Rudman's city: Slow progress as always in choosing sewer plan

By BRIAN RUDMAN

The ugly, 88-year old Hobson Bay sewer has between five and 10 years of life left.

After that, the Auckland eastern bays gentry had better wind up their car windows each time they pass by. For who knows? One day the pipe that carries 25 per cent of the isthmus' liquid waste could suddenly blow a hole in its side.

Trevor Jones, Watercare Services general manager, wastewater, says such a nightmare is unlikely.

But just in case, the structure has been corseted with stainless steel straps. In addition, an emergency repair team is at the ready to do repairs "very quickly," if the need arises.

Meanwhile, the consulting over a replacement sewer drags on.

I was flicking through historian Graham Bush's book Moving Against the Tide on Friday and discovered that when it comes to procrastination, we Aucklanders don't change.

His book about the battle to site Auckland's sewage treatment plant at Mangere recounts the decades it took to get the existing Hobson Bay pipeline built - part of the system that drained the city's wastes through what is now Kelly Tarlton's aquarium into the harbour.

Nearly a century on, the same issues of cost versus environment rumble on and on.

Last Friday it went back before the Auckland City Council.

Six months ago, one committee of council rejected Watercare's preferred option, which was to encase the existing structure in a reinforced concrete shell. They preferred an underground option instead.

On Friday, a combined meeting of three committees revisited the issue and called on Watercare to do some more consultation and report back within three months.

In October the option to me seemed clear. The old eyesore had to go. Adding a concrete sheath only enlarged the monstrosity. The additional cost seemed worth it. Watercare's figures then were that the sheath option would cost between $23 million and $26.5 million, the underground option between $44 million and $47 million.

But now I discover the underground option has gone up a further $14 million to somewhere around $60 million.

The additional cost is for laying an overflow pipe from the new Hobson Bay pump station out to the shipping channel in the harbour. This was a little refinement not mentioned in the public consultation process last year.

It wasn't there because Watercare's proposal for this option was to let the overflow pour straight out of the pumping station and into Hobson Bay. Considering the uproar that occurs each time the North Shore beaches are polluted from pipeline overflows, this scenario had more to do with cost than political sense.

Every sewage pumping station needs a safety valve in case of power failure or rain storms that overwhelm the system's capacity. Without it, sewage would start backing up and geysering up in places none of us would want even to contemplate.

In the case of the proposed Hobson Bay plant, overflows could occur six or eight times a year. Heavy rain in Auckland recently caused overflows in one pump station for six hours.

Just why Watercare thought an option that relied on Hobson Bay acting as an open-air, untreated-sewage holding tank six or eight times a year would be acceptable, I don't know. But it is not.

Another problem with an underground pumping station are the smells. Air, I'm told, is sucked into pipes upstream, and then released into the atmosphere when it gets to the station, spreading the pungent odours it has collected during the trip.

This is another complication not broached in initial consultation documents.

Because the original underground option is environmentally unacceptable, we seem to be left with two choices: the renovated old pipe or the underground alternative with its emergency harbour channel overflow.

I've decided to sleep on it.

Councillor Juliet Yates, chairwoman of the planning committee, raises yet another curly one: "Auckland City is spending a vast amount of money as its contribution to cleaning up the Manukau Harbour and people are happy about that.

"I can't help wondering if this may not be the time we ask whether there are options that might prevent overflows into the Waitemata Harbour at all, as it has very popular bathing beaches - more so than the Manukau."