Milestone for Ahuriri Lagoon wetland project

The Co-Governors of Te Waihora / Lake Ellesmere (Environment Canterbury, Te Rūnanga o Ngāi Tahu, Selwyn District Council, Christchurch City Council and the Department of Conservation) announced the symbolic first planting for a $3.5-million project.

The project is for a constructed wetland to improve water quality and biodiversity, as well as to ensure the future of mahinga kai in the Ahuriri Lagoon and downstream Huritini / Halswell River.

Attended by many of the people involved in the development of the project, the ceremony marked the start of the project’s 130,000-plant planting phase, following successful completion of engineering and earthworks.

Working together to restore wetland

On behalf of Taumutu Rūnanga, Craig Pauling said it was very pleasing to see everyone working together so effectively to build on the decade of work the Rūnanga had committed in and around the site.

“This was traditionally a rich wetland and a significant mahinga kai for Ngāi Tahu. It is great to see work underway to help make this happen again,” he said.

Co-Chair Steve Lowndes (Environment Canterbury) said the project was “truly phenomenal, a massive undertaking”.

“The site looks so different from when we were here in February to bless the project,” he said. “It fits the Environment Canterbury ethos of moving from planning to on-the-ground action.

Rebuilding the lagoon

Attendees planting the first trees. This is the start of a large planting project involving 80,000 aquatic plants and 48,000 terrestrial, all locally eco-sourced.

Addressing attendees, Steve Lowndes said: “150 years ago you would be neck deep in water. You are standing where the Huritini / Halswell River flowed into Ahuriri Lagoon. The lagoon was a huge area of open water. It connected with Te Waihora when the lake level was high, and when the lake level was low it still stood as an independent waterbody.

“However, from the late 1800s the lagoon was gradually drained, and the ecological and mahinga kai values were all but lost. The Co-Governors are now grasping the opportunity to turn this around.”

On behalf of the Ahuriri Lagoon Steering Group, local landowner Stewart Miller said that “realistically” he expected to be standing at the site “in 2030”. “The right design and believing in it has led to funding and the fairytale coming true,” he said.

Stu Farrant of Morphum Environmental and Greg Stanley (Environment Canterbury) talked about how plants had been selected and the considerable planning needed to deliver a planting plan of this size.

“It’s great to see bird species already using the space,” Greg Stanley said.

Background

The project is funded by the Government’s Freshwater Improvement Fund, Environment Canterbury, and NIWA.

The design of the constructed wetland has been developed with input from rūnanga, the Ahuriri Lagoon Steering Group (representing the community, including neighbouring farmers), consultants, officials and staff.

The project also has a Mātauranga Māori monitoring programme to gauge the changing value of the site for iwi, and an applied research component to measure improvements in water quality.

Ahuriri is a site of great significance for Ngāi Tahu and has a long history as a mahinga kai resource for Ngāi Tahu whānau.

The wetland is being set up as a demonstration site to show what can be achieved with constructed wetlands for nutrient “stripping”, meaning intensive monitoring and demonstrating results to landowners in the catchment.

The project is due for completion by 2022.

Watch the progress

Drone footage of the site can be found here.

The same flight path is being followed regularly to show progress on the project.

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