The main sewer which carries all Upper Hutt's sewage is at risk under State Highway 2 near Melling Station. File photo. Photo: Google Maps
Wellington Water plans to dig up part of one of the region's arterial routes in April for urgent repairs on a major Hutt Valley sewage pipe, warning there will be significant traffic disruption.
RNZ reported last year that the 60-year-old Western Hills main sewer which carries all Upper Hutt's sewage was at risk in two places.
One of those is under State Highway 2 near Melling Station, where Wellington Water documents said the pipe had a high risk of failure due to corrosion.
It stated that if the pipe failed, it could cause large volumes of sewage to flow into the Hutt River for "extended periods " and trigger the collapse of a section of State Highway 2 that sits above the pipeline.
Wellington Water told RNZ it planned to line that section of pipe to prevent "environmental and transportation impacts on State Highway 2 if the pipe fails".
A spokesperson said the earliest it can start work was in April, due to the liner being bespoke and manufactured overseas.
It anticipated that one traffic lane will need to be closed along State Highway Two and that temporary speed limits will need to be put in place.
"We're currently working through traffic management options with NZ Transport Agency Waka Kotahi to make sure we have selected the best practical option, but it is inevitable that traffic will be significantly disrupted."
Wellington Water said lining the pipe would be less impactful on road users than fully replacing it.
The water provider said it would cost $5.2 million.
It could not say yet how long the urgent work would take.
Hutt South MP and Transport Minister Chris Bishop told RNZ he could already sense the "palpable frustration" from Hutt Valley residents, Wellingtonians and commuters.
"It reflects the fact our water infrastructure in the Wellington region is in a severely degraded state as I think everybody knows."
Bishop said NZTA and Wellington Water needed to work together to minimise disruption as much as possible.
"I think the last thing we would want is an exploding pipe under State Highway Two, nobody would like that, so the work has to happen but what we have got to do is make sure it causes as least inconvenience as possible."
Hutt Valley Chamber of Commerce chief executive Patrick McKibbin said locals needed to be made aware of the effects of the works.
"Communicating to both residents around the Hutt Valley through the various channels that exist or directly to businesses will be really important."
McKibbin said it was a busy area of the road so it would be challenging at time for businesses that travelled through the region.
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