New Zealand's mapping of underground infrastructure is increasingly inaccurate. The Detail finds out how new technology could help us better understand what lies beneath - and prevent unnecessary outages, delays and cost blowouts.
A manhole at Auckland Airport Photo: The Detail/Alexia Russell
For decades we've been looking at what sits on top of the land: new stadiums, much needed housing, bigger airports.
Two devastating storms and a cyclone have changed that.
Now the spotlight is on the hidden world of what lies beneath - and what's on the maps of utility providers and councils around the country is often a far cry from the reality of infrastructure under our feet. In many cases, especially if landmarks have washed away, those power cables, stormwater and sewage pipes, broadband and comms lines are hard to find.
The Detail speaks to Sam Wiffen, the CEO of Reveal, a New Zealand company that's a global leader in mapping the utilities we have underground. They're the ones who spray paint the lines, letters and arrows on the ground when work's about to start. Currently they have crews in Hawke's Bay, where they're helping to locate transmission wires that have been ripped away from above-ground structures that aren't there any more.
But Wiffen's company isn't just about fronting in emergencies; it's about mapping what's below us to make sure that on a daily basis, emergencies don't happen in the first place.
Ella Trafford (foreground), utility surveyor, with a ground penetrating radar unit (GPR) and Gina Swanney (background), field technician, with GPS locator Photo: The Detail/Alexia Russell
That means when a contractor puts a spade in the ground, or uses a digger, they don't stumble upon a vital piece of infrastructure that could take out power, water - or worse.
In 2020 in New Zealand there were 12,861 such "strike reports" - more than 30 a day - and conservative estimates put the cost of those at almost $90 million. But Reveal says if you add in factors such as, road closures, traffic delays, business disruption, damage investigations and more, the more realistic cost is around $2.5 billion a year. They also contribute hugely to project delays and cost blowouts.
All companies and councils that have underground infrastructure have some idea of what's there, but as development intensifies and time and price pressures go on contractors, the maps of what's there, what's new and what's changed are increasingly inaccurate.
"What records we have do not often match what is actually underground, and therein lies the challenge and the reason we exist," says Wiffen.
There's so much that can go wrong.
For example a contractor might use maps from various utility providers to dig up the road and put new cables in. Maybe there's a boulder or tree roots in the way so the cable's been re-routed, but time is money and the contractor is on the way to the next job so the change isn't recorded. The next time work needs to be done there, someone puts a digger through the cable.
These issues could be forestalled by some detailed surveying work beforehand, and operations such as Auckland Airport make sure they do it - the consequences of going through a pipe there are too severe for the thousands of travellers who pass through every day.
But Wiffen says most contractors, particularly in housing, have razor-thin margins. Factoring in such surveys raise costs and will likely mean they'll be a losing bid.
Instead, they build in variations to their contracts, which mean if they strike utilities not on the plan, they get paid for the delays and extra work. It's a systemic problem, says Wiffen - there is no motivation on anyone's part to spend the money for detailed surveying, in spite of how much those mistakes cost.
Ground penetrating radar ranges in price from 30 thousand dollars to around a million for top models, but Wiffen says as technology improves and gets cheaper, more companies will begin using it. His dream though is that one day, the underground will be mapped by crowd sourcing - where everyone will upload pictures from their iPhone to a sort of google maps of the underground, every time they dig a hole in their back yard.
As for 'building back better' in Hawke's Bay, Wiffen says the best thing we could do is accurately record where things are when they go back in the ground using GPS, not how far something is from a landmark that might one day wash away.
Hear more about why we need to map our underground infrastructure in the full podcast episode.
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