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Over the next six months, contractors will be seen around Dunedin measuring and checking the soundness of about 3000 walls supporting roads or land and property next to a road.
The data, added to that from about 1300 walls in the city's metropolitan area that have already been assessed, will be forwarded to council staff, who will then complete a risk assessment exercise to identify which walls need attention, and when.
Council asset management engineer Geoff Young said the work had not been done before, and would help update the council's records so it could better manage its responsibility to maintain the road network.
''If you haven't measured something, you can't manage it, so we are looking to know what we have got, so we can better manage it.
"If that has a financial implication we need to know what that is, so we can set aside money for it.''
In most cases, the inspection could be carried out from the roadside or footpath, but at times inspectors would need to enter properties to gather the necessary information about the wall.
Some of the walls were privately owned, but the council was keen to record them where they could have an effect on the road.
In cases where a wall was at risk of imminent collapse, a letter would be sent to landowners informing them of the situation.
The council had the power to require property owners to fix retaining walls threatening public property but, in the main, this was an information gathering exercise, Mr Young said.