chose to go with the full bored tunnel option a few years back. It was simply cheaper and easier to go well underneath the lava flow.
Now, looking at all this information, it seems like there is a possibility that hasn’t been looked at yet. Why not build another bored tunnel – similar to the one that is to go underneath Avondale Heights – underneath Allan Wood Reserve? The lengths are fairly similar, at around 1.2 km, and you could build the two tunnels at the same time (just have two road-header machines to build them: these machines are relatively cheap). A bored tunnel would be significantly cheaper than the cut & cover option – because it would go underneath the lava flow (and from the Avondale Heights experience it seems like cut & cover tunnels aren’t necessarily cheaper than bored tunnels anyway). It seems reasonable to estimate that a bored tunnel under Allan Wood Reserve might only cost somewhere in the region of $212 million over and above the current cost of the surface level option (that was the difference for the Avondale Heights tunnel). It means NZTA wouldn’t have to purchase land off Ontrack or Auckland City Council through Allan Wood Reserve, it means that NZTA wouldn’t have to off-set the amount of open space land they’re going to take away from the community (potentially a very significant mitigation cost that I don’t think has been taken into account yet) and it means that Allan Wood Reserve would retain its character and not be split down the middle by a giant six lane motorway.
To illustrate more clearly, the two maps below show firstly what is proposed for the Allan Wood Reserve end of the motorway, and second what could be built instead. The small blue (surface area) between the two tunnels would be capped eventually, but I have shown a gap to illustrate that it would effectively be built as two separate tunnels that were eventually linked together.
Current proposal:
Whilst this would be a better outcome, I’m still not really convinced that it’s worth spending $1.4 billion (or more, if my mitigation was taken up) on a motorway project. As I explained a couple of posts ago, building more roads tends to simply result in further traffic being induced to drive on those roads. Even NZTAs own traffic analysis seems to show this quite clearly, with the map below showing both the expected increases in traffic volumes (in red) and decreased volumes (in green) along various roads in the area as a result of the Waterview Connection being built. While traffic flows on some local roads will certainly be reduced, overall it is clear that more traffic will use the road than simply vehicles diverted from somewhere else. Quite simply, that is induced traffic:
Furthermore, these only show the average daily flows – not the peak flows. Generally when traffic space is ‘opened up’ and congestion is (momentarily) reduced people will shift from driving during the “shoulder peak” times (just before and after peak hour) to driving during peak hour. This means that the peak flows can actually increase to an even greater extent than shows up when simply using average daily flows. As congestion generally only happens around peak hour, this further leads to situations where building more roads doesn’t actually do anything to reduce congestion.
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Good post. As I have stated before, I am very much against the idea of spending hundrewds of millions of dollars, especially in a recession protecting local parks e.t.c
Why don’t I get hundreds of millions spent on parks in my community? Because transit isn’t going to build a road throgh it? If we really want to spend hundreds of millions of dollars on parks, instead of allocating the money to comunities with parks with roads going through them, we should look at which communities will have the fewest and worst parks per capita once all planned roads are built and give the money to those communities.
You like me are a strong advocate of improved public transport in Auckland. Every dollar spent on mitigating the impact of roads on communities like Waterview is one less dollar to go on public transport. Think about that.
The daily flows map is quite interesting. Particularly interesting is that the map shows Hepburn Rd in Glendene extended all the way through to Rosebank Road. Is this another road to be built? I am also curios about the extra 3000 cars on Great North Road between New Lynn and Avondale.
And while I would prefer no Waterview connection at all for the next 20 years, with the money spent upgrading the train network (electrification, plus CBD rail loop), with Waterview only built once Aucklands rail system is as good as its motorway system. I have thought of a compromise only building the SH20-New North Road section of motorway, through Allan Wood reserve, extending Rosebank road using a 6 lane bridge/viaduct (or tunnel) over the rail line and Blockhouse Bay road to link up with the new motorway, and widening the rest of Rosebank Road and perhaps the part of Dominion Rd between the CBD and SH20 to 3 lanes each way (some houses may be demolished). I wonder why this option was never looked at, and what the cost/benefit ratio would be for it.
Other than that my next favourits option is full surface option one (the most direct, and probably cheapest route), then full surface option 3, then the current option.
The obsession with time savings benefits as a justification for a project like Waterview Connection is quite strange actually. Most people drive to work outside their work time, so any benefit is simply to their increased ‘spare time’. If a few extra minutes was really that important, why doesn’t the government buy everyone a dishwasher? There’d be a lot of time-savings benefits to my private life if I had a dish-washer.
I have thought about the Rosebank Link option. However, the effects on the local community would be pretty extreme. You’d still have a road through Allan Wood Reserve, you’d have an ugly as hell viaduct over Avondale, you’d have the issue of Avondale College and then you’d just put a tonne more traffic onto Rosebank Road. Whilst Rosebank Road could be widened, all that extra traffic would stuff things up pretty quickly.
I see where you’re getting at with your “if it has to be built, then let’s waste as little money on it as possible” theory. However, most of the alternative options would have truly horrific effects on local communities: particularly option 1 and a surface level option 3. The main point is that you can’t build what I would call an acceptable option for much less than $1.7 billion (what’s proposed plus a tunnel under Allan Wood Reserve). That’s a crap load of money to tie up in a road when there are so many public transport projects (that are actually increasing in their use, unlike state highways) just crying out for funding.