Ōnuku Rūnanga is calling on Akaroa residents to see sense and back a long-overdue wastewater treatment upgrade without delay.

Akaroa’s wastewater has been treated and discharged into the harbour at the bottom of the historic and sacred Takapūneke Reserve since the 1960s.

The Christchurch City Council has proposed the establishment of a new wastewater treatment plant at the top of Old Coach Rd. Storage and land-based irrigation would occur on land planted in native vegetation at Hammond Point and Robinsons Bay.

Ōnuku Chairperson Rik Tainui says messaging promoted by Friends of Banks Peninsula, a local group opposed to the scheme, is delaying urgently needed protection of Akaroa Harbour and the recreational and cultural benefits that a healthy harbour provides.

“They’re saying ‘sanity not sewage overflows’, but what they want allows regular harbour discharging to continue. That’s far from sane for a community that values boating, kayaking, and receives economic return from wildlife tours.”

Rik Tainui says with the new treatment plant in place, harbour discharge of raw sewage would occur once every four to five years in extreme weather events. Right now, raw sewage is going into the harbour up to nine times a year and treated wastewater is being piped directly into our harbour.

“Ōnuku Rūnanga is speaking up as kaitiaki to protect the delicate ecosystem and biodiversity of the harbour to ensure that anyone who wants to fish, gather kai moana, swim or operate commercially in our harbour can do so safely. Discharging wastewater into our harbour is culturally offensive. We don’t want wastewater in the harbour. This new system will reduce it,” he says.

Ōnuku Rūnanga Environmental Advisor Debbie Tikao says the community deserves better information about the new wastewater scheme.

“Friends of the Banks Peninsula claim there is no plan B and that the scheme isn’t future proofed nor considers climate change. That is incorrect.”

Debbie Tikao says the proposed scheme has multiple built-in mechanisms such as subsurface wetlands, a modular and adaptable treatment plant, and additional land for irrigation.

“What the city council has designed meets the cultural values of Ōnuku. It is resilient and adaptable. It has multiple positive biodiversity outcomes for the peninsula. It’s a win for the whole community.”

Debbie Tikao says the council is using an adaptive management process for monitoring wastewater, which means the scheme can be modified and enhanced as needed.

The rūnanga has carefully reviewed and considered what is proposed, she says.

“We’re confident the experts involved in the design and implementation have found ways to reduce the volume of groundwater and stormwater getting into the wastewater network. That will improve our system’s capacity and reduce harbour overflow risk in wet weather.”

Between 2020 and 2023, the council completed $4.75 million of improvements and repairs in the Akaroa wastewater network and $1.78 million on the Duvauchelle network.

Notes:

The proposed wastewater treatment upgrade features multiple backstops to prevent wastewater flowing into the harbour, including:

• 10 covered storage tanks with a 24,000m capacity
• A constructed wetland to take a further 2100m capacity
• A covered wet weather flow storage tank for untreated wastewater
• Irrigation of treated wastewater to parks and land planted with native trees
• A wetland basin for additional treatment, which will receive a small continuous flow of treated wastewater from the treatment plant

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