KEY POINTS:
When is the Hobson Bay sewer replacement underground pipeline going to be started? Or has it been sidelined while other higher profile projects get political attention?
- Charles Goldie, Remuera.
Work on replacing the concrete sewer across Hobson Bay with a 3km tunnel has started but it will be a few years before the highly visible 90-year-old concrete tunnel is demolished.
A 3.7m-diameter concrete-lined tunnel which travels from Logan Terrace in Parnell to the Orakei Domain will open up the bay for recreational purposes and improve views of the area. It may even allow a new ferry service.
But the ageing sewer, a constant eyesore for hundreds of homes and public viewing points which overlook the bay, will not be demolished until 2010.
Clive Nelson of Watercare Services said the building site at the Orakei Domain had been completed allowing the construction phase of Project Hobson to begin.
Mr Nelson said work at the Orakei Domain would be focussed on construction of two shafts for several months before more preparation work begins at Shore Road in Remuera.
A large primary shaft, which is 22 metres in diameter, is being excavated at the domain.
"This will eventually house the new high-powered sewage pump station. This pump station will move wastewater from the new tunnel into the existing sewer," said Mr Nelson.
Construction of a second temporary access shaft, through which the tunnelling machine will be assembled, will begin shortly.
The sewer main will be replaced with a larger capacity tunnel for carrying and storing wastewater which Watercare expects will meet projected growth in the area.
Contractors Fletcher Construction and McConnell Dowell are handling the $118 million project.
Watercare decided on a tunnel after public feedback on three alternatives: encasing the old sewer in a new concrete jacket, replacing it with a shallow buried sewer, or a tunnel.
Encasement was the cheapest option in a 2002 estimate of $26.5 million versus $47 million for a tunnel. However, the price shot up in late 2005 as a result of an Auckland City Council, Metrowater and Watercare decision to increase the diameter of the tunnel and make other changes.
Auckland Rowing Association is leading the charge to develop the bay as a recreational marine park when the sewer goes.
Watercare project manager Mike Sheffield says the tunnel will help the marine environment because it will practically eliminate wastewater overflows into Hobson Bay, which is part of the Waitemata Harbour. The main carries a quarter of Auckland's wastewater to the Mangere Wastewater Treatment Plant.
Mr Nelson said tunnelling was expected to start as scheduled in December.
