Tunnelling beneath the city's surface

The footsteps of history echo under Dunedin's streets, in tunnels, sewers and bunkers with hidden tales to tell. Reporter Chris Morris goes digging.

Walk Dunedin's streets and the telltale signs of history are everywhere.

Soaring church spires, faded brick warehouses and even the layout of the streets themselves weave together to tell the city's story above ground.

But, below the surface, another layer of the Dunedin story lies hidden - out of sight and out of mind to many. Dig down, however, and a fascinating history waits to be discovered.

How many people have clambered through the city's brick sewers, which remain in impressive condition - their brick arches and tunnels big enough to drive a small car along in places - despite sections serving the city for up to 150 years?How many people recall stepping down into the underground toilets in the Octagon, Exchange and elsewhere around the city - the remains of which are buried under the city's new street paving stones - more than a century after their construction?And how many people realise, as they stroll across Rattray St or Cumberland Sts, that tunnels run beneath their feet, or that World War 2-era bomb shelters once scattered across the city are still buried, intact but forgotten, below the surface?Dunedin City Council worker Mike McCann has spent much of his career looking after the engineering marvel that is the city's oldest sewer network, built brick-by-brick more than a century ago and still hiding in the darkness beneath Dunedin's streets.

As the bustling cars and busy feet clatter by above, down below the network of brick sewers carries the city's stormwater from the hills to spill into Otago Harbour.

For more than 100 years, the old sewers took both sewage and stormwater to the harbour, until sewage was finally separated in the 1980s, leaving the oldest sewers for stormwater only.

The network has remained hidden to most, but occasionally a visitor's headlamp illuminates the darkness.

And, when it does, the light reveals the impressive world of brick archways and architecture that has been Mr McCann's office - of sorts - for more than 25 years.

As the Dunedin City Council's drainage reticulation supervisor, Mr McCann was in charge of a small, five-strong team that maintained the ageing infrastructure.

That meant donning orange overalls and a hard hat, turning on the headlamp and gas detector, connecting to a winch, and descending into the void.

It is a trip Mr McCann has made many times while checking the sewers for signs of wear and tear.

More recently, advances in technology meant many of the city's large pipes could be inspected by camera or sonar, avoiding the need to send workers into a potentially dangerous environment.

However, the architecture of the old sewers made the cameras less effective, meaning workers like Mr McCann still needed to venture inside.

Health and safety rules meant his team were the only people to venture inside in recent years, although two Otago Daily Times journalists joined city council staff and councillors on an unsettling stroll through the sewers in 2005.

They found tunnels devoid of the expected dank smell, replaced instead by the aroma of alcohol, coming from the nearby Speight's Brewery.

Mr McCann said the sewers, buried 2.5m underground, usually contained ''just a musty sort of smell'', but were close enough to the surface that cars could be heard rattling over manhole covers, as could trains rumbling along above sewers near the Railway Station.

So, too, could the sound of water when it began to rain heavily upstream, or a water hydrant was turned on, Mr McCann said.

''It sounds like there's a river coming ...that's about the time to get out,'' he said.

Asked if he felt Dunedin people appreciated what was under their feet, he said: ''Not at all.''

''The architecture in there would have been as good, if not better, than what's above the ground.''

The sewers were among the engineering marvels of their day, but, such was the quality of their construction, some of them were likely to still be in use another century from now, council water and waste services manager Laura McElhone said.

''They look like they're about 10 years old. It's bizarre. They are in really good nick.''

Another massive tunnel and key part of the city's network of sewers, the main intercepting sewer, also still ran nearby.

Built in the early 1900s, it stretched the length of Cumberland St, from the Botanic Garden south, and acted as a state highway for the city's effluent, collecting the contents of smaller pipes and transporting the results to the Tahuna wastewater treatment plant.

However, the old sewers were far from the only hidden treasures under Dunedin's streets, Dunedin art historian and writer Peter Entwisle said.

Also scattered around the city were the remains of tunnels built for convenience, bomb shelters and bunkers to protect against World War 2 aggression, and possibly even the remains of ornate below-ground toilets, sealed over and forgotten years ago.

One tunnel ran under Rattray St, stretching 75m from the Speight's Brewery to what was once the malthouse and cellar on the opposite side of the road, now home to the Harvey Norman department store.

The ODT visited and found the far end of the tunnel, at the Harvey Norman end, firmly bricked up.

However, enter the Speight's shop, duck down a narrow flight of stairs and, behind another door, the Speight's side of the tunnel is still there, stretching 25m under the road.

Built in 1898, originally of brick, the tunnel was used by workers to roll casks of beer from the brewery along rails to the cellar, while pipes running through it carried well water and malt back the other way.

The narrow passage was later given a cement floor and its bricks plastered over, although rails running along its floor remained visible.

The tunnel fell largely into disuse from the 1940s, Speight's historian Donald Gordon said, and the ODT found it full of brewery clutter, which meant it was kept off the brewery's official tour.

Only a small plaque marked its existence, but the Speight's tunnel was not the only hidden passage still running under Dunedin's streets.

Across town, Dunedin Hospital boasted two - both built in the 1960s - one of which was now sealed up, while the other carried steam pipes and was closed to the public.

Mr Entwisle said one of the tunnels ran under Cumberland St, between the hospital's clinical services block and the nurses' home, and was built in the 1960s for nurses to cross safely.

It proved unpopular, and eventually the pedestrian overbridge that spanned Cumberland St was built instead, crossing the road in the same area, he said.

''What they found was the nurses didn't particularly care to use it [the tunnel]. I don't know if they were spooked by it, or they just thought it was too inconvenient ... but instead they kept on dashing across the road.''

A third tunnel, built in 1957, could still be found at Wakari Hospital, running 115m from the main hospital block to the nurses' home.

Photos published in the Evening Star when it opened showed nurses strolling four abreast along its length, and Southern District Health Board spokesman Steve Addison said it was still there.

The fear of bombardment during World War 2 had also prompted the construction of bomb shelters around the central city, Exchange and even at the University of Otago, many of which were still intact.

Peter McGrouther, the university's northeast sector facilities manager, took the ODT on a tour of WW2-era bomb shelters built under the Geology and Archway West buildings during the 1940s.

One was a long, thin corridor running down the back of the Geology building's southern end, while a second was found in the building's old basement, which had been converted from use as a morgue and strengthened.

A third shelter was down two flights of stairs in the basement of the international office, below ground level.

However, more mysterious were old engineering drawings from 1942 depicting plans to build an underground bunker with space for up to 80 people under the neatly trimmed lawn next to Marama Hall.

A similar structure was proposed for somewhere between the university and professors' houses, but it was not known if either was built.

''That's the thing - this sort of history is lost,'' Mr McGrouther said.

''We are not sure if they were built or not.''

Other bunkers could still be found scattered through central Dunedin, in cellars and more unlikely places.

Mr Entwisle said ''quite a few'' shelters had been built around the Octagon, the Exchange and surrounding streets, to protect the city's busiest places during World War 2.

One shelter built in 1941, under a Bond St building built in 1901, was used last year for the launch of a Dunedin fashion label. It still had some of its original features, including a water reticulation system and shelving for rations.

Mr Entwisle said the remains of another could be found directly below the entrance to the Dunedin Public Art Gallery.

''You know when you walk in the front door of the art gallery? It's under your feet.

''They lowered its ceiling ... but it's essentially still there.''

More impressive could be the remains of Dunedin's underground conveniences - public toilets that used to dot the central city, with staircases leading down below ground.

Perhaps the most well known was the toilet in the Octagon, near the Regent Theatre, which opened in 1910 and was finally closed with the redevelopment of the Octagon in 1989.

It was destroyed in the process, council heritage policy planner Dr Glen Hazelton said, but Mr Entwisle said other impressive examples might remain, buried underground.

That included another of the conveniences built in the Exchange, directly under the Cargills Monument, which opened in 1910 and was closed in 1961.

Council records showed it, too, was demolished and filled in, but Mr Entwisle said that might not be correct.

''They just piled stones down it when they covered it over.

''If you opened it up and pulled all the rocks out, it would still be dressed as it was.''

Mr Entwisle said the toilets had become ''pretty awful, very dirty, very grubby'' places by the time they were being closed, and also associated, rightly or wrongly, with ''indecent practices''.

However, the decorative interior of the toilet under the Cargills Monument would be reminiscent of the Dunedin Railway Station, he said.

''Not as grand as that, but definitely of that sort ...They weren't thinking this is just some sort of utilitarian thing, at all.

''If they saw the ones that we provide, these sort of plastic Portaloo thingies, they'd think we'd really lost the plot.''

- chris.morris@odt.co.nz