Scientists go remote on rivers

ALL ABOARD: Niwa is using this remote-controlled boat to measure river flows.
ALL ABOARD: Niwa is using this remote-controlled boat to measure river flows.

Scientists are using a remote-controlled boat to measure river flows in New Zealand.

Niwa hydrologist Evan Baddock said the miniature speedboat, called a Q-boat, was a great improvement over traditional methods of measuring water flow.

"It's like a quantum leap forward in technology."

Niwa principal technician Wayne McGrath said the two-metre-long Q-boat would operate in water currents of up to about two metres per second (7kmh) and up to 300 metres from an operator.

He said the main advantage of the boat was that rivers could be measured where there was no bridge. Traditional methods also took longer.

"The Q-boat was the only one of its type in the country."

Waikato Regional Council environment monitoring programme manager Jim Price said using the boat was much safer.

"Staff no longer had to stand on road bridges to get these measurements."

The Q-boat measures river flow using a type of sonar called an Acoustic Doppler Current Profiler (ADCP), which sits inside the waterproof boat.

McGrath said it worked by detecting the reflection of sonar from particles in the water.

Baddock said it measured water current at different depths, along with the width and depth of the river. The data recorded was sent to a laptop using enhanced Bluetooth.

Niwa said the boat was also more accurate than traditional methods.

McGrath said the ADCP could sometimes be hindered by river conditions.

"If the channel has a lot of weed that upsets the measurement."

Niwa won a contract to use the boat to measure river flow for the Waikato Regional Council.

The Q-boat was supplied by Oceanscience. Its testing on the Clutha, Pomahaka and Taieri Rivers was funded by the Ministry of Science and Innovation.

Baddock said the Q-boat cost about US$7,000 (NZ$8,850) to US$8,000 (NZ$10,100). He said there were plans to buy more boats if Niwa could find the funds.

McGrath said controlling the Q-boat was a lot like using any other remote-controlled boat.

"You can have a lot of fun with it."