Wetland rafts hold promise for farms

Developed by Massey University, the wetlands consist of native wetland plants in buoyant ‘rafts’ that sit on the water surface. These are capable of removing large amounts of nutrients: the rafts filter water in drains and runoff before it enters waterways.

This ‘Living Water’ project has located floating wetlands in drains around Lake Areare (near Ngaruawahia) to monitor the technology. The drains are “nutrient enriched”, the trial partners say. 

DOC ranger Michael Paviour, leading the work in Waikato, says good early results are seen in the trial.

“The wetlands have only been installed for a short time, but initial tests and rapid plant growth show they’re doing a good job of removing nutrients from the water.

“The floating wetlands are not a ‘silver bullet’ for raising water quality but, used with silt traps and riparian planting, they are practical and effective.”

Living Water leader Tim Brandenburg says the floating wetlands could help farmers manage nutrient levels in ponds and drains.

“Floating wetlands don’t just remove nutrients from waterways, they also attract birds and insects and the grasses can be harvested as a feed supplement.”

The trial will run until mid 2017 and if the good results continue the floating wetlands could be in waterways nationwide.