Watercare’s boss slams council over spills
Email shows differences with council on overflows into harbour when it rains
Auckland Council is allowing developments to occur knowing there is no adequate stormwater system and this will result in more frequent harbour spills, says Watercare chief executive Raveen Jaduram.
The wastewater system was designed for toilet and other household wastewater and, as much as practical, stormwater needed to be removed, Jaduram said in an email to councillor Mike Lee last year.
The email highlights differences between the council and its water business about how to deal with overflows from 41 sites into the Waitemata Harbour almost every time it rains. About 99 per cent of the overflow is stormwater. Just 0.2 per cent, or two litres for every 1000l, is from toilets.
Council Healthy Waters general manager Craig Mcilroy has told the Herald wholesale separation of 16,000 homes on the old combined sewer-wastewater does not make economic or social sense.
It would cost $1.5 billion, on top of the $1.7b already planned for new interceptors and feeder services to the Mangere waste treatment plant, to build separate stormwater pipes for all 16,000 homes in the combined sewer-stormwater pipes, he said.
In the email, Jaduram was critical of the council’s approach to stormwater. He said the inflow of stormwater into the combined system caused an immediate increase in flow that was significantly larger than the wastewater flow.
The use of detention tanks in new developments to slow down the stormwater flow when it rains “is not a sustainable solution”, Jaduram said.
“What is required is investment by council in proper stormwater infrastructure. Continuing to accept stormwater into the wastewater system erodes hydraulic capacity that could be used to service growth and provide better levels of services to existing customers.
“Council is allowing developments to occur knowing full well that there is no adequate stormwater system and that additional stormwater discharges to a Watercare combined sewerage system is going to result in more frequent spillages,” Jaduram said.
The Watercare boss stands by his comments to Lee on the use of stormwater detention tanks, but declined to be interviewed.
In a statement, Watercare said a joint party made up of Watercare and Auckland Council staff was investigating wet-weather overflows and associated issues and would report back to the council. The findings will be part of the council’s next long-term
What we are doing is dumping enormous amounts of raw sewage into Waitemata Harbour. Mike Lee
budget that will go out for public consultation next year.
Last night, Mcilroy said future growth would not have a significant impact on water quality issues.
“The adverse effect of more housing will be offset by short-term improvements such as requiring onsite detention of stormwater in combined areas before the new interceptors are built,” he said.
Lee said Jaduram’s email was revealing, honest and courageous for a public servant.
“It’s a clear warning to Aucklanders that we have a major problem that has yet to be solved.
“Clearly there is a significant shortfall in parts of the city to the most basic facilities of any civilised society. What we are doing is dumping enormous amounts of raw sewage into Waitemata Harbour,” Lee said.
In the meantime, about 690 properties in Freemans Bay, Waterview, Okahu Bay and Newmarket are having their sewage and stormwater separated. — Nikki Preston