The Central Interceptor
The Central Interceptor (CI) tunnel is 4.5 metres in diameter and will run for 14.7 kilometres from Grey Lynn under central Auckland and the Manukau Harbour to Māngere. The tunnel will lie between 15 and 110 metres below the surface.
Along with two smaller link sewer tunnels we are building, the main CI tunnel will collect wastewater from the existing network and take it to the Māngere Wastewater Treatment Plant.
Read more on Watercare's website: https://www.watercare.co.nz/Central-interceptor