How Watercare plans to stay ahead of Auckland's population growth


Watercare is planning to spend $4.9 billion on infrastructure projects over the next 10 years to provide capacity in its network for 195,000 new Auckland homes.

Tomorrow Watercare will release its latest asset management plan (AMP) that sets out how it plans to stay ahead of Auckland’s growing demand for water and wastewater services.

Statistics New Zealand has projected medium growth of 700,000 people for Auckland over the next 30 years.

Watercare chief executive Raveen Jaduram says: “Watercare’s networks already have the capacity to allow 45,000 new homes to connect today. Over the next 10 years, we will expand that to provide capacity for a further 195,000 new homes."
The AMP outlines what infrastructure Watercare will deliver, where, when and how much it will cost over a 20-year horizon.
Almost half (46 per cent) of the $4.9 billion 10-year investment will go towards providing capacity for growth. This includes treatment plant and process upgrades, the construction of new reservoirs, pump stations, and pipelines.

The remainder will be spent on replacing existing assets (44 per cent), and improving the level of service to customers (10 per cent).

Jaduram says Watercare’s major strategic projects are planned and staged to ensure water and wastewater networks continue to have sufficient capacity to meet demand as Auckland’s population increases.

“The Waikato Water Treatment Plant has been built in such a way as to support staged expansions. The plant has already undergone two projects since 2013 to increase its capacity. We are now preparing for further expansions that will enable the plant to meet demand over the next 20 years,” he says.

Improving network resilience by maximising the use of existing assets is also a key priority in planning projects.

“We are building infrastructure as well as better utilising our existing assets. By doing this we can keep the costs of water supply and wastewater services for our customers to a minimum,” says Jaduram. 

For example, the area serviced by the Pinehill reservoir on the North Shore has a very high local demand. Rather than building a second reservoir at Pinehill, Watercare plans to maximise the use of the existing one by building a  pump station and connecting watermain from  the Albany Reservoir Complex to push a higher volume of water to the Pinehill Reservoir.

The resilience of the wastewater network will also be improved through increased connectivity across the region. For example, Watercare is about to construct the $538 million Northern Interceptor which will divert flows flows from north-west Auckland – which currently travel to the Mangere Wastewater Treatment Plant – to the Rosedale Wastewater Treatment Plant on the North Shore.

This has two major benefits; it utilises spare capacity at the Rosedale plant and it gives the Māngere plant greater capacity to support growth in the central and southern areas.

Jaduram says the Rosedale plant has considerable capacity to deal with future growth and the diversion of nearby wastewater will help Watercare to better manage growth right across Auckland.

Watercare receives no money from council and does not pay any dividends.

“We are self-funded so almost 70 per cent of our investment will come from our customers and those who create growth,” says Jaduram.

Key water projects:

Hūnua 4 Watermain, $376 million
Hūnua 4 is a 32-kilometre water pipe that will ultimately connect the reservoirs in Redoubt Rd, Manukau, to those in Khyber Pass, Grafton.

It provides security of the water supply and allows for population growth in Auckland.

Construction began in 2012 and is expected to be completed in 2020.

The pipe diameter varies from 1.6 metres to 1.9 metres.

North Harbour No. 2 Watermain, $264 million
This watermain will service growth areas in Auckland’s north by increasing the conveyance of treated water from the west to the Albany Reservoirs.

It provides an additional route for conveying water from the west to the north to provide security of the water supply. Currently, one pipe (North Harbour No.1) carries water from Titirangi to supply people living in the North Shore, Whangaparaoa and Orewa. This pipe was built between 1975 and 1985 and Watercare is unable to carry out maintenance on it without disrupting the local water supply.

Construction will begin in 2018.

Huia Water Treatment Plant upgrade, $185 million
The Huia Water Treatment Plant, Auckland’s third largest, is nearing the end of its operational life and needs to be replaced in order to continue supplying a growing Auckland with high quality water from the western water supply dams.

Key wastewater projects:

Central Interceptor, $950 million
A 13-kilometre wastewater pipeline is planned to travel between Western Springs and the Mangere Wastewater Treatment Plant.

The pipeline will increase the capacity of the wastewater network, replace ageing infrastructure and reduce wastewater overflows.

Construction is likely to commence in 2019.

Northern Interceptor, $538 million
This large wastewater pipe will divert flows from north-west Auckland – which currently travel to the Māngere Wastewater Treatment Plant – to the Rosedale Wastewater Treatment Plant on the North Shore.

This has two major benefits; it utilises spare capacity at the Rosedale plant and it gives the Māngere plant greater capacity to support growth in the central and southern areas.

Construction of stage one will begin in 2017.

Mangere Wastewater Treatment Plant upgrade, $136 million
Construction of an additional biological nutrient removal (BNR) facility at the Māngere treatment plant site is underway.

This facility will use the same technology currently employed at the plant to remove nitrogen and phosphorus from the wastewater stream, improving the quality of the treated wastewater before it is discharged to the environment.

Other upgrades at the plant will include the construction of additional sludge digestion capacity and solids stream processing upgrades to increase processing capacity and replace the ageing sludge tanks.

Works will be completed in 2018.