The wetland at the Manawatū Wastewater Treatment Plant adds an extra filtration process that helps to break down any remaining contaminants in the water before it is released into the Ōroua River.

Council partnered with Ngāti Kauwhata on this project, as the river holds special significance to them. Earthworks on the wetlands began back in August 2022, which involved moving approximately 30,000 cubic metres of soil. The inlet and outlet structures were built, and planting is now complete.

The constructed wetlands consist of two shallow bays that act as a natural filter through land contact and the biological plant absorption which purifies the treated wastewater further before reaching the Ōroua River.

The two bays have been planted with over 80,000 native plants specifically selected for their treatment properties. All of the plants have been sourced and grown by our own Kawakawa Nursery.

The wetland is designed to treat over 6 million litres (6000 m3) of wastewater per day and will take 3 days for the water to travel its length. In the short time since planting finished there is already native birds and aquatic life starting to appear, adding to the Manawatū ecological system.

The access road in the middle of the wetland has been constructed using recycled material from Central Demolition’s concrete crushing operation which is nearby. It’s another great example of how that partnership between Council and Central Demolition has been beneficial for both parties, and the wider community.