Weaving a new solution

Large woven ‘uwhi’ mats laid by divers are being trialled as an alternative method to suppress growing weed problems at Lakes Rotoiti and Tarawera.

The dive team kitted up in wetsuits ready to dive
Te Arawa Lakes Trust Dive team. Left to right Joe Butterworth, Te Aaio Reedy, Cory O’Neill, Soweeta Fort D'arth.
Credit: Te Arawa Lakes Trustexpand/collapse

Te Arawa Lakes biosecurity manager William Anaru is hopeful that the new mats will limit growth of exotic weed while allowing native weeds to grow, providing a viable alternative to current ways of dealing with exotic lakeweed, which include herbicides, harvesting, clearing and bottom lining.

Interestingly, the word ‘uwhi’ is new, as is the process of laying the mats on lakebeds, but the knowledge to create the mats is old. Anaru describes the process of drawing on an 800-year-old weaving technique as being “a prime example of using traditional knowledge/matauranga Māori to tackle a modern problem.”

The project, led by Te Arawa Lakes Trust, is a collaboration between the Government Jobs for Nature Programme and Te Roopu Raranga ki Rotorua, a Rotorua weavers’ group.

Work to design and create the uwhi was undertaken at Te Puia Māori Arts & Crafts Centre in Rotorua over November this year, with contribution from Master weaver Christina Wirihana. Te Roopu kaumatua and Heritage New Zealand Pouhere Taonga Traditional Arts Specialist, Jim Schuster, was also involved in the process. He explains that the new name ‘uwhi’ came about as traditional woven mats are “not put on the bottom of a lake.”

Aquatic plants are important to the health of our lakes and waterways, improving water quality, and providing habitat for wildlife. But our once pristine lakes and waterways are being overrun by invasive exotic aquatic weeds which, unimpeded, can impact recreational use of our lakes and rivers as well as farm irrigation.

Exotic aquatic weeds also impact water drainage and power generation. Human activities are most often to blame for the transfer and spread of these larger, denser invasive weeds which prevent native species from thriving, a problem that climate change and the resulting warmer lake waters will only exacerbate.

The newly laid uwhi will be monitored regularly to assess the efficacy of exotic weed control. Further trials are likely.

- Niki Partsch