Matamata-Piako District Council has been fined $67,500 for unlawfully discharging at least 2.8 million litres of wastewater and untreated human effluent into Mangawhero stream over five days in April 2023.

The district council was sentenced for the offending in the Hamilton District Court this week.

In her sentencing decision, Judge Melinda Dickey said the council’s offending was “highly careless but not deliberate”.

“The fact remains, however, that multiple alarms were raised and their being ignored had serious consequences.”

The spill happened at the district council’s Matamata treatment plant on April 6, 2023.

Having cleaned the plant’s wet well, a plant employee reset the system according to standard procedure. Three pumps in the well stopped running, allowing sewage to build up.

Having just cleaned the well and reset the system, the operator thought the critical-level warnings he received via text message were false.

Meanwhile, sewage backed up, flowing through conduit pipes to the electrical control panel, the base of a control box and started flowing out of vents.

Eventually, the effluent reached a nearby surface water drain and flowed about 430m to the Mangawhero stream, which flows into Waihou river.

The problem was not discovered until April 10.

Waikato Regional Council prosecuted the case, with Matamata-Piako District Council pleading guilty at an Environment Court hearing a year later in Morrinsville District Court. Photo / Danielle Zollickhofer

Over that Easter long weekend, an estimated 2.8m to 5.25m litres of wastewater was illegally discharged into the Mangawhero stream.

Judge Dickey said it was essential that there be back-ups in place so the right people could be alerted about problems when they happened.

“Here, reliance was placed on one person,” the judge said.

“It was not until another wastewater operator logged on to the database that a problem was identified.”

Judge Dickey said the district council had provided “no more than would be expected from any other defendant” under the circumstances.

“I note the council has not followed up on its suggested restorative justice process.”

The judge did not award the district council any sentencing discount for improvements to its systems.

She said Mangawhero stream was “of significant cultural, spiritual, and environmental importance” to iwi.

Waikato Regional Council prosecuted the case, with Matamata-Piako District Council pleading guilty at an Environment Court hearing a year later in Morrinsville District Court.

The district council was sentenced this week to a fine of $67,500 for breaching the Resource Management Act 1991. The maximum penalty for the offence was a fine of $600,000.

Matamata-Piako District Council chief executive Don McLeod said the district council didn’t take lightly “incidents like this”.

“The care and protection of our environment is a core part of the council’s business and an incident like this is our worst-case scenario.

“We sincerely apologise to those who are affected, including local iwi.”

McLeod said a thorough investigation after the spill led to changes in the treatment plant’s systems within a couple of weeks after the event.

“We’ve also recently implemented a new district-wide SCADA monitoring system, which provides a much higher standard of remote monitoring and alarms.”

Matamata-Piako District Council chief executive Don McLeod

McLeod said he was disappointed with the regional council’s decision to prosecute.

“We always alert Waikato Regional Council of incidents of this nature, no matter how large or small because we want to do the right thing and learn from it.”

McLeod said the district council had been “working hard” to upgrade its water and wastewater systems, with about $45 million allocated to improvements at the Matamata Plant “over the next few years”.

“The first contract for this work is soon to be awarded.”

McLeod said dealing with the prosecution took time and money.

“While the majority of the costs are covered by insurance, the process impacts significantly on staff morale and detracts from the projects we’re already working hard to deliver across our district,” McLeod said.

“Ultimately, we serve the same ratepayers, and we would prefer to work alongside Waikato Regional Council and focus on progressing this critical work, and meeting the standard that regional council and the community want to see.”

Maryana Garcia is a Hamilton-based reporter covering breaking news in Waikato. She previously wrote for the Rotorua Daily Post and Bay of Plenty Times.