Floating wetlands to combat algal scum
Home » Blog » Lynda Brendish » Floating wetlands to combat algal scumA Bay of Plenty Regional Council and Te Arawa Lakes Trust initiative is working with schools and the community to construct floating wetlands on Rotorua lakes. They hope to provide new habitat for fish and birds, and hopefully remove some harmful nutrients from the lakes' waters.
Photo: Whangamarino School students. Image supplied by Environment Bay of Plenty.
Lakes in the Rotorua district have been suffering from declining water quality for some time. The Ministry for the Environment says the problem has become "significantly worse" in recent years, and only last month Environment Bay of Plenty warned residents to avoid a "dense green algal scum" washing up on the shores of Lake Rotorua.
But new floating wetlands, part of a programme implemented by the Bay of Plenty Regional Council and the Te Arawa Lakes Trust, could play a part in combating the excess of chemical nutrients that contribute to the algal blooms.
The wetlands consist of an artificial construction of coconut matting and foam with plastic material holding it together, and can then be planted up with natives to form a new habitat for native plants and wildlife.
Bay of Plenty Regional Council Lake Operations Manager Andy Bruere said the floating wetland is multipurpose, giving people and community groups the opportunity to get involved in wetland restoration and providing an environmentally friendly and aesthetically pleasing way of removing nutrients from lake waters.
Some of the first of these floating wetlands are being built and managed by Whangamarino School, but the plan is open to any community group, hapu group or school to initiate and manage their own.
Bruere said the Council may be able to assist with grants and training for groups wishing to participate.
Another floating wetland is already being trialled on Lake Rotoehu, with resource consent already obtained to expand to 11 other regional lakes. A parallel trial in an experimental tank is being tested to see how much nutrient, like nitrogen or phosphorous, can be removed by the artificial construction.
The constructed wetland idea has seen success in other places around the world, so hopefully we'll see more of these in Rotorua, and less algal scum—dense, green or otherwise.
