One the major prerequisites we need to build the houses we need to combat our housing crisis is infrastructure, without it, the development can’t occur. This post is about a highly but often forgotten element of infrastructure Three Waters – Water Supply, Wastewater & Stormwater. In part 1 I focused on Wastewater, part 2 will focus on Water Supply.

Watercare supplies quality drinking water to around 1.4 million Aucklanders. This water is collected from 27 water sources throughout the Auckland region, including dams, rivers and underground aquifers, however, to serve the coming growth we will need to make major upgrades to the Water Supply. Much of Auckland’s water supply comes from dams such as Mangatangi (Built 1977), Mangatawhiri (1965), Cosseys (1955), Wairoa (1975) and Hays Creek (1967) which are in the Hunua Ranges in South Auckland. The water from these dams are treated at Ardmore Water Treatment Plant in South Auckland.

Auckland also has Waitakere and Waitakere Saddle (1910), Upper Nihotupu (1923), Lower Nihotupu (1948), Upper Huia (1929), & Lower Huia (1971) dams which are treated at three water treatment plants in West Auckland: Huia, Huia Village, and Waitakere. We also source from the Waikato River which is treated at Waikato Water Treatment Plant in Tuakau (2002) as well as source from groundwater supply at Onehunga, Muriwai, Hamiltons Road (Algies Bay/Snells Beach), Waiuku, and Bombay.

While we have recently completed the Hunua No.4 Watermain a 28km Watermain from Redoubt North Reservoir in Manukau to Epsom, we will also need to build the following according to the Long Term Plan.

  1. Hunua No.4 Watermain Extension ($66m) This will extend the new Hunua Watermain through to the Khyber reservoirs in the central city to serve the large growth occurring in the City Centre & Fringe. 2020+.
  2. Hunua 4 Extension

    North Harbour Watermain duplication ($196) Duplicates the North Harbour Watermain from a new Titirangi No 3 Reservoir to the Albany Reservoir in order to provide for growth in Albany & Rodney. The project will also allow Watercare to repair the old North Harbour Watermain if something occurs without affecting a large area – 2013 – 2023.

    North Harbour No. 2 Main
  3. Runciman Road Reservoir ($47m) This project is important to protect the long run security of the water supply from the Waikato River, it involves the provision of additional storage reservoir capacity to maintain security of supply standards for increasing water demand arising from growth – 2015 – 2025
  4. Runciman Road Reservoir No.2 ($43m) This is stage 2 of the above timed to meet growth – 2026 – 2035.
  5. Waikato Water Treatment Plant Expansion ($55m) This expands the capacity of the current treatment plant to provide capacity for growth as well as resilience in case of an issue at another major treatment plant – 2020 – 2021.
  6. Waikato Water Treatment Plant No.2 and Watermain ($400m) Provides additional capacity & resilience by increasing the capacity of water that can be taken from the Waikato River – 2015 – 2025
  7. Waikato Water Treatment Plant No.2 capacity upgrade ($316m) Expands the capacity of the above treatment plant – 2012 – 2021
  8. Hunua No.1 and Huia No.1 watermains ($90) Replaces Hunua No.1 & the Huia No.1 watermain which is approaching end of asset life – 2012 -2021
  9. Huia Water Treatment Plant upgrade ($241m) This is the upgrade or replacement of the old Huia Water Treatment Plant which is reaching the end of asset life 2012 – 2023

    Huia Water Treatment Upgrade
  10. Huia No.2 Watermain replacement ($110m) Replaces Huia No.2 Watermain which is approaching end of asset life – 2026 – 2035
  11. Waitākere Water Supply Treatment upgrade ($123m) Replaces Waitākere Water Supply Treatment which is approaching the end of asset life – 2026 – 2035.

These projects are also 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.

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13 comments

  1. Auckland has almost doubled in population since the last dam was built, the increased demand has come virtually entirely from the Waikato River (which was originally planned as just an emergency backup).
    Do they have any plans for another dam (presumably to the North of the city)? I could see around Paremoremo or Riverhead or even further north perhaps in Waiwera/Puhoi area. Of course this would be an expensive piece of infrastructure.

  2. A few notes: Auckland no longer receives water from the Hay’s Creek Dam, the site (and associated Papakura Treatment Plant) have been mothballed for decades. The Waitakere Saddle Dam is about the size of a swimming pool, and not a significant source of water.

    Regarding point #8, I understood that the Hunua 4 was the effective replacement for the Hunua 1, and was not aware of any proposal to replace was is ultimately a small main by today’s standards.

    1. In addition to the minor treatment plants you mentioned (“Muriwai, Hamiltons Road (Algies Bay/Snells Beach), Waiuku, and Bombay”), there are also water treatment plants in Helensville, Wellsford, and Walkworth. Each of these supply to a standalone network, independent of the main metropolitan network, and can often face significant supply constraints. For example, the Walkworth plant is limited by the height of the river, and can be significantly constrained during drier periods (which we’re expecting more of due to climate change), resulting in water needing to be trucked up to Walkworth to ensure continuity of supply.

      Lastly, Onehunga typically operates on a separate network to the rest of Auckland. A series of valves can be opened to join the two networks if required however.

    2. Just lastly I would say that much of the work that WSL indicates in its water asset strategy is mostly a ‘filling in’ of the existing largely gravity fed system. That is to say, we’ll be building new water mains, and adding new reservoirs to move around and store water more efficiently, but with the exception of the Waikato upgrades, no new capacity is really being added. These upgrades will allow some quarter million new homes. But as this blog often notes, we expect some 400,000 new homes through to 2041. Once the limits of the Waikato consent are reached, a serious conversation needs to be had about where additional water is going to come from, what economic and environmental cost this might have, and ultimately whether we might need to stop being so profligate with our water.

      1. Do we have realistic options to significantly reduce water consumption?

        I would imagine that a reduction in water fees for owning a functioning rain tank could really help reduce outdoor use, for example? Alternatively increases in water price to control demand?

        1. In theory higher density will result in less water usage (less watering the garden, washing the car etc) also most new builds now do use grey water to some extent.
          Other than that there probably isn’t a lot since generally Aucklanders aren’t too bad with their water use (having to pay for it unlike unmetered parts of the country and also paying volumetric wastewater, plus a lot of savings were implemented in previous droughts – half flush toilets etc). Certainly more could be done if more properties had tanks installed for toilets etc but that would be quite costly and generally takes up valuable space. In theory there is plenty of capacity in the Waikato for probably another million people in Auckland (or more) however it isn’t the best water and is expensive to transport and treat compared to fresh clean water in a dam.

        2. I wonder if new high density (eg 4-storey apartments) should be required to have rainwater tanks below, and smaller roof top tanks (with, say, solar pumps to transfer the water up). This could provide water for outside use and toilets. Possibly easily year-round, except drought years, if the rainwater tanks are big enough.

  3. It’s worth noting that Watercare is fully self funded. The fully cover all opex and capex costs from water and wastewater service charges, growth charges and borrowing . No money is received from local or central government.

    Also worth noting is their asset base is approximately $8bn, and as a result have access to significant borrowing (generally about ~30% of capex).

  4. No comment on the current opposition to all options for the Huia Water Treatment Plant Upgrade? First the Oratia NIMBYs opposing the Parker Rd site (which certainly had some issues – why did they need to take over any of the neighbouring houses with such a large site already owned?), and now a group with a number of concerns about the precedents that would be set by allowing significant development within the Conservation Zone/Waitakere Ranges Heritage Overlay (for the Huia site).

  5. Katherine, you are quite right the Huia replacement plant should go to 130 Parker Road where Watercare own an 8 hectare site. This would involve no loss of houses and no environmental destruction. It is also an excellent site technically. The Titirangi site is poor, the area has geotechnical issues, it’s an historic Maori battleground, Auckland Council have given it Significant Ecological Area status and the soil movement envisaged risks spreading Kauri dieback into the regional park below.

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