Wellington close to running out of water after leak discovered in main supply pipe
A large cavity and broken water pipe was discovered under Featherston St in central Wellington. The broken pipe saw the capital come close to running out of water.
Wellington came dangerously close to running out of water after a leak was found in the city's main supply pipe.
Workers found a valve connected to the city's main pipe underneath Featherston St, near Wellington Railway Station, was leaking at 1pm on Friday.
They also discovered a 10 to 15 cubic-metre hole - big enough to fit a people mover - had been created under the road by the leaking water eating away at it.
Utilities company Wellington Water believe the magnitude 7.8 Kaikoura earthquake on November 14, which was felt strongly in Wellington, or one of its aftershocks, caused the leak.
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Given the size of the cavity, Wellington motorists were also "lucky" that Featherston St was a strong road, Wellington Water spokesman Alex van Paassen said.
Collapsed earth around the hole where the pipe is being fixed was thought to have been caused by the November 14th earthquake.
The erosion of the road was "exactly the kind of conditions," that could lead to a sinkhole, he said.
"[It was] like having a water blaster, working away there and drilling into the surrounding earth and gradually wearing it away."
Each day, about 50 million litres flows through the supply pipe, which is connected to Wellington's Macalister and Carmichael reservoirs.
Contractor Justin Glover inspects the damage.
It was touch-and-go on Friday whether the capital would have enough water on Saturday morning, as the two reservoirs supplying the central and eastern suburbs slowly emptied out during the evening.
Acting CEO of Wellington Water Mark Kinvig said they came "pretty close" to sending out a call asking all Wellingtonians to cut back their water use to only the bare essentials.
"There's really only one main supply pipe into central and eastern Wellington, and this was it."
The main Wellington pipe is the large white pipe lying horizontally, the damaged pipe is the vertical pipe shown coming off the main pipe.
Fortunately, the repair workers managed to patch the leak by 3am on Saturday.
Workers were back at the site on Sunday morning to permanently repair the valve, which is attached to the 800mm main pipe, buried four metres deep.
A careful check on exposed pipes was carried out after the November earthquake, but given many of Wellington's pipes were buried quite deep it was "a bit tricky" to check them individually, van Paassen said.
Wellington Water staff and contractors working on the broken pipe.
Wellington City Council spokesman Richard MacLean said the council became aware of the leak after it was spotted by staff looking at footage from traffic cameras in the area.
The council was unlikely to push for changes to the way pipes were checked given the Featherston St leak was discovered and fixed in good time, he said.
"We are just glad that we spotted the leak before the problem became dangerous."
The leak was repaired on Sunday, but work will continue throughout Monday to fill the hole and re-seal the road.
Wellington Region Emergency Management (Wremo) regional manager Bruce Pepperell said the incident was a reminder that residents needed to be self-sufficient and well prepared.
"The ramifications of the earthquake will be with us for some time yet."
Kinvig said the vulnerability of Wellington city's water supply was well known, and the earthquake was a wake-up call for people and businesses to plan for a loss of water supply.
Plans were in place to make it more resilient, including building a 35-million litre reservoir in Prince of Wales Park, and for an alternative pipeline into the city.
But both of these projects will cost tens of millions and take years to complete.
Wellington Chamber of Commerce chief executive John Milford said the leak was a concern, given the impact that water restrictions would have had on the city.
"We came close to losing water for everything but essential services, and that would have been disastrous, causing huge disruption in the CBD and likely forcing most of it to be closed down," he said.
"That would be a serious threat to our economy, not to mention the disruption to people's lives as homes went without water."
The business community would being seeking assurances from the city and regional councils that they were doing all they could to ensure the capital had a sustainable and resilient water supply, Milford said.
- Stuff
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