City’s main water pipeline repaired
The pipeline providing Nelson’s main supply of drinking water has been fully repaired, three months after a 12m section was wiped out by a slip during the region’s ‘‘atmospheric river’’ of rain.
The Nelson City Council said forestry hauling machinery was used to replace the main break in the pipe on a precarious hillside in the Maitai Valley – a job it said would normally take more than double the time.
Group manager infrastructure Alec Louverdis said council staff, contractors and consultants worked ‘‘against the clock’’ to first restore access to the site, repairing Maitai Valley Rd, which was severely damaged by floods and slips in several locations.
‘‘This alone was a major engineering feat, but the team then had to develop a plan for repairing a 12m missing section of the pipeline –167m up from the road, across the river, on a very steep hillside with no easy way to transport supplies to the site.’’
They developed an ‘‘innovative solution’’ using a forestry hauling machine, typically used to pull logs uphill with a cable, he said. The machine from Moir Logging was modified to lift a bridge, pipes and equipment to the worksite.
Everyone involved in the repair of the pipeline, which carries raw water from the
Maitai Dam to a treatment plant, deserved the ‘‘highest praise’’ for their effort and ingenuity, Louverdis said.
‘‘We were all very conscious of the need to restore this critical asset for our community as soon as possible. A job of this size would normally take more than half a year to complete.’’
Nelson mayor Nick Smith said the repair was a ‘‘major milestone in the city’s recovery from the devastating August weather event.’’
‘‘We are fortunate that council invested a decade ago in a smaller duplicate pipe that was also nearly lost,’’ he said.
Smith thanked the council’s engineering staff and contractors, who included Fulton Hogan, Tonkin & Taylor, Staig & Smith, Ground Anchor Systems, Moir Logging, Thelin Construction, Helliwell Contracting and Lift N Shift.
Staff were now turning their attention to building a pedestrian bridge alongside the pipeline to restore full pedestrian and cyclist access to the Coppermine Trail.