In order to build the houses we need to combat this housing crisis one the major prerequisites of this is infrastructure, without it, the development couldn’t succeed. This post is about a highly but often forgotten element of infrastructure Three Waters – Water Supply, Wastewater & Stormwater focusing in this part on Wastewater.
Central Interceptor Video
Watercare defines wastewater in simple terms as “Wastewater, also known as ‘sewage’, is 99.97 percent water as the majority comes from showers, baths, and washing machines. The remainder includes organic matter such as human waste and food scraps, fats, oil and grease, and debris such as sand, grit, and plastic. Wastewater can also include such things as household chemicals, paint, and pharmaceuticals that can be harmful to our health and to our harbours and waterways”
In the current Metropolitan Area Watercare has wastewater treatment plants at Rosedale, Māngere, Army Bay and Pukekohe. The first major wastewater system built in Auckland was the Orakei Mains in 1914 which was effective at removing wastewater but polluted the waters heavily. The Mangere treatment plant was opened in 1960 (Extended 1980 & Upgraded 2005) alongside the Eastern & Western Interceptors which connect to Mangere treatment plant after opposition was made to the previous 1930s proposal for Browns Island. Later the Southern Interceptor was built in 1965 & the South-West Interceptor in the 1980s. In the North Rosedale treatment plant was opened 1962, with multi-stage upgrades occurring since the 1990s. Hibiscus Coast is served by Army Bay treatment plant which was built 1982 (Upgraded 1998 & 2005). Treatment areas also exist in the non-metropolitan area at Denehurst, Omaha, SnellsAlgies, Helensville, Waiwera, Warkworth, Kawakawa Bay, Bombay, Waiuku, Kingseat, Clarks Beach/Glenbrook/Waiau, Clevedon, Beachlands / Maraetai and Wellsford.
However going forward we will need to make major upgrades to our wastewater system if we are to serve the growth, many of these have been budgeted in the Long Term Plan such as
- Central Interceptor; ($944m) a tunnel stretching 13 kilometres from Māngere Wastewater Treatment Plant to Western Springs, which will replace an ageing system and provide additional capacity in central, southern and eastern Auckland. The project will also deliver environmental benefits by reducing the volume of wet weather overflows into Auckland’s harbours by 80 per cent. The project also provides support for the ageing Western Inteceptor tunnel under the Manukau Harbour – 2017 – 2025.
- Northern Interceptor Stage 1; ($135m) The complete Northern Interceptor will move the West wastewater to Rosedale from Mangere, as well as provide wastewater infrastructure to the growing North-west taking pressure off the Mangere treatment plant & enabling the North-west development. Stage 1 is a pipeline between Rosedale & Hobsonville – 2015 – 2021.
- Northern Interceptor Stage 2; ($102m) This stage runs a pipeline from Hobsonville to Te Atatu diverting wastewater to Rosedale from Swanson, Massey and Glen Eden as well as enabling growth in Redhills, Whenuapai, Kumeu, Huapai and Riverhead. 2022 – 2028
- Waterfront Interceptor ($350m) 3.5 km conveyance and storage tunnel from Ponsonby to St Mary’s Bay increases capacity & reduce overflows. Requires Central Interceptor. 2026 – 2035.
- Central Interceptor Optimisation Works ($299m) Additional works to maximise investment in Central Interceptor Spine through collector and link sewers maximising the large investment which is the Central Interceptor. 2026 – 2035.
- Māngere Wastewater Treatment Plant Upgrade (75m) Needed to provide capacity for growth. 2015 – 2025.
- Rosedale Wastewater Treatment Plant upgrade (48m) Needed to provide capacity for growth. 2015 – 2020.
- Pukekohe Trunk Sewer and Wastewater Treatment Plant upgrade ($106m) Needed to provide for growth at Pukekohe, Paerata, Tuakau and Pokeno. 2015 – 2025
- Pukekohe Wastewater Treatment Plant capacity upgrade ($95m)
These projects are integral if we are to provide for the growth to tackle this housing crisis, however, it is key that an integrated approach is taken to infrastructure where AC/AT/NZTA/Watercare/Panuku/Crown work together on each area as a complete package of Three Waters, Transport, Planning & Community/Social Services to make work & not in isolation of each other.