Hobson Sewer Pipe Goes


Tomorrow morning, powerful hydraulic jaws will begin to demolish the sewer pipe that has carved a concrete path across Hobson Bay for nearly a century.

The sewer pipe was constructed between 1908 and 1914 to serve up to 300,000 people.

At the time it transported the wastewater to Okahu Point, where it was released without treatment into the harbour via a 300-metre outfall pipe.

More recently, the sewer pipe transported the flow to a pump station in Orakei to be pumped to the Mangere Wastewater Treatment Plant for advanced treatment.

Works to replace the sewer pipe, and the 40-year-old pump station it connects to, have been underway for three years.

Last month, the new tunnel and pump station entered service full time.

Project Manager Mike Sheffield says these assets are proving their worth already.  “During last week’s torrential downpours, the high-capacity tunnel and pump station did exactly what they were designed to do – kept the combined wastewater and stormwater within the sewer system.

“This meant that for the first time in around 100 years, there were no wastewater overflows from the Orakei overflow point into the eastern bays.”

The demolition work is expected to take four months to complete. Two crews will break up the concrete with hydraulic jaws and collect it off the seabed using hydraulic diggers. This method was chosen as it creates less dust and noise than alternative methods, minimising disruption to the community. Concrete from the demolition will be used by Watercare to form roads around Pond Two – a former oxidation pond undergoing rehabilitation next to the Mangere Wastewater Treatment Plant.

By Christmas, Aucklanders will be able to enjoy a greater range of recreational activities in the bay as the sewer pipe will be gone, along with all signs of construction.




  1. Christopher says:

    In memory of my grandmother: she would walk across this pipe every day in her late mid-late 70s with friends. It was her way of keeping fit.

    And I used to walk from her place in Remuera across the pipe to my grandfather’s place in Parnell. Friends and I would walk the other way up to the railway bridge. That pipe was more than a pipe.

  2. dsadas says:

    I thought we had seperate sewer and stormwater drains so why does heavy rain affect the sewer system?

  3. Bevan says:

    Normally, the flows of stormwater and sewerage are separated, but when there are storm events with heavy inflows of rain into the stormwater system, it can get overwhelmed. City engineers designed the two systems to mix in that scenario to prevent flooding of city streets and damage to the system. Of course, that meant that during storm events sewage contamination occurred at the beach.
    Things are slowly getting upgraded to reduce or exclude the need for this to happen, but of course replacing these old pipes buried underneath the city costs an enormous amount of money. You might have heard of councils closing beaches for a day or two after heavy rains because of high bacteria counts and contamination??

  4. Lti says:

    I thought that the problem was due to storm water being incorrectly channelled into sewers. So during heavy rain, the sewers - not having the required capacity - would overflow.

  5. max says:

    “Incorrectly” only because it shouldn’t happen. That it would happen once in a while was always an accepted fact, to my knowledge. They had less stringent opinions about public waterbody standards then.

  6. Ian says:

    Christopher, when you say “across the pipe” do you mean the length of it? If so, an epic journey. I had heard stories of women pushing prams along the pipe but in all my years in Auckland I never saw anyone walking the pipe. As you say, more than a pipe.

  7. J says:

    I used to ride my bike along the pipe on the weekend when I was at school, or walk it if with people who didn’t have a bike. It got a bit complicated when you reached the railway tracks near the Outdoor Boating Club, but was still a shortcut to Mission Bay, or Parnell in the other direction.

  8. rtc says:

    Is it all gone now? They seem to have gone quiet in regards to updates about the demolition progress.

  9. GBAK says:

    To all the graff writers out there and in auckland i would just like to say rest in peace to the huge roller painted G.B.A.K pieace that took 3 nights and no it was not done with boats!!crew members stood in the water an painted away haha well thats all i had to say about the great pipe.btw the GBAK piece was lengend haha


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