Auckland’s Watercare have selected Ghella-Abergeldie Harker Joint Venture as the preferred bidder for the construction of the Central Interceptor wastewater tunnel.
The Central Interceptor will run for 13-km from Western Springs to a new pump station at the Mangere Wastewater Treatment Plant, at a depth of 22- 110 m. It will cross Manukau Harbour at about 15 m below the seabed. Along the route it will connect to the existing wastewater network, which will divert flows and overflows into the tunnel. At 4.5 m diameter, it will be Auckland’s largest wastewater tunnel and the biggest wastewater project ever undertaken in New Zealand.
Over the next two months Watercare will work with the joint venture on a range of conditions and issues relating to their bid. If the conditions and issues can be successfully worked through, the Central Interceptor team will take a recommendation to Auckland’s Watercare Board of Directors in the first quarter of 2019.
If the conditions and issues cannot be successfully worked through, Auckland’s Watercare will start liaising with the second bidder – who cannot be named at this stage. Parts of the old Auckland City Council area have no stormwater system, so when it rains the stormwater goes into the wastewater pipes and then overflows into streams and beaches. It was designed to do that in the early 1900s because it was acceptable back then – and with fewer houses, there was more land for the rain to soak into.
The Central Interceptor will address wet-weather overflows by collecting the wastewater and stormwater from these overflow points and transporting it for treatment. The Central Interceptor will reduce overflows into central Auckland waterways that flow into the Harbour by at least 80 per cent. It also provides time for Auckland Council to install stormwater pipes in areas where there are none. Construction will begin next year and continue until 2025. For further information click nz/18 for the tunnelbuilder archive and also visit https://www.watercare.co.nz. 49/18.
https://www.watercare.co.nz/About-us/Projects-around-Auckland/Central-Interceptor
