Business North November 2021

62 | Watercare: Central Interceptor Central Interceptor on track from page 60 Watercare preferred fuel supplier. From delivery and compliant storage, to diesel exhaust fluid, fuel cards and lubricants - we’re a one-stop shop for all your petroleum needs. 0800 383 566 alliedpetroleum.co.nz QUICK FACTS • The Central Interceptor tunnel is the largest wastewater infrastructure project in New Zealand and the most significant wastewater investment in Watercare’s history. • It will be New Zealand’s longest bored tunnel. It will hold 226,000m3 of water – the equivalent of 90 Olympic-sized swimming pools. The Central Interceptor is designed to have a life of 100 years. It will cater for population growth. Over the next 30 years, Auckland is expected to increase by one million. • It will run underground from Grey Lynn to Watercare’s Māngere Wastewater Treat- ment Plant. •Most work will occur underground. There will be 16 construction sites - three major sites and 13 others. •The project will include a tunnel between 15 and 110 metres underground and 4.5 metres in diameter. It will have two link sewers and several shafts along the route for collecting and transferring wastewater into the tunnel. Construction will include structures at the connection points such as access shafts, drop shafts, flow control structures, overflow structures, grit traps, air vents and air treatment facilities. Project innovations - page 64 Shayne Cunis says that a deliberately col- laborative approach has been taken to the massive project: “One of the reasons we are having such a good outcome is because we have clearly defined and jointly shared the risk on this project rather than expecting the contractor to take it all on. “Having those conversations early has set a good foundation and the project is under budget at this stage as we are working togeth- er for the best outcome to deliver the project safely, sustainably and to the highest possible standard for the people of Auckland. “Watercare is an engaged client. We’re the experts in what the project will do but not in how to build it so it’s a matter of working with the joint venture collaboratively, each con- tributing our various areas of expertise. We also work closely with the stakeholders and community to ensure they understand what we are doing and to get feedback.” Auckland is serviced by approximately 8,000 kilometres of public wastewater pipes. Older parts of the city have combined networks, with sewer lines dating back to the 1900’s, with substantial extensions during the 1950’s and 1960’s. The specific need for a new central intercep- tor was identified in studies between 2005- 2008 as many of the drainpipes in central Auckland are old and when it rains wastewa- ter overflows into waterways. The Central Interceptor will enable other work such as the Western Isthmus Water Quality Improvement programme to take place. The full programme of work is expected to be complete by 2028. The Central Interceptor and Watercare’s western isthmus strategy aim to reduce over- flows in the area by up to 80 per cent. S hayne says the benefits to Aucklanders will be clear: significant improvement in storm- water and wastewater overflows with the result being an improvement to the health of waterways. Shayne points out that forward thinking is important to keep up with Auckland’s growth: after all the Central Interceptor has been ten years in the planning and will be six years in the making. He says building New Zealand’s largest wastewater tunnel is a once in a lifetime project for the team. The Central Interceptor tunnel is due for completion in 2026. Visitors stand in front of a giant Central Interceptor tunnel segment during a recent public open day. INFRASTRUCTURE