Aviation risk grounds island

HEYDAY: An aerial photo of the floating wetland soon after it was first launched. PHOTO/FILE

Rotorua's floating wetland will be anchored permanently near Sulphur Point after it was identified as a potential aviation risk.

The wetland, which spells out Rotorua when seen from the air, was originally going to be moved to a site offshore from the Rotorua Airport. But airport management has decided against it.

"They were concerned at a possible risk to aviation from the wetland attracting birdlife," said Rotorua Lakes Council water solutions director Andy Bell.

The wetland was damaged in November 2013 after it looked like a boat had been intentionally rammed into it, the council said at the time. It was not known who caused the damage. It is moored at Sulphur Point and will likely stay there for good.

Mr Bell said repairs had been completed by the Northland-based company that built it and at its cost under warranty.

"We understand the company had to procure the required base material from USA then put together the components at their Northland plant," Mr Bell said.

"The actual remedial work carried out on the floating wetland here was over a period of about a month or so.

"At the contractor's cost, a floating wave-absorbing strip is being made for positioning in front of the floating wetland to further protect it from possible future wave damage."

He said the floating wetland was a "very small piece" of a much wider approach to lake water quality improvement.

"It's difficult to identify its specific contribution. However, monitoring of plant growth patterns on the floating wetland indicate that it is working effectively to remove nutrients from the water."

It is believed to be the Southern Hemisphere's largest man-made floating wetland and has a life expectancy of 20 years. Its purpose is to remove excess nitrogen and phosphorus from Lake Rotorua and to double as a tourist attraction. The wetland has been at Sulphur Point since December 2012.