Keith Rankin: Moving Auckland’s Port – The Tamaki Ship Canal

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Ports of Auckland.

Article by Keith Rankin.

The Nation on Saturday (4 June), ran a panel interview (including Phil Goff and Winston Peters) about where and when Auckland’s main Waitemata Harbour port would be moved to some other location, just as most other big city ports around the world have outgrown their original city locations (The future of Auckland’s Port).

While the key assumption that Auckland’s main port will someday be moved en masse rather than incrementally is probably not correct, all the alternative port options mentioned were unconvincing. Clearly the best location for a new port is the Manukau Harbour, near the substantial infrastructure around the airport, the Otahuhu freight rail terminus, and the existing Metroport in Southdown. The obvious problem is that large numbers of large ships cannot and should not negotiate the dangerous Manukau Bar.

Winston’s preference of Whangarei could only be a solution for a partial move, rather than a complete relocation of Auckland’s container port. The infrastructure needed to get this mass of goods from Whangarei to Auckland (and points south) would be both expensive and an environmental nightmare. (I am imagining a rail tunnel underneath Glen Eden, from Henderson to Mangere.) Other suggested options, such as having a port like Sydney’s Botany Bay in the Firth of Thames, seem as far-fetched.

So I put on my engineer’s hat, and thought, “why not use the Tamaki River and build a ship canal across the Otahuhu portage, into the basin of the Manukau Harbour east of Onehunga’s Mangere Bridge?” The 3km route I thought looked best goes south of Sylvia Park between the Eastern Line railway (which is also the North Island Main Trunk) and Panama Road, coming into the Mangere Inlet of the Manukau between Southdown and Westfield, just a kilometre from Metroport Auckland. My vision was that the Mangere Inlet east of the Mangere Bridge would be dredged, with a causeway just east of Mangere Bridge built from the tailings, creating a large shipping marina bordered by Mangere, Favona, Otahuhu, Westfield, Southdown, Te Papapa and Onehunga. A locking system could connect the new harbour with Port Onehunga, exploiting the two-three hour tidal difference between Auckland’s two coasts.

A Tamaki canal was first proposed in 1860 by one Colonel Moule at £22,876 (Paddle your way around Auckland, Colin Moore, NZ Herald 25 Feb 2002). In 1887 Public Works engineer JW Blair upped the cost to £250,000 (reported in Waitemata-Manukau Canal, NZ Herald 6 Jun 1907). Interest was quite high in the 1907-11 period (eg Waitemata-Manukau Canal, NZ Herald 5 Sep 1911). The idea was back on the agenda in 1960: “District must get behind Tamaki ship canal project now that there is a distinct possibility, it would open the way for new industries in area”. And in 1962, for the Otahuhu Golden Jubilee publication, a section was titled History of the Canal Scheme.

More recently we have this amusing piece by Chris Barton (Canals in Auckland’s south, NZ Herald 8 Apr 2005). And there’s this interesting 2007 (9 Feb) blog entry (and visualisation) by scientist David Haywood (The Geeks Shall Inherit the Earth), which refers to this entry (Manukau Harbour, European Settlement) in the 1966 Encyclopedia of New Zealand (“Future development of the harbour will depend largely on the construction of a canal linking it with the Waitemata, where the tides are approximately two hours later”).

In all these times the suggested solution was on a much more visionary scale than the problem being addressed. Now, however – as expressed on The Nation – the problem really has come. Port Waitemata has reached its growth limits (or exceeded them, given the city’s need to reclaim its harbour and gulf as Auckland’s playground and tourist magnet). Yet the visionary thinking that characterised our past seems to have gone.

I searched the newspaper literature for arguments why a Tamaki Ship Canal could not be built as a part of solution to Auckland’s growth. I could find none. Much bigger ship canals were built long ago in Greece (Corinth, completed 1983), Manchester (also 1893), and Kiel (1895). The Tamaki proposal seems puny in comparison. Yet this seemingly obvious piece of development infrastructure for Auckland is almost never mentioned in polite circles. If planned for, it could be a perfect ‘shovel-ready’ project for New Zealand’s next Great Depression (probably in the late 2020s); as the Sydney Harbour and Golden Gate bridges proved to be in the 1930s.

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