Council working to fix stormwater issues

Friday, 11 August 2017

The raw human sewage in Invercargill's stormwater has been highlighted by Public Health South which wants the public to be better informed when water quality issues arise.

Public Health South was the last of the public submitters to speak at a hearing before three commissioners in Invercargill this week.

The Invercargill City Council has applied for a permit to discharge water and contaminants from stormwater systems into surface water bodies and into open drains, for a term of 35 years.

A total of 147 discharge pipes draining to the Waikiwi Stream, Waihopai River, Otepuni Stream, Kingswell Creek and Clifton Channel are covered by the application.

'The major issue with this consent for Public Health South is that the stormwater discharge contains raw human sewage which is a prohibited activity…', health protection officer Kate Marshall said.

Marshall said Public Health South was 'neutral' in respect to its position, with its only concern that the consent conditions be adequate to protect human health.

Public Health South wanted the city council to better communicate with the public about contaminants such as raw sewage being in the stormwater discharge, and it wants the public regularly updated on the content of stormwater discharges.

Access to and enjoyment of fresh, clean surface water in urban settings should be a goal of any modern city, Marshall said.

'As things currently stand there are potential health risks posed to our community from the raw sewage found in the waterways … faecal coliform bacteria in urban surface waters commonly exceed World Health Organisation standards for recreation.'

Already, events such as the Mud Run at Daffodil Bay, scheduled for March this year in the New River Estuary, was prevented due to potential health risks posed by the poor state of the sediment.

'The venue was swiftly changed and clean mud was trucked in from a Southland farm.'

Environment Southland says the city council application to discharge water and contaminants from stormwater systems should be turned down because the receiving waters and the New River Estuary would be affected.   

Environment Southland principal consents officer Stephen West, speaking at the hearing on Friday after public submissions had been completed, said Environment Southland still opposed the application.

'The sewage contamination of the discharge is the key issue.'

The sewage caused the discharge to breach the water quality standards, making it a non complying activity, he said.

Invercargill City Council lawyer Michael Morris said the council had not been sitting on its hands in terms of its investment in the city's stormwater network.

The council had put in  a reticulated sewage network at Makarewa to avoid overflow of septic tanks into the Waikiwi Stream, and a system is being constructed in Kennington to avoid contamination the city knows will be occurring in the Waihopai River.

The council had undertaken investigations to resolve issues where it had identified sewage contamination, Morris said.

As had already been noted, Morris said: 'This is a war and each investigation is simply a battle within that war.' 

When a connection is found to cause a contamination, it has been fixed, 'but that does not mean the contamination is resolved, it means there is another battle to be fought somewhere else, potentially on that system. 

'And the city is committed to continue to do that.'

There had been much made about the age of the network but only 10 per cent of the city's stormwater network was 100 years or older, he said.

There had been a significant upgrade of the network since the 1984 flood and the council had continued to spend money on the renewal of its stormwater network and would continue to do so.

In all the investigations so far, other than discharge of two 'constructed overflows', the source of the contamination was from private properties, and not as a result of the city's network failing, Morris said. 

The council had options available which would allow it to do the work on private properties and charge it back to the owners, but would rather it was done voluntarily.

The three hearing commissioners will wait for the city council to provide further written evidence before making their decision on the council application.