It's almost one year on since Te Arawa Lakes Trust placed uwhi, or woven flax mats, on the beds of three lakes in the Rotorua region to eradicate invasive weeds.
And the traditional method to fixing the modern-day problem is working.
Lake Rotomā is one of 18 lakes in Rotorua, the homelands of Te Arawa people. The waters there were once full of native aquatic life and kai.
"Our kōura (freshwater crayfish), kōaro (climbing galaxias fish), kākahi (freshwater mussel), tuna (eel), inanga (whitebait), morihana (gold fish), those kinds of ika (fish) have sustained our people for millennia, hundreds of years," said William Anaru, biosecurity manager at Te Arawa Lakes Trust.
But the introduction of pest species has threatened their survival. Te Arawa Lakes Trust is trying to restore the mauri, the lifeforce of the lakes, by using uwhi pinned to the lake bed.
"The purpose of the uwhi is to suppress the weed by blocking out the sunlight and then they rot away and die underneath," Anaru said.
There are four invasive weeds that Te Arawa Lakes Trust is trying to eradicate in the lakes to help restore the mauri and replenish the aquatic native life - and it's already working.
"Our monitoring that we've seen is a really good die-off of weed underneath, but we've also seen the return of our taonga living underneath the uwhi where they couldn't live before," Anaru said.
The uwhi mats use native harakeke, or flax, and are made by Rotorua weavers. It's a local solution that replaces hessian mats made from the jute plant brought in from overseas.
"It's never been done before and the idea that they originally had was that it would be really great to produce a covering for the lake bed that was made of a natural material, and harakeke obviously came straight to mind," said weaver Cathy Schuster, from Te Rōpu Raranga ki Rotorua.
Over $400,000 has gone into the project.
"It's about not just the restoration of the ecosystems of our lakes but our relationship and connection to those lakes and our ability to continue to be and express more fully what being a kaitiaki (guardian) and bring the mauri of back these lakes," said Nicki Douglas, environmental manager at Te Arawa Lakes Trust.
It's been so successful in the lakes they're now trying it in a river.
"We are going to give it a go in Kaikaitahuna or Hamurana Springs with the hapu out here, Ngāti Rangiwewehi, just to try it in a river system to see how they hold up," Anaru said.
Using traditional knowledge to bring the life, or mauri, back into the waterways of Rotorua.
