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Karori wall a quake risk THE AWARD WINNERS

More than 200 retaining walls in ‘poor’ condition

Bronte Metekingi bronte.metekingi@stuff.co.nz

A central Wellington retaining wall that collapsed and blocked a city street for months was one of more than 200 in a ‘‘poor’’ state, according to the Wellington City Council’s own assessments. Thirty-five other walls were in a worse condition than the one at the top end of The Terrace.

But there is just one that keeps Wellington City Council wall expert Brad Singh up at night: The 200-metre-long, 7.5-metre-high wall above Chaytor St, the main route in and out of Karori, which is at risk of collapsing in a sizeable earthquake.

Clouds have loomed large over the recent months in Wellington, causing parts of the city to literally crumble. Until now the council has insisted that 2022 has not been any worse than other years for slips.

Singh, the council’s infrastructure manager, now says this year was the worst in at least five years and the numbers had been underreported until now because contractors were so busy with clearing slips they hadn’t had the time to file the paperwork.

‘‘There have been 700 slips and counting,’’ he said.

The council has released, after a request under the Local Government and Official Information and Meetings Act, its 2018 report into its retaining wall on The Terrace. It shows the wall was deemed in a poor condition in 2018 and due for intervention between 2021 and 2028.

It warned that failure of the 3.6m high wall could result in one lane of the road being ‘‘inundated’’, several metres of footpath being destroyed, access being cut, and damage to private land but not to a house.

By August 18, 2022 all things listed had happened. This was, at the time of the slip, one of the largest Wellington had seen this year. It damaged sewerage and gas connections to one house, and caused temporary evacuation of more than 25 residents from eight homes.

Singh said it could optimistically be ‘‘weeks’’ before that section of The Terrace was open, but it could be months, weather and scale-of-the-fix dependent.

The council has now released figures about the 2941 retaining walls it owns. Of those, 171 were in poor condition, and a further 35 were considered very poor.

Singh said the rating could be for structural or aesthetic reasons. The walls in question could be as small as a metre high to major walls that would take out roads if they collapsed.

But it was the wall above Chaytor St that concerned him the most despite being last checked and described as being in an ‘‘average’’ condition.

The wall could collapse in a big earthquake, blocking off a busy road.

‘‘It does keep me awake because of the impact if something did happen,’’ he said.

Fixing some bigger retaining walls around the city, such as an ongoing project at the bottom of Landfill Rd, could come with the price tag of somewhere between $200,000 to $300,000. Fixing a huge slip in Ngaio Gorge, which came down in 2017, was expected to cost about $2 million.

Wellington City councillor Simon Woolf, who lives in Karori, said there were already plenty of banks not retained, that caused trouble for residents of the suburb. Collapse of the Chaytor St wall would be a ‘‘really big problem’’, he said.

‘‘We are the biggest suburb in New Zealand – that would choke us,’’ he said.

Wellington Mayor Andy Foster, another Karori resident, said the council had applied for government funding to spend $7m fixing the Chaytor St wall, but this was declined, so now the council had to take it on.

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2022-10-01T07:00:00.0000000Z

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https://fairfaxmedia.pressreader.com/article/281479280295707

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