The closing of the twin bridges across the Waitaki River between Kurow and Hakataramea at night has been extended.
The 130-year-old, single lane wooden bridges will close to vehicles and pedestrians at 8pm, re-opening at 7am, as a precaution after scouring was discovered at one pier.
They first closed on Thursday night, reopening after a detailed inspection yesterday, then closing last night. They will be closed tonight and tomorrow night.
The inspection yesterday, before the bridges reopened, showed the pier remained solid and the affected bridge was reopened just after 7am, but a watch was being kept on a pile downstream, New Zealand Transport Agency highways operation manager Peter Connors said.
"Both the pier and pile will be monitored over the next few days to see whether the scouring back-fills with gravel from the river," he said. "If this does not occur, there is a possibility of having to underpin the pier."
Similar work was successfully carried out recently on a nearby pier.
Another inspection would be made on Monday, followed by a decision on whether any further closures would be needed.
While monitoring of the pier and pile was being carried out, closing the bridges at night was a necessary precaution because it was difficult to detect any changes in the scouring in the hours of darkness, he said.
Emergency services have been notified, and will be making alternative access arrangements in the event of an emergency.
The agency was conscious of the importance of the bridges to the community, and thanked residents for their patience during the closures.
