Changes in Waka Kotahi NZ Transport Agency funding requirements mean the Central Otago roading team has to identify priorities in overhaul of the district’s ageing bridge network, the Central Otago District Council (CODC) was told at its monthly meeting on Wednesday (August 30).

A draft bridge strategy developed by the CODC roading team has identified priorities and provided insights into an estimated $20M overhaul of the district’s bridge network.

CODC infrastructure manager Quinton Penniall told the council at least 30 of the district’s bridges were at the end of, or would be nearing the end of, their useful lives within the next 10 years, with an estimated cost of $20M to replace them all. 

“Our current budget for bridge maintenance and renewals is $660,000 per annum or $7.6M over the 10-year period. This replacement backlog will continue over the next 30 years as a ‘bow wave’ of bridges reach the end of their useful lives.

“We receive a 51 per cent funding subsidy from Waka Kotahi for bridge and structure component renewals and Waka Kotahi is responding to this bridge replacement cycle throughout New Zealand by setting clear criteria to qualify for funding.”

There were three bridges requiring immediate repair or replacement, Quinton said. 

These were the Little Valley Bridge at Alexandra; the Maniototo Road Bridge, which was earmarked for replacement and possible divestment. (where the council passed ownership of the bridge to another entity); and the Scott Lane Bridge near Kyeburn, which was badly damaged by the January 2021 floods, and would be either replaced with a lower-level service structure or not renewed at all. 

Quinton said the council was looking at addressing three problem bridges in the next three years, but understanding at least 30 in following years.

“This isn’t going away. This is just the beginning,” he said.

The draft Transportation Activity Management plan needed to be submitted the following day (August 31) to Waka Kotahi, with the CODC having a further opportunity to refine the submission ahead of a final submission, due on December 8, 2023.

Crs Stu Duncan and Tracy Paterson, who lead the council’s roading portfolio, commended the roading team on their plan of attack for the next 30 years.

The council approved the approach to bridge inspections, maintenance and replacements to be included in the Draft Transportation Activity Management plan.