Geotechnical investigations begin for Devonport watermain upgrade

Watercare will begin geotechnical investigations in mid-September along the proposed 4.5-kilometre route for the planned $40m Devonport watermain replacement.

Watercare project manager Raj Unka says the new watermain replaces an ageing pipeline and supports future population growth.

“The Devonport 2 Watermain has reached the end of its design life after serving the community since 1960. It’s one of two major watermains supplying drinking water to the Takapuna, Hauraki, Bayswater and its surrounding suburbs.

“The new pipeline will be approximately 450mm in diameter - 150mm bigger than its predecessor – and will stretch from the corner of Killarney and Auburn streets to the bulk water supply point near 95 Lake Road, Belmont.

“It will follow a revised route that avoids private properties and recreational parks, making better use of road corridors to support future maintenance access.

“It will operate alongside the existing Devonport 1 Watermain, which will remain in service once the new pipeline is commissioned.”

Although construction of the new pipeline is not scheduled to begin until early 2027, these early geotechnical investigations will help Watercare gain a clearer understanding of existing underground services and ground conditions.

Unka says the data gathered will also help refine the pipeline’s design and construction methodology.

“These investigations will run through to late November and include a range of survey and testing activities such as drone aerial surveys, topographical ground surveys, and potholing on berms and roads.”

“Temporary traffic management will be in place at various locations along the route to ensure the safety of both our crews and the public.”

Unka says once the geotechnical investigations are complete, the project team will move into the preliminary and then the detailed design phase.

“After these investigations, we’ll go back to the drawing board to finalise the pipeline route and develop the construction methodology.

“It’s likely that further traffic management will be required to support this next phase of work. We remain committed to keeping the community informed as the project progresses.”

“The geotechnical investigations are expected to continue through to late October.”