Tunnel boring machine begins work in Wairau Road

Projects, 23/08/2017

Watercare will be using some clever technology to install a new pipeline under Wairau Road as part of a $14 million upgrade to wastewater services in the area.

It’s believed to be the first time in New Zealand that a tunnel boring machine will be used to lay a wastewater made of Glass fibre Reinforced Plastic (GRP). The new pipe will run along Wairau Road to the Wairau Pump Station. The work will take place in a small area of the median strip near MacDonald’s and motorists are asked to take care as they pass by.

The tunnel boring machine will create a one-metre diameter tunnel before hydraulic pipe jacking equipment, thrusts a section of pipe into place. A separate machine will pump excavated earth (in a watery slurry form) to the surface, where it will be removed. 

There are considerable benefits to using this type of machine as opposed to digging an open trench and laying pipe sections into place with a crane. Watercare’s project manager Mahinda Attanayake says one of the main gains is speed: “The tunnel boring machine has been imported especially for this project and will be able to drill up to 150 metres at one stretch, so we can get the job done faster.

We have spent a long time trying to work out ways that we can reduce the impact on the local community while we get this essential work done.”

Kaipatiki Local Board Chair, Danielle Grant says: “Watercare has worked with the local board for some time on this project and we are pleased that they have been able to use technology to help reduce traffic disruption along Wairau Road.”

The tunnelling method will also be less noisy and safer for construction crews, as there will be no open trenches. The pipes are being stored on Watercare land at Schnapper Rock Road from where they are transported to site as needed.

The new pipe and new pump station (to be built in 2019) will handle 60 per cent of the North Shore’s wastewater and the new line will mean fewer wet-weather overflows on the North Shore. The pipeline project is due for completion in a year’s time and is likely to involve lane closures in View Road from September to December.