Whangarei council study targets sewage overflows at Parua Bay beaches

The beach on Ritchie Rd, Parua Bay, has been closed multiple times due to sewage spills. Photo / NZME

The results of a pilot study in Whangārei Heads could bring much-needed relief to residents frustrated by repeated raw sewage spills contaminating beaches and the harbour.

The Whangārei District Council (WDC) has completed a targeted investigation into stormwater inflow in the Parua Bay wastewater network after years of public outcry and mounting pressure from the Northland Regional Council (NRC).

NRC earlier this year said it was considering enforcement action over the ongoing pollution.

The pilot study focused on an area upstream of the Ritchie Rd storage tank, where the majority of connected Parua Bay properties were located.

Results revealed stormwater entering the wastewater system during rain events could increase flows by more than eight times the normal volume.

The surge overwhelms the system and leads to overflows that have repeatedly closed beaches and raised concerns about public health and marine life.

The beach at Ritchie Rd, Parua Bay, was contaminated with sewage in January this year. Photo / Facebook

Kevin White, a Parua Bay resident and registered drain layer who helped install the original system in the mid-2000s, previously told the Advocate the infrastructure was poorly designed and unfit for the area’s rapid growth.

Using smoke testing and digital GIS modelling, the study identified vulnerabilities in public and private infrastructure, including damaged manholes, low-lying gully traps, and hydrogen sulfide corrosion.

WDC engineers were now preparing a remediation programme, with much of the work to be completed as maintenance under existing operational budgets.

A WDC spokeswoman said the council was working closely with property owners to address private sources of stormwater inflow, such as roof water discharging into gully traps.

“Quite often these can be relatively quick fixes,” the spokeswoman said.

She said the council was providing advice and following up to ensure progress.

Flow meters and level sensors were now monitoring the system 24/7.

“As these stormwater entry points are corrected, we expect to see a drop in wet weather flows and a reduction in overflows and nuisance flooding,” the spokeswoman said.

The council was also extending the pilot study to Taurikura and McGregors Bay, where stormwater inflow had also been detected.

The NRC, meanwhile, confirmed that enforcement action remained a possibility.

Colin Dall, NRC group manager regulatory services said, WDC must carry out sufficient work to stop unauthorised discharges from the sewerage system in the Parua Bay area.

While no specific deadline had been set, the NRC acknowledged that long-term solutions would require a thorough assessment and could be costly to implement.

In the meantime, the NRC acknowledged WDC was taking interim measures such as transporting wastewater by tanker during high-flow periods and regular environmental sampling to monitor contamination levels.

The WDC spokeswoman said community engagement had been central to the pilot study’s success.

WDC had held public drop-in sessions, emailed updates to local groups, and maintained a dedicated project webpage. Feedback from residents had helped identify hotspots and build a digital database to guide future decisions.

The council said this work would also inform a broader review of the Whangārei Heads wastewater system to ensure it could meet the needs of a growing population.

Sarah Curtis is a news reporter for the Northern Advocate, focusing on a wide range of issues. She has nearly 20 years’ experience in journalism, much of which she spent court reporting in Gisborne and on the East Coast. She is passionate about covering stories that make a difference.