Napier’s ageing outfall pipe leaking

Napier’s ageing wastewater outfall pipe is leaking and should be replaced at a cost of $20-40 million, according to a staff paper going before the city council soon.

It also says that unless the outfall is fixed the council will face enforcement action.

The city’s 1.54km-long wastewater sea outfall pipe is nearly 50 years old and has had issues from the outset due to poor construction. In late 2018 a leak was found at a fibreglass joint in the pipe, about 700 metres from shore.

In March the Hawke’s Bay Regional Council told the Napier City Council to repair the leak by October 30, and to provide long-term options for repairing the joint by the same date. The regional council told the city council that if the discharge isn’t stopped by then, it intends to commence enforcement action.

In April this year a plume was spotted closer to shore. An inspection by divers revealed a leak from a previous repair that had failed, about 600m from shore.

It’s unknown at this stage what impact the latest leak is having on the environment as samples are still being analysed. Previous analysis has shown little impact from the leaks, according to the staff paper.

Staff have told councillors that they want to apply to the regional council for a variation to the outfall’s resource consent, which expires in 2037. The variation would allow treated wastewater to be discharged at the joint.

Staff have told councillors the outfall is in poor condition and the leaks highlighted the need for council to increase the amount it spent on the outfall in order to operate within consent conditions.

The paper suggests that $11.6 million budgeted to replace the outfall in 2024-2028 be brought forward and that planning works get under way this year.

It also said the cost was likely to rise to between $20m and $40m.

Repairing the current leaks was not easy and came with a very real risk that they could be made worse.

Staff say a dive team could undertake the lowest risk repairs in the short term, while planning was started for a replacement outfall. They said the council also had to develop an emergency plan to manage any additional damage or failure of the pipeline.

Councillors will discuss this and other options at its meeting on Thursday.