A 19th-century culvert that has failed in St Clair, Dunedin, causing flooding and damage to properties during storms, will need to be replaced by a new stormwater main.
Repairs have been described as urgent by the Dunedin City Council, although it is understood sinkholes caused by the defective culvert have been present for years and construction of the replacement pipe is not expected to be completed before mid-2022.
Council Three Waters group manager Tom Dyer said a pre-1900 stone culvert in the vicinity of Motu St had failed in several places, causing small sinkholes to form.
Most of the old pipe was located under private property and in some cases under residential buildings.
Mr Dyer said the council was aware of five sinkholes and temporary repairs had been carried out for two of them.
The council planned to install a new stormwater main on a different alignment to the failed culvert, he said.
The old culvert would be filled in to prevent further collapse.
Mr Dyer expected construction to start this year and be complete in the middle of next year.
Property owners in St Clair have had a hard time with the elements in recent years.
Six homes in Motu St and Allandale Rd were evacuated in December 2018 because of the danger posed by a landslip.
Five houses there could not be occupied for almost two years.
Drainage systems were overwhelmed during heavy rain in South Dunedin in 2015, resulting in widespread flooding.
