Otago Regional Council is using helicopters to monitor rivers after heavy rain washed out roads.
Three council members collected data from five North Otago rivers, including the Waikouaiti and Kakanui. Photo: Supplied
The practice, known as "heli-gauging", sees monitoring equipment towed multiple times across the river by a helicopter.
A council spokesperson said it was cheaper, faster and more accurate than any other method used around the world.
The spokesperson said yesterday three staff members collected data from five North Otago rivers, including the Waikouaiti and Kakanui.
The heli-gauging method was often the only possible option when a region was inundated by flood water and was very reliable at forecasting floods, the spokesperson added.
"At that time they had gauged the Waikouaiti, Waianakarua, Kauru and Kakanui (pictured) rivers, and were also looking to gauge the Shag River," leam leader monitoring, Eve Bruhns, said.
To safely measure time critical flood peaks, an acoustic doppler current profiler was towed across the river multiple times to get a highly-accurate flow data, Bruhns said.
An acoustic doppler current profiler was towed across the Kauru river multiple times to get a highly-accurate flow data. Photo: Supplied
State Highway 1 at the Waikouaiti bridge area was closed yesterday until 4.30pm.
The flow rate of 470 cumecs (cubic metres) that was recorded in the Waikouaiti river at about 9.45am yesterday was not exceptional, she said.
Similar flows have been previously recorded around the Waikouaiti, most recently, in July 2017, November 2018 and January 2021. A flow of approximately 550 cumecs was recorded in January 2021.