Achievement of Significant Drainage Milestone in Project Auckland: Hiwa-i-te-Rangi

Watercare’s gigantic Tunnel Boring machine, known as Hiwi-i-te-Rangi, has recently reached a noteworthy achievement during its excavation of the Central Interceptor Tunnel. It has successfully achieved the halfway point of its 14.7-kilometre journey to central Auckland, marking this remarkable feat with a breakthrough into a shaft at May RD in Mount Roskill.

The Central Interceptor project is hailed as the largest wastewater infrastructure endeavour in New Zealand’s history, holding the promise of seriously addressing wet weather overflows into waterways and the Waitemata Harbour. Furthermore, the tunnel will intersect with two link sewers connecting the Mangere Wastewater Treatment Plant and Grey Lynn.

Amidst the jubilant cheers of construction teams, Shayne Cunis, the Executive Programme Director of Watercare Central Interceptor, announced the breakthrough of the cutter head, with a diameter of over five meters, through a 69-meter-deep shaft wall. Cunis emphasized that despite the considerable challenges faced, this breakthrough signifies a crucial moment in the project’s progress.

Cunis urged everyone to take a moment to appreciate this significant achievement, emphasizing that the project remains on track to meet its planned 2026 completion date, despite obstacles such as COVID-19 lockdowns, closed borders, global shipping delays, and adverse weather events. The top priority remains ensuring the safe delivery of the project.

According to Cunis, one of the most thrilling moments in the project journey thus far was the 2022 crossing of Manukau Harbour, spanning from Mangere Bridge to Hillsborough. Underwater tunnels are a rarity in New Zealand, and this 1500-meter section was completed in less than 11 weeks.

The Central Interceptor project has reached several milestones. Following the completion of the undersea bridge in December 2022, the first link sewer, responsible for collecting flows from Mount Roskill and Blockhouse Bay, was finished in March of this year. Construction has also commenced on a second link sewer, set to be built in two segments, intersecting the main shaft at Wairere Avenue in Mount Albert.

Cunis extended his appreciation to the construction partners of Ghella Abergeldie JV, as well as the dedicated teams from Jacobs, AECOM, Delve Underground, Watercare, and the subcontractors. He acknowledged their tremendous efforts in ensuring the project’s successful delivery.

Francesco Saibene, the Project Director of Ghella Abergeldie JV, also commended his tunnelling team for their hard work, emphasizing that reaching the halfway point is a moment of celebration for all involved.

Meanwhile, significant progress is being made on the nearby Mangere Pump Station project, where six pumps and inflow pipes are being installed to facilitate the transfer of flows from the main tunnel to the treatment facility for processing.

The planned timeline includes completing both the connection sewers and Section 1 of the primary tunnel, stretching from May Rd south, by the middle of 2024. Initiating the first segment will relieve strain on the aging Western Interceptor.

Cunis emphasized that resilience has consistently been a primary motivator for this project, alongside the objectives of accommodating future expansion and delivering environmental benefits. Once Section 1 becomes operational, Watercare’s operations teams will have the opportunity to perform essential maintenance on the Western Interceptor.

These upgrades are exciting for all drainlayers in the Auckland area. As our infrastructure grows more and more exciting drainage developments will take place. Drainage NZ specialize in Public and Council drainage works, if you have a project planned, why not have us tender for you.