Banks Peninsula residents want $94m wastewater scheme canned

Thursday, 9 May 2024

Christchurch City Council is planning on building a $94m wastewater treatment scheme in Akaroa.

Banks Peninsula residents have found a way to save the city council close to $100 million - cancel Akaroa’s wastewater treatment scheme.

The Christchurch City Council has allocated $94m in its draft 10-year budget on a controversial scheme to plant native trees in Robinsons Bay and Hammond Point and irrigate them using treated wastewater stored in tanks and in a wetland.

The council agreed to the plan in December 2020, but at that point the cost was estimated to be between $54m and $63m.

About 1200 homes and businesses are expected to benefit from the scheme - a cost of $78,000 per connection.

Many residents have long been opposed to the plan and some called for it to be scrapped at a long-term plan hearing on Wednesday.

Suky Thompson and Brent Martin, of Friends of Banks Peninsula, said the group wanted the council to develop another solution that was cheaper to build and run and was more resilient to climate change.

Residents have long been opposed to the scheme. This photo was taken in 2016.

The group, which has been involved with the council’s wastewater proposals since 2007, said a recently council-commissioned report by consultants Beca found the scheme was designed on incorrect wastewater flows.

Thompson said the Beca report showed the scheme was too small to cope with all of Akaroa’s wastewater, causing the system to overflow both raw and treated sewage into Akaroa harbour during heavy rain or prolonged wet weather.

This could happen more than once every five years, the group said.

The scheme also includes building a new treatment plant on Old Coach Rd and a new pump station next to the Children’s Bay boat park, which were already consented.

The group was concerned about the location of the pump station, which they said was prone to flooding. Raw and treated sewage would overflow into the sea at this area, they said.

Suky Thompson and Brent Martin, of Friends of Banks Peninsula, speak about the Akaroa wastewater scheme at the Christchurch City Council long term plan hearings on Wednesday.

A consent has yet to be granted for discharging the wastewater, however, Environment Canterbury has confirmed the consent would be publicly notified and it expected to publish the notification details in the coming week.

The group has called for the council to cancel this consent. It said the council had already spent $13.9m on the project.

Akaroa’s wastewater is currently sent into the harbour through a 100m pipe, which is considered “culturally repugnant” by Ngāi Tahu, and in 2015 Environment Canterbury refused to grant the city council another long-term consent.

The council has been trying to find a solution since then.

Friends of Banks Peninsula wanted the council to divert some of the money to fix Akaroa’s broken pipes, which were leading to high levels of stormwater and groundwater entering the wastewater system.

If the council was unable to resolve the overflow levels then it should abandon its land-based scheme and consider building a longer outflow pipe towards the harbour entrance, Thompson said.

Parts of Robinsons Bay will be planted in natives, which will be irrigated using treated wastewater.

Councillor Yani Johanson said he was quite alarmed by what he was hearing and asked for staff feedback on the issue.

Councillor Sara Templeton cautioned the group against calling for the budget to be cancelled because then there would be no money for any wastewater treatment.

Mayor Phil Mauger said the group was preaching to the converted and its stance was “music to my ears”.

Council acting head of three waters Gavin Hutchison said the council was confident the proposed design would meet its objectives.

The decision to irrigate treated wastewater to land has not changed as a result of the Beca report as it was considered a robust, sustainable solution and supported the cultural and environmental aspirations highlighted during the consultation process, he said.

“The solution to discharge highly treated wastewater to land followed significant consultation by interested parties and the local community. ”

Hutchinson said the Beca report updated previous modelling with information collated over the last three years.

“As a result there have been some large storms measured during these times, and council has taken this into account with regards to the proposed treated wastewater storage proposed.”