The current wastewater treatment plant at Akaroa. Photo: Supplied/Christchurch City Council
A new wastewater system proposal for Akaroa is too expensive and does not address the town's leaky pipes, Banks Peninsula residents say.
Christchurch City Council first looked into moving the current wastewater treatment plant at Takapūneke Historic Reserve more than a decade ago.
The council said on its website it had been "widely acknowledged" that building the plant at the reserve was "extremely insensitive".
In 1830, Te Miharanui, the rangitira (chief) of the Māori pa at Takapūneke was killed, along with about 200 of his people by Te Rauparaha of Ngāti Toa, with the help of the captain aboard the British ship Elizabeth. The current plant was constructed on the site in the 1960s.
The council was granted consent in 2015 to build a new treatment plant on Old Coach Road, as well as a new pump station nearby and to upgrade wastewater pipes and connections.
However, a consent to build a new outfall pipe into Akaroa Harbour was declined because the council "had not adequately investigated alternatives" and "a harbour discharge was offensive to Ngāi Tahu", the council said.
Takapūneke Historic Reserve was the site of an 1830 slaughter. Photo: Carmel Sepuloni
It dropped an appeal of that decision in 2019, and engaged in community consultation in 2020. This produced the current proposal, which would see treated wastewater irrigated onto land planted with native trees at Hammond Point and Robinsons Bay, and the Recreation Ground at the northern end of Akaroa.
A wetland basin would also be constructed, alongside a series of storage tanks.
A meeting was to be held on Saturday morning by residents' group Friends of Banks Peninsula to educate locals on the proposal and the possible next steps.
Friends of Banks Peninsula deputy chair Suky Thompson said while the council had moved away from sending treated wastewater directly into the harbour, it remained fixated on discharging it.
"Our preference is to see the council develop a system that has a strong reuse component to it. Akaroa runs out of potable water almost every summer and there are restrictions on water usage. We'd also like to see our pipes fixed ... they're in such bad condition."
Hammond Point, where the council intends to irrigate treated wastewater. Photo: Supplied/Christchurch City Council
The council had made some pipe upgrades in 2019 and 2020, which was detailed in the proposal report completed by engineering consultancy firm Beca. It found 78 percent of the town's 2023 winter wastewater flow was leakage, where stormwater and groundwater was getting into the pipes.
Climate change would make the likelihood of further storms more frequent, and treated wastewater overflows into the harbour were to be expected, the report said.
"Council should expect that the design basis settings for the Akaroa Wastewater Scheme will be exceeded on occasions in future."
"We had a big storm in July 2023 - 70 percent of the water going through the system was stormwater infiltration, so the whole [proposed] system has to be hugely bigger than it needs to be, to cope with all the stormwater that shouldn't be there in the first place," Thompson said.
The cost of the scheme was sitting at $93m in the council's 2024 Draft Long-Term Plan, which was too expensive for what was being proposed, Thompson said.
"This is for a community with 1000 sewer connections in it. So it's a cost of about $100,000 per connection. That might be OK if what we were going to get out of it would be a really wonderful sort of future-focused system that tries to solve some of the issues. But instead what we're going to get, under the current proposal, is a system that is going to perform worse."
Friends of Banks Peninsula expected the council to file another consent application in the coming months, and wanted to use the Saturday meeting as an opportunity to get residents up to speed.
The current consent for the existing wastewater treatment plant is set to expire in 2030.