View source for Engineering:Central Interceptor

The '''Central Interceptor''' is an upcoming Watercare Services infrastructure project to bore a giant wastewater pipe underneath the [[Place:Auckland|Auckland]] Central Isthmus, to carry wastewater flows from parts of the city to the Mangere Wastewater Treatment Plant.

Apart from being intended to allow for population growth in Auckland and the resulting increased wastewater demands, it also is aiming to reduce the amount of wastewater overflows from the older combined wastewater/stormwater systems in western Auckland, which currently, on strong rainfall days, are forced to dump excess water (contaminated by faeces) into the Waitematā Harbour. The new capacity is expected to reduce these overflows by at least 80%, reducing the times per year that contaminated stormwater is dumped into the harbour from 52 days a year to 10 or fewer days.<ref name="TappedAut2019">{{cite book |title=Tapped In (newsletter) |date=Autumn 2019 |publisher=Watercare}}</ref> Sixteen access shafts, up to {{convert|65|m}} deep, will be constructed.<ref>{{cite journal |last1=Clarke |first1=Jennie |title=100 not out |journal=EG<!-- issued by Engineering New Zealand --> |date=2018 |issue=4 |page=32}}</ref>

The new interceptor will be Auckland's largest wastewater project in history, costing approximately $1.2B,<ref name="HERALDMARCH">{{cite news |title=Central Interceptor: Auckland's new $1.2 billion sewer tunnel to clean up beaches |url= https://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=12212221 |accessdate=31 March 2019 |publisher=The New Zealand Herald |date=14 March 2019}}</ref> and being 13 km long (plus side branches), and 4.5m diameter.<ref name="TappedAut2019"/> It is to run from Western Springs to Mangere.<ref name="HERALDMARCH"/>

==Construction==
The construction contract was signed in March 2019 with the Ghella Abergeldie Joint Venture. Construction is expected to be from 2019 to 2024.<ref name="TappedAut2019"/>

Construction will be via [[Engineering:Tunnel boring machine|tunnel boring machine]], and the course will take the tunnel 15m underneath the Manukau Harbour, though (due to the height of the Central Isthmus), in other areas if will be as much as 110m below properties.<ref name="HERALDMARCH"/>

In May 2021, Watercare reported that the project was 8 months into what was expected to be a 5 year construction period.  A {{convert|200|m}} long tunnel boring machine had been delivered and was being prepared for service.  Local school children have gifted a name for the tunnel boring machine: ''Hiwa-i-te-rangi''.<ref>{{cite news| url=https://www.rnz.co.nz/national/programmes/checkpoint/audio/2018797430/new-pipeline-to-make-auckland-s-polluted-beaches-a-thing-of-the-past | title=New pipeline to make Auckland's polluted beaches a thing of the past| first=Louise| last=Ternouth| work=RNZ| date=28 May 2021| access-date=1 June 2021}}</ref>

==References==
{{reflist}}

[[Category:Sewerage infrastructure]]

{{Sourceattribution|Central Interceptor|1}}