A pair of freshwater monitoring buoys installed last week at Lake Wānaka and Lake Wakatipu to measure water health are believed to be the deepest of their kind in the country.

The buoys, which were installed to monitor the health of the two lakes, have been placed in locations with depths of around 220m (at the mouth of Roys Bay in Lake Wānaka) and 350m (500m offshore from Island Spur at Lake Wakatipu).

“The chosen sites in these nationally significant water bodies will provide us with baseline monitoring, to assess changes in the lakes due to climate change, or other factors such as catchment development,” Otago Regional Council (ORC) lakes scientist Hugo Borges said.

“They will become a key part of our overall lakes monitoring programmes focused on monitoring water quality.”

ORC lakes scientist Hugo Borges on Lake Hayes with one of the freshwater monitoring buoys.

The buoys operate entirely remotely and transmit data to ORC databases in near real-time, measuring oxygen levels, phytoplankton (algae) growth, water temperature, conductivity, and lake-water clarity.

“A weather station mounted on the buoy will also provide near real-time data on meteorological parameters,” Hugo said.

The data won’t just be used by the ORC: it will be accessible to the public, as well as universities, environmental organisations and lake managers who are researching waterway projects.

Hugo said the ORC intends to operate the monitoring buoys permanently as part of its long-term State of the Environment monitoring programmes. 

At least one more buoy is also being considered for deployment to Lake Hāwea during the 2022-2023 financial year, he said.

It is recommended all watercraft stay at least 50m away from the monitoring and marker buoys, to avoid any disturbance of the mooring system.

The buoys are 120-150kg each and are 1200mm in diameter by about the same height; above the water. 

Each monitoring buoy is held in place by three cylindrical spar buoys which are anchored to the lakebed. The buoys weigh 120-150kg each and 1200mm in diameter. They have LED beacons and marks.

PHOTOS: ORC