Story: Bridges and tunnels
Page 6 – Road and utility tunnels
Because cars are better at climbing hills than trains are, New Zealand has fewer road tunnels. Some are very short, such as several on the coast road near Kaikōura – and some are significant, despite being short. Wellington’s hilly topography has made road tunnels especially important. The Mt Victoria tunnel (1931) linked the city’s airport and eastern suburbs with the city; the Karori, Seatoun and Northland tunnels had already helped open up those suburbs. The Terrace tunnel (1978) brought the northern motorway into the city centre.
Wellington’s Mt Victoria tunnel is known for drivers tooting their horns as they pass through, almost deafening the few hardy pedestrians. Some suggest that the tooting began as a tribute to Phyllis Simmons, who was buried alive in the spoil from the project by a tunnel labourer, George Coates. Coates was hanged at Mt Crawford prison in 1931.
New Zealand’s two longest road tunnels are the Homer Tunnel and the Lyttelton tunnel.
The Homer Tunnel was first suggested in 1890 as a route to Milford Sound. Work on it finally began in 1935 as an unemployment relief project with little more than shovels and wheelbarrows. With heavy rain and snow, and tent accommodation, the working conditions were awful, and three workers were killed by avalanches. Hole-through came in 1940, but it was not until 1954 that the first car used the tunnel, which is 1,255 metres long.
Miles of tiles
The Lyttelton road tunnel is lined with 1.25 million tiles. If all the tiles were placed end to end they would stretch 185 kilometres.
In 1961, 100 years after the first sod was turned for the Lyttelton–Christchurch rail tunnel, work began on a road tunnel to link the city and port. As with the Auckland Harbour Bridge, an authority was set up to take responsibility for the construction – and as with the Rimutaka tunnel, the tender went to a combination of an American firm, Kaiser Engineers, and a local firm, Fletcher Construction. The tunnel, 1,900 metres long, opened in 1964. Tolls were charged until 1978.
Tunnels have also been constructed in New Zealand for hydro-electricity schemes, city infrastructure, and defence.
- Manapōuri power scheme: between 1964 and 1968 a 9.8-kilometre tunnel was built between the west arm of Lake Manapōuri and Doubtful Sound to provide a tailrace for the Manapōuri power scheme. Sixteen men died during the construction. A second tunnel was completed in 2002.
- Tongariro power scheme: during the 1970s, 10 tunnels were excavated as part of this scheme, which involved taking water from the south-east and western side of Mt Ruapehu to the Rangipō and Tokaanu power stations north of the mountain. The Moawhango tunnel, 19.2 kilometres long, was one of the longest hydro tunnels in the world, and the longest ever constructed from only two entrances, one at each end.
- Auckland city infrastructure: a 9.4-kilometre tunnel was completed in 2000 for new 110-kV cables from the Penrose substation into central Auckland. In 2009 a 3-kilometre sewerage tunnel was being built under Hobson Bay in Auckland.
- Defence purposes: in 1942, as anxiety about Japanese air raids intensified, air-raid shelters were constructed under Albert Park in Auckland. At the same time gun emplacements involving extensive tunnels were built at Stony Batter on Waiheke Island, and on Wright’s Hill in Wellington.