Mr Hannah said the project began when he and his colleagues in the council's regional services unit decided they needed a specialised platform to house an Acoustic Doppler Current Profiler (ADCP) - a device that uses sonar to accurately measure water velocity and depth.
"It is like a very advanced fish-finder which we drag across rivers to measure the flow," Mr Hannah said.
The platforms on the market at the moment, which were used to carry ADCPs, did not handle New Zealand flood conditions well, he said.
"So we designed and built our own from a modified kayak. It was designed so it could be safely towed across flood waters either by hand, off the side of a jet-boat, below a cableway, or from a helicopter. The boat performed so well that we trialled towing it from a helicopter.
"Industry experts in America, Australia, and here in New Zealand tell us this may be the first time a helicopter has been used to gauge river flows with an ADCP anywhere in the world."
Its design improves the quality of data collected and makes it safer to deploy in challenging flood conditions than present designs on the market.
The new gauging method is also cost-effective and safer than traditional methods, because it does not require staff to be on the water during a flood.
At a recent New Zealand Hydrological Society conference, Mr Hannah received a cash prize for the best presentation. It was titled "Change and improvement in operational hydrology".
He will use the prize money to travel to Melbourne in August where he will make a similar presentation to the Australian Hydrographers Association on the helicopter gauging method and the kayak.
