While many Wainuiomata residents are aware of the tunnel connecting the suburb with Gracefield, far fewer know that a second tunnel runs almost parallel to it, also passing beneath the Eastern Hills to Seaview.
Known as the Waiwhetu Tunnel, it was the original water-supply tunnel carrying water from Wainuiomata towards Wellington. Constructed as part of the Wainuiomata Waterworks scheme in the early 1880s, the brick-lined tunnel runs for approximately 1.1 kilometres through the hills from near Waiu Street to the slopes above Gracefield. It contained a 750 mm water pipe and was completed in February 1883.
For close to a century, the tunnel formed an important link in Wellington’s water supply. Eventually, however, the old pipeline was no longer large enough for the region’s growing needs. By the 1970s, a new 1,100 mm water main was required, but the larger pipe could not fit through the narrow Victorian tunnel.
The solution was the nearby unfinished Wainuiomata road tunnel. Work on that tunnel had begun in the 1930s as part of an ambitious road connection between Wainuiomata and the Hutt Valley, but construction stopped during the Depression. Almost 50 years later, the abandoned project was revived, the tunnel was completed through to Waiu Street in 1980, and instead of carrying cars, it was used to carry the new water main.
The old Waiwhetu Tunnel was consequently retired from service. Today, the two tunnels lie only metres apart at the Wainuiomata end, but emerge at Gracefield at different heights on the hillside. One is a largely forgotten relic of Wainuiomata’s pioneering 1880s waterworks, while the other began as an abandoned road project before ultimately taking over the older tunnel’s role nearly a century later.
