McConnell Dowell is proud to share that the St Marys Bay project team in Auckland reached a major milestone with three sections of the tunnel boring machine (TBM), ‘Hinehōaka’, being carefully lowered into the Pt Erin shaft.
A competition would normally be run amongst local school children to come up with a name for a new TBM, though due to Covid-19 the project team and Auckland Council Healthy Waters employees were challenged to submit their ideas. One of the more creative and poignant submissions, Hinehōaka, was chosen. Hinehōaka, the Māori deity of sandstone reflects the cliffs around Pt Erin and St Marys Bay which are primarily made from sandstone.
Hinehōaka is now positioned on a steel cradle where the new tunnel will begin inside the Pt Erin shaft. Over the next few weeks the team will connect the hydraulics, perform surveys, set up the guidance system and test the TBM before she begins tunnelling in early July. Hinehōaka will create a new 2km long pipeline for the St Marys Bay Area Water Quality Improvement project in three tunnelling sections or drives.
The stormwater storage pipeline will meet an increasing demand on the sewer system as Auckland’s population grows. It will also significantly reduce combined wastewater and stormwater discharges and by improving water quality, will make local beaches safer for people and wildlife.
The scope of works includes:
- Building a new 2km long, 1.8m diameter stormwater storage pipeline.
- Constructing three shafts at Pt Erin, St Marys Road Park and the corner of London and New streets.
- Performing three tunnelling drives to connect the shafts and create a tunnel out to the outfall location in the Waitemata Harbour.
- Assembling a 468m long high-density polyethylene (HDPE) marine outfall assembled in Kaiaua, Coromandel then towed 90km to Auckland.
- Building a new pumping and screening station and odour control unit in the Pt Erin Park shaft.
- Constructing a new weir structure and odour control unit in the St Marys Road Park.
Construction began in January 2020 and is scheduled for completion in mid-2021.