Fulcrum
Given the election and the rush by both major parties to spend up big in “infrastructure” the biggest news is National’s bold $30 billion-plus plan. To be clear, building roads is infrastructure, although some of the more recent ‘shovel ready’ projects announced by the Government are really stretching the definition beyond the limit.
In Saturday’s Herald Sir Michael Cullen had a swing at National’s roading plan with the headline “National trapped on highway to the past”. It was typical Cullen, both making solid points and throwing plenty of snark around at the same time. He complained about projects running over budget and time (Central Rail Link anyone?). He complains about allocating money away from other worthy projects such as water and wastewater and the long-term decline in the state of infrastructure overall.
Hmmm… just trying to think about all the major infrastructure projects completed in the nine years of the Clark Government. Anyone? Nine years of neglect?
What is National trying to build? A number of the projects planned by the National Government 2017 such as the upgrades to highways south of Whangarei, the northern access to Tauranga, the Cambridge to Pairere upgrades and the Palmerston North bypass were iced by the new Government when they took office only to be put back into play in January with an eye to the election.
The big long-term plan from National, is a four-lane expressway from Whangarei to Tauranga, via Hamilton.
Once the current expansion of the Auckland motorway system is completed to Warkworth and the Hamilton section of the Waikato Expressway is finished you will be able to drive on the motorway/expressway for around 200 km end to end. That’s about 58% of the distance from Whangarei to Tauranga via Cambridge.
This leaves around 147 km of expressway to build. 72km from Whangarei to Warkworth and 75km from Ruakura to Tauranga; an alternative would be to start the expressway to Tauranga from Piarere which would make the additional expressway shorter but the overall distance longer. Why will become clear in a moment.
Where National’s plan gets interesting and a bit weird is the announcement of tunnels through the Brynderwyn Hill and the Kaimai Ranges. Drilling through the Brynderwyn Hill doesn’t make a lot of sense. Routing the road to the west through less difficult land will be a lot cheaper and will avoid the lower speeds required in a tunnel as well as all the safety and air movement kit needed for tunnels.
There has been an ‘in pencil’ plan for a while to route the rail network south from Marsden Point which could follow the same route, joining the existing rail network at around Maungatoroto. Bashing holes through the Brynderwyn Hill just doesn’t stack up.
The Kaimai tunnel plan makes a bit more sense as there are no options for a lower road over the Kaimai Ranges. The northern access to the Bay of Plenty via the Karangahake Gorge cannot be expanded given the road follows the river and is already very narrow in places. The southern access over the Kaimai Ranges to the southeast of Matamata is okay at the moment but is likely to reach capacity sometime in the next 15 to 20 years.
The cheerleaders on the Bay of Plenty side are all gung-ho for a road tunnel, but they probably haven’t thought through all the implications. The existing rail tunnel took 11 years to build and was opened in 1978 by the then Prime Minister Rob Muldoon. It’s almost 9 km long and runs slightly northeast from the Waikato side to near Apata. News about a road tunnel through the Kaimai Ranges has been around for over 10 years, with both Hamilton and Tauranga mayors beating the drum harder over time for the tunnel.
The most likely place for a road tunnel would be somewhere near the existing rail tunnel, and your correspondent would expect that a new dual-track rail tunnel would be part of the mix as well. Three tunnels; each about the diameter of the Waterview tunnels in Auckland. The Waterview tunnels are the longest in New Zealand at 2.4km, so any Kaimai tunnels would be nearly four times longer.
Given 50 odd years of improvements in drilling technology punching the holes through the Ranges may not be the biggest problem. It’s the safety and air movement issues, along with the approaches on both sides that will require the real money. The tunnels would have to link with the existing planned road upgrades north of Tauranga as well as realignment and upgrade of the rail network.
The Waikato side of the existing tunnel is near the locality of Gordon, more or less in the middle of nowhere, thus an expressway would have to be built across from Hamilton (hence from Ruakura) to link it all up – that is a distance of about 50km. If the link-up expressway comes from Piarere to the south then the distance is only 40km of new expressway, but the overall distance is increased by 40km (more or less).
So how much is this going to cost? All the numbers below are in current dollars; the timing is unknown for most of this build other than to say ‘sometime over the next 20 years’ and there are good numbers about current high level costs for existing projects.
The Waterview tunnels cost around $300,000 per meter to build. That was fairly easy drilling through soft Auckland rocks (well it’s a bit bullish to call the mudstone under most of Auckland ‘rock’ but that description will suffice for now). The Kaimai Ranges are in parts made of much harder stuff.
Let’s call it $500,000 per meter as a ballpark figure. Three tunnels of 9 km each is $13.5 billion. Add to that around $1.5 billion for the 50km expressway from Hamilton to the tunnel entrance; this is $30,000 per meter which is about in line with the expected costs of the Hamilton section of the Waikato Expressway currently being built.
On the Tauranga side there are announced plans to build the Northern Links and the Te Puna to Omokoroa expressway at a combined cost of $940 million ($67,000 per meter), which still leaves another 6 – 8 km of expressway to link to the western outfall of the tunnels – call it another $540 million.
And the expressways in Northland? Whangarei to Port Marsden is priced at around $692 million for 26km. The section from Port Marsden to Te Hana at around $800 million for 20km and the Te Hana to Warkworth section at $1.2 billion for 26km. Call it $2.7 billion all up.
The spend in today’s money would be more or less $19.2 billion for all of the above. But is it worth it? That’s the subject of the next column from your correspondent.
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