This comes after the severe Teviot Valley flooding in November 2017 and flooding in November 2018 and it hinges on one culvert.
NZ Transport Agency senior network manager John Jarvis said the existing 1sq m culvert would be replaced in the new year with a 4m-wide and 2m-high culvert with increased flood-carrying capacity at Pumphouse Creek on State Highway 8 about 500m north of Roxburgh.
Following the floods, a catchment study was conducted by the Otago Regional Council, and the NZTA had been working closely with council staff to help improve the resilience of the section of SH8.
"Gravel was accumulating and blocking this undersized culvert following heavy rain in the hills, which has occurred more frequently over recent years.
"Not only is the existing culvert unable to deal with these heavy rain events, an existing water treatment pumphouse owned by Central Otago District Council immediately downstream also becomes vulnerable to damage and possible outages to the residents of the town when it floods."
The larger culvert would help channel floodwaters and gravel under the road and below the pumphouse to the Clutha River once it was operational, he said.
Teviot Valley Community Board chairman Raymond Gunn said the upgrade would safeguard not only Central Otago District Council infrastructure and private property but also provide reassurance to the community and businesses they would not be cut off for extended periods in the future.
The NZTA was working on improving two other culverts at the southern end of Roxburgh — at the golf course and Black Jacks Creek, which also flooded in large rainfall events.
The total cost of the work is expected to be about $575,000.
