The sink hole at 3pm on Monday compared to just after 12pm Tuesday. Photo: RNZ / Delphine Herbert
Diversions, detours and lane shifts are expected to be in place for months on a busy central Auckland road as the council continues to deal with a growing sinkhole, and says heavy rains could cause more to open elsewhere.
Part of College Hill Road near the police headquarters started to cave in on Monday and by Wednesday the collapse was big enough to swallow a car.
The hole would probably get bigger because of rain, Auckland Council Healthy Waters strategy head Andrew Chin told Morning Report.
And more could open up, in other places in the city, he said: "[That's] not a surprise at all. The system's under a massive amount of stress, the ground is absolutely saturated so there's a lot of ground movement, so where the infrastructure's in a fragile state you'll start to see these problems cropping up."
It probably will be getting bigger because of the rain" - Auckland Council Healthy Waters strategy head Andrew Chin
The rain had opened the sinkhole because of a dodgy stormwater pipe.
"It's an old pipe, over 100 years old ...an old clay pipe," Chin said.
"It probably will be getting bigger because of the rain. What's happening is ... as the rainfall falls into the hole it washes the dirt into the pipe and it keeps flowing down the pipe and making the hole larger."
Repairs to the stormwater pipe had been planned after the Auckland Anniversary deluges and had been weeks from starting, but had now been brought forward. The pipe would need to be replaced through the whole street, from England Street down to Victoria Street West.
Chin has said it would take about four months to fix the pipe.
Businesses in the area were concerned about the loss of business while the road was disrupted.
Auckland Council Healthy Waters strategy head Andrew Chin Photo: (RNZ / Teresa Cowie )
Council staff would keep the area safe in the meantime, Chin said.
"It's only going to get marginally worse ... the team's gone out with a ground-penetrating radar and gone all the way up the road.
"We knew about the pipe - it was old and we'd surveyed it.
"In the Anniversary Day floods the damage started to really accelerate, so we had a project not only to repair the pipe, but to do an upgrade, make a much larger pipe and improve the overall situation right down the road. ... It had been designed [and] the contract had been awarded and they were due to start in early August, so that's all just been brought forward now."
For now, Auckland Council recommended motorists use Franklin Road to avoid College Hill Road.
Eastbound lanes through the College Hill Road to the central city were closed, with one westbound lane open for traffic heading toward Ponsonby. And a diversion was in place for drivers to access Gudgeon Street and a detour through England, Ireland and Scotland streets.