New stormwater solution improving quality of life in Northcote

With around 1,500 new homes being built in the Northcote Development, improving its existing infrastructure is crucial to supporting the neighbourhood’s increased density.

Being delivered by Piritahi, the last stages of the comprehensive new stormwater network upgrade, including the 2.1 metre diameter pipeline installed using a tunnel boring machine, is nearing completion. We will then begin works on Te Ara Awataha greenway to restore the natural stream currently flowing through buried pipes.

Work on Te Ara Awataha will see it's natural stream restored above ground.

The new stormwater management plan was implemented in collaboration with Healthy Waters and Kāinga Ora. The solutions involved will eliminate the significant flooding issues that Northcote has experienced in the past.

“Our work will help to improve the quality of the homes and the wellbeing of the people who live in the area.” said Tamsyn McDonald, Acting Project Director for Northcote from Kāinga Ora – Homes and Communities.

Servicing the community into the future and enabling further development, the improved infrastructure will also have a number of positive environmental outcomes.

2.1 metre diameter pipes to installed as part of Northcote's stormwater network upgrade.

The new network delivers a functional solution to managing the increased stormwater volumes from within Northcote before it discharges into the Waitematā harbour. The improvements also deliver additional public amenity for the area, with an improved Greenslade Reserve providing playing fields and playgrounds for the local community, and the Greenway a landscaped public space.

Due to the presence of native fish in the original streams, water passages have been incorporated into each of the projects, allowing them to continue their natural migration.

A challenge that arose in this project was the potential that the volume of water released during a major storm had to cause significant scouring of the existing Hillcrest stream. A special outlet structure has been designed to help control this flow, and a rock apron will be constructed to dissipate the energy of the water before it reaches the stream.

The rocks for the apron were sourced from Piritahi works within the Roskill Development, where we are currently excavating basalt rock as part of a major stormwater network upgrade. The total weight of the rocks used for construction of the apron will be approximately 700 tonnes.  

“We’re starting to achieve some of the outcomes we wanted to from the beginning,” said Tamsyn. “A lot of work goes into planning and design so seeing it actually happening is really cool.”

“It’s a wonderful example of everyone working together in partnership. We’re all part of the solution.”